Nature of anaemia in rheumatoid arthritis. 8. Iron content of synovial tissue in patients with rheumatoid arthritis and in normal individuals.

Moderate anaemia of a hypochromic, normocytic type is a common feature of rheumatoid arthritis (Freireich, Ross, Bayles, Emerson, and Finch, 1957a). Disturbance of iron metabolism is a prominent feature of this anaemia. The plasma iron is low in the presence of active disease (Bruzzone and Massimello, 1940: Nilsson, 1948), but there is no significant increase in the plasma iron-binding capacity (Jeffrey, 1953; Roy, Alexander, and Duthie, 1955). A rise in the plasma iron and haemoglobin levels occurs when the activity of the rheumatoid arthritis is suppressed by adreno-corticotrophic hormone (ACTH) or corticosteroids (personal observations). Roy and others (1955) and Weinstein (1959) demonstrated no abnormality in iron absorption from the gut in patients with rheumatoid arthritis, but Raymond, Bowie, and Dugan (1965) suggested that there was a mild impairment of absorption. There is no abnormal loss of iron in the urine of these patients (Lawson, Owen, and Mowat, 1967). Gastrointestinal blood loss occurs in patients who take salicylates (Scott, Porter, Lewis, and Dixon, 1961), but Baragar and Duthie (1960) found no evidence to suggest that continued salicylate therapy enhanced the degree of anaemia in patients with rheumatoid arthritis. There is a rapid clearance from the plasma of iron given by intravenous injection in patients with rheumatoid arthritis (Roy and others, 1955; Freireich and others, 1957a; Weinstein, 1959). When the activity of the disease is suppressed by the administration of ACTH, the clearance of saccharated oxide of iron is restored to the pattern found in control subjects (personal observations). Using small amounts of transferrin-bound "9Fe, a number of observers (Freireich and others, 1957a; Weinstein, 1959; Raymond and others, 1965) have