Cutaneous vascular immunofluorescence in rheumatoid arthritis. Correlation with circulating immune complexes and vasculitis.

The presence of immunoglobulin and complement in the cutaneous blood vessels of clinically uninvolved forearm skin was studied in 70 patients with rheumatoid arthritis, using immunofluorescent techniques. Patients with evidence of these immune deposits had a greater prevalence of circulating immune complexes, vasculitic skin lesions, subcutaneous nodules, high titer rheumatoid factor and other findings suggestive of active vasculitis. Biopsy of uninvolved forearm skin may be a useful tool in assessing those patients with rheumatoid arthritis suspected of having a systemic vasculitis.