Anti-Saccharomyces cerevisiae Antibody in Pediatric Crohn’s Disease Patients without Mucosal Healing Is a Useful Marker of Mucosal Damage

BACKGROUND/AIMS: We evaluated whether anti-Saccharomyces cerevisiae antibody (ASCA) titers are associated with diagnostic findings, disease activity, Paris classification phenotypes, and persistence after infliximab (IFX) treatment in children with Crohn’s disease (CD). We also investigated the role of ASCA as a predictor of mucosal healing (MH) and clinical remission (CR). METHODS: This study included 61 CD patients aged 19 years or younger who were diagnosed and treated between September 2010 and January 2019 and followed for at least 1 year. ASCA was regularly measured at the diagnosis of CD and at least 1 year after IFX therapy. RESULTS: The average follow-up period was 3.8±3.4 years (range, 1.0 to 7.2 years). Regression analysis showed that the ASCA titer was the only factor associated with Simple Endoscopic Score for Crohn's Disease (SES-CD) or CR among all the parameters. In patients who had achieved MH (SES-CD=0), ASCA immunoglobulin G (IgG) was not associated with MH, but in patients without MH, ASCA IgG was associated with SES-CD (p=0.005) and CR (p<0.001). The cutoff value of ASCA IgG in patients with CR was 21.8 units. However, there was no difference in the relapse rate between the ASCA IgG-positive and -negative groups during the follow-up period. CONCLUSIONS: In patients who have not achieved MH, ASCA IgG is closely related to mucosal damage and CR. Unlike Western studies, ASCA IgG may be more helpful in predicting prognosis than immunoglobulin A in Korean patients, but it is not an appropriate indicator to predict the relapse of CD. (Gut Liver 2021;15-770)