Occurrence of positive immunofluorescence in the dermo-epidermal junction of sun-exposed skin of normal adults.

A bright, continuous, granular deposition of immunoreactants at the dermo-epidermal junction (DEJ) of lesional skin is highly suggestive of cutaneous lupus erythematosus (LE). A recent study of the direct immunofluorescence (IF) of sun-exposed skin in normal adults has demonstrated findings similar to the bright, continuous granular pattern found in cutaneous LE. This data suggests that positive IF from sun-exposed cutaneous lupus lesions is nonspecific. Forty-one healthy adults, without a history of dermatoses or photosensitivity, presenting to the dermatology clinic for the excision of skin cancers were studied. Excess non-lesional tissue, removed from Moh's excision sites (sun-exposed face and neck) in order to obtain appropriate cosmetic closure, was examined for the deposition of immunoreactants. The specimens were incubated with fluoresceinated monovalent anti-human immunoglobulin specific for IgG, IgA, IgM, C3, Clq, and fibrinogen and examined independently by 2 immunodermatologists without prior knowledge of patient or site. None of the samples demonstrated immunoreactant deposition consistent with cutaneous LE. IF of several specimens (21/41) had a weak (1+ or 2+), interrupted pattern of fibrinogen at the DEJ,--a common, non-specific finding. Weak, interrupted, linear and granular patterns were seen with IgM (10/41), Clq (9/41), IgG (2/41), IgA (2/41), and C3 (1/41). Fibrinogen was the only immunoreactant demonstrating a bright (3+), continuous, granular pattern (4/41). This data suggests that sun-exposure alone does not induce the deposition of immunoreactants at the DEJ in a pattern similar to that found in cutaneous LE.