SEQUENTIAL ADMINISTRATION OF CYCLOPHOSPHAMIDE AND GRANULOCYTE-COLONY-STIMULATING FACTOR RELIEVES IMPAIRED MYELOID MATURATION IN FELTYS-SYNDROME

A patient with Felty's syndrome (FS) and persistent profound neutropen ia developed recurrent infections and sepsis syndrome. No impairment o f granulocyte-macrophage colony development was observed in vitro. Mar row morphology revealed an absence of mature neutrophil forms despite administration of granulocyte-colony stimulating factor (G-CSF). Howev er, pretreatment with bolus cyclophosphamide (CY) permitted the growth factor to relieve this impairment of late myeloid maturation and resu lted in a brisk, albeit short, burst of neutrophilia. This suggests th at immune interference in myelopoiesis can be overcome by growth facto r administration if immune activity is adequately dampened by immunosu ppressive therapy. (C) 1993 Wiley-Liss, Inc.