Hemophilia B Glossary
Explore our comprehensive collection of terms, encompassing medical terminology, everyday language, slang, colloquialisms, abbreviations, and valuable resources.
A
Accumulator
Adverse Event (AE)
See: Copay accumulator adjuster program
A negative occurrence experienced by a subject in a clinical study that is associated with the treatment being studied. See also Serious Adverse Event (SAE).
Advocacy is defined as any action that speaks in favor of, recommends, argues for a cause, supports or defends, or pleads on behalf of others.
Advocacy
Amicar is a prescription medicine used to treat the symptoms of Fibrinolytic Bleeding. Amicar may be used alone or with other medications. It is often recommended before dental procedures, and to treat nose and mouth bleeds. It is taken orally, as a tablet or liquid. Please seek the advice of a medical professional regarding all medications.
Amicar
Amino acids are the molecules that are strung together in a chain to produce a protein. There are 20 different amino acids that make up almost all of the proteins in the body, plus a few specialized amino acids in certain proteins.
Amino Acid
Something that inhibits clotting. There are natural anticoagulants in the clotting system, which help control the clotting process. There are also anticoagulant drugs that are given to patients with cardiovascular disease to prevent the formation of unwanted clots that could cause damage by blocking blood vessels, especially in the heart, lungs, and brain.
Anticoagulant
Any of various foreign substances, including viruses, bacteria, proteins, etc. that when introduced into the body induce an immune response. See also Allergen and Immunogen.
Antigen
An atom is the smallest unit of matter that can still be identified as an element. An atom consists of a nucleus containing positively charged particles called protons and uncharged particles called neutrons. Negatively charged particles called electrons orbit around the nucleus. The number of protons in the nucleus uniquely defines the type of element the atom represents. For instance, a hydrogen atom has one proton, a carbon atom has twelve, and an oxygen atom has sixteen protons. The element oganesson has the largest number of protons with 118.
The number of electrons and neutrons in the atom of an element can vary. If there are the same number of electrons as protons, the atom will be neutral, i.e., have no charge. If there is an excess of electrons over protons, the atom will have a negative charge. If there are fewer electrons than protons, the atom will have a positive charge. A charged atom is called an ion.
The number of neutrons in the nucleus is usually about the same as the number of protons, but it varies. Neutrons help to stabilize the nucleus. Variations in the number of neutrons produce isotopes. For instance, uranium-238, the most commonly occurring isotope, has 146 neutrons in its nucleus. Uranium-235, the next most abundant with 143 neutrons is less stable and is the isotope used for nuclear power and weapons. When the uranium-235 isotope breaks apart, it releases a large amount of energy. Note that the atomic numbers, 238 and 235 refer to the total number of neutrons plus protons.
Atom
Ayr Saline Nasal Gel - B.F. Ascher & Company, Inc.
Helps moisturize and soothe dry noses due to colds/flu, allergies, winter dryness, low humidity, CPAP/BiPAP, chronic sinusitis, air travel, nosebleeds, radiation therapy, oxygen therapy. Ayr Gel is dye-free, paraben-free, and gluten-free. Manufactured in U.S.A. for B. F. Ascher & Co., Inc. Ayr gel is often recommended for patients who have nosebleeds due to dry nasal passages. Please seek the advice of a medical professional in regard to all medications.
Ayr Saline Nasal Gel
B
There are several definitions of a base.
In chemistry, a base is the opposite of an acid. An acid increases the number of hydrogen ions (H+) in a solution. A base increases the number of hydroxyl ions (OH-) in a solution.
“Base” is also used as a name for the individual molecules that make up DNA and RNA. There are five different molecules, also called nucleotides, adenine (A), guanine (G), cytosine (C), thymine (T) and uracil (U), that are strung together in various orders to form a DNA or RNA molecule. The order of the bases in the DNA or RNA molecule determines which amino acids are strung together to produce the protein specified by the DNA or RNA molecule.
Base
"Many biological molecules are polymers. (A plastic is a type polymer.) A polymer is a collection of subunits (monomers) that are bonded together, one after the other, to form a long molecule, like beads on a string. Most of the polymers that we deal with in everyday life are made of a single type of subunit. For instance, polyethylene is a long string of ethylene molecules bound together in a long chain. Individual ethylene molecules form a colorless gas, but when you string them together you get a translucent solid used to make milk bottles and other containers. Most non-biological polymers are made of only one, or just a few monomers.
Polyethylene is made only of ethylene molecules. Using E to represent ethylene, a polyethylene molecule would look like: …EEEEEEEEEEEEE… The ethylene molecules are joined together in a long chain, often thousands of ethylene molecules long. The ellipses (…) indicate that the pattern keeps repeating. Some more advanced polymers use more than one monomer to get a wider range of properties. For instance, we might want to make a polymer from both A and B subunits. It might look like …ABABABABABAB… or even a random arrangement like …AAABBABBBBAA….
Biological polymers use a wider range of monomers. Proteins are made up of amino acids strung together. As described below, there are more than 20 different types of amino acids that are used to make proteins in the body. With that many monomers to choose from, a huge number of different proteins can be made. Each type of protein consists of a specific arrangement of amino acids in a specific order. If the order changes, or if a different amino acid is used in a certain location along the chain, you have a different protein.
Proteins and carbohydrates are both biological polymers, as are DNA, which makes up our genes and RNA, which is involved in protein production."
Biological Molecules
Something that can be measured in the body that indicates the condition of something that cannot be easily measured. For instance, in hemophilia B, the level of factor IX, which can be measured, is used as a biomarker for the severity of the person’s hemophilia. It would be better to be able to actually measure the clottability of the person’s blood, but so far, there is not a good assay for that. Therefore, the factor level is used as a biomarker or surrogate to estimate the severity of a person’s hemophilia. Biomarkers are often only approximate. We know, for instance, that people with factor IX levels less than 1% usually have severe disease. However, about 15% of people with less than 1% factor IX bleed less than would be expected.
Biomarker
Bleeder
This term, offensive to some, is used to refer to someone with hemophilia.
Example: They have to use factor when they are injured because they are a bleeder.
Men with hemophilia often refer to other men with hemophilia as their "blood brother" because they both have been diagnosed with a bleeding disorder.
Blood Brother
Bleeding Disorders Awareness Month has been observed each March since 2016, after being designated as a national health observance by the U.S. Department of Health and Human Services. BDAM aims to increase awareness of inheritable blood and bleeding disorders among the public, as well as bring them to the attention of policymakers, public authorities, industry representatives, scientists, and health professionals. Prior to BDAM, March was known “Hemophilia Awareness Month” – a designation confirmed by President Ronald Reagan in March 1986.
