In-vitro studies of ineffective erythropoiesis in rheumatoid arthritis.

Ineffective erythropoiesis was assessed in a series of 32 patients with rheumatoid arthritis by means of a new in-vitro method which measures the release of haem from a labelled cohort of erythroblasts in culture. Haem release was significantly increased in patients with the anaemia of chronic disorders but was normal in those who were not anaemic or who had an iron-deficiency anaemia. In 2 patients with anaemia of chronic disorders haem release returned to normal after successful antirheumatic therapy. The increased ineffective erythropoiesis in patients with rheumatoid arthritis and anaemia of chronic disorders appeared to be unrelated to functional iron deficiency and was not attributable to a serum factor.