R-h-erythropoietin counteracts the inhibition of in vitro erythropoiesis by tumour necrosis factor alpha in patients with rheumatoid arthritis.

Anaemia of chronic disease (ACD) is a common extra-articular manifestation of rheumatoid arthritis (RA). Tumour necrosis factor alpha (TNF alpha) plays an important role in the development of ACD. The objective of the present study was to assess inhibition of in vitro colony-forming unit erythrocyte (CFUe) and blast-forming unit erythrocyte (BFUe) growth by TNF alpha and to examine whether this suppression could be counteracted by adding increasing concentrations of recombinant human erythropoietin (EPO) (r-h-EPO) to bone marrow cultures of RA patients with ACD and without anaemia (controls). Bone marrow cells of RA patients with ACD and control patients were cultured. The cultures were incubated with increasing concentrations of r-h-EPO (0.25; 0.5; 1; 2 U/ml), each in combination with increasing quantities of TFN alpha (0; 50; 100; 200; 400 U/ml). CFUe and BFUe were assessed after 7 and 14 days, respectively. Dose-dependent inhibition of BFUe and CFUe by increasing concentrations of TNF alpha was observed in ACD and controls. Regarding CFUe (ACD patients) incubated with 0.25 U/ml EPO, 50 U/ml TNF alpha caused 28% suppression compared to cultures without TNF alpha. Increasing the concentration of r-h-EPO from 0.25 U/ml to 2 U/ml completely restored the number of CFUe. A similar pattern was observed in BFUe growth in both groups. These data demonstrated the suppressive effects of TNF alpha on erythropoiesis in vitro and that the suppressed erythropoiesis could be partly corrected by the addition of excess r-h-EPO to the cultures. No significant differences were observed between ACD and control RA patients.(ABSTRACT TRUNCATED AT 250 WORDS)