Warm autoimmune hemolytic anemia with mimicking anti-c and -E specificities

An 18-month-old male was admitted to a hospital with a hemoglobin of 4.1 g/dL and a reticulocyte count of 53 percent. There was no history of prior transfusion. Serologic evaluation revealed the presence of both a positive direct antiglobulin test (DAT) and an indirect antiglobulin test (IAT). The patient’s red blood cells (RBCs) typed as group A, C–D–E–c+e+ (cde/cde). Evaluation of the IAT revealed the presence of anti-c and anti-E. All other major antibodies were ruled out. Upon adsorption of the patient’s serum with ficin-treated Cde/Cde RBCs, both antibody specificities were adsorbed; however, the antibodies were not adsorbed with native (untreated) Cde/Cde RBCs. Furthermore, the autoantibody was not adsorbed by Rh_null cells, thereby suggesting Rh specificity. The serum was incompatible with cde/cde RBCs and compatible with Cde/Cde RBCs. The patient was successfully transfused with Cde/Cde RBCs followed by resolution of his anemia, as evidenced by an increased and stable hemoglobin. It was concluded that the autoantibody had mimicking anti-c and -E specificities. This is a report of an unusual case of autoimmune hemolytic anemia because the Rh autoantibody appeared to have dual mimicking specificities, and the patient’s RBCs were antigen negative for one of the antibody specificities, i.e., anti-E. Immunohematology 2002;18:19–22.