Supplementary Material for: Histological Predictors for Therapeutic Response to Integrin Inhibitors in Patients with Ulcerative Colitis

Introduction: It is crucial to predict the effectiveness of advanced therapies before their administration in ulcerative colitis (UC). Only a few studies have revealed predictive histological factors. Here, we sought to determine whether conventional histology of pretreatment endoscopic biopsy specimens can predict the response to integrin inhibitors.
Methods: In the present single-center retrospective study, we examined histopathological findings before initiating an integrin inhibitor. Primary response (PR) was defined as a ≥3-point decrease in the partial Mayo score at 14 weeks. Logistic regression was used to identify the factors predictive for a PR.
Results: We analyzed 21 biological and Janus kinase inhibitor-naïve patients with UC. The median baseline Mayo score was 7 (IQR, 6–8), and the C-reactive protein was 0.36 (IQR 0.11–0.74). Histological findings included large lymphoid follicles (LF) in 61.9% (13/21), basal plasma cell infiltration (BP) in 52.4% (11/21), and eosinophilic infiltration (EO) in 42.9% (9/21). PR at 14 weeks was achieved in 54.1% (12/21). Among PR patients, LF was present in 91.7% (11/12), BP in 41.7% (5/12), and EO in 25.0% (3/12). PR was observed in 76.9% (10/13) of LF-positive patients vs. 12.5% (1/8) of LF-negative patients (p = 0.01). LF was significantly associated with the response to integrin inhibitors, whereas BP and EO were not.
Conclusion: The presence of LF in biopsy specimens predicts the response to integrin inhibitors in patients with UC. Conventional histological examinations may aid in predicting therapeutic responses to advanced therapies.