The treatment regimens and disease activity could alter the salivary myeloperoxidase levels in patients with inflammatory bowel diseases.

INTRODUCTION: Inflammatory bowel diseases (IBDs) are related to alternating periods of exacerbation and remission; therefore, it is necessary to develop non-invasive diagnostic tools to control disease activity and improve therapeutic effectiveness. Recently, we found that patients with ulcerative colitis (UC) who qualified for biologic therapy had significantly lower salivary myeloperoxidase (MPO) levels.

OBJECTIVES: This cross-sectional study aimed to assess the impact of IBD activity and applied treatment on salivary antioxidant status as reflected by MPO, catalase and total antioxidant status levels.

PATIENTS AND METHODS: The study group comprised 99 patients diagnosed with Crohn's disease (CD) and 61 patients with UC. The Crohn's Disease Activity Index and modified Mayo scale were used to estimate the clinical activity of CD and UC, respectively. Unstimulated whole mixed saliva was collected. Salivary levels of selected antioxidant markers were measured with enzyme-linked immunosorbent assays and colorimetric assays.

RESULTS: Patients with clinically active UC showed significantly decreased salivary MPO levels (medians 79.4 vs 94.8 ng/mL) with significant correlations with endoscopic stage on the Mayo scale (RS = 0.423, P = 0.02). ROC analysis confirmed the potential usefulness of MPO concentrations in predicting clinically active UC (AUC=0.654, P = 0.03, cut-off <210.4 ng/mL). Moreover, in patients treated biologically and without steroid therapy, salivary MPO concentrations were negatively correlated with neutrophil counts in UC patients and positively with C-reactive protein level in CD patients.

CONCLUSIONS: Salivary MPO levels changed depending on the disease activity in patients with UC. Decreased MPO concentrations in the saliva could be a predictor of clinically active UC.