Penicillin-induced immune hemolytic anemia. Occurrence of massive intravascular hemolysis.

A patient with penicillin-induced immune hemolytic anemia had massive intravascular hemolysis with hemoglobinemia and hemoglobinuria. Substantial amounts of complement components C3 and C4 were detected on the patient's red blood cells (RBCs), in addition to the usual IgG antibody to penicillin. The patient's serum demonstrated a high titer of antibody to penicillin (8,000), which did not cause hemolysis in vitro, but did cause complement fixation when incubated with normal serum. The presence of complement components on the patient's RBCs, and the finding that the serum fixed complement in vitro suggests that penicillin-antipenicillin immune complexes may have been present in the serum. We attribute the severity of the hemolysis to participation of the complement system in the hemolytic process and to the high titer of antibody to pencillin.