Nature of anaemia in rheumatoid arthritis. XI. Changes in iron metabolism induced by the administration of corticotrophin.

Moderate anaemia of a hypochromic, normocytic type is a common feature of rheumatoid arthritis and disturbance of iron metabolism is a prominent feature of this anaemia. Several previous reports in this series have described abnormalities in the metabolism of iron in this disease (Roy, Alexander, and Duthie, 1955; Richmond, Gardner, Roy, and Duthie, 1956; Richmond, Roy, Gardner, Alexander, and Duthie, 1958; Gardner and Roy, 1961; Owen and Lawson, 1966; Lawson, Owen, and Mowat, 1967), and the present state of knowledge has been reviewed by Mowat and Hothersall (1968). The plasma iron is low in the presence of active disease (Bruzzone and Massimello, 1940; Nilsson, 1948), and the level is well correlated to the activity of the disease (Engstedt and Strandberg, 1966). When the activity of the rheumatoid arthritis is suppressed with corticotrophin or corticosteroids, some aspects of the abnormal metabolism of iron are corrected. An improvement in haemoglobin concentration and plasma iron values has been reported (Hench, Kendall, Slocumb, and Polley, 1949; Fladee, Newns, Smith, and West, 1959; M.R.C. Report, 1959; Strandberg, 1966). The rapid clearance from the plasma of iron given by intravenous injection is restored to the pattern found in healthy controls (personal observations). Owen and Lawson (1966) reported a diminished release of endogenous iron from senescent red cells in patients with rheumatoid arthritis. The abnormality was corrected by the administration of corticosteroids. Richmond and others (1956), using the Prussian blue method, found no stainable iron in the bone marrow of 31 per cent. of patients with rheumatoid arthritis. It is well recognized that only iron in the form of haemosiderin will be detected in this way. In the synthesis of haemoglobin, iron from both ferritin and haemosiderin is utilized (Shoden, Gabrio, and Finch, 1953). It is thus necessary to estimate the total quantity of iron in the bone marrow in any study of iron utilization or storage by the bone marrow. Kerr (1957) has shown that the iron content of the bone marrow in patients with anaemia associated with rheumatoid arthritis is significantly less than that in non-anaemic controls, but not as low as that found in patients with iron deficiency anaemia. The present study was undertaken to assess the effect of corticotrophin on plasma iron values, the urinary excretion of iron, the haemoglobin concentration, and the iron content of the bone marrow in patients with rheumatoid arthritis.