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 iluoresceinated monovalent anti‐human immunoglobulin specific for IgG, IgA, IgM, C3, Clq, and fibrinogen and examined independently by 2 immunodennatologists 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.