Letter to the Editor
Copyright ©The Author(s) 2024. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Feb 7, 2024; 30(5): 512-515
Published online Feb 7, 2024. doi: 10.3748/wjg.v30.i5.512
Can serum immunoglobulin G4 levels and age serve as reliable predictors of relapse in autoimmune pancreatitis?
Jun-Min Song, Si-Yu Sun
Jun-Min Song, Si-Yu Sun, Department of Gastroenterology, Shengjing Hospital of China Medical University, Shenyang 110004, Liaoning Province, China
Author contributions: Sun SY contributed to the paper framework; Song JM authored the manuscript; both authors collaborated on finalizing the manuscript before submission.
Conflict-of-interest statement: There are no conflicts of interest to report.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Si-Yu Sun, MD, PhD, Professor, Department of Gastroenterology, Shengjing Hospital of China Medical University, No. 36 Sanhao Street, Shenyang 110004, Liaoning Province, China. sunsy@sj-hospital.org
Received: December 11, 2023
Peer-review started: December 11, 2023
First decision: December 22, 2023
Revised: December 23, 2023
Accepted: January 12, 2024
Article in press: January 12, 2024
Published online: February 7, 2024

We are writing in response to the paper published in the World Journal of Gastroenterology by Zhou et al. The authors identified higher serum immunoglobulin (Ig) G4 levels and age over 55 years as independent risk factors for disease relapse. Despite notable strengths, it is crucial to address potential biases. Firstly, the cohort study included 189 patients with autoimmune pancreatitis (AIP) type 1 (with higher IgG4 seropositivity and higher relapse) and 24 with type 2 (with lower IgG4 seropositivity and lower relapse). Consequently, most, if not all, AIP type 2 patients were assigned to the normal group, possibly inflating the association of higher serum IgG4 levels with relapse and potentially exaggerating the association of older age with relapse. Secondly, the authors did not provide sufficient details regarding AIP diagnosis, such as the ratio of definitive vs probable cases and the proportion of biopsies. In cases where histological evidence is unavailable or indeterminate, AIP type 2 may be misdiagnosed as definitive type 1, and type 1 may also be misdiagnosed as probable type 2, particularly in cases with normal or mildly elevated serum IgG4 levels. Lastly, in this retrospective study, approximately one-third of the consecutive patients initially collected were excluded for various reasons. Accordingly, the impact of non-random exclusion on relapse outcomes should be carefully considered. In conclusion, the paper by Zhou et al offers plausible, though not entirely compelling, evidence suggesting a predictive role of elevated serum IgG4 levels and advanced age in AIP relapse. The foundation for future investigations lies in ensuring a reliable diagnosis and accurate disease subtyping, heavily dependent on obtaining histological specimens. In this regard, endoscopic ultrasound-guided fine-needle biopsy emerges as a pivotal component of the diagnostic process, contributing to mitigating biases in future explorations of the disease.

Keywords: Autoimmune pancreatitis, Immunoglobulin, Endoscopic ultrasound, Relapse, Age

Core Tip: This paper assesses the strengths and potential biases of the provided study. Accurate diagnosis and subtyping are crucial for both clinical practice and research. In this context, endoscopic ultrasound-guided fine-needle biopsy emerges as a pivotal component of the diagnostic process, playing a key role in mitigating the introduction of various biases in future investigations of autoimmune pancreatitis.