Glutathione transferase in the urine: a marker for post-transplant tubular lesions

Basic glutathione transferase released from the proximal tubular epithelium in the kidney was monitored in the urine of 69 recipients of renal allografts. The enzyme was isolated from human liver and the urinary analysis performed with radioimmunoassay. Patients receiving cyclosporine A without toxicity or rejection did not excrete this enzyme in their urine; whereas the urine of patients with cyclosporine A-induced nephrotoxicity contained significant amounts of the transferase (P less than 0.001). Patients with allograft rejection also showed increased urinary concentrations of the basic glutathione transferase, but had significantly lower values than patients with cyclosporine induced nephrotoxicity (P less than 0.001). During aminoglycoside and co-trimoxazole treatment, the urinary concentration of this transferase also increased. Patients with renal infarction showed a sudden increase in urinary transferase to very high levels. The results indicate that quantitative analysis of the basic glutathione transferase in urine is useful for monitoring renal tubular lesions present in various complications following transplantation, such as cyclosporine and antibiotic induced nephrotoxicity and renal infarction.