Predictors of autoimmune hemolytic anemia in beta-thalassemia patients with underlying red blood cells autoantibodies.

In beta-thalassemia patients, erythrocyte autoantibodies can remain silent or lead to Autoimmune Hemolytic Anemia (AIHA).The aim of this study was to identify predictors of AIHA in beta-thalassemia patients with positive Direct Antiglobulin Test (DAT), in Tunisia. This longitudinal prognosis study was carried out on beta-thalassemia patients with a positive confirmed DAT. Predictors of AIHA were identified the Kaplan-Meier method. A Cox model analysis was used to identify independent predictors. Among 385 beta thalassemia patients, 87 developed positive DAT (22.6%). Autoimmune hemolytic anemia was occurred in 25 patients. Multivariate analysis showed that AIHA was independently associated with beta-thalassemia intermedia and similar family history of AIHA. Splenectomy in patients with positive DAT was independently associated with an increased risk of AIHA (HR = 6.175, CI: 2.049-18.612, p < 0.001). The risk of developing AIHA was higher during the first 72 transfusions. Autoimmune hemolytic anemia was significantly associated with polyspecific DAT (anti-complement and anti-IgG), blood group AB and prior alloimmunization. Whereas transfusion by phenotypic and leukoreduced blood was a protective factor. In summary, splenectomy after autoimmunization, prior alloimmunization, DAT specificity (IgG with complement), thalassemia intermedia, AB blood group and family history of AIHA were strongly associated with AIHA. Leukoreduced blood transfusion had a proven preventive role.