Autoimmune neutropenia with cyclic oscillation of neutrophil count after steroid administration.

A 16-year-old female patient was evaluated for pancytopenia. She had a white blood cell count of 1.6 x 10(9)/L with 0.02 neutrophils and a platelet count of 19 x 10(9)/L. In the bone marrow, mature granulocytes were markedly decreased in number, but no atypical cells were present. Antineutrophil antibody was demonstrated by flow cytometry, and the level of platelet-associated immunoglobulin G was increased. A diagnosis of autoimmune neutropenia and thrombocytopenia was made. Interestingly, neutrophil and platelet counts fluctuated cyclically after the initiation of prednisolone therapy. The neutrophil count fluctuated between 0.1 x 10(9)/L and 7 x 10(9)/L, and the platelet count fluctuated between 19 x 10(9)/L and 175 x 10(9)/L, in 4-week cycles. Following splenectomy, neutrophil and platelet counts normalized. We believe the immune mechanism of recurrent neutropenia in this patient differs from that in other patients with cyclic neutropenia reported with stem cell disorders.