Studies in cutaneous immunofluorescence. II. Histological and direct immunofluorescence observations in clinically normal skin of patients with rheumatoid arthritis.

Twenty patients with rheumatoid arthritis (RA) had a biopsy taken from clinically normal skin. These were examined for histological and immunological abnormalities and were compared to those of 8 patients with osteoarthritis (OA). No 'lupus band; linear deposition of immunoglobulin or complement at the dermo-epidermal interface was seen in any patient in either group. Perivascular deposits were seen in 5 out of 20 (25%) patients with RA. These were IgM in all 5 cases with additional C3 in 2 cases (10%) and additional fibrin in one case (5%). No immunoprotein deposits were seen in specimens from any OA patient. 4 of the 5 patients with perivascular immunoprotein deposits had circulating ANAs present and dilutions of 1/256 or higher but normal DNA binding. A sparse perivascular, predominantly lymphocytic infiltrate was seen in 13 out of 20 (65%) patients with RA and 3 of 8 (35%) patients with OA.