Steroid responsive cyclical neutropenia.

A 19-year old girl with severe cyclical neutropenia associated with life-threatening infection and who responded dramatically to the administration of oral prednisolone is described. During reduction and eventual cessation of steroid therapy normal or near normal neutrophil counts have been maintained, and there has been parallel improvement in clinical well-being. Prior to therapy and at a time of peak blood neutrophil count low numbers of granulocyte-macrophage progenitor cells (CFU-C) were found in the patient's bone marrow, and her lymphocytes co-cultured with normal marrow failed to show the inhibitory effect normally seen with normal lymphocytes. The findings in this patient are compared with those in the two other cases where cyclical neutropenia has been shown to respond to steroids.