Evidence supporting a role for immune complex-mediated inflammation in the pathogenesis of bullous lesions of systemic lupus erythematosus.

Evidence supporting an immune complex pathogenesis of bullous lesions in systemic lupus erythematosus includes immune deposits, acute inflammation, and blister formation at the cutaneous basement membrane zone. Since cutaneous immune deposits are a general feature of lupus, an attempt has been made to determine whether deposits in lupus patients with blisters are functionally different from those in patients without blisters. Skin was obtained from 4 consecutive patients with blisters and 14 controls. The groups were matched for clinical and serologic features, duration and activity of disease, and treatment. Skin was examined by direct immunofluorescence for immune deposits and by the leukocyte attachment assay for quantification of complement-activating immune complexes. Clinically normal, viable skin from 1 patient with blisters and 1 patient without blisters was incubated in organ culture with normal human leukocytes and serum complement. All patients in both groups had immune deposits at the basement membrane zone with an equivalent incidence of the major Ig classes. Deposits in patients with blisters were slightly more intense and a linear pattern of fluorescence seen in 75% of these patients was not seen in controls. The leukocyte attachment assay showed significantly greater (p less than .02) cell attachment in patients with blisters (mean = 167) than in patients without blisters (mean = 64) and greater cell attachment in peribullous than normal skin from the same patient. Organ culture showed complement-dependent migration of leukocytes and histologic features similar to those in spontaneous lesions in skin from the patient with blisters but not in skin from the patient without blisters. These results provide evidence supporting immune complex and complement-dependent inflammation in the pathogenesis of bullous lesions in systemic lupus erythematosus.