The ABO Blood Group System - Case Study Example

THE ABO BLOOD GROUP SYSTEM By Student’s Name Code + Name of Course Professor/Tutor Institution City/State Date The ABO Blood Group System Abstract The ABO blood group is a critical determinant of compatibility in transfusion. This research will review published information regarding genetics, significance, and testing in the ABO blood group system. This essay depicts that blood group types are inherited, and they vary in different people. The discoveries of the study reveal that the ABO blood group system constitutes of antigens, their resultant antibodies, and the gene codes for the antigens. Introduction The ABO system is considered as the most significant blood-group mechanism in transfusion medicine. The discovery of the ABO blood system generated great excitement about 100 years ago, but until then, all blood had been supposed to be similar, and the usual tragic blood transfusions consequences were never understood. With increased understanding of the ABO group, blood transfusion all over the world became safer, while the scientists ventured into studies of the initial human inheritable characteristics. General Discussion Discovery and Significance In 1900, Karl Landsteiner documented several tests, which recognized the ABO Blood Group System (Storry & Olsson 2009, p.48). He discovered that an individual lacks antibodies to his own antigens (Storry & Olsson 2009, p.54). Every individual has antibody to the antigen he or she lacks (only in the ABO structure) (Murphy 2013, pg. 33). Individuals with blood group A have antigen A, and their antibody is anti-B. For individuals of blood group B, the antigen is B, while their antibody is anti-A. The antigens of blood group AB are A and B, and they have no antigens (Harmening 2012, pg. 12). Individuals with blood group O neither have anti-A or anti-B antigens while their antibody is anti-A, B. The antigens of ABO blood group remain important in transfusion medicine (Murphy 2013, pg. 41). The major cause of death resulting from blood transfusion is an error where an incompatible kind of ABO blood is transfused. The antigens of the ABO blood group also seem to have been significant throughout human evolution because the incidences of diverse ABO blood kinds vary among unalike populations, signifying that a specific blood type conferred a choice advantage, for instance, resistance against a contagious illness (Imelda 2010, pg. 12). Genetics and Biochemistry Blood groups are genetic and are derived from both parents. The ABO gene controls the ABO blood type with three forms of alleles contingent with classical genetics: IA, IB, and I (Svensson, Hult, Stamps, Ångström, Teneberg, Storry, & Olsson 2013, pg. 1459). The gene codes an enzyme known as glycosyltransferase, which alters the carbohydrate composition of the antigens of the red blood cells and it is located on the ninth chromosome. The IA allele provides type A, and IB provides type B, while i generates type O blood. Given that both IB and IA are dominant over i, only ii individuals have blood type O. People with IAi or IAIA have type A blood, while those with IBi or IBIB have type B. IAIB individuals have both phenotypes (Svensson, et. al, 2013, pg. 1459). This is because A and B exhibit an exceptional dominance association – codominance, which suggests that A and B couples can have an AB baby. If both couples with type A and B are heterozygous (IBi,IAi), they can as well have a type O baby. The cis-AB phenotype contains one enzyme, which generates both A and B antigens. The resultant red blood cells will not often express A or B antigen on one level as would be anticipated on common group B or A1 red blood cells that can assist in solving the problem of a seemingly genetically difficult blood group (Goebel, Halm-Heinrich, Parkner, Rink, Heim & Bugert 2013, pg. 3). Despite the fact that children’s blood types are exclusively determined by inheritance, paternity can no longer be lawfully established by grounding on conventional blood typing. Biochemistry: The ABO blood group system constitutes antigens, their resultant antibodies, and the gene codes for the antigens (Bugert 2009, pg. 16). This is because the antibodies and antigens of these systems are very dominant and they generate strong agglutination reactions in case of wrong transfusions. An individual of blood group A possesses the A gene that codes for the N-acetyl galactosamine transferase enzyme. Human blood groups depend on the glycosyltransferases, which catalyzes the formation of glycosidic code between monosaccharides (Svensson et. al, 2013, pg. 1460). This enzyme transmits the sugar N-acetyl galactosamine into the precursor sugar on the H matter, thus generating into the A matter or A-antigen of the same red blood cell. An individual of blood group B has B gene, which is a code for the D-galactose transferase enzyme. This enzyme transmits the sugar D-galactose into the sugar terminal of the H substance, resulting into the B matter or B antigen. Antigens and Antibodies The ABO Blood variety antigens are not only present on the red blood cell’s surface. Some individuals also secrete them in their body fluids like urine, saliva, and tears (Reid, Lomas-Francis & Olsson, 2012, pp. 12). The ability of people to secrete them is dependent on genetics. The ABO blood group system involves two antigens, A and B. People with the A antigen on their red blood cells do have the A blood