RESEARCH PROJECT TOPIC ON
Abo And Rhesus (Rh) Gene Distribution Among Socio-Economic Classes In A Mixed Population In Rivers State, Nigeria
The blood group Rhesus factor of six hundred and thirty one individual (100 females, 531 males) who came to the university of Port Harcourt blood bank and Braithwaite memorial Hospital Blood Bank (also in Port Harcourt) to donate blood were determined. The individuals aware classified into three different socio-economic, classes.
Different theories that points to the fact that a difference should be observed in the distribution of the ABO blood groups among the social classes were discussed.
Analysis of the data revealed that 613 (97.15%) of the total sample were Rh +ve while 18 (2.85%) were rh –ve. 158 (25.04%) of the total sample belonged to the petty Bourgeoisic class, 147 (23.30%) belonged to the working class while 326 (51.66$) belonged to the peasantry class.
There were little differences in the distribution of these various ABO and Rhesis phenotypes among the socio-economic classes. Group A and B were fairly less than expected in the peasantry class. In the working class, group A and B were more than expected while o was less than expected. In the petty Bourgeoisie class, groups A and O were less than expected while group B was more than expected. The percentage of AB individuals in the petty Bourgeoisie class was as expected.
INTRODUCTION AND LITERATURE REVIEW
The human blood groups (ABO) are classified on the basis of antigenic nature of the red cell membrane (Landsteiner 1907). Antigenic specificity are known to be determined by the terminal carbohydrate residues attached to common carbohydrate chains of the red cell surface (Kabat 1956). Specific transferees, that is, N – acetylgalactosaminyi transferees (A –enzyme) in blood group A persons and galactosyltransferase (B – enzyme) are responsible for transferring the carbohydrates to the terminal galactose of the H – substance of the 0 red cell surface with both enzymes absent in group o persons. Recently the blood group antigens have been used as classical markers in studying human populations; thus the terminal gelatos residues remain open, exhibiting blood group o specificity. The blood groups, A, B and O and consequently the expression of the transferees, is highly polymorphic in man.
Although the transmission of A and B enzymes is compatible with mendelian inheritance, it has not been clear whether the expression of these blood transferees is related to allelic structural genes or is under regulatory control.
Blood groups and the underlying antigens were discovered by Landois and ponfick in 1875. They found that red blood cell of a animal of one species were agglutinated when mixed with the serum of an animal of another species (human serum clumps red cell of lower mammals). They also reported that the antibodies responsible for the agglutination increased in titre after immunization (Bordet 1898).
In 1930, karl Landsteiner made the first all-human equivalent of the above observation and therefore the discovery of human ABO blood groups. Karl is said to be the father of blood groups and immunohematology. Karl in 1901 tested the blood specimens from members of his laboratory staff by mixing the serum of each individual with the red cell of each of the other individuals in succession. He noticed strong agglutinations in some, but not in others. On the basis of this reaction he was able to divide human blood into three distinct groups presently designated as A, B, and o. von decastello and sturli (1908) both pupils of karl later discovered the fourth and least frequent group in human populations called AB group. After the discovery of the ABO blood groups, suggestions were made that blood groups were inherited (Epstein and ottenberg 1908) which were later confirmed (von Dungern and Hirszfeld 1910). Opinions as to the precise manner of inheritance varied until Beinstein (1924) brought out the now most acceptable postulate of three alleles A, B and O which fitted best the population and family data.
The proteins in the plasma of red cells of each individual are slightly different from those of everyone else therefore a transfusion can cause an immunotype reaction. From quite soon after birth, an infants plasma develops dantibody – like proteins called agglutins. These will react specifically with proteins in the red cells from some other blood and the resulting immune reaction causes clumping (agglutination) and lysis of the red cells. The red cell proteins involved are the agglutinogens. Fortunately, the agglutin – Agglutinogen reaction is not universal and it is found that human blood falls into 4 groups according to their content of agglutins and agglutinogens.
