Urinary detected renal antigens in the early diagnosis of kidney graft rejection.

The determination of renal antigens in the urine with an immunoassay, based on monoclonal antibodies (moabs), is a noninvasive test system for the analysis and monitoring of renal injury. New moabs allowing an immunohistologic dissection of the human nephron were generated by a direct intrasplenic immunization of mice with pathologic urine samples. A sandwich enzyme immunoassay was developed to quantitate renal cell membrane antigens in the urine samples. A sandwich enzyme immunoassay was developed to quantitate renal cell membrane antigens in the urine. While antigen excretion in healthy individuals is low, preliminary data of a clinical investigation suggest the usefulness of these assay systems in diagnosis of tubular injury in human kidney transplant recipients. The immunoassay can provide very early hints of renal graft rejection prior to the appearance of clinical symptoms or the detection by routine clinical laboratory investigations.