Mucosal interleukin-8 expression as a predictor of subsequent relapse in ulcerative colitis patients with Mayo endoscopic subscore 0

Background and aim: Complete endoscopic mucosal healing is defined as a Mayo endoscopic subscore of 0. Some patients diagnosed with a Mayo endoscopic subscore 0 may present with subsequent clinical relapse. Here, we aimed to demonstrate mucosal cytokine profile as a predictor of clinical relapse in ulcerative colitis patients with a Mayo endoscopic subscore of 0 as a marker of mucosal healing.

Methods: We conducted prospective observational pilot study to examine the relationship between mucosal cytokine expression and subsequent relapse of UC patients diagnosed with a Mayo endoscopic subscore of 0. We enrolled 55 patients, and expression of cytokines tumor necrosis factor-α, interferon γ, interleukin-1β, interleukin-2, interleukin-4, interleukin-5, interleukin-6, interleukin-7, interleukin-8, interleukin-9, interleukin-10, interleukin-12, interleukin-13, interleukin-15, interleukin-17A, interleukin-17F, interleukin-18, interleukin-21, interleukin-22, interleukin-23, interleukin-27, and interleukin-33 was measured by quantitative real-time PCR using rectal mucosa biopsy materials. Cytokine expression levels were compared between patients who relapsed between March 1, 2016, and March 30, 2020, of the study period and those who remained in remission.

Results: Ten cytokines, including interleukin-2, interleukin-4, interleukin-8, interleukin-10, interleukin-12, interleukin-15, interleukin-17A, interleukin-21, interleukin-23, and interleukin-33, were significantly elevated in patients with subsequent relapse compared with those who remained in remission. Interleukin-8 expression was the most useful predictor.

Conclusions: In the rectal mucosa of ulcerative colitis patients with Mayo endoscopic subscore 0, levels of several cytokines were elevated in cases of subsequent relapse. Among these, interleukin-8 expression was the most useful for predicting relapse.