Prevalence and specificities of red blood cell alloantibodies in transfused Ugandans with different diseases.

BACKGROUND AND OBJECTIVES: Alloantibody formation against red blood cell (RBC) antigens is a common complication of transfusion therapy. However, the prevalence of RBC alloimmunization is hardly known in Black Africans. In Uganda, the practice is to transfuse ABO/D compatible blood without screening for immune antibodies. The aim of this study was to determine the prevalence and specificities of RBC alloantibodies in transfused Ugandans.

MATERIALS AND METHODS: Using a cross-sectional design, transfused patients at Mulago Hospital in Kampala, Uganda were investigated. Demographic characteristics and transfusion histories were recorded. EDTA blood samples were obtained from consenting patients and RBC alloimmunization was demonstrated using immunohaematological tests.

RESULTS: A total of 214 transfused patients (mean age, 30.3 years; F/M ratio, 1.0) were investigated. Thirteen patients (6.1%) possessed RBC alloantibodies whose specificities were six anti-E; three anti-S; one each of anti-D, -K and -Le(a); and two samples were pan-reactive. Eleven (84.6%) of the alloimmunized patients had experienced up to 10 transfusion episodes. The number of units of blood transfused and the transfusion episodes were significantly associated with the RBC alloimmunization rate (P = 0.01).

CONCLUSIONS: The prevalence of RBC alloimmunization in transfused Ugandans was 6.1% and was associated with the number of donor exposures. This immunization rate is similar to that observed in transfused Caucasians despite differences in RBC antigen distributions. Patients with malaria were less likely to develop RBC alloantibodies. Alloantibodies were mainly against E and S antigens. We recommend the introduction of pretransfusion antibody tests in Uganda depending on the recipient's diagnosis.