group. Moreover, they have anti-B antibodies within their serum. Individuals with the B antigen on the exterior of their red blood cells have the B blood group and the serum in their bodies is anti-A antibodies. People of blood group O lack the A or B antigen on their RBCs surface, but they have anti-A and anti-B antibodies within their serum, whereas AB blood group people do possess both surfaces of the RBC of the A and B antigens, but no antibodies within their serum (Reid, Lomas-Francis & Olsson, 2012, pp. 22). Antibodies to foreign antigens within the ABO group are often present in blood plasma before the initial contact with blood of a dissimilar ABO type. When individuals are exposed to these antibodies, they may develop long-lasting active protection to their antigens and afterwards to the antigens present on the RBCs surfaces. This normally happens in babies within the initial six months after birth. Testing techniques ABO typing is normally conducted by placing a sample of blood in a centrifuge, and separating the RBCs from serum or plasma (Daniels 2013, p.161). A forward type or "front," and reverse type or "back," are then performed. The forward or front type assumes an individual's red blood cells and they are mixed with commercial reagents of anti-A antibody alongside isolated anti-B antibody (Daniels 2013, p.162). The test measures observable agglutination or absence of agglutination. The reverse or back type mixes a person’s plasma with reagent, red blood cells positive for antigen A, and different reagent red blood cells positive for antigen B. Moreover, the test measures observable agglutination or its absence. The occurrence of this reaction is labelled with a positive sign (+) while the absence is represented with the number zero (Daniels 2013, p.172). ABO Subgroups and ABO Blood Grouping Discrepancies The ABO subgroups or subtypes are described as a blood type, which have most of the chemical features of type O, A or B, but which have a slight difference in a share of the structure, which can be identified through testing (Khatun, Biswas, Habibullah, Islam, Shill,Rahman & Shaheen 2012, pg. 82). These variations may happen through several mutations like, amino acid substitution, frame shift mutations, single-point mutations, deletions, and single missense mutations. The variation amount establishes if it is clinically noteworthy enough to lead to hemolysis. The most typical subgroups of A are A1 (nearly 80% of all individuals of type A) and A2 (about 20% of all type A people) (Ségurel et. al, 2012, pg. 18493). Most commercial reagents for testing use the A1 RBC antigen. The occurrence of a few discrepancies normally occurs between the back and front typing between an A2 person cells, and the A1 reagent cells (Reid, Lomas-Francis & Olsson, 2012, pp. 12). Although unusual, another discrepancy in ABO blood grouping may result from particular bacterial malignancies and infections, which may lead to an acquired ‘B’ typing from an individual of type A. Conclusion With increased comprehension of the ABO group, there have been safer blood transfusion. Landsteiner’s combination of the cells and serum of all the investigators in his laboratory led to the discovery of four different arrays of agglutination. In the ABO blood group system, any individual lacks antibodies to his or her own antigens. The antigens of ABO blood group are found on the RBC surface and are important in transfusion medicine. On the other hand, antibodies to foreign antigens within the ABO group are often present in blood plasma. The forward type and reverse type tests can be performed to establish ABO typing. Finally, this study has found that the typical subgroups of A are A1 and A2 and discrepancies may occur in the back and front typing tests between an A2 person’s cells and the A1 reagent cells. Another discrepancy may result from particular bacterial infections. Bibliography Bugert, P 2009. DNA and RNA profiling in human blood methods and protocols. Humana Press. Daniels, G 2013. Human blood groups. John Wiley & Sons. Goebel, M, Halm-Heinrich, I, Parkner, A, Rink, G, Heim, M & Bugert, P 2013, ‘A Novel ABO Gene Variant Leads to Discrepant Results in Forward/Reverse and Molecular Blood Grouping.’ Transfusion Medicine and Hemotherapy, Vol. 40, no. 6, pp. 3-13. Harmening, D 2012. Modern blood banking and transfusion practices. FA Davis. Ségurel, L, Thompson, E, Flutre, T, Lovstad, J, Venkat, A, Margulis, S, & Przeworski, M 2012, ‘The ABO blood group is a trans-species polymorphism in primates.’ Proceedings of the National Academy of Sciences, vol. 109, no. 45, pp. 18493-18498. Imelda, B 2010. Essential Guide to Blood Groups. John Wiley & Sons. Khatun, A, Biswas, J, Habibullah, M, Islam, A, Shill, N, Rahman, A & Shaheen, S 2012, ‘B Subgroup: Bx blood Group in a Patient: A Case Report.’ Bangabandhu Sheikh Mujib Medical University Journal, Vol. 5, no. 1, pp. 81-82. Murphy, M 2013. Practical transfusion medicine (4th ed.), Wiley-Blackwell. Reid, M, Lomas-Francis, C, & Olsson, M 2012. The blood group antigen factsbook. Academic Press. Storry, J & Olsson, L 2009, ‘The ABO blood group system revisited: a review and update.’ Immunohematology, Vol. 25, no. 2, pp. 48-59. Svensson, L, Hult, A, Stamps, R, Ångström, J, Teneberg, S, Storry, J, & Olsson, M, 2013, ‘Forssman expression on human erythrocytes: biochemical and genetic evidence of a new histo-blood group system. Blood, vol. 121, no. 8, pp. 1459-1468. Read More