Bleeding Disorders Awareness Month
A blood transfusion is a common procedure in which donated blood or blood components are given to you through an intravenous line (IV). A blood transfusion is given to replace blood and blood components that may be too low. There are times that individuals with hemophilia require a blood transfusion because of rapid or excessive blood loss.
Blood Transfusion
"This is the application that an organization submits to FDA to get a product licensed. The primary standard that FDA uses to approve a product is safety and efficacy. In the early history of FDA, products only needed to be safe. This led to a number of “snake oil-type” products on the market that were safe but didn’t necessarily do anything. Now a product has to actually work before it is licensed.
The two major sections of a BLA are the results of the clinical studies and the CMC section. CMC stands for Chemistry, Manufacturing and Controls. The CMC section describes in great detail exactly how the product is made and tested. A product being marketed has to exactly follow the description submitted to FDA in the CMC section, otherwise it’s considered “adulterated” and can’t be distributed."
Biologic License Application (BLA)
A butterfly needle is used to access a superficial vein and can be used for drawing blood as well as for an IV injection. These needles are much easier to use and are much less painful for patients. This is because of the winged tubing which allows for greater flexibility.
Butterfly Needle
C
CAAPS
See: Copay accumulator adjuster programs
There are camps or retreats for hemophiliacs, unaffected siblings, and other related individuals. These camps are usually funded through grants and are managed by national or local chapters of hemophilia associations.
Camps
"Carbohydrates are made of sugar molecules strung together in a chain. A single sugar molecule like glucose is called a monosaccharide. Glucose is the main energy source for the body. Sucrose, which we commonly call sugar or table sugar, is a disaccharide consisting of two sugar molecules bonded together. Sucrose is a combination of glucose and fructose.
Longer chains of sugar molecules are called oligosaccharides or polysaccharides. A starch is a polysaccharide, a polymer of glucose molecules. Another polymer of glucose is cellulose, which is a long chain composed of several hundred or thousand glucose units. It is used by plants as a structural component in their cell walls.
DNA and RNA are also based on sugar molecules. DNA, deoxyribonucleic acid is a polymer of deoxyribose sugars. RNA, ribonucleic acid is a polymer of ribose sugars. See more detail in the sections on DNA and RNA."
Carbohydrate
"The term carrier is used to refer to someone who carries the affected gene for hemophilia and may or may not be diagnosed with hemophilia. Carriers of hemophilia are most often women. You are encouraged to visit an HTC to get your factor levels tested if you are a carrier of hemophilia. If you are born female, and your father was diagnosed with hemophilia, you are what is known as an "obligate carrier." It means that because your father can only give you an X chromosome, then the X chromosome passed to you form your father with hemophilia, is factor deficient.
Carrier
CDC
see: Center for Disease Control and Prevention.
Cells are the smallest structural units of living matter and compose all living things. Cells are usually microscopic. Cells have a cellular membrane that encloses the cell. The main body of a cell is called the cytoplasm, which contains the machinery for making proteins, for metabolism, and for other cellular functions. A separate section of the cell, surrounded by another membrane, is the nucleus. The nucleus of most cells contains a complete copy of the genome, the complete collection of all the genes in the organism. Some single cells are complete organisms, such as bacteria or yeast. Others are specialized building blocks of multicellular organisms, such as plants and animals.
Cell
A method for growing cells outside the body in a laboratory environment. Recombinant factor products are produced in cell culture using cells that have been genetically engineered to produce factor proteins.
Cell Culture
The cells early in development are all identical. The process of cells changing into specific types of cells is called differentiation. The initial cells are called pluripotent stem cells. “Pluripotent” means that they can change into any other kind of cell such as skin cells, liver cells, muscle cells etc.
Cell Differentiation
The cellular membrane is the membrane surrounding each cell, also called the cell wall. It is a complex structure, not just a simple divider. The wall itself is made of lipids (fats), which prevents all of the water-soluble molecules from freely crossing the membrane in either direction. The membrane is flexible except in certain kinds of cells where it is strengthened by more rigid molecules. The membrane contains numerous molecules that allow the cell to communicate with the outside and to transport materials into or out of the cell.
Cellular Membrane
Center for Biologics Evaluation and Review (CBER)
The section of the Food and Drug Administration (FDA) that regulates biological products. Biological products include clotting factors and other protein-based treatments for hemophilia. They also include vaccines, antitoxins, other blood and plasma products, etc.
Centers for Disease Control and Prevention (CDC)
The Centers for Disease Control and Prevention is a good source of information about all diseases and disorders.
A chapter-based organization is any organization that has local branches in multiple areas and shares a common mission. In the bleeding community you may be told to reach out to your local chapter. This means a branch of a larger non-profit organization that has members or affiliates in your area.
Chapter
Chemical Bonds
Chemical bonds connect two atoms or molecules together.
Chemistry, Manufacturing and Controls (CMC)
The section of an FDA submission that describes the composition, manufacturing method and specifications of a product.
CHO cells are one of the cell types used in the production of recombinant factor products.
Chinese Hamster Ovary (CHO) Cells
Christmas disease is another name for a factor IX deficiency or hemophilia B. The disorder was first reported in the medical literature in 1952 in a patient with the name of Stephen Christmas, so it was referred to as "Christmas Disease" originally.
Christmas Disease
Chromosomes are structures in the nucleus of a cell that hold the genes. They can be thought of as simple racks on which the genes are hung, but they also have additional properties that help organize and control the genes. Chromosomes are located inside of your cells. Your body is made up of billions of cells. Each chromosome has hundreds or even thousands of genes. Your genes determine physical traits like eye color, height, and even whether you will have hereditary disorders like hemophilia B.
Chromosomes
Circulation
The circulation is the movement of blood throughout the body in the bloodstream.
Clearance
Clearance is the process of removing items from the body.
An experimental study carried out in humans. There are four stages of clinical studies, which are usually carried out in order but may be combined in some studies. The four stages and the areas they cover are:
Phase I: Safety and tolerability
Phase II: Dosage
Phase III: A study in a large number of patients
Phase IV: An optional post-licensure study
Clinical studies are regulated by the FDA and provide the data needed to license a drug. Prior to receiving approval to conduct a clinical study, an organization must conduct pre-clinical studies to show that the product is likely to be safe and effective in humans.
Clinical Studies or Trials (Clinicals)
A fibrin network that also contains activated platelets and other blood cells that seals up an injury in the wall of a blood vessel. The fibrin network is the final product of the coagulation cascade. The cascade produces thrombin (factor IIa), an enzyme that converts fibrinogen (factor ) to fibrin, which sticks to itself to form the fibrin network.
