Prevalence of Anti Erythocyte Alloimmunization to Sub-Saharan African Blood Donors

A part from any incompatible blood transfusion, anti-erythrocyte alloimmunization is observed to pregnant women. It is the result of the passage of red blood cells carrying antigens different from those of the mother during pregnancy and delivery. The Rhesus D system is the most involved; but there are also other systems involved in this alloimmunization. Non-transfusion alloimmunization is an extremely rare event in the order of 1 of 4000 to women in Europe and in most cases concerns the Rhesus D. In sub-Saharan Africa, there are no statistics collected on foeto-maternal alloimmunization. As part of our postgraduate thesis on the sensitization status of red blood cells to acridine, we used the technique of looking for irregular agglutinins. The goal was to find anti-erythrocyte alloimmunization to blood donors in sub-Saharan Africa. We conducted a two-year multicenter prospective and descriptive study of 903 blood donors in Cote d'Ivoire, Benin and Cameroon. The samples were analyzed in the laboratories of the National Blood Transfusion Center of Cote D'Ivoire and Frankfurt according to the technique of the RAI gel card of the BIORAD company after centrifugation and incubation using test red cells treated with S-303. In the case of a positive reaction, identification is made by a panel of red blood cells in the different blood group systems. In our study population, there is a male predominance with a male/female ratio of 7.42. We found a very low prevalence of alloimmunization to non-transfused blood donors (0.9% or 8 cases out of 902). 4 anti-erythrocyte antibodies have been identified (1 Ac anti D and 3 AC anti S); 2 pan-agglutination, 2 unidentified Ac (insufficient serum) and suspicion of anti-glutathione. Anti-erythrocyte alloimmunization to sub-Saharan Africa blood donor is about 0.9% in our series. It remains high compared to European data. This alloimmunization is mainly observed to women with low frequency antigens to black peoples.