Impaired iron uptake and transferrin binding by erythroblasts in the anaemia of rheumatoid arthritis.

Serum and bone marrow from 18 patients with rheumatoid arthritis (RA) and five healthy controls were studied in order to establish a possible role of impaired iron uptake and transferrin binding by erythroblasts in the pathophysiology of anaemia of chronic disease (ACD) in RA. Iron incorporation into erythroblasts was reduced in patients with ACD using a method based on incubation of erythroblasts with radiolabelled 59Fe-125I-transferrin. It correlated negatively with C-reactive protein (CRP). In iron deficient RA patients it tended to be reduced as well. These patients had the same level of RA disease activity as in ACD. Transferrin binding by erythroblasts was significantly impaired in ACD compared to controls, although it tended to be reduced in all RA groups. These findings suggest that impaired iron uptake by erythroblasts, probably due to decreased transferrin binding to erythroblasts, might be a pathophysiological factor in ACD in RA.