Clot
A molecule in the clotting system that promotes clotting. Clotting factors range from individual elements like calcium to large proteins like factor VIII. Clotting factors are proteins found in the blood that causes the blood to coagulate or clot.
Clotting Factor
Coagulation
The process by which a blood clot is formed.
Also called the clotting system. This is a large system of molecules that work together to produce a clot to stop bleeding. It includes both clotting factors and anticoagulants.
Coagulation Cascade
The Coalition for Hemophilia B, Inc., strives to make quality of life the focal point of treatment for people with hemophilia B and their families through education, empowerment, advocacy, and outreach.
For 30 years we have pursued our mission through a family-oriented approach—because hemophilia is a disease that affects the whole family. Our programs bring patients with hemophilia B together from all over the USA, connecting them with their common bond and empowering them to gain support, lifetime friends, and the knowledge needed to make important life decisions and to act as advocates on their own behalf. Hemophilia B doesn’t discriminate. The Coalition for Hemophilia B is a national non profit that is dedicated to fostering a diverse, equitable, and inclusive experience for everyone across our organization, both internally and externally. Our team members have decades of experience in hemophilia B and interact daily with the hemophilia community via phone, email, social media, and the web.
Coalition for Hemophilia B
The CFR is the complete list of all U.S. federal regulations for all of the administrative agencies in the government. The FDA regulations covering pharmaceuticals are in Title 21 of the CFR, referred to as 21 CFR followed by a section number. For instance, the Good Manufacturing Practice regulations are in 21 CFR Part 210, referred to as 21 CFR 210. The CFR is available for free on the internet.
Code of Federal Regulations (CFR)
A group of three nucleic acid units in a gene. Each group of three codes for an amino acid in a protein produced from the gene. More than one codon may code for a specific amino acid.
Codon
A method used to increase efficiency in production of recombinant proteins and gene therapy. Since more than one codon may code for a given amino acid, researchers have looked at the efficiency of the different codons to find the ones that help produce a given part of a protein most efficiently. For instance, the amino acid proline can be specified by the codons CCU, CCC, CCA or CCG. Each of these codons would tell the protein production machinery in a cell to put a proline in the next spot in a protein chain, but not all with the same efficiency.
Codon-optimization
The primary structural protein that makes up the body. It is the most abundant protein in the body making up about one-third of the total protein in the body. It is mostly found in connective tissue such as cartilage, bones, tendons, ligaments, and skin. Collagen also provides strength and structure for the blood vessels. There are several different forms of collagen. Recent research has shown that factor IX binds to the collagen IV in the walls of blood vessels, but it’s exact function is still unknown.
Collagen
Compound
This is the industry term for the accessories that are provided with a medication. The componentry consists of things like filters, diluent, syringes, double-ended needles, etc.
Congenital fibrinogen deficiency is a very rare, inherited blood disorder in which the blood does not clot normally. It affects a protein called fibrinogen (also known as factor I). This protein is needed for the blood to clot.
Congenital Fibrinogen Deficiency
Copay accumulator adjuster programs (CAAPs)
CAAPs prevent the costs covered by drug manufacture's copay assistance programs from being counted toward a yearly out-of-pocket maximum.
These programs make it more difficult for patients to be able to afford life saving medications, like factor.
The purpose behind this program is to save the insurance company money by encouraging patients to seek out generic or less expensive medication. In our community that isn't possible as generic factor replacements aren't offered at this time.
We strongly encourage that you advocate for your rights and speak out agains the CAAPs.
When you hear someone refer to "copay assistance" or "copay assistance cards" or even a "copay savings program" they are referring to programs funded by the pharmaceutical manufacturer that comes in the form of copay cards or coupons that are a way to save on medications.
They help people afford expensive prescription medications by lowering their out-of-pocket costs.
You can find more information about copay assistance by reaching out to us at contact@hemob.org(opens in a new tab) or checking your manufacturer's website for more information.
Copay Assistance
Some health insurance companies have copays or coinsurance as part of your health insurance plan. Copays are set amounts that you would pay to visit a physician, a specialist, an emergency room, or get your medications. Copays are different from coinsurance because coinsurance is usually a percentage that the customer or patient pays for a service or medication rather than a set amount.
Copays and co-insurance vary from plan to plan, state to state, and based on the services or medication you are obtaining. It is very important that you reach out to your health insurance company before receiving services or ordering medication to determine what the patient responsibility (cost) will be for the service or medication.
Copay or Co-Insurance
Current Good Manufacturing Practice (CGMP)
The GMPs are a set of regulations that govern the manufacture of pharmaceuticals. Since they are often updated and improved, FDA prefers to add the “C” for “Current” to the name. According to FDA:
“Adherence to the CGMP regulations assures the identity, strength, quality, and purity of drug products by requiring that manufacturers of medications adequately control manufacturing operations. This includes establishing strong quality management systems, obtaining appropriate quality raw materials, establishing robust operating procedures, detecting and investigating product quality deviations, and maintaining reliable testing laboratories.”
The cGMP regulations are given in 21 CFR 210 for all pharmaceuticals with additional regulations for biologics, like clotting factors, in 21 CFR 600.
Cytoplasm is the material inside a cell, except for the nucleus. The cytoplasm is enclosed by the cell membrane. The cytoplasm contains most of the cell machinery for metabolism, waste disposal and protein production.
Cytoplasm
Cytotoxic
“Cyto” refers to cells, so this is something that is toxic to cells.
D
As described in the section on proteins, proteins depend on their structure for their activity or usage. Denaturing a protein is unfolding a protein so that it loses its structure.
Denature
Development
In biology, development is the process of growth to maturity (adulthood).
Differentiation
Differentiation is the process of a stem cell transforming itself into a specific type of cell. Early in the development of a body, all of the cells in an embryo are embryonic (also called pluripotent) stem cells, cells that can transform into any other type of cell.
Deoxyribonucleic acid. Genes are made of DNA molecules strung together in a chain. Each individual DNA molecule is called a nucleotide. There are four different nucleotides that make up human genes: adenine (A), cytosine (C), guanine (G) and thymine (T). They are often abbreviated by A, C, G and T. Each group of three nucleotides along the chain is called a codon and indicates which amino acid should come next in the protein made from the gene. For instance, the codon AGA codes for the amino acid arginine.
DNA
Domain
A section of a protein defined by a specific structure or function.
Double Blind Study
A type of clinical study in which neither the patient or the doctor knows which treatment they are getting/giving.
E
Effectiveness. To be licensed for sale by the FDa, a product must be both safe and efficacious.
Efficacy
Enzyme
An enzyme is a protein that promotes a chemical reaction. Enzymes are actually biological catalysts that participate in a reaction but are not used up.
