Membranous nephropathy associated with an unusual phenotype of chronic lymphocytic leukemia

The nephrotic syndrome is uncommon in patients with chronic lymphocytic leukemia. When present, the most frequently documented cause is membranous nephropathy, although several other glomerular lesions have also been described. This report describes a patient with chronic lymphocytic leukemia of an unusual surface marker phenotype recently suggested to be associated with an increased incidence of proteinuria. Renal biopsy specimens demonstrated membranous glomerulonephritis. Immunofluorescence staining demonstrated glomerular deposition of IgG and C3, but not the human T-lymphocyte antigen, T65, which had been found on circulating leukemia cells.