TABLE 1: AGGLUTINS AND AGGLUTINOGENS FOUND IN THE DIFFERENT BLOOD GROUPS
Type A blood contains A agglutinogens and B – agglutins. Type B blood conteins B agglutinogens and agglutins. If some type B blood cells are introduced by transfusion into type A plasma, then the B agglutins of the A type [lasma react with the B agglutinogens causing clumping of red cells. If the reverse kind of transfusion is made, similar results follow. Type O blood contains neither A nor B agglutingens. Therefore the transfusion of red cells from this blood typoe into either A or B types O individuals are universal donors. However this blood contains both and B agglutins and the transfusion of either type A or B blood into a type O individual will cause agglutination. Group AB is the reverse type of O since it contains both A and B agglutinogens and neither nor B a gglutins. Persons of this blood type can receive a transfusion of any other type since there are nor can receive a transfusion of any other type since there are no agglutins to reacty with whatever agglutinogen may be introduced. They are therefore known as universal recipients.
Besides the four principal blood typoes already described there are many more antigen – antibody groups. One of the more important from the clinical standpoint is the rhesus (Rh) factor, so called because it was first discovered in Rhesus monkeys. The Rh factor is an agglutinogen present in the blood of about 85% of the white population. Those with the agllutinogen are said to be Rh positive.
The rh and Abo blood groups do have selective value by virtue of the mechanism of isosensitization in pregnancy. Thus a group of mother may lose a certain number of group A (genotype AO) and group B (genotype BO) foetusew and similarly a sensitized Rh – ve mother may lose a certain number of Rh +ve babies either from still births or neonatal deaths from Rh hoeemolytic disease. Therefore an equal number of genes o and A or B are lsot in every generation so that in popilations in which gene o frequency is higher than 50%, there would be a tendency after some generations for the genes A and B to be completely eliminated.
On the otherhand, where gene o is less than 50% gene o would tend to be eliminated, leaving only genes A and B behind. Similarly in populations having a grequency of less than 505 for Rh gene, the Rh-ve blood type should eventually be eliminated (wiener 1942). This hypothesis receives support from existence of some tribes of American Indians all of whom are group o and Rh +ve (Landsteiner, ,matson and wiener 1942).
Among the Orangutans and Gibbons only A, B and AB groups occur presumably due to the eliminations of gene o by isosensitization in pregnancy (whiener 1965) migration and crossing over between populations having different blood patterns have accounted for the presence of the 4 Abo blood groups and both Rh +ve and rh –ve blood groups.
Blood groups are of use in clinical pratice (potter 1947), immunohepatology (moore, Humphrey and Lovette-moseley 1968; Zmijewski 1968) transfusions (Mollison 1967), medicolegal aspects of medicine (Race and sanger 1950).
Studies top establish associations between particular blood groups and such diverse conditions as feeblemindedness, syphilis, malaria, dental caries have led to no useful result since no one hs used blood grouping in differential diagnosis that is. The fact that a patient is of blood group a woul;d not affect one’s decision as to whether or not he had a peptic ulcer. Moreover, no one has offered any satisfactory explanation as to how one’s blood group could directly affect one’s susceptibillity to duodenal ulcer or to dcaricinoma, nor how one’s blood group could affect on’s temperament or susceptibility. In contrast to this is the etaclished relationship of blood group incompactibility and erythroblastosis foetalis, blood grouping tests are useful for diagnosis of Rh haemolytic disease or of ABO haemolytic disease, and the results of tests on a single patient are informative, without resources to long series of caes or an elaborate analysis. thus Although the field of blood grouping has made great advances because of the increasing number of facts accumulated through the years (prokop, unlenbruck 1966) it has also move paradoxically backwoards as a results of the existence of a large body of myths, misconceptions, and false information which can be traced to the failure of understanding fundameentals (wiener 1955, 1960, 1961). One such myth led to a number unrewarding studies on the distribution of the ABO blood groups and other blood groups in various diseases and to various claims such as those that blood group o persons are more likely to develop peptic ulcers and adenomas of the pituitary glands than are individuals of thoer blood group o persons are more likely to develop peptic ulcers and adenomas of he pituitary glands than are individuals of thoer blood groups and that group A persons are determined and subject to diseases like pernicious anemia, cancer of the stomach, diabetes mellitus and fractured femurs (wiener 1956, Bourdel 1960, Boyd 1966).