Erythrocyte
See red blood cell.
Latin for outside the body. This usually refers to a process that is performed outside the body, for instance, in a lab.
Ex vivo
F
Coagulation is the process where blood looses its fluidity externally while still maintaining constant flow in the blood vessels. A series of steps leading to the formation of fibrin protein fibre involving different clotting factors. There are about thirteen known clotting factors:
Fibrinogen (Factor 1)
Prothrombin (Factor 2)
Thromboplastin (Factor 3)
Calcium (Factor 4)
Proaccelerin or Labile Factor (Factor 5)
Stable Factor (Factor 6)
Antihemophilic Factor (Factor 8)
Christmas Factor (Factor 9)
Stuart - Power Factor (Factor 10)
Plasma Thrombin antecedent (Factor 11)Hegman Factor (Factor 12)
Fibrin Stabilising Factor (Factor 13) .
These factors interact together to bring about coagulation cascade. These clotting factors are in an inactive state and must be activated to bring about blood clotting. Generally, the three stages involved in clotting formation are: formation of prothrombin activator, conversion of prothrombin into thrombin and finally thrombin is converted to fibrin.
It is this fibrin produced that stabilizes the platelet plug which is called 'clot'.
Upon repair of the vessel, the clot is eliminated and digested by an enzyme called plasmin.
It is very important that the body regulates hemostasis properly as it can lead to thrombosis wherein excess and haemorrhage where there is little hemostasis.
Factor
A protein involved in forming blood clots in the body. It is made in the liver and forms fibrin. Fibrin is the main protein in a blood clot that helps stop bleeding and heal wounds. Also called factor I.
Fibrinogen
The process of breaking down a clot. Fibrinolysis starts are the same time as clotting. In the beginning, the clotting process overwhelms the fibrinolysis process, so a clot is formed. Later on when clotting is complete, the clot gradually breaks down over a period of time while healing occurs. Fibrinolysis is carried out by the enzyme plasmin, which is formed by activation of the inactive molecule plasminogen.
Fibrinolysis
A way to gather qualitative research about users or customers by gathering them in a group, physically or virtually, and asking guided questions or exercises; learn more about behaviors, values, beliefs, desires or reactions to concepts; in recruiting, often preferable to have multiple, varied, homogeneous groups to encourage free discussion and then compare results across groups; focus groups are small by nature and can gather more in-depth information than a questionnaire or other methods; data is not always representative across all users or customers, unless well-designed with variety of users or customers, or desired users/customers
Focus Group
An agency in the U.S. federal government whose mission is to protect public health by making sure that food, drugs, cosmetics, and nutritional supplements are safe to use and truthfully labeled. The FDA approves for licensure all treatments of bleeding disorders used in the United States, including plasma-derived therapies, recombinant therapies, monoclonal antibodies and gene therapies.
Food and Drug Administration (FDA)
Formulation
The combination of inactive ingredients in a product. These usually involve various salts and other compounds to keep the active ingredient stable in the final package, as well as during processing.
Freeze drying is a method for stabilizing a product. In freeze drying a product in solution is frozen and then dried while it is still frozen, often under vacuum. Many biological products (and foods) are not stable in solution and will degrade. To give them a longer shelf life, they are often freeze dried.
Freeze Drying or Lyophilization
One of the main functions of the cells in the body is to produce proteins. Some proteins are produced by most of the cells in the body, but others are only produced by specific cells. For instance, factor IX is only produced in liver cells. The protein production process is complex and is comprised of many steps:
Regulation First, the regulatory elements in a gene decide that a certain protein should be produced. The regulatory elements control when and how much of a protein product should be made, and in which cells. Once a cell decides to produce a protein, mechanisms in the nucleus unwind the gene from its chromosome to make it accessible.
Transcription Next, a copy of the gene is made as an RNA molecule. An enzyme called RNA polymerase copies the DNA gene into RNA. The RNA molecule is called a messenger RNA (mRNA). The messenger RNA is a template that the protein production machinery in the cytoplasm of the cell will use to make the protein. By making an RNA template or copy, the gene is protected from damage. The mRNA is excreted from the nucleus into the cytoplasm.
mRNA Processing The mRNA must be further processed before it is suitable for protein production. First, it is an exact copy of the gene sequence, so it includes both exons, which code for the protein, and introns, which are not needed. A process called RNA splicing removes the introns and splices together the exons. Other reactions add an endcap to the mRNA chain and add other groups to stabilize the mRNA.
Translation Once the mRNA has been processed and is ready for production of the actual protein, it is taken over by ribosomes. Ribosomes are large protein complexes that match up each codon in the mRNA with a corresponding transfer RNA (tRNA). tRNAs are small RNA molecules that bind to amino acids in the cytoplasm. For instance, when the ribosome comes across a codon in the mRNA that says that a lysine should be the next amino acid in the protein chain it is producing, it looks for a tRNA bound to a lysine. That lysine is then attached to the growing chain of amino acids for the protein being produced. This process of adding the correct amino acids to the growing chain continues until all of the sequence in the mRNA has been completed.
Folding The new protein comes out of the ribosome as a linear chain of amino acids with no specific structure. However, most proteins have a specific three-dimensional structure that is required for their functionality. It appears that the specific amino acid sequence completely determines the final 3D structure of the protein, but the process of folding into that structure is still being discovered.
Post-translational modifications Once the basic protein chain is made it may be further processed in the cell. Many proteins have carbohydrate molecules added as side chains. Proteins that are going to be secreted from the cell may have a molecule called a signal peptide added to it. The signal peptide directs the new protein molecule through the secretion process and, in some cases, to wherever it is supposed to be in the body.
Some proteins, including factor IX and some related clotting factors, may have other modifications. In factor IX a portion of the protein called the gla region is modified in a reaction requiring vitamin K. In that region, all of the glutamate amino acids have a carboxy group (COOH) added to produce gamma-carboxy glutamic acid (gla) amino acids.
G
Gene
A chain of DNA molecules that specify the structure of a protein. In addition to the part of the chain that specifically shows the protein structure, genes also include regulatory elements, which are sections of the chain, often at the beginning of a gene, that control when and how much protein is made from the gene. Many genes also include introns, which are sections of DNA that do not specify the structure of the protein. Introns were once thought to be useless sections of DNA, but are now being shown to have specific functions. The actual gene sequences that do code for the protein are called exons.
