Erythropoiesis in the anaemia of rheumatoid arthritis.

Erythropoietic activity and mean red-cell lifespan were measured using 59Fe-transferrin in 32 anaemic patients with active rheumatoid arthritis (RA) and in 20 haematologically normal subjects. Marrow iron turnover (MIT) in the patients was normal and in only 11 was red-cell lifespan less than 70 d. Ineffective iron turnover (IIT) was significantly increased in those patients in whom there was evidence of iron deficiency (serum ferritin less than 12 microgram/l) but in the remaining patients IIT was significantly less than in the normal subjects. In a further 19 patients with simple iron deficiency anaemia IIT was significantly increased. The marrow response to chronic inflammatory disease is clearly distinct from that seen in simple iron deficiency and this suggests different pathogenic mechanisms for these two anaemias.