Red Blood Cell Alloimmunization in Patients with Sickle Cell Disease from Abha, Asir Region, Saudi Arabia

Background. Red blood cell (RBC) transfusion is a mainstay of treatment for sickle cell disease (SCD), but is associated with alloimmunization, leading to delayed hemolytic transfusion responses and limiting availability of suitable blood. There is little regional data from the south of Saudi Arabia. Method. This cross-sectional study was performed in Abha, Asir Region, from 2018 to 2020. Two hundred patients aged 14–69 years with SCD were examined for RBC alloantibodies. Blood samples were screened for antibodies and phenotyped (ABO; Rh D, C, c, E, e; K; Fya, Fyb; Jka, Jkb; Lea, Leb; M, N, S, s) using the gel method on an automated platform (Ortho Clinical Diagnostics). Results. Alloantibodies were detected in 29 of 200 patients (14.5%; 95% CI 10.3 to 20.0%): 16 of 116 males (13.8%) and 13 of 84 females (15.5%). Fifteen of the twenty-nine had multiple antibodies. The most prevalent specificity was anti-E (17 patients, 58.6% of positives) followed by anti-K (11, 37.9%), anti-c (7, 24.1%) and anti-C (4, 13.8%). In 27 of 29 (93.1%) Rh‐ or K‐positive individuals, antibodies to these antigens were detected. Positive individuals had received a median of 12 transfusions (range 5-26). Conclusions. In Abha, approximately one in seven SCD patients who had transfusion were alloimmunized largely against Rh (E, c, C) and Kell (K) antigens. Further large prospective trials are suggested, along with prophylactic Rh and K matching, preferably prolonged matching, and leukoreduced units.