Myelopoietic effect of bone marrow fibroblasts cultured from patients with myelofibrosis.

Bone marrow fibroblasts (BMF) have been shown to be able to support granulopoiesis. The present studies were designed to see whether BMF in patients with agnogenic myeloid metaplasia (AMM) are also able to support granulopoiesis. Myeloid colony-stimulating activity (CSA) was assayed in BMF derived from the three groups of patients. 1) Group I: Patients with hip fracture but without underlying hematological disease; patients with solid tumor but without bone marrow metastasis; and patients with iron deficiency anemia. 2) Group II: Patients with myeloproliferative disorders other than AMM. 3) Group III: Patients with AMM or myelofibrosis with prior history of polycythemia vera. CSA was determined in a bilayer agar culture system in which BMF served as a feeder layer and either mouse or human marrow cells were employed as target cells. There was no difference of CSA production by BMF among these three patient groups. These studies suggest that BMF cultured from patients with myelofibrosis exhibit similar myeloid stimulating activity as do BMF from other patients. A significant correlation was also found between CSA production by BMF and white blood cell counts in patients with myelofibrosis (group III). This suggests that BMF may have a role in either supporting or producing CSA for granulopoiesis in myelofibrosis.