Abstract
Autoimmune neutropenia (AIN) is a common form of neutropenia in infancy and early childhood. AIN in childhood is primarily characterized by increased destruction of neutrophils as a result of antineutrophil antibodies against neutrophil antigens. Several human neutrophil antigens (HNA) have been recognized and classified. Antineutrophil antibodies are detected by the combination of granulocyte immunofluorescence test and granulocyte agglutination test. Antineutrophil antibodies are detected in 50 to 70% of patients with chronic benign neutropenia and HNA-1 is a frequent target of autoantibodies. In our laboratory several monoclonal antibodies are developed to recognize neutrophil antigens. A spontaneous resolution of neutropenia associated with the disappearance of neutrophil autoantibodies is observed within several months to a few years in the majority of children with AIN. The clinical course of infants with AIN showed the efficacy of the prophylactic use of SMX-TMP on the incidence of infection during neutropenic periods. From a study that quantified the strength of antineutrophil antibodies, the duration until spontaneous resolution of neutropenia was dependent on antibody strength at the time of diagnosis. The quantification of antineutrophil antibodies is useful for considering the diagnosis of AIN and considering the clinical course of neutropenia in childhood. In this article, we describe the clinical characteristics of AIN in childhood based on our evidence.
