Fenoprofen nephropathy: lipoid nephrosis and interstitial nephritis. A possible T-lymphocyte disorder.

Five patients are presented, each of whom had an acute idiosyncratic reaction to fenoprofen calcium (Nalfon) characterized by acute renal failure and marked proteinuria. Renal pathology was similar in all patients. Light microscopy revealed marked lymphocytic inflammatory infiltrates and normal glomeruli. Immunofluorescent staining was minimal or absent. Electron microscopy showed fusion of podocytes in otherwise normal glomeruli. Two patients were studied using T-cell and B-cell specific fluorescent staining, which revealed that the interstitial infiltrates were composed exclusively of T-lymphocytes. This finding is considered in relation to prior experimental and theoretic work. It is suggested that the various clinical and pathologic findings in fenoprofen nephropathy are all manifestations of a disordered cell-mediated immunity.