Erythrocyte Alloimmunization in Children With Sickle Cell Anemia in Kilifi, Kenya

Sickle cell anemia (SCA) management in sub-Saharan African relies on transfusion, whose safety is compromised by lack of extended blood group matching beyond ABO and Rhesus D antigens, plus absence of routine alloantibody screening. To determine the incidence of erythrocyte alloimmunization in multiply-transfused children with SCA in Kilifi, Kenya, we retrospectively studied 98 children with SCA, admitted to Kilifi County Referral Hospital from 2003-2023. Plasma samples collected over the follow-up period through a routine ward surveillance study were screened for alloantibodies. Alloantibodies were detected in 14/98 (14.3%) participants and an autoantibody was detected in 1/98 (1.0%). Anti-e was found in two children, while anti-E, anti-M, anti-S, anti-s, anti-Lu^a & anti-Le^b were each found in single individuals. Five children had pan-reactive alloantibodies and three had antibodies of unidentified specificity. Older age was significantly associated with the development of alloantibodies (P = 0.027). Our alloimmunization rate of 14.3% is higher than previously reported from East Africa (2.9-8%). Since most alloantibodies were specific to Rhesus and MNS blood groups, and older age was significantly associated with alloimmunization, this underscores the importance of routine alloantibody screening in multiply-transfused children and suggests the need for extended antigen matching in SCA patients to improve transfusion safety.