Bone Marrow Fibroblastoid Colony-Forming Cells (F-CFC) in Aplastic Anaemia: Colony Growth and Stimulation of Granulocyte-Macrophage Colony-Forming Cells (GM-CFC)

S ummary . Colonies of fibroblast-like cells have been grown from the mononuclear cell fractions of bone marrow aspirated from normal individuals and patients with aplastic anaemia. Some of the characteristics of the fibroblastoid cells have been determined and their granulocyte-macrophage colony-stimulating activity (CSA) in semi-solid agar culture has been used as a functional test of their influence on granulopoiesis.
The incidence and growth rates of fibroblastoid colony-forming cells (F-CFC) from aplastic patients'bone marrows were not markedly different from normal either before or after treatment by allogeneic bone marrow transplantation or with antilymphocyte globulin (ALG).
Confluent monolayers of fibroblastoid cells grown from normal marrow were, on the whole, poor stimulators of granulocyte-macrophage colony-forming cells (GM-CFC) and CSA was not detected in the supernatant medium. Fibroblastoid monolayers derived from many of the aplastic bone marrows studied were efficient stimulators of GM-CFC but, like the monolayers grown from normal cells, did not release CSA into the culture medium.
Addition of methylprednisolone (MP) to the cultures had little effect on fibroblastoid cell growth, induced fat-accumulation by some of the fibroblastoid colonies comprising the monolayer and reduced the abilities of the monolayers to stimulate GM-CFC.