TREM2 and autoimmune pancreatitis: We observed a significant increase in CXCL9+ (P = 0.0051) and CXCL13+ macrophages (P = 0.042), which expressed higher levels of chemoattractant molecules, as well as TREM2+ macrophages (P = 0.0069) in AIP pancreatic tissues (Fig. 3c and Additional file 1: Fig. S4d-f).