Skin immunopathology in system lupus erythematosus.

The role of skin immunopathology in the evaluation and management of patients with systemic lupus erythematosus (SLE) remains controversial. Four simultaneous biopsy specimens from nine patients with SLE (two from buttock and two from forearm skin) were evaluated. Specimens from eight of nine patients showed symmetrical deposits. A poor correlation of skin biopsy score and clinical activity score was noted. A positive correlation was noted between serum C3 levels and skin biopsy score, but a poor correlation was noted with criteria for active nephritis with the exception of microscopic hematuria. In most instances, findings from a single skin biopsy specimen are sufficient and of diagnostic value but correlate poorly with other measurements of disease activity. Serial studies suggested that persistence of cutaneous deposits for many months after flares of SLE may in part explain poor correlation with active disease.