Leukocyte subtypes can be used to evaluate the severity of ulcerative colitis (UC). In this study, we examined the relationship between the lymphocyte-to-monocyte ratio (LMR) and the Mayo endoscopic score (MES) in assessing endoscopic activity in UC. Eighty-nine samples of leukocyte subtypes and biomarkers, including fecal calprotectin (FC), the fecal immunochemical occult blood test (FIT), and C-reactive protein (CRP), from 71 patients with UC were retrospectively investigated, along with the MES. The MES was significantly correlated with the LMR, FC, the FIT, and CRP. There were significant differences in the LMR, FC, the FIT, and CRP between groups with an MES 2 (p = 0.001, p = 0.003, p p < 0.001, respectively). In the receiver operating characteristic (ROC) analysis for predicting mucosal healing (MES 0 or 1), the areas under the curve (AUCs) for the LMR, FC, the FIT, and CRP, were 0.712, 0.860, 0.908, and 0.796, respectively. In the analysis of patients without immunomodulators, the correlation of the MES with the LMR and CRP was significant. The LMR can be used to assess endoscopic activity in UC, particularly in patients without immunomodulators.
