Cellular distribution of platelet-derived growth factor, transforming growth factor-beta, basic fibroblast growth factor, and their receptors in normal bone marrow.

We performed an immunohistochemical study on 5 normal marrow samples and 3 fibrotic marrow samples to investigate the cellular distribution of various isoforms of platelet-derived growth factor (PDGF), transforming growth factor-beta (TGF-beta), basic fibroblast growth factor (bFGF), and their corresponding receptors. Immature hematopoietic precursors strongly expressed PDGF-B, all the TGF-beta isoforms, PDGFRbeta, TGFbetaRI and II, and FGFR1, 3, and 4. Megakaryocytes stained primarily for PDGF-B, TGF-beta2-3, and PDGFRbeta. Histiocytes displayed intense TGF-beta1, bFGF, and FGFR2 expression. Fibroblasts and endothelial cells carried receptors for all the aforementioned cytokines. The last 2 cell types also expressed the ligand cytokines to varied degrees.