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BLOOD GROUPS, BLOOD TYPING, BLOOD TRANSFUSIONS AND BLOOD DISORDERS HISTORY Experiments with blood transfusions, the transfer of blood or blood components into a person's blood stream, have been carried out for hundreds of years. Many patients died as a result of this procedure. It was not until 1901 when the Austrian Karl Landsteiner discovered human blood groups, that blood transfusions became safer. Mixing blood from two individuals can lead to blood clumping or agglutination. This can have fatal consequences. Karl Landsteiner discovered that blood clumping was an immunological reaction which occurs when the receiver of a blood transfusion has antibodies against the donor blood cells. Karl Landsteiner's work made it possible to determine blood types and thus paved the way for blood transfusions to be carried out safely. For this discovery he was awarded the Nobel Prize in Physiology or Medicine in 1930. BLOOD GROUPS The differences in human blood are due to the presence or absence of certain protein molecules called antigens and antibodies. The antigens are proteins located on the surface of the red blood cells (RBCs) and are inherited. The antibodies are proteins in the blood plasma that develop shortly after birth. Individuals have different types and combinations of these molecules. The blood group you belong to depends on what you have inherited from your parents. There are more than 20 genetically determined blood group systems known today, but the ABO and Rh systems are the most important ones used for blood transfusions. Not all blood groups are compatible with each other. Mixing incompatible blood groups leads to blood clumping or agglutination, which is dangerous for individuals. Karl Landsteiner was involved in the discovery of both the ABO and Rh blood groups. ABO BLOOD GROUPING SYSTEM According to the ABO blood typing system there are four different kinds of blood types: A, B, AB or O (null). If you belong to the blood group A, you have A antigens on the surface of your RBCs and B antibodies in your blood plasma. If you belong to the blood group B, you have B antigens on the surface of your RBCs and A antibodies in your blood plasma. If you belong to the blood group AB, you have both A and B antigens on the surface of your RBCs and no A or B antibodies at all in your blood plasma. If you belong to the blood group O, you have neither A nor B antigens on the surface of your RBCs but you have both A and B antibodies in your blood plasma. Rh FACTOR BLOOD GROUPING SYSTEM Many people also have the Rh factor (protein) on the RBCs surface. This protein was originally discovered on the blood cells of the Rhesus monkey (hence the name Rh factor). This is also an antigen and those who have it are called Rh+. Those who do not have it are called Rh-. A person with Rh- blood does not have Rh antibodies naturally in the blood plasma (as one can have A or B antibodies, for instance). But a person with Rh- blood can develop Rh antibodies in the blood plasma if he or she receives blood from a person with Rh+ blood. The donor’s Rh antigens can trigger the production of Rh antibodies. A person with Rh+ blood can receive blood from a person with Rh- blood without any problems. BLOOD GROUP NOTATION According to above blood grouping systems, you can belong to one of following eight blood groups: A Rh+ or A+ B Rh+ or B+ AB Rh+ or AB+ O Rh+ or O+ A Rh- or A- B Rh- or B- AB Rh- or AB- O Rh- or O- DETERMINATION OF A PERSON’S BLOOD GROUP A person’s blood group (or blood type) can be determined using the following steps: 1. Three separate blood samples from the same person are mixed with three separate reagents. Each reagent contains one of the antibodies = A, B or Rh. 2. Observe each mixture and note where agglutination (clumping) has occurred. The agglutination indicates that the blood has reacted with a certain antibody and therefore is not compatible with blood containing that kind of antibody. If the blood does not agglutinate, it indicates that the blood does not have the antigens binding the special antibody in the reagent. WHAT HAPPENS WHEN BLOOD CLUMPS OR AGGLUTINATES For a blood transfusion to be successful, ABO and Rh blood groups must be compatible between the donor blood and the patient blood. If they are not, the RBCs from the donated blood will clump or agglutinate. The agglutinated RBCs can clog blood vessels and stop the circulation of the blood to various parts of the body. The agglutinated cells also crack open and the contents leak out in the body. The RBCs contain hemoglobin which becomes toxic when outside the cell. This can have fatal consequences for the patient. The A antigen and the A antibodies can bind to each other in the same way that the B antigens can bind to the B antibodies. This is what would happen if a B blood person (A antibodies) receives blood from an A blood person. The RBCs will be linked together, like bunches of grapes, by the antibodies. As mentioned earlier, this clumping can result in death. BLOOD TRANSFUSIONS Of course you can always give A blood to a person with blood group A, B blood to a person with blood group B and so on. But in extreme cases (when the same blood type is not available) you can receive blood with another type of blood group, or donate blood to a person with another kind of blood group. The transfusion will work if the person who is going to receive blood has a blood group that doesn't have any antibodies against the donor blood's antigens. But if a person who is going to receive blood has antibodies matching the donor blood's antigens, the RBCs in the donated blood should clump. Fortunately, the antibodies in the donated blood become diluted in the recipient’s blood if the transfusion is done slowly. Slow transfusion usually avoids serious consequences. This is why certain donor blood types can be given to more than one