Peripheral blood mononuclear cells from patients with rheumatoid arthritis suppress erythropoiesis in vitro via the production of tumor necrosis factor alpha

Abstract

Anemia is a frequent manifestation of rheumatoid arthritis, with a probably multifactorial etiology. We investigated the effect of peripheral blood mononuclear cell supernatants (PBMCS) from rheumatoid arthritis (RA) patients on hematopoietic colony formation in vitro, by using a methylcellulose assay. PBMCS from patients suppress in vitro erythroid (BFU-E), mixed-lineage (CFU-GEMM) and to a lesser degree granulocyte-macrophage (CFU-GM) progenitors. PBMCS from anemic RA patients were more suppressive for BFU-E than those from non-anemic patients. Addition of antibodies to tumor-necrosis factor alpha (TNF alpha) almost completely reversed the inhibition of BFU-E and CFU-GEMM, but had little effect on the CFU-GM colony formation. Antibodies to interferon-gamma (IFN gamma) and interleukin-1 (IL-1) were not effective. The above data suggest that PBMCS from RA patients suppress in vitro erythropoiesis via the production of TNF alpha; a pathogenetic role for TNF alpha in the anemia of RA can be implied.