Abstract
Recently, autoimmune pancreatitis (AIP) has been classified into two subtypes: type 1 as a pancreatic manifestation of IgG4-related disease (IgG4-RD), and type 2 related with a granulocytic epithelial lesion (GEL). Different from type 2 AIP, T helper type 2 (Th2) immune response is predominant over Th1 in type1/IgG4-RD. Recent human and experimental animal studies have suggested a possible involvement of innate immunity in addition to acquired immunity, such as genetic background, bacterial/viral infections, complement activation via classical pathway, or IgG4-production of monocytes/basophils with TLR/NOD stimulation. Based on these findings, we have proposed a hypothesis for the development of type1 AIP, one of the IgG4-RD.