blood type recipient when an exact match is not available. This is demonstrated in the chart below. Blood Group Antigens Antibodies Can give blood to Can receive blood from AB A and B None AB AB, A, B, O A A B A and AB A and O B B A B and AB B and O O None A and B AB, A, B, O O RED BLOOD CELL DISORDERS Anemia Anemia (uh-NEE-me-eh) is a condition in which a person’s blood has a lower than normal number of RBCs, or the RBCs don’t have enough hemoglobin. As a result, people with anemia feel tired, along with other symptoms, because their bodies are not receiving enough oxygen. Remember that oxygen is required for cellular respiration (formation of ATP for energy). Without ATP, normal chemical reactions that keep the cell functioning properly do not occur. In severe or prolonged cases of anemia, the lack of oxygen in the blood can cause serious and sometimes fatal damage to the heart and other organs of the body. Poor nutrition may contribute to inadequate red blood cell production, especially deficiencies in iron and certain types of vitamin B. When an increased production of RBCs is necessary, such as during pregnancy or after an episode of bleeding, these nutrients are even more critical. Iron and vitamin B supplements are often prescribed to prevent anemia. Iron Deficiency Anemia Iron Deficiency Anemia is the most common cause of anemia in the United States. It occurs when the body either has depleted all iron stores or is unable to use the iron available to make adequate amounts of hemoglobin. For Americans, however, lack of dietary iron is rarely the sole cause of this anemia. Usually, people have blood loss as well. Young women are at particular risk, because of monthly blood loss with menstruation. Up to 10 percent of women in their reproductive years have iron deficiency, and, in about half of those cases, it is severe enough to cause anemia. Pregnant women also are at risk, which is why prenatal vitamins containing extra iron are recommended during pregnancy. Iron-deficiency anemia is less common in men and in postmenopausal women in the United States. Low iron levels in these groups is a warning that abnormal bleeding could be occurring due to undiagnosed medical conditions such as ulcer disease or colon cancer. The highest amounts of iron are found in meat, spinach, raisins, lentils and enriched flour. Iron is absorbed most efficiently, however, from red meat which is why pre-menopausal women who don't eat much meat are at particular risk for iron-deficiency anemia. Other factors also contribute to how much iron is absorbed in the body. Vitamin C enhances the absorption of iron from the intestine, so if you combine foods with iron and vitamin C, you will increase the amount of iron absorbed. Citrus fruits are well-known for their vitamin C content, but many vegetables are also a good source of vitamin C, such as tomatoes, cauliflower, broccoli and potatoes. Vitamin B12 Deficiency / Pernicious Anemia A vitamin B12 deficiency produces unusually large RBCs with a shortened life span. Older Americans may have B12 blood levels that are below the optimal range even when there is no anemia. This usually is due to an inability to absorb vitamin B12 rather than a dietary deficiency, although strict vegetarians are at risk because vitamin B12 is found only in animal products. Another cause of vitamin B12 deficiency is pernicious anemia, an autoimmune disease in which the immune system attacks the specialized stomach cells that produce a protein called intrinsic factor. This protein is essential to the absorption of vitamin B12 from food. Vitamin B12 deficiency also can develop as a complication of gastrointestinal surgery and certain diseases of the intestine, preventing adequate absorption. Good sources of vitamin B12 include liver, tuna, cottage cheese, yogurt and eggs. Most standard multivitamin supplements also provide the recommended daily allowance of vitamin B12. Aplastic Anemia Aplastic Anemia is a rare, potentially fatal disease in which the bone marrow doesn't make enough blood cells. People with aplastic anemia have low levels of all three types of blood cells. In aplastic anemia, something either destroys the stem cells located in the bone marrow or drastically changes the environment of the bone marrow so that the stem cells can't develop properly. Several factors can cause this problem, such as exposure to radiation (radiation sickness), chemotherapy, environmental toxins (insecticides), some medications, and certain viral infections, including viral hepatitis, HIV and infectious mononucleosis (Epstein-Barr viral infection). WHITE BLOOD CELL DISORDER Leukemia Leukemia is a form of cancer that affects the body's blood-making system, including the lymphatic system and bone marrow. Leukemia is either acute (coming on suddenly) or chronic (lasting a long time). In acute leukemia, immature blood cells reproduce quickly in the bone marrow, where they eventually crowd out healthy cells. When present in high numbers, these immature, abnormal cells sometimes can spread to other organs, causing damage. Acute lymphoid leukemia Acute lymphoid leukemia occurs when lymphoid stem cells reach the lymphoblast stage without developing into normal blood cells. These abnormal cells crowd out healthy blood cells. They can collect in the lymph nodes and cause swelling. Acute myeloid leukemia Acute myeloid leukemia occurs when myeloid stem cells reach the myeloblast stage and reproduce without developing into normal blood cells. Immature myeloblast cells crowd the bone marrow and do not develop into healthy normal blood cells. This leads to anemia (not having enough RBCs), bleeding and bruising (due to a lack of platelets), and frequent infections because there are not enough protective white blood cells. Chronic leukemia Chronic leukemia may be lymphoid or myeloid but occurs when the body produces too many blood cells that have developed