Clinical characteristics of autoimmune pancreatitis with IgG4 related kidney disease

Abstract Purpose To clarify the clinical characteristics of autoimmune pancreatitis (AIP) in immunoglobulin (Ig)G4-related kidney disease (IgG4-RKD). Patients and methods A total of 92 patients with AIP were divided into an IgG4-RKD-positive group (RKD-P group, n = 13) and an IgG4-RKD-negative group (RKD-N group, n = 79) on the basis of the diagnostic criteria for IgG4-RKD. Clinical characteristics, including: age; sex; the presence of extrapancreatic lesions other than renal lesions, proteinuria, and hematuria; serum concentrations of IgG, IgG4, IgE, and creatinine; and urinary concentrations of liver-type fatty acid binding protein, α1-microglobulin, β2-microglobulin, and N-acetyl-β- d -glucosaminidase were compared between the RKD-P and RKD-N groups. The clinical course of the RKD-P group was also characterized. Results The prevalence of extrapancreatic lesions other than renal lesions was significantly higher in the RKD-P group (84.6% vs 43.0%, p p p p Conclusions Patients who had AIP with IgG4-RKD were more likely to have extrapancreatic lesions other than those in the kidney, and their serum creatinine and urinary β2-microglobulin concentrations were significantly higher than in those without IgG4-RKD.