The significance of cutaneous immunoglobulin deposits in lupus erythematosus and NZB/NZW F1 hybrid mice.

In 50 to 60 percent of patients with systemic lupus erythematosus (SLE), a band of immunoglobulins beneath the epidermis of visibly normal skin. This highly specific finding has been used as a diagnostic test (Lupus Band Test) for SLE. Similar immunoglobulin deposits are found in an inbred strain of New Zealand mice which spontaneously develop an autoimmune disease with many features of SLE. Subepidermal immunoglobulin deposits are found most frequently in SLE patients with proliferative glomerulonephritis, hypocomplementemia, and serum antibodies to native DNA (anti-nDNA). When anti-nDNA levels are suppressed by cyclophosphamide, these deposits disappear. The subepidermal accumulation of immunoglobulin in SLE patients and in the mouse model apparently depends on the presence of antibody to native DNA. It is proposed that serum anti-nDNA precipitates with nDNA which is released locally from epidermal nuclear breakdown.