Bone marrow fibroblast function in relation to granulopoiesis in aplastic anaemia.

Fibroblasts grown from the bone marrow of normal individuals and incubated with colony-stimulating factor (CSF) enhance the stimulating activity of this CSF on granulocyte-macrophage colony-forming cell (GM-CFC) proliferation. For this study, the ability of fibroblast monolayers grown from the marrows of six patients with severe aplastic anaemia to increase the activity of CSF has been compared with the activity of normal fibroblasts. Tests of this function showed subnormal CSF-enhancing activity by fibroblasts grown from the marrows of three of the six aplastic patients. Since cultured bone marrow fibroblasts are thought to represent an important component of the haemopoietic microenvironment, the results suggest that some of the patients had a microenvironmental abnormality at the time of study. One of the patients whose fibroblasts were abnormal was reinvestigated after he had been given a graft of allogeneic bone marrow cells. His post-graft fibroblast function was normal, showing that the abnormality was reversible.