IgG4-associated idiopathic tubulointerstitial nephritis complicating autoimmune pancreatitis.

It has been well documented that autoimmune pancreatitis (AIP) [1], also known as sclerosing pancreatitis [2], is frequently associated with fibrosclerotic diseases, such as Sjögren’s syndrome [3,4], primary biliary cirrhosis [5], primary sclerosing cholangitis [3–5] or retroperitoneal fibrosis [6]. However, as yet, there have been no reports on renal complications of AIP, except for hydronephrosis, caused by retroperitoneal fibrosis. Recently, Hamano et al. [2] reported that the pathogenesis of sclerosing pancreatitis is closely related to the presence of immunoglobulin (Ig) G4. We describe here a patient with AIP in association with tubulointerstitial nephritis (TIN), which is strongly suspected to be induced by immune complexes containing IgG4.