Twenty percent of biopsy specimens from sun-exposed skin of normal young adults demonstrate positive immunofluorescence.

Fifty normal healthy adults, aged 18 to 41 years, without a history of systemic diseases, dermatoses, or photosensitivity and who were not receiving medication were studied. Paired 3-mm punch biopsy specimens were obtained from the sun-exposed and the non-sun-exposed skin. The data from the study revealed a bright continuous band of immunofluorescence (IF) along the dermoepidermal junction in 10 (20%) of 50 sun-exposed skin biopsy specimens, as compared with none from non-sun-exposed skin biopsy specimens with the use of polyvalent antisera. Fractionated monospecific immunoglobulin demonstrated a bright continuous band of IF composed of IgG alone in one patient, IgA alone in two patients, IgG and IgA in combination in two patients, and the combination of IgG, IgM, and IgA in five patients. There was a statistically significant increase in positive IF in men (seven of 15) vs women (three of 35). This information suggests that in the examination of a patient suspected of having lesions of cutaneous lupus erythematosus, positive IF from sun-exposed skin is nonspecific and adds little information to the clinical and histopathologic findings.