We have evaluated the autoantibody pattern, the production of specific immunoglobulins against bacteria in the urinary tract and lymphocytes populations in peripheral blood of primary renal glycosuria patients. All the affected members present autoantibodies against various antigens. In nine patients immunofluorescence revealed antibody coated bacteria in urine specimens. Imbalances in lymphocytes subpopulations are also present, with a reduction of OKT8+ cells and an increase of B and natural killer cells. These results support previous observations about immunological abnormalities in these patients.