Unusual glomerular lesion in a patient receiving long-term interferon alpha

A 60-year-old man with long-standing chronic myelogenous leukemia presented with renal insufficiency and proteinuria after more than 6 years of therapy with daily interferon alpha injections. He also manifested unusual skin lesions and a low-titer antinuclear antibody (ANA). Percutaneous renal biopsy disclosed an unusual glomerular lesion characterized by global, diffuse, and marked widening of the lamina rara interna, and focal segmental mesangial proliferation. Discontinuation of the drug resulted in resolution of the proteinuria, but not the renal insufficiency. These glomerular changes have not been reported previously as a complication of this form of malignancy and are similar to lesions reported in newborn rats and mice receiving interferon alpha. The potential role of interferon alpha in the development of this glomerular disease is discussed.