Cyclosporine for the treatment of granulocytopenia in Felty's syndrome.

A patient with Felty's syndrome was treated with cyclosporine, initially 10 mg/kg/day and then 4 mg/kg/day. The neutrophil count increased by 6 weeks and was normal at 3 months. Over the subsequent 27 months the neutrophil count was closely related to the cyclosporine dosage and there was no evidence of cyclosporine toxicity. This case indicates that cyclosporine may have a role in the treatment of Felty's syndrome.