One of the main functions of the cells in the body is to produce proteins. Some proteins are produced by most of the cells in the body, but others are only produced by specific cells. For instance, factor IX is only produced in liver cells. The protein production process is complex and is comprised of many steps:
Regulation First, the regulatory elements in a gene decide that a certain protein should be produced. The regulatory elements control when and how much of a protein product should be made, and in which cells. Once a cell decides to produce a protein, mechanisms in the nucleus unwind the gene from its chromosome to make it accessible.
Transcription Next, a copy of the gene is made as an RNA molecule. An enzyme called RNA polymerase copies the DNA gene into RNA. The RNA molecule is called a messenger RNA (mRNA). The messenger RNA is a template that the protein production machinery in the cytoplasm of the cell will use to make the protein. By making an RNA template or copy, the gene is protected from damage. The mRNA is excreted from the nucleus into the cytoplasm.
mRNA Processing The mRNA must be further processed before it is suitable for protein production. First, it is an exact copy of the gene sequence, so it includes both exons, which code for the protein, and introns, which are not needed. A process called RNA splicing removes the introns and splices together the exons. Other reactions add an endcap to the mRNA chain and add other groups to stabilize the mRNA.
Translation Once the mRNA has been processed and is ready for production of the actual protein, it is taken over by ribosomes. Ribosomes are large protein complexes that match up each codon in the mRNA with a corresponding transfer RNA (tRNA). tRNAs are small RNA molecules that bind to amino acids in the cytoplasm. For instance, when the ribosome comes across a codon in the mRNA that says that a lysine should be the next amino acid in the protein chain it is producing, it looks for a tRNA bound to a lysine. That lysine is then attached to the growing chain of amino acids for the protein being produced. This process of adding the correct amino acids to the growing chain continues until all of the sequence in the mRNA has been completed.
Folding The new protein comes out of the ribosome as a linear chain of amino acids with no specific structure. However, most proteins have a specific three-dimensional structure that is required for their functionality. It appears that the specific amino acid sequence completely determines the final 3D structure of the protein, but the process of folding into that structure is still being discovered.
Post-translational modifications Once the basic protein chain is made it may be further processed in the cell. Many proteins have carbohydrate molecules added as side chains. Proteins that are going to be secreted from the cell may have a molecule called a signal peptide added to it. The signal peptide directs the new protein molecule through the secretion process and, in some cases, to wherever it is supposed to be in the body.
Some proteins, including factor IX and some related clotting factors, may have other modifications. In factor IX a portion of the protein called the gla region is modified in a reaction requiring vitamin K. In that region, all of the glutamate amino acids have a carboxy group (COOH) added to produce gamma-carboxy glutamic acid (gla) amino acids.
Gene Expression or Protein Production
An new type of treatment that adds a new gene or replaces or repairs a mutated (changed) gene inside the body's cells to help prevent or treat certain diseases. The first hemophilia gene therapy, for hemophilia B has been approved in November, 2022 (CSL Behring - Hengenix). A second gene therapy for hemophilia B (Pfizer) is expected to to have its licensure submission later in 2023 or early 2024. A gene therapy for hemophilia A (BioMarin) has submitted a licensure application to the FDA as well.
Gene Therapy
The modification of genes in an organism. This may be done to produce a product like recombinant factor IX or to investigate something in an animal.
Genetic Engineering
The complete collection of genes in the body. Except for some specialized cells, such as red blood cells and reproductive cells, every cell in the body has a complete copy of the genome in its nucleus.
Genome
Glycoprotein
A protein with one or more carbohydrate (glycol) side chains.
Addition of carbohydrate molecules to a protein or other molecule. The carbohydrates are usually chains of sugar molecules strung together and attached to the protein molecule in specific places. Many mammalian proteins (proteins in mammals) are glycosylated, but we still don’t really know what the purpose is.
However, we don’t know whether there may be some more subtle or unrecognized difference caused by the different glycosylation patterns. That’s why one manufacturer uses human cells to produce their recombinant factor IX product.
Note that different species glycosylate proteins differently. That is, they use different arrangements of sugar molecules in their carbohydrate chains. For instance, recombinant factor IX made in CHO cells will have a different glycosylation pattern (type and order of the sugar molecules in the chain) than a factor IX made in the human body. This doesn’t seem to make a lot of difference. The CHO cell-produced factor acts very much like the human cell-produced factor.
One purpose seems to be to control the degradation of proteins. The body tries to always have proteins that are in good shape. It is constantly making new proteins and removing old ones. As a glycosylated protein circulates in the blood stream, it encounters conditions that tend to degrade it. One thing that happens is that some of the sugar molecules on the end of the carbohydrate chain attached to the protein get knocked off.
When the liver sees a protein with missing sugars, it decides that it must be an “old” molecule that needs to be replaced. It breaks down the protein into its individual amino acids, which can be recycled to produce new proteins, to take it out of circulation. That’s why the factor products we use have a half-life. After the factor molecules from an infusion have been circulating for a while, they get beat-up just like any other protein in the bloodstream. Then they are taken out of circulation.
Glycosylation
H
Haemophilia
In some other countries hemophilia has alternate spellings.
The amount of time taken for half of an infused dose of medication to be removed from the circulation.
Half-Life
When someone says they ""had a bleed"" or are ""having a bleed"" it means that either due to injury or spontaneously they are bleeding or bled somewhere in their body. Individuals can ""have bleeds"" in their muscles, joints, brains, or from any blood vessel.
Usually when someone has a bleed, they follow up with factor for treatment.
Bleeds are not always visible so you have to learn the signs and know how to treat them. Keep a record of your bleeds and communicate those to your hematologist or HTC center.
Having a Bleed/Had a bleed
Hemo B
Also known as hemophilia B and factor IX deficiency
Hemophilia
Hemophilia (heem-oh-feel-ee-ah) is a bleeding disorder that causes you to bleed longer than normal when injured or sometimes without any cause.
There are different of hemophilia:
Hemophilia A – low levels of factor VIII (8). About 1 in 5,000 males is born with hemophilia A each year.
Hemophilia B – low levels of factor IX (9). About 1 in 25,000 males is born with hemophilia B each year.
Hemophilia C: A deficiency or absence of clotting factor XI (11).
The host cell is the cell that produces a recombinant protein like factor IX. If the host cells are non-human cells, like CHO (hamster) cells, they may produce other hamster proteins in addition to the recombinant protein. These are the host cell proteins, and they are considered contaminants that have to be removed. Since they come from a different species, they can cause an immune reaction in the patient receiving the treatment.
Host Cell Proteins
HTC
HTC is an acronym for Hemophilia Treatment Center.
Human Embryonic Kidney (HEK) Cells
Human cells used to produce some recombinant factor products.
I
Immunogenic
Something that causes an immune reaction.
Immunoglobulin
Immunoglobulins are antibodies.
