THE DISTRIBUTION OF ABO BLOOD GROUPS AMONG BASRAH GOVERNORATE POPULATION

ABO blood grouping is currently considered as one of the essential immunological tests done before many clinical interventions; on the top of them are clinical blood transfusion procedures. In a period of 14 months, 620 blood samples were collected from normal individuals including 294 males & 326 females after demographic study of each one. Samples were tested for ABO grouping using the standardized methods. Results were analyzed statistically using the SPSS analytical system. Results showed that blood group O was the most prevalent type among the whole Basrah Governorate, in all its districts & among both sexes, while the blood groups B & A came next, where as B group was a little bit higher in the whole sample of the Governorate & among females while the A was a little bit higher among males. The AB blood group was the least of the four among all. There was little variation in the distribution of the four blood groups among the different regions of Basrah Governorate but with conservation of the above mentioned graduation. Those results were comparable to the results registered in some neighboring countries, but differ more or less from other far countries. Introduction he discovery of ABO blood group system at the end of the nineteenth century laid the foundation for clinical transfusion practice. The first discovery of A, B & C (which was later on renamed as O) blood groups was by Karl Landsteiner in 1900-1901. This was followed by the finding of De Castello & Sturli the fourth, AB blood group in 1902. In 1910 von Dungren & L. Hirszfeld had confirmed that the inheritance of A & B characters obeys the Mendelian laws of hereditary, with the presence of the A or B antigens dominant to their absence and in 1924, the theory of inheritance of the ABO antigens had been postulated by Bernistein as being due to three alleles of genes: A and B, O, and therefore resulting of 6 genotypes AA and BB and AO and BO, and AB and OO, and 4 phenotypes (A,B,AB & O). Thomson et T al had extended the 3 allele theory of Bernstien into 4 alleles : A1,A2, B & O, hence, discovering the most common A subgroups: A1 & A2. This had been completed by the profound work of: Aaron & Rosenfield, 1964, Mourant 1976 & Yamamoto et al 1990. The structure & symthesis of A & B antigens was founded by the pioneering work in 1950s of Morga, Watkins & Kabat. The ABO Blood Group system is composed of both antigens on RBCs membrane & naturally-occurring antibodies in the serum. Antigens are glycoproteins existing on red cell membrane, composed of 3 components: an H antigen, a glycoprotein, present on the surface of O blood group red cells, which represents the precursor molecule of both A & B antigens. On top of which, either NBas J Surg, September, 16, 2010 101 Distribution of abo blood groups Zuhair ALBarazanchi, Talib Al-Buslimy & Dhamia Suker acetyl galactosamine molecule is added to yield the A antigen or D-galactose molecule to yield the B antigen. The A& B antigens expressed on red cells are determined by the A or B genes located on the long arm of chromosome. These genes code for the enzyme glycosyl transferase which attaches different carbohydrates (sugar) molecules to the terminal galactose of H antigen oligosaccharide chain. These oligosaccharide chains are attached to phospholipid on red cell membrane & to proteins (glycoproteins) in plasma. A & B antigens usually appear on the fetal red cells in the beginning of the 2nd trimester of pregnancy & their antigenecity (estimated by the number of antigenic determinants per each red cell) increases steadily during fetal development & in post natal life they appear weaker than those of adults (the number of antigenic determinants was estimated around 300 000 & 1000 000 respectively) till reaching that of adults by the age of 3 years. However, The antibodies in the serum of ABO blood group system are almost always natural, cold-reacting, IgM antibodies that cant cross the placenta & thus cant lead to the development of hemolytic disease of newborn (HDN). They are very weak or negligible in potency during intrauterine & early post natal life. They start to be of considerable importance by the age of 6 months, growing up in potency till by the age of 1 year, when they will be as potent as adults, sera. Yet, immune antibodies of IgG may develop & can thus be the reason of ABO HDN(Table I). Table I: Antigens & antibodies distribution in ABO blood group system. Antibody Antigen Blood group


Introduction
he discovery of ABO blood group system at the end of the nineteenth century laid the foundation for clinical transfusion practice 1 .The first discovery of A, B & C (which was later on renamed as O) blood groups was by Karl Landsteiner in 1900-1901.This was followed by the finding of De Castello & Sturli the fourth, AB blood group in 1902 2,3 .In 1910 von Dungren & L. Hirszfeld had confirmed that the inheritance of A & B characters obeys the Mendelian laws of hereditary, with the presence of the A or B antigens dominant to their absence 4 and in 1924, the theory of inheritance of the ABO antigens had been postulated by Bernistein as being due to three alleles of genes: A and B, O, and therefore resulting of 6 genotypes AA and BB and AO and BO, and AB and OO, and 4 phenotypes (A,B,AB & O) 5 .Thomson et T al had extended the 3 allele theory of Bernstien into 4 alleles : A1,A2, B & O, hence, discovering the most common A subgroups: A1 & A2 6 .This had been completed by the profound work of: Aaron & Rosenfield, 1964, Mourant  1976 & Yamamoto et al 1990 [7][8][9] .The structure & symthesis of A & B antigens was founded by the pioneering work in 1950s of Morga, Watkins & Kabat [10][11][12] .
The ABO Blood Group system is composed of both antigens on RBCs membrane & naturally-occurring antibodies in the serum.Antigens are glycoproteins existing on red cell membrane 13 , composed of 3 components: an H antigen, a glycoprotein, present on the surface of O blood group red cells, which represents the precursor molecule of both A & B antigens.On top of which, either N-acetyl galactosamine molecule is added to yield the A antigen or D-galactose molecule to yield the B antigen.The A& B antigens expressed on red cells are determined by the A or B genes located on the long arm of chromosome 9 .These genes code for the enzyme glycosyl transferase which attaches different carbohydrates (sugar) molecules to the terminal galactose of H antigen oligosaccharide chain.These oligosaccharide chains are attached to phospholipid on red cell membrane & to proteins (glycoproteins) in plasma 1,9,11,14,15 II) 2,16,18 .However, in Africans (black people), B is in general a much stronger antigen than in Europeans (white people) 8 and black people have a higher level of Bspecified glycosyl transferase in the serum 19 .
Based on quantitative agglutination, about 50% of black people have stronger B than white people 20 .Results did not show any significant difference between regional distribution & various blood groups at the level of P <0.05.

Discussion
The distribution of ABO blood groups throughout the province of Basrah showed a highest prevalence of O blood group, followed by A and B nearly equally& the least was the AB blood group.The same distribution was seen among both genders with the exception that there was a slightly higher A than B frequency among males while there was a slightly higher B frequency than A among females & & the AB group was slightly less than that of males.These results agreed to some extent with the results of some of local, Arab, neighboring and international studies & differed from some others as well.
The study conducted by Fatihallah.

Table V : Distribution of the ABO blood groups among different districts of Basra Governorate
31 has been noted (Garraty et al., 2004)30that the blood group O is the highest among whites and American Indians in North America (56.5% and 54.6% respectively).WhileMalekasgar (2004)31study among Indians showed that the distribution of ABO groups among males was different than among females where, among males, blood group A was the highest, (36%), followed by the O (30.7%), the B (22.7%) and the AB (10.7%), while among females blood group B was the most common (39.2% 0, followed by the O, (30.4%), the A (26.6%) and finally the AB, (8.9%).AB was the least.Those observations were more or less similar to other local, national registries as well as these registered in the neighboring countries while it was more different than other countries far from Iraq.This may stimulate another study to include racial, other ethnical factors (blacks vs. whites, Kurds vs. Arabs vs. Turks) to notice any difference in the frequency of ABO blood group among them.