Digital ulcers/gangrene and immunoglobulin classes/complement fixation of anti-dsDNA in systemic lupus erythematosus patients.

The immunoglobulin classes/complement fixation of anti-dsDNA were studied in sera obtained from 17 systemic lupus erythematosus (SLE) patients with digital ulcers and/or gangrene (Group A); 13 SLE patients with leg ulcer, peripheral neuropathy or livedo (Group B); 24 SLE patients with Raynaud's phenomenon (Group C); and 18 SLE patients with active lupus nephritis (Group D). Antibodies to dsDNA of IgG and IgA classes were commonly present (often in high titers) in Groups A and D. However, complement fixation of anti-dsDNA was more common in Group D than in any of the other 3 groups.