Red blood cell alloimmunization in transfused patients in sub-Saharan Africa: A systematic review and meta-analysis

Abstract Background and objectives Previous studies of Sub-Saharan Africans show significant alloimmunization to red blood cell (RBC) antigens, but country-specific data are limited. Thus, the aim of this study was to estimate, by meta-analysis, the overall proportion of red blood cell alloantibodies among transfused patients. Methods We systematically searched Medline, Embase, and the Africa-Wide Information database to identify relevant studies in any language. Case reports, comments, letters, conference abstracts, editorials, and review articles were excluded. Of the 269 potentially relevant articles, 11 studies fulfilled our selection criteria. Results Overall proportions of alloimmunization were 6.7 (95% CI: 5.7, 7.8) per 100 transfused patients. With regard to antibody specificity, among clinically significant antibodies, anti-E ranked as the most common, followed by anti-K, anti-C and anti-D. Conclusion Meta-analysis of available literature quantifies and qualifies the clinical challenge of RBC alloimmunization among transfused patients in Sub-Saharan Africa. These results should drive policy decisions in favour of routine testing of RBC antigens and irregular antibodies for transfused patients as a standard of care throughout Sub-Saharan Africa.