Immunopathology of the nephrotic syndrome associated with renal vein thrombosis. Report of two cases and brief review of the literature

Renal tissue from two patients with the nephrotic syndrome and renal vein thrombosis was studied by immunofluorescence microscopy in addition to conventional histologic and electron microscopic technics. Granular deposits of immunoglobulins G (IgG), M (IgM) and beta₁ C/beta₁ A globulin (one case) were seen by fluorescence microscopy along the basement membranes in a pattern similar to that observed in patients with chronic membranous nephropathy and in the experimental model of chronic serum sickness. Renal vein thrombosis, associated with the nephrotic syndrome, is not clearly separated clinically or pathologically from primary glomerular disease with the nephrotic syndrome. In view of the lack of experimental evidence to show that either the glomerular lesion or the proteinuria is the result of elevated venous pressure alone, the pathogenesis of the lesion must remain in doubt.