Aberrant Methylation of is Associated with the Pathogenesis of Autoimmune Pancreatitis.

IgG4-related disease (IgG4-RD) is an autoimmune disease of unknown cause. is a transcription factor involved in immune responses, and its dysfunction leads to uncontrolled immune responses. We performed, to our knowledge, the first methylation analysis in type 1 autoimmune pancreatitis (denoted simply as AIP), a representative IgG4-RD. We conducted methylation array analysis on AIP samples using the Illumina Infinium MethylationEPIC array. We identified a potentially important methylation abnormality in AIP, which was further confirmed using the quantitative SYBR green methylation-specific polymerase chain reaction (QSG-MSP) method. Using immunohistochemistry, we analyzed expression in lymphocytes in 11 lymph nodes with AIP (LN-AIP) and 20 lymph nodes with pancreatic ductal adenocarcinoma (PDA; LN-PDA). LN-AIP and LN-PDA refer to lymph nodes from patients with AIP and PDA, respectively. All selected PDA patients lacked lymph node metastases. By array analysis, was more highly methylated in LN-AIP than in LN-PDA ( = 0.0275). was also more highly methylated in LN-AIP than in LN-PDA by QSG-MSP validation ( = 0.0331). Immunohistochemical analysis indicated that expression was significantly lower in LN-AIP than in LN-PDA ( = 0.0250). Aberrant methylation and reduced expression may be characteristic of AIP. Further validation is warranted.