FOXP1 and autoimmune pancreatitis: In view that previous study has identified relying on serum IgG4 concentrations for diagnosing type 1 AIP can result in misdiagnosis rates exceeding 10% and omission rates of 15.5%,[29] further studies need to be done and to evaluate the diagnostic significance of FOXP1+ transition B cell levels in AIP patients’ peripheral blood.