The lupus band test as a measure of disease activity in systemic lupus erythematosus.

One hundred twenty-seven biopsy specimens from clinically normal light-protected skin of 88 patients with active and inactive lupus erythematosus (LE) were examined for deposits of IgG, IgM, IgA, and C3 at the dermal-epidermal junction (DEJ). Deposits were found in 91% of those with active disease and in 33% of those with inactive disease. The finding of such deposits reflected active disease just as did a decrease in serum C3 and C4 levels, elevated anti-double-stranded DNA, the presence of LE cells, lymphopenia, and an elevation of the ESR. The presence or absence of deposits in repeated biopsy specimens indicated changing disease activity, as estimated clinically, just as did changes in the other variables mentioned. Neither immunoreactants in skin nor any other laboratory abnormality reflected renal disease or other type of organ involvement. Deposits of IgG were not more commonly found in patients with renal disease.