Flare of arthritis with successful treatment of Felty's syndrome with granulocyte colony stimulating factor (GCSF).

A 58-year-old white male with Felty's syndrome was successfully treated with granulocyte colony stimulating factor (GCSF). GCSF can correct the granulocytopenia of Felty's syndrome and may be a beneficial therapeutic adjunct in patients who have serious infections associated with neutropenia. The patient developed a flare of arthritis concomitant with increased circulating neutrophils following GCSF therapy.