Polymyalgia rheumatica (PMR): clinical, laboratory, and immunofluorescence studies in 13 patients.

Thirteen elderly patients with polymyalgia rheumatica (PMR) are presented. The clinical and laboratory findings suggest that many progressive symptoms are due to the non-specific inflammatory changes in various organs of the body, especially in muscles and joints. An immunofluorescence study of muscle biopsy specimens revealed IgG, IgA, and fibrinogen deposits in the perifascicular area of the perimysium. This finding suggests that immune complexes play a role in the pathogenesis of this condition and that the pathophysiology of PMR is an interstitial inflammatory process. We think that the inflammatory findings affecting the interstitial tissue of muscles in the immunofluorescence study are relatively specific to PMR, and will be affected by steroid treatment.