CTLA4 and autoimmune pancreatitis: Furthermore, single-nucleotide polymorphisms (SNPs) in five non-HLA genes, cytotoxic T lymphocyte-associated antigen 4 (CTLA4) [21,22], tumor necrosis factor-α (TNF-α) [22], cationic trypsinogen (PRSS1) [23], Fc receptor-like 3 (FCRL3) [24], and KCNA3 (potassium voltage-gated channel, shaker-related subfamily) [25] have been linked to AIP.