Prevalence and risk factors for red blood cell alloimmunisation among sickle cell patients in Mwanza City, Tanzania

Erythrocyte alloimmunisation can lead to complications such as delayed haemolytic transfusion reaction. Objective This study investigated the prevalence of and risk factors for red blood cell alloimmunisation among multiply transfused sickle cell disease (SCD) patients in Mwanza City, Tanzania. Methods From May 2017 to July 2017, this descriptive, cross-sectional, hospital-based study enrolled 200 participants with SCD who had received at least two units of blood in the previous year. Blood count was performed using a Sysmex haematology analyser. Antibody screening was done by the tube method using a panel of three screening cells with known antigenicity. Results Of the 200 patients enrolled, 108 (54%) were female. The median age was 4.5 years (interquartile range [IQR] = 6), the median number of transfusions was 3 (IQR = 1), and the median pre-transfusion haemoglobin level was 6.6 g/dl (IQR = 2.7). Prevalence of alloimmunisation was 8.5% (17/200) with immunoglobulin G, and one patient developed cold immunoglobulin M antibodies. Blood groups reported were Rhesus C and E, Kell, Kidd and Duffy. There was no statistically significant association between the number of transfusions and the risk of alloimmunisation. Conclusion The rate of alloimmunisation in multiply transfused SCD patients was 8.5% and higher than other studies in East Africa. Thus, there is a need for extensive red blood cell screening and matching to minimize alloimmunisation and risk of delayed haemolytic transfusion reaction, particularly in SCD and chronically transfused patients.