IRON DEPOSITS AND CATABOLIC PROPERTIES OF SYNOVIAL TISSUE FROM PATIENTS WITH HEMOPHILIA

Haemophilic arthropathy is characterised by iron deposits in synovial tissues. We investigated the suggestion that iron plays an important r ole in synovial changes. We obtained synovial tissue from six patients with haemophilia during arthroplasty, finding that brown haemosiderit ic tissue was often adjacent to tissue with a macroscopically normal a ppearance in the same joint. Samples from both types of synovial tissu e were analysed histologically and biochemically to determine cataboli c activity. Macroscopically haemosideritic synovium showed a significa ntly higher inflammatory activity than that with a normal appearance. Cultures of abnormal synovial tissue gave a significantly enhanced pro duction of IL-1, IL-6 and TNF alpha compared with cultures of synovial tissue with a normal appearance. In addition, the supernatant fluids from the cultures showed greater catabolic activity from haemosideriti c tissue, as determined by the inhibition of the synthesis of articula r cartilage matrix. We conclude that in patients with haemophilic arth ropathy, local synovial iron deposits are associated with increased ca tabolic activity.