part way (as far as myelocytes or lymphocytes) but often cannot function like mature blood cells. Chronic leukemia usually develops more slowly and is a less dramatic illness than acute leukemia. PLATELET DISORDER Thrombocytopenia Thrombocytopenia is the medical term for a low blood platelet count. Platelets (thrombocytes) play an important role in blood clotting. They stop blood loss by clumping together at the site of a blood vessel injury and forming plugs in vessel holes. If for any reason your blood platelet count falls below normal, this is called thrombocytopenia. Complications may range from none at all to severe bleeding. Most people have more than 150,000 platelets per microliter of blood. Anyone with fewer platelets has some degree of thrombocytopenia. The risk of bleeding increases as the platelet count decreases, so people with less than 10,000 platelets per microliter of blood are at high risk of severe bleeding. BLOOD CLOTTING PROTEIN DISORDER Hemophilia Hemophilia is a rare, inherited bleeding disorder in which your blood doesn’t clot normally. If you have hemophilia, you may bleed for a longer time than others after an injury. You also may bleed internally, especially in your knees, ankles, and elbows. This bleeding can damage your organs or tissues and, sometimes, be fatal. People born with hemophilia have little to none of a protein needed for normal blood clotting. The protein is called a clotting factor. There are several types of clotting factors, and they work together with platelets to help the blood clot. When blood vessels are injured, clotting factors help the platelets stick together to plug cuts and breaks at the site of the injury to stop the bleeding. Without clotting factors, normal blood clotting can’t take place. Sometimes people with hemophilia need injections of a clotting factor or factors to stop bleeding. Hemophilia can be mild, moderate, or severe, depending on how much clotting factor is in the blood QUESTIONS TO ACCOMPANY BLOOD GROUPS, TYPES, TRANSFUSIONS AND DISORDERS 1. Define agglutination: ________________________________________________________ 2. Name the person that discovered there are human blood groups and the year he was awarded the Nobel Prize for his discovery. ______________________________________ 3 A. Antigens and antibodies belong to the category or organic compounds named _________. B. Antigens are located ___________________ while antibodies are located ______________. C.(Antigens / Antibodies) are inherited characteristics while (antigens / antibodies) form shortly after you are born. 4 A. Name the three proteins that may be found on the surface of human RBCs. ______________ B. Name the two proteins that may form in human plasma shortly after birth. _______________ 5. Complete the following chart for each blood type listed. If proteins are absent use an O. BLOOD TYPE ANTIGENS PRESENT ANTIBODIES PRESENT A+ BAB + O+ O6. List two reasons why blood agglutination is dangerous to the human body. __________________________________________________________________________ __________________________________________________________________________ 7. Why can type O blood be given to all four blood types even though it contains both A and B antibodies? ________________________________________________________________ 8. List two causes of anemia and explain why anemic persons are always tired. ____________ __________________________________________________________________________ __________________________________________________________________________ 9. Why is oxygen necessary to keep body organs healthy? _____________________________ __________________________________________________________________________ 10 A. In iron deficiency anemia, what vitamin deficiency may contribute to the condition and why? __________________________________________________________________________ B. How is the iron used? ________________________________________________________ 11 A. What happens to your RBCs if you do not take in enough vitamin B12 through diet? ________ __________________________________________________________________________ B. Explain the difference between Pernicious Anemia and dietary vitamin B12 deficiency. ______ __________________________________________________________________________ __________________________________________________________________________ __________________________________________________________________________ OVER 12 A. List two reasons (not factors) why stem cells in the bone marrow malfunction in Aplastic Anemia. ___________________________________________________________________ B. Name the types of blood cells that are affected by Aplastic Anemia. ____________________ 13 A. What is the difference between acute and chronic Leukemia? _________________________ __________________________________________________________________________ B. In Acute Lymphoid Leukemia, do the immature cells crowd out the healthy cells? _________ Where else can they collect and what does this cause? ______________________________ C.In Acute Myeloid Leukemia, do the immature cells crowd out the healthy cells? ___________ Why can chronic anemia be a side effect of this condition? ___________________________ 14 A. What is Thrombocytopenia? ___________________________________________________ B. Explain how the platelets function during the formation of a clot? ______________________ __________________________________________________________________________ 15 A. If a person has Hemophilia, what is lacking in her/his blood? __________________________ B. How does your answer to 15 A help the platelets? __________________________________ __________________________________________________________________________ C.What determines if a person has mild, moderate or severe Hemophilia? _________________ __________________________________________________________________________