This is a relatively new expression that means in a computer. It refers to an experiment that is run on a computer via simulation to mimic a real experiment. Its accuracy depends on the accuracy of the computer model in describing the process under investigation.
In silico
Latin expression for “in glass.” It is used to describe an experiment or treatment carried out in the laboratory. It was originally used to describe a procedure carried out in glass test tubes or other glass labware, but now is generally used to describe any procedure done in a laboratory. It is similar to “ex vivo.”
In vitro
Latin expression for “within the living.” It is used to describe an experiment or treatment done in a living body.
In vivo
The FDA-approved use for a product. An organization cannot market a product for any use except the approved indication. However, a physician can prescribe any licensed product for any indication at his/her discretion. Thus, for instance, a company cannot market a factor IX product for prophylaxis unless that is an approved indication. However, a physician can prescribe such a product for prophylactic use even without an approved indication.
Indication
This is a committee that oversees and approves clinical studies at an institution. There is usually an IRB at every institution that is involved in a clinical study. For instance, if a company wants to perform a clinical study of a new factor product, they have to file an IND application to get permission from the FDA, but that’s not enough. The company will often have their own IRB to review the application before it even goes to FDA. In addition, every hospital or clinic doing the actual study will also have their own IRB to evaluate the application before that site becomes part of the study.
Institutional Review Board (IRB)
An unlicensed drug that is being given to human subjects is an investigational new drug. However, the term “IND” is more often used to refer to the “IND Application” that is submitted to the FDA to get permission to use the unlicensed drug in people.
The IND contains all of the information known about the drug. It will contain information on all the research studies done on the drug, on the formulation and composition of the final product, on the manufacturing process, on all the controls used to verify that the product is safe and has been manufactured properly, on the componentry used to package the drug, on the stability and storage conditions for the product, on the distribution method to ensure that the product that is received by the participating hospitals or clinics remains in good condition, etc.
The IND will also include all the information that will also be transmitted to the physician and patient. The most important part of this is probably the “informed consent” document.
Investigational New Drug (IND)
J
K
K-tape, also called kinesiology tape, Kinesio tape, or KT, is an elastic cotton strip with an acrylic adhesive used to treat pain and irritation caused by injuries or other physical disorders.
Kineseology Tape
L
This not only includes the actual label on the product package but also everything that has been submitted and approved by FDA for the product. The prescribing information is a summary of all the labeling. A product that does not meet all the specifications approved by FDA is called “mis-labeled” or “mis-branded” and cannot be distributed.
Labeling
Leucocyte
See white blood cell.
Lyophilization
See Freeze Drying.
M
The process by which the body converts food into energy. Almost all cells perform metabolism to power their cellular processes
Metabolism
Sometimes you may hear people identify using only the terms mild, moderate, or severe when describing their hemophilia.
Mild hemophilia is defined by factor levels between 5-40% of normal blood clotting factor levels.
Mild (Hemophilia)
Sometimes you may hear people identify using only the terms mild, moderate, or severe when describing their hemophilia.
Individuals with moderate hemophilia A are at risk for prolonged bleeding following surgery, dental procedures or trauma. Easy or excessive bruising may also occur. By definition, affected individuals have 1-5% of normal factor clotting activity.
Moderate (Hemophilia)
Monoclonal Antibody (mAb)
A synthetic antibody produced
Hemophilia can be caused by a mutation or change, in one of the genes, that provides instructions for making the clotting factor proteins needed to form a blood clot. This change or mutation can prevent the clotting protein from working properly or to be missing altogether. These genes are located on the X chromosome
Mutation
N
National Hemophilia Awareness Month/ Bleeding Disorders Awareness Month
Bleeding Disorders Awareness Month has been observed each March since 2016, after being designated as a national health observance by the U.S. Department of Health and Human Services. BDAM aims to increase awareness of inheritable blood and bleeding disorders among the public, as well as bring them to the attention of policymakers, public authorities, industry representatives, scientists, and health professionals.
Prior to BDAM, March was known “Hemophilia Awareness Month” – a designation confirmed by President Ronald Reagan in March 1986.
NORD - acronym for the National Organization for Rare Disorders (www.rarediseases.org). Since 1983, NORD has been a national steward and a steadfast partner helping those who battle and care for rare disease feel seen, heard, supported and connected. NORD is a full-service, mission-driven nonprofit reimagining a future where every person with a rare disease, and their families live their best lives.
NORD
Nucleus
The central compartment within a cell that contains the genes.
O
When the FDA approves a drug, it is licensed for use in a specific indication. However, once a drug is on the market, a physician can prescribe the drug for any other indication that they think it will help. FDA relies on the doctor’s training and experience to determine that the drug is safe and effective for that use. This is called off-label use because the drug is being used for a different indication than the one it is labeled for.
Off-Label Use
Factor is sometimes delivered "on demand" when a patient is injured or has a scheduled procedure that may cause bleeding.
You may hear someone say, "We factor on demand.
On Demand
Out of Pocket Maximum - An out-of-pocket maximum, also referred to as an out-of-pocket limit, is the most a health insurance policyholder will pay each year for covered healthcare. Your health plan may have an in-network out of pocket maximum and an out-of-network out of pocket maximum.
Out of Pocket Maximum
P
A parenteral drug is any drug that is given by a route other than the mouth or intestine. Most hemophilia drugs are parenteral. Parenteral drugs that are injected into the body require much more stringent manufacturing processes than non-parenteral drugs that are taken by mouth. They are usually much higher purity and are usually sterile. They often have more restrictive storage conditions.
Parenteral Drugs
Pathology
Bhe study of disease. An abnormal medical condition may also be called a pathology.
The process of attaching polyethylene glycol (PEG) chains to the proteins in a product. The long PEG molecules tend to wrap around the protein and tend to hide it from the surrounding environment. In hemophilia PEGylation is usually used to increase the half-life of a product. The PEG chains hide the factor molecules from the liver cells that want to remove it from circulation.
PEGylation
A company that produces therapies to treat diseases. Within hemophilia, there are multiple pharmaceutical companies that manufacture gene therapies, monoclonal antibodies, recombinant therapies and blood clotting factors for the treatment of bleeding disorders.
Pharmaceutical Company
The clear, yellowish, fluid part of the blood that carries the blood cells. The proteins that form blood clots are in plasma. Initial blood clotting factors were derived from plasma that is collected throughout the country.
Plasma
One of several types of blood cells. Platelets are part of the clotting process. Once they are activated due to an injury, they stick together to form a plug to seal the injury and prevent blood loss. A clot is formed of a fibrin network that surrounds and stabilizes the platelet plug. A clot usually also contains other types of blood cells that are caught up within the fibrin/platelet matrix. New platelets are constantly being produced from stem cells in the bone marrow.
