Abstract
A 12-year-old male child was presented in the emergency with features of anemia and mild icterus on day+67 of HSCT. The child was suffering from Fanconi anemia and undergone HSCT from ABO-matched, fully HLA matched sibling donor. The diagnosis of mixed type AIHA due to cytomegalovirus reactivation was made in the immunohematology laboratory and blood group discrepancy was the first sign of AIHA in this patient. Though the cold agglutinin titer was not significant but the clinical symptoms and laboratory evidences were suggestive of significant hemolysis due to underlying IgG autoantibody. In addition the high complement avidity of IgM autoantibody might also be a contributing factor for clinically significant hemolysis in this case. The patient was successfully treated with phenotype matched blood transfusion, rituximab and oral steroid therapy.