Introduction: Inflammatory bowel diseases (IBDs) present with alternating periods of exacerbation and remission; therefore, it is necessary to develop noninvasive diagnostic tools to control the disease activity and improve therapeutic effectiveness. Recently, we have 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 system as reflected by the levels of catalase, total antioxidant status, and MPO.
Patients and methods: The study group comprised 99 patients diagnosed with Crohn disease (CD) and 61 patients with UC. The Crohn 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 markers were measured with enzyme‑linked immunosorbent assays and colorimetric assays.
Results: The patients with clinically active UC showed significantly decreased median (interquartile range) salivary MPO levels (79.4 [30.1-157.5] vs 94.8 [58.2-274.7] ng/ml) with significant correlations with the endoscopic stage on the Mayo scale (R = 0.423; P = 0.02). Receiver operating characteristic analysis confirmed a potential usefulness of MPO concentrations in predicting clinically active UC (area under the curve = 0.654; P = 0.03; cutoff <210.4 ng/ml). Moreover, in the patients treated with biologics and without steroid therapy, salivary MPO concentrations negatively correlated with neutrophil counts in the individuals with UC and positively with C‑reactive protein level in the patients with CD.
Conclusions: Salivary MPO levels changed depending on the disease activity in the patients with UC. Decreased MPO concentration in the saliva could be a predictor of clinically active UC.