Platelet
These are modifications made to a protein molecule after the main protein chain has been produced. One common modification is glycosylation, adding carbohydrate side chains to the protein molecule. The factor IX molecule is glycosylated and also has several other post-translational modifications. The first twelve glutamic acids in the protein chain are modified by an enzyme to become γ-carboxyglutamyl amino acids. This change helps factor IX bind to calcium and to surfaces. Another change to the 64th amino acid in the chain also helps that binding. There are also two peptides (short protein sequences) connected to the end of the protein chain that are chopped off before factor IX is secreted out of the cell into the bloodstream.
Post-Translational Modification
These are the laboratory studies that are required before a product under development can be used in humans for clinical studies. These include toxicity and safety studies, some of which are performed in animals. Other studies are required to show that the product has a good chance of working. They also include stability (shelf life) studies to show that the product remains potent long enough to be useful. These often involve formulation and packaging studies. Other pre-clinical studies include development of assays to measure the active ingredient and other characteristics of the product. Finally, they also include at least partial development of the manufacturing process for the product – see Process development.
Pre-clinical studies
Prescribing Information (PI), also called Package Insert (PI) or Direction Insert (DI)
This is the leaflet contained in each package of a product. It is actually a highly-regulated document that describes everything that FDA has approved about the product. It is considered a major part of the labeling. An organization marketing a product cannot claim anything about the product that is not listed in the PI.
Primary Packaging
This is the packaging that is directly in contact with the product. For a factor IX product, the primary packaging is the vial and stopper. For a sterile product like factor IX, the primary packaging is also the “sterile barrier,” the barrier that keeps microorganisms out of the product.
With biologics, the primary type of product used in hemophilia, it is often said that “the process is the product.” That’s because these products are made from complex starting materials and the final products are often also complex mixtures. Even small changes to a production process can have significant changes to a product. FDA expects organizations conducting clinical studies to use the same product that will eventually be licensed, so the production process must be at least mostly worked out before starting clinical studies. Small changes to a process can often be accommodated in the early phases of clinical studies, but Phase III studies must use product produced using the final process. Any major process changes could require an organization to repeat some or all of the clinical study phases.
Process development
Prophy
Prophy is short for prophylaxis or prophylactic treatment.
Prophylaxis is an attempt to prevent disease. In the case of hemophilia, a prophylaxis regimen of treatment is a proactive form of treatment where the individual infuses on a regular basis to prevent breakthrough bleeds. A prophylaxis regimen attempts to keep the individual's clotting levels at a higher point in order to prevent bleeding episodes. In the community people often use the shortened version of this word and say, "He is on prophy."
Prophylaxis
Proteins are long chains of amino acids. The bonds between amino acids are known as peptide bonds. Most of the functions in the body are produced and controlled by proteins. The functions of the protein are determined by the order of amino acids in the chain. Proteins have at least three levels of structure, all of which are required to give a protein its function:
Primary Structure: The sequence of amino acids in the protein chain.
Secondary Structure: The secondary structure of a protein consists of sections of the protein chain that fold together to form specific types of structures, such as:
Alpha-helix: A section of a protein in which the chain winds around in a spiral or helix to form a cylindrical structure.
Beta Pleated Sheet: A section of a protein in which the chain winds back and forth in a plane to form a flat rectangular section.
These structures are held together by hydrogen bonds (see Chemical Bonds) between the individual amino acids.
Tertiary Structure: The tertiary structure is the overall three-dimensional shape of the protein that is stabilized by interactions between the various side chains on the amino acids.
Proteins
Protocol
The instructions for carrying out a study
Q
R
An alternative to plasma derived blood clotting factor. Recombinant factor products are made in a laboratory using recombinant technology. These products are not made from human blood.
Recombinant products offer a potentially safer option than plasma-derived products because they avoid potential blood-borne transmission of infectious diseases. In the United States, treatment with recombinant products is the standard of care.
Recombinant Factor
Red blood cells carry oxygen to all the tissues of the body. Red blood cells are also known as erythrocytes. New red blood cells are constantly being produced from stem cells in the bone marrow.
Red Blood Cell
The oldest of three brothers (Robert and Randy) with hemophilia who contracted HIV from contaminated blood clotting factor when they were less than eight years old. Born to Arcadia, Florida natives Louise and Clifford Ray, the family was exiled from Arcadia as community members feared contracting the disease. Memorial Elementary, in DeSoto County, would not allow them to attend school due to their diagnosis. They became the subject of a federal court battle against the DeSoto County School Board to allow the children to attend public school despite their diagnosis. The Rays were victorious in their legal battle, winning a $1.1 million settlement. They were allowed to go back to school, but the Ray home was burned down a week after the 1987 decision, forcing the family to leave Arcadia.
After the arson of their home, the Ray Family settled in nearby Sarasota. The brothers attended Gocio Elementary School.
Ricky Ray became an activist in the fight against AIDS. In 1992, he allowed camera crews to document his declining health and stated he wanted America to see what AIDS did to people. President Bill Clinton spoke to him and thanked him for his work raising awareness on AIDS. Ricky Ray died in 1992 at age 15.
Ricky Ray
Legislation passed by Congress and signed into law by President Bill Clinton in 1998. This legislation, named after Ricky Ray, provided a one-time compassionate payment of $100,000 by the US government to individuals (or their families) who contracted HIV through the used of contaminated blood clotting factor. You can read more about that here.
Ricky Ray Hemophilia Relief Act
S
The method for increasing the volume or mass of a production process. New medical products are usually developed at a small scale in a laboratory. That is often called lab-scale If the product looks promising, an organization will develop a larger scale process, first usually in a larger production facility called a pilot plant. That is often called pilot-scale. Pilot plants are often used, not only to devise larger scale production methods, but also to produce product for all of the development activities required for product licensure, such as for clinical studies, for stability studies, for toxicity studies, etc. Depending on the product, the process may go through one or several different pilot scales. Finally, the pilot scale process is scaled-up to a full scale or production scale process and installed in a manufacturing plant.
Scale-Up
The secondary packaging includes all the rest of the packaging outside of the primary packaging. For a factor IX product, it would include the aluminum cap that keeps the stopper in place, the vial label, the individual cardboard box, the direction insert, any additional needles, transfer devices and the sterile water used for reconstitution. For manufacturers and distributors, the secondary packaging also includes the outer cardboard cartons that hold a number of individual packages.
