Leukocyte colony stimulating factors for rheumatologists.

The leukocyte colony stimulating factors (recombinant granulocyte colony stimulating factor and granulocyte macrophage colony stimulating factor) have become widely used in hematology and oncology to raise neutrophil levels in patients with neutropenia. They have been used primarily by rheumatologists to treat neutropenia accompanying infections in patients with Felty's syndrome or systemic lupus erythematosus and in infected patients made neutropenic with drug therapy. These factors have been lifesaving. The drugs generally are well tolerated and adverse effects usually are easily treated. Some of the adverse effects of the agents may mimic de novo rheumatic conditions such as vasculitis and Sweet's syndrome. There may be important future roles for these growth factors in treatment protocols for patients with rheumatic disease using more aggressive chemotherapy regimens.