Kidney-derived urinary antigens assayed with monoclonal antibodies for the detection of renal damage.

For the quantitation of kidney-derived Urinary Antigens (UA) monoclonal antibodies specific for antigens localized in cells of defined subunits of the nephron were applied in sandwich ELISA. Antigen excretion was measured in the urine of healthy individuals, patients suffering from various diseases, kidney transplant recipients, and healthy volunteers receiving therapeutic doses of antibiotic drugs. In healthy individuals, in patients with diseases primarily affecting the glomerulus, and in inactive phases of chronic diseases antigen excretion was low. Toxic drug effects enhanced antigenuria. Excretion of some or all of the antigens always indicated tubular alterations. The tests thus provide information on location and extent of acute primary tubular damage.