Predictors of red cell alloimmunization in multitransfused Egyptian patients with β-thalassemia.

CONTEXT: Thalassemia is a major health problem in Egypt. Red blood cell alloimmunization is an important complication in transfusion-dependent patients.

OBJECTIVES: To determine alloimmunization prevalence in Egyptian patients with β-thalassemia and to evaluate risk factors that could influence alloimmunization, with the hope of minimizing transfusion-associated risks in those patients.

DESIGN: Records of 272 patients with β-thalassemia who are receiving regular blood transfusions, matched for ABO-Rh(D), were analyzed. Alloantibody identification was performed by DiaMed-ID microtyping system. Autoantibodies were detected by direct Coombs test.

RESULTS: Alloimmunization incidence was 22.8% with 123 alloantibodies detected in 62 patients. The most common alloantibody was Rh-related (37.4%; 46 of 123), comprising anti-E (14.6%; 18 of 123), anti-D (8.9%; 11 of 123), anti-C (8.9%; 11 of 123), and anti-c (4.9%; 6 of 123), followed by anti-Kell (26%; 32 of 123), → anti-MNS (9.8%; 12 of 123), → anti-Kidd (8.9%; 11 of 123) → anti-Duffy (8.1%; 10 of 123), → anti-Le (5.7%; 7 of 123), → anti-Lu (2.4%; 3 of 123), and → anti-P1 (1.6%; 2 of 123). Anti-D antibodies developed in 34.5% of all Rh-negative patients. Eighty percent of all anti-D antibodies developed in patients older than 18 years. Males had the highest alloimmunization incidence. Alloimmunization incidence increased with the number of units transfused (P = .01). Patients who received unfiltered blood had a higher alloimmunization rate than did those who always received leukoreduced blood (P < .001). Splenectomized patients had a higher alloimmunization rate (32%; 40 of 125) than did those who did not have a splenectomy (16.3%; 24 of 147; P = .003). Autoantibodies occurred in 1.5% (4 of 272) of all patients.

CONCLUSION: Transfusion of leukoreduced and phenotypically matched cells for selective antigens may help reduce expenses and risks of alloimmunization in patients with thalassemia.