Cutaneous lupus erythematosus: direct immunofluorescence and epidermal basal membrane study

Biopsy specimens of cutaneous discoid lesions of 71 patients with cutaneous lupus erythematosus (CLE) were studied. The material was examined by direct immunofluorescence (DIF) to establish positivity and morphologic patterns of immunoglobulins and complement deposits in the basement membrane zone (BMZ). A correlation between DIF results and thickening of the epidermis basement membrane (BM) stained by periodic acid-Schiff (PAS), obtained from 31 matched biopsy specimens, also is presented. Direct immunofluorescence had positive results in 66.20% of the 71 examinations and 70.97% of the matched examinations, whereas PAS showed BM thickening in 100% of the specimens. This observation stresses the importance of such histopathologic findings in the diagnosis of discoid lesions in CLE. There was no correlation between DIF patterns and PAS-stained BMZ thickening. These findings merit additional study. In conclusion, an accordance between PAS-stained BM thickening and immunoglobulin deposits has occurred in 70.97% of cases. This phenomenon does not depend on the presence of immunocomplexes, for it occurs even in cases in which immunocomplex deposits were not detected.