Membranous nephropathy with repeated flares in IgG4-related disease

IgG4-related disease (IgG4-RD) is associated with the infiltration of IgG4-positive plasma cells into various organs. Nephropathy of IgG4-RD is generally interstitial nephritis and glomerulonephritis is rare. We describe a case of membranous nephropathy (MN) without interstitial nephritis associated with IgG4-RD symptoms including lymphadenopathy and pulmonary and pleural lesions. Treatment with steroids improved these clinical symptoms, but withdrawal of steroids induced the repeated relapse of MN. Finally, flaring of MN was prevented by the combination of steroids and cyclosporine. This is the first report of the successful treatment of MN associated with IgG4-RD by this combination therapy.