Background: IgG4-related autoimmune pancreatitis (IgG4-AIP) is a rare autoimmune pancreatic disorder, with elevated carbohydrate antigen 19– 9 (CA19-9) observed in some patients. Objective: This study aims to compare the clinical features of IgG4-AIP patients with elevated versus normal CA19-9 levels to clarify the clinical significance of CA19-9 in this condition. Methods: This study conducted a retrospective analysis of the clinical data of 41 patients with IgG4-AIP who underwent CA19-9 testing at Yichang Central People’s Hospital from January 2019 to April 2025. In this study, the normal reference range for CA19-9 levels was defined as 0 to 39 U/mL. Results: Among the 41 patients with IgG4-AIP, 23 patients (56.10%) had normal CA19-9 levels, while 18 patients (43.90%) exhibited elevated CA19-9 levels. Patients with elevated CA19-9 levels were more likely to be misdiagnosed as having pancreatic tumors (55.56% vs. 13.04%) and had a higher incidence of bile duct involvement (88.89% vs. 26.09%), whereas the incidence of lymph node involvement (22.22% vs. 56.52%) was lower ( P 0.05). Conclusion: Patients with elevated CA19-9 levels in IgG4-AIP exhibit more complex clinical features. Clinicians should consider CA19-9 level differences when evaluating and managing IgG4-AIP patients to guide personalized diagnostic and therapeutic strategies. Keywords: IgG4-related autoimmune pancreatitis, IgG4-related disease, carbohydrate antigen 19-9
Han et al. (Sun,) studied this question.