Serum free light chain assessment in type 1 autoimmune pancreatitis

/Object: Some patients with type 1 autoimmune pancreatitis (AIP), the pancreatic manifestation of IgG4-related disease, have normal serum IgG4. The aim of this study is to investigate the diagnostic value of measuring serum free light chains (FLCs) in type 1 AIP. Thirty-seven patients with type 1 AIP, and 21 healthy, 17 alcoholic chronic pancreatitis (ACP), 21 idiopathic chronic pancreatitis (ICP) and 20 pancreatic cancer (PC) patients were enrolled. Serum IgG4 and FLC concentrations were measured using sFLC Freelite assays on a nephelometric analyzer. Active AIP patients have significantly higher serum levels of κ (median 30.97 (12.3–227.0) mg/L) and λFLC (median 20.53 (12.36–102.7) mg/L)) than healthy controls (κFLC; median 12.5 (3.1–52.1) mg/L), λFLC: median 12.45 (5.4–39.5) mg/L) (p