Note that all of this secondary packaging is also regulated under CGMPs, for good reason. For instance, there have been instances where a manufacturer has received cardboard cartons from a vendor that were contaminated with mold. After the product was packaged in the outer cartons and shipped from overseas to the U.S. distributor and the individual product packages were distributed to patients, an infectious mold outbreak occurred. It turned out that some of the outer cartons had gotten a little damp, the mold had grown and mold spores somehow migrated into the space on top of the vial stopper. When a needle was pushed through the stopper, some of the mold spores were pushed into the product and infected a patient.
This is a good illustration of what CGMP is all about. First, the moldy cartons should have never entered the pharmaceutical plant. Everything that enters a pharmaceutical manufacturing plant has to be tested and approved first. The mold spores probably migrated to the stoppers during all of the temperature and pressure changes during air shipment to the U.S. Even so, the distributor receiving the shipment should have noticed that the outer cartons had become damp, even if they were dry by the time they reached him.
Under CGMP, the distributor should have noted the damaged cartons and sent the shipment back to the manufacturer. You can’t just take the seemingly-undamaged vial packages out of the outer carton and still distribute them. There is a chain of control that must be intact in order to have confidence that the product is OK. Even though the individual vial packages look all right, there is no way to tell whether there might be mold spores on the stopper.
The final mistake was that the patient didn’t do a good job of disinfecting the stopper before he inserted the needle. The instructions on how to setup and perform an infusion are also part of CGMP because they are approved as part of the package insert. They are expected to be followed by the user. Fortunately, the patient survived.
Secondary Packaging
Severe hemophilia occurs in individuals with less than 1% of normal factor clotting activity. In contrast to the mild or moderate forms of the disease, severe hemophilia is associated with spontaneous bleeding episodes.
Severe (Hemophilia)
Severity Level - commonly referred to stating the form of hemophilia, whether mild, moderate or severe.
Severity Level
Specialty pharmacies work with patients and physicians to provide medications for chronic and more severe illnesses. Specialty pharmacies serve patients with serious health conditions who require complex treatment therapies. Such pharmacies typically provide nursing services and assist with product administration.
Specialty Pharmacy
Hemophilia is usually an inherited bleeding disorder in which the blood does not clot properly. This can lead to spontaneous bleeding as well as bleeding following injuries or surgery. Blood contains many proteins called clotting factors that can help to stop bleeding.
Spontaneous Bleed
Hemophilia is usually an inherited bleeding disorder, but there are also cases of spontaneous mutation where there is not a family history. The two types of hemophilia are caused by permanent gene changes (mutations) in different genes. Mutations in the FVIII gene cause hemophilia A. Mutations in the FIX gene cause hemophilia B. Proteins made by these genes have an important role in the blood clotting process
Spontaneous Mutation
For a sterile pharmaceutical, this is the part of the packaging that forms the barrier between the product and the outside world to keep the product from being contaminated by microorganisms. For a vial of factor IX, the sterile barrier is the glass vial and rubber stopper
Sterile Barrier
Short hand reference to subcutaneous. Subcutaneous injection is an injection under the skin in lieu of an intravenous injection.
Sub Q
Subcutaneous injection is an injection under the skin in lieu of an intravenous injection.
Subcutaneous Injection
T
Thrombosis
Local coagulation or clotting of the blood in a part of the circulatory system.
This is the device, often a double-ended needle, that is used to transfer the diluent from its vial into the product vial to reconstitute the freeze-dried product.
Transfer Device
Peaks and troughs are the highest and lowest concentrations of a medication in an individual’s body. They are used to determine dosing intervals, or how much time should pass between each new administration of the drug. Peak and trough levels are particularly useful for therapeutic drug monitoring, which is the process of measuring drug concentrations at intervals to ensure a consistent concentration of a medication remains in an individual.
Trough
U
V
Von Willebrands or Von Willebrand Disease (VWD)
Von Willebrand Disease (VWD). VWD is a blood disorder in which the blood does not clot properly. Blood contains many proteins that help the blood clot when needed. One of these proteins is called von Willebrand factor (VWF). Unlike hemoophilia, which is male dominated, VWD is identified equally between men and women.
Vector
In gene therapy, a vector is the object used to deliver the new gene into cells. All of the hemophilia gene therapies, so far, use viruses as vectors to deliver new genes into the nucleus of liver cells. However, use of other carriers beside viruses is also being explored. For instance, the lipid nanoparticles used to deliver RNA into cells for the COVID vaccines may also be able to deliver DNA genes.
W
White blood cells are part of the immune system. They are also called leucocytes. White blood cells make up about 1% of the blood. New white blood cells are constantly being produced from stem cells in the bone marrow. There are a number of different types of white blood cells, including:
Granulocytes: Granulocytes are a type of white blood cell that has granules (small particles) containing enzymes that are released during infections, allergic reactions, and asthma. Granulocytes include several different types of white blood cells:
Basophils: Basophils are involved in allergic reactions.
Eosinophils: Eosinophils kill parasites and cancer cells and are involved in allergic reactions.
Neutrophils: Neutrophils kill bacteria and fungi and remove foreign debris.
Lymphocytes: Lymphocytes produce antibodies and help fight viruses. There are two main types of lymphocytes:
B Lymphocytes (B Cells): B lymphocytes make antibodies.
T Lymphocytes (T Cells): T lymphocytes help kill cancer cells and help control immune reactions.
Monocytes: Monocytes remove damaged cells. They are relatively large cells that can engulf and remove foreign agents, such as bacteria and viruses and other foreign material from the body. They can also differentiate into either of the following types of cells:
Dendritic Cells: Dendritic cells are involved in the antibody production process. They engulf foreign agents and process them to place parts of the foreign agent on their cell surface. B cells and T cells then interact with the dendritic cells to produce antibodies against the surface antigens.
Macrophages: Macrophages migrate outside of the blood stream to reside in many types of body tissues where they can engulf foreign bodies to remove them from the body.
White Blood Cell
X
X Chromosome
The X chromosome is one of the two sex chromosomes that are involved in sex determination. Humans and most other mammals have two sex chromosomes (X and Y) that in combination determine the sex of an individual. Females have two X chromosomes in their cells, while males have one X and one Y. Hemophilia is an x linked condition, prevalent in males as they only have one X chromosome, whereas women have two X chromosomes.
Y
Y Chromosome - The Y chromosome is one of the two sex chromosomes in humans (the other is the X chromosome). The sex chromosomes form one of the 23 pairs of human chromosomes in each cell. The Y chromosome spans more than 59 million building blocks of DNA (base pairs) and represents almost 2 percent of the total DNA in cells.
Each person normally has one pair of sex chromosomes in each cell. The Y chromosome is present in males, who have one X and one Y chromosome, while females have two X chromosomes.