A Case of Combined Autoimmune Neutropenia and Thrombocytopenic Purpura : Identification of Autoantibodies against Specific Antigens

Abstract

There have been few reported cases of autoimmune neutropenia combined with thrombocytopenic purpura with clearly identifiable autoantibodies against specific antigens. We here describe the case of 6-month-female with autoimmune neutropenia and thrombocytopenic purpura in whom we were able to identify autoantibodies against NA1 antigen of neutrophils, and GPIIb/IIIa and GPIb/IX antigens of platelets at her acute stage. Virologic studies including parvovirus B19, cytomegalovirus, and Epstein-Barr virus were all negative. Following treatment with 1 g/kg γ-globulin, platelet counts increased gradually and reached the normal level at 3 months. Neutrophil counts were refractory to the γ-globulin treatment, but they exceeded 500 /μl at 5 months, and the patient did not suffer from any serious infection by prophylactic administration of sulfamethoxazole and trimethoprim. A review of the Japanese literature revealed that the occurrence of autoimmune cytopenia has two age peaks, one at around 1 year and one after 10 years, and the latter cases tend to have certain underlying disorders.