Abstract: Immunopathological examinations were performed on the skin specimens taken-from the extensor surface of the mid-third upper arms (the sun-exposed clinically normal skin) from 77 cases with LE and 84 cases with various other diseases. It was found that in the patients with SLE the positive incidence and the fluorescence intensity of the LBT closely correlated with the clinical disease activity. Considering the, immunoglobulin class composition and the fluorescence intensity of IgG, the LBT correlated with the active nephropathy too. This suggests that the LBT on the sun-exposed clinically normal skin of patients with SLE can be used not only for diagnosis but also to aid in assessing clinical disease activity, active nephropathy and prognostication.