Discoid lupus erythematosus as part of a larger disease spectrum. Correlation of clinical features with laboratory findings in lupus erythematosus.

This study compares the immunologic features of a homogeneous group of patients with discoid lupus erythematosus (DLE) strictly limited to the skin (group 1) with those of patients with active discoid skin lesions plus visceral involvement (group 2) and with those of lupus erythematosus (LE) patients with proliferative glomerulonephritis (group 3). Positive antinuclear antibody (ANA) was found in 4% of group 1, 93% of group 2, and 100% of group 3. Low total hemolytic complement (CH50) was found in 4% of group 1, 47% of group 2, and 100% of group 3. Antibodies to native DNA (nDNA) were not found in group 1, were rarely found in group 2, and were present in nearly all patients in group 3. No group 1 patient had subepidermal immunoglobulin deposits in normal skin, 20% of group 2 had this finding, and 100% of group 3 had this finding. The ability to develop chronic discoid skin lesions appears to be associated with a reduced incidence of immunologic parameters of disease activity. The data suggest that patients with active discoid skin lesions rarely have severe renal disease.