IL-6-INDUCED ANEMIA IN RATS - POSSIBLE PATHOGENETIC IMPLICATIONS FOR ANEMIA OBSERVED IN CHRONIC INFLAMMATIONS

Anaemia of chronic disease (ACD) is frequently found in rheumatoid art hritis (RA). In the pathogenesis of ACD both cytokines, such as tumour necrosis factor-alpha (TNF-alpha), IL-1 and IL-6 as well as a relativ e deficiency of erythropoietin (EPO), are thought to play a key role. In the present study the role of IL-6 in the pathogenesis of this anae mia was investigated. IL-6 was administered intraperitoneally to rats for 14 sequential days. It appeared that IL-6 was able to induce anaem ia. No evidence for suppression of bone marrow erythropoiesis or enhan ced sequestration of erythrocytes in the liver was found. However, dec reased plasma and bone marrow iron contents were observed in anaemic r ats. Blood loss in intestinal tissue was demonstrated using erythrocyt e labelling with (99m)technetium. Histologically this was associated w ith inflammatory cell infiltration, oedema and bleeding in the intesti nal wall. In conclusion, IL-6 induced anaemia in rats. This anaemia wa s caused by intestinal blood loss.