THROMBOSIS of the renal veins associated with the nephrotic syndrome has been recognized since 1939.1 Since then, more than 50 cases have been reported and reviewed.2,3 While it is generally agreed that the renal vein thrombosis is responsible for the development of the nephrotic syndrome, the mechanism for the development of proteinuria is unclear and has received little attention. The demonstration of γ-globulin in the glomeruli and lung as described in the following report suggests that an immune mechanism may be involved. Report of a Case This 44-year-old man was well until three years prior to death when he had a myocardial infarction from which he recovered uneventfully. Six months prior to death, he noted ankle edema and was found to have proteinuria. He had no symptoms referable to his urinary system and had no symptoms of congestive heart failure. Physical examination three months prior to death