THE PHENOTYPE FREQUENCIES OF ABO, Rh, Kell, KIDD AND DUFFY ANTIGENS AMONG BLOOD DONORS IN LAGOS

Abstract

Background Blood group antigens are macromolecules attached to different components of the red cell membrane. They persist throughout life and therefore serve as identity markers. A total of 30 blood group systems are recognized by the International Society of Blood Transfusion (ISBT), some of which are not clinically significant. Clinically significant red cell antigens are those whose antibodies are capable of reacting at body temperature leading to accelerated cell destruction. They include the ABO, Rh, Kell, Kidd and Duffy antigens. Only the A, B and Rh’D’ antigens are routinely tested for in most blood banks in the country. Allo-immunization to red cell antigens contribute to morbidity and mortality in transfused persons. The frequency of the clinically significant red cell antigens and antibodies in a given population determines the availability of compatible blood units for transfusion. Knowledge of blood group cell system is also of biochemical, genetic, immunologic, obstetric, pathologic and forensic interest.

Objective The frequency of the A, B, D, C, c, E, e, K, Jka, Jkb, Fya, Fyb antigens in the blood donor population and their likelihood of causing Haemolytic Transfusion Reaction (HTR) and Haemolytic Disease of the New born (HDN) was determined.

Methodology A total of 350 blood donors were tested. A pre-tested questionnaire was used to collect information on the socio-demographic characteristic and blood donation pattern of it subject. Data derived from the study was subjected to both descriptive and inferential statistics using Epi-info

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version 6.0 with statistical significance set at 0.05. Serological method was used for the determination of the frequency of red cell antigens. The A, B and D antigens were tested using the tube technique. The Rh (C, c, E, e), Kell (K), Kidd (JKa, JKb) and Duffy (Fya, Fyb) was determined by the gel column technique.

Result The median age of the blood donors was 34years with a range of 18 to 57years. About 61% were first time donors. There was a significant association between age and history of previous blood donation (P=0.03). There was also significant association between marital status and previous history of blood donation (p=0.02). About 77% of the blood donors were willing to donate blood voluntarily. There was no association between sex and frequency of the Rh (D, C, c, E, e), Kidd and Duffy antigens. In the ABO system, the prevalence of the O, A, B, AB blood group was 52.6%, 22.7%, 20.6% and 4.0% respectively. About 96.0% of the donors were Rh D positive. The frequencies of the C,c.E,e antigens were13.4%, 98.9%, 24.9% and 96.3% respectively. The frequency of the K, Jka and Jkb antigen was 0.03%, 74.9%, 4.9% respectively. All the blood donors tested negative for the Fya and Fyb antigens.

Conclusion There is need for extended phenotyping for the C, E, Jka antigens in our environment, particularly in patient who will require multiple blood transfusion, to prevent alloimmunization. The Fya, Fyb antigens are unlikely to be the cause of HTR and HDN in our environment.