[Primary chronic autoimmune neutropenia successfully treated with sirolimus]

We report a 74-year-old man with severe chronic primary neutropenia (neutrophil count: 390 per millimeter cube) uncovered following surgery for perianal abscess collection. Clinical, laboratory and roentgenographic findings revealed no abnormality. Antineutrophil antibodies were positive in two consecutive serum samples. Under cyclosporine, neutrophil count reached 1970 per millimeter cube. However, this therapy was discontinued due to new onset of severe renal failure. After six weeks, neutrophil count was 950 per millimeter cube and sirolimus was started, resulting in renal function improvement and resolution of neutropenia.