Clinically significant red cell alloantibodies in patients with warm autoimmune hemolytic anemia

It has been generally accepted that the prevalence of clinically significant red cell alloantibodies is higher in patients with warm autoimmune hemolytic anemia (AIHA) than in other patients. In the present study, immunohematologic testing was performed in 328 polytransfusion patients with internal diseases. The patients were divided into two groups, i.e., without and with clinical signs of warm AIHA. Identification of red cell antibodies was performed in nonadsorbed sera of all patients, and in autoadsorbed and auto- and alloabsorbed sera of patients with warm AIHA. In the AIHA group, antibodies indicating red cell specificity were detected in 38.5% and 24.3% of patients in nonadsorbed and autoadsorbed sera, respectively. Clinically significant red cell alloantibodies were demonstrated in 10.3% nonadsorbed sera of patients free from signs of warm AIHA and in 10.4% auto- and alloadsorbed sera of patients with signs of warm AIHA. Study results showed the prevalence of clinically significant red cell alloantibodies in patients with signs of warm AIHA depend on the method of identification used rather than on the enhanced immune response induced by the autoimmune process.