Recently a non-toxic system for whole body hyperthermia (WBH) used at the University of Wisconsin has been shown to induce soluble tumor necrosis factor-receptor (sTNF-R) I and II when patients are heated systemically to 41.8C for 60 minutes. This observation might provide a biological basis for the therapeutic application of WBH to rheumatoid diseases, for which there is a positive anecdotal clinical experience. Inherent in the hypothesis which is the basis for this protocol is the concept that the induction of TNF receptors by WBH may induce a remission in patients with active rheumatoid arthritis. Beyond clinical response the biological endpoint for this investigation includes cytokine levels, TNF levels, sTNF-R levels and changes in cellular TNF receptors.