Role of serum cytokine profile in ulcerative colitis assessment

Several cytokines are overexpressed in the colonic mucosa of patients with ulcerative colitis (UC). The measurement of these parameters in plasma could be useful in diagnosis and disease assessment.

In all, 