Tubular dysfunction in systemic lupus erythematosus.

20 patients with systemic lupus erythematosus undergoing renal biopsies had their tubular function assessed by maximal concentrating ability, maximal urinary acidification and fractional urinary excretion of beta 2-microglobulin. 80% of patients showed disturbances in one or more of the parameters tested with fractional beta 2-microglobulin excretion being most frequently abnormal. No correlation was found between the histological changes and functional disturbances.