Five cases of autoimmune neutropenia in infancy or early childhood.

Five cases of chronic neutropenia which developed mainly in infancy were investigated and followed up for 5 to 34 months. Antineutrophil antibody levels were assayed by the direct and indirect immunofluorescence methods using flow cytometry. Selective neutropenia, myeloid hyperplasia and/or maturation arrest of myeloid series cells in the bone marrow, and the demonstration of antineutrophil antibody in the sera and on autologous neutrophils, indicated that the neutropenias involved were autoimmune in nature. Two cases exhibited spontaneous recovery 12 and 14 months respectively after the diagnosis, with concomitant marked decreases in antineutrophil antibody levels. Our study of these five cases supports the view that this disorder may be a clinical entity with a relatively consistent clinical presentation and course. Within this framework of the disorder, however, a clear heterogeneity in clinical presentation and course was also noted in our cases. Clinical severity in this disorder may be enhanced by arrested maturation of myeloid series cell in the bone marrow.