Sex distribution of ABO and Rh blood have also been studied but the results so far have been somewhat incoherent and the evidence accumulated so far has been greatly empirical. There are proportionately more women in group o than men and more men in group A than women in certain areas of England (Fisher and Roberts 1943). This difference was highly significant in south west England but not significant in Yorkshire. Work by Janet vaugan at slough showed no sec defence in the ABO blood group distribution with particular reference to the ratio A: (A + O)
A sampled population at Enugu in the Eastern part of Nigeria showed a 66.6% Rh –ve females and 33.3% Rh –ve males. Male: female = 1:2 )Ikechebelu 1984).
Dawson, working Dublin showed no significant variation in the distribution of the various ABO phenotypes and Rh blood group among the occupational groups studied in county Dublin, though two exceptions were highlighted in both North and sourth city areas where a significantly higher frequency of group A was observed among clerical and professiodnal women blood donors who are manual workers.
Several workers have reported the likelihood of finding genetic differentiation within socially stratified human population, at least form the theoretical point of view (Halsey 1958, Thoday and Gibson 1970, Hernstein 1973, Hensen 1973).
So far, not much work has been done on ABO genes and their distribution in socio-economic groups.
In 1983, Beardmore and Karimi – Booshehri reported that ABO genes are differentially distributed in socio-economic groups in England (South west England and part of Yorkshire) with occupation serving as a criterion for socio-economic classification. Group A phenotype was found to be more and group o less than expected in social classes II to V. they noticed that an individual had about 15% probability than chance dictated of being placed in classes I and II. The Rhesus +ve distribution was not significantly different between the classes. They assumed that this non-random distribution of the ABO phenotypes in the diffent socio-economic groups was not due tyo sampling, historical or migrational effects and therefore concluded that this observed association is likely to result from pleitropic effects of the ABO alleles (or genes closely linked to them). On attributes influencing occupational type, social mobility and social class. Gibson et al 1973 found an association between intelligence quotient Wehsler adult intelligence scale and specific ABO blood group phenotypes.
During the first world war, Hirszfeld and AHirszfeld, 1919 demonstrated for the first time that blood group frequencies differed systematically and significantly between popullations. Since ABO genotype distributions are determined by pedigree studies of the ABO group phenotypes of families, this finding by the Hirszfelds formed the basis for the many studies on blood group distribution in differenct parts of the world. A lot of information on ABO blood group phenotype between the races such as Negroes, caucasioans and Chinese (Mongolinas) are now available. Among these three races, the caucasiona exhibited the greatest degree of polymorphism while the Chinese exhibited the least polumorphism.
Ikechebelu (1973) working at Nsuka, studied the distribution of ABO and rhesus blood groups among Igbos of Eastern Nigeria. He found that group o was highest with 56% followed by groups A 26.5% then group B 15.6% and group AB 1.59%. 95.7% of the sampled population were rhesus positive and 4.3% were rehesus negative.
Associations between the Abo blood groups and different geographical areas have been noted (Mourant 1954, Mourant et al 1958).
Studies on blood group is a very important aspects of medical science. Before the 20th century, lots of deaths most have occurred due to blood transfusion reactions (incompatibility).
Therefore, considering the fact that not many works have been done on blood group distribution as regards social, economic, or cultural groups, this project will serve to investigate whether there are any significant differences in the ABO blood groups and socio economic classes of a small sample of subjects in Rivers state of Nigeria.
KEYWORDS; sc genotype, blood group ss, sc genotype nairaland, characteristics of ss genotype, ac and sc blood group, genotype as and ac, how many genotype do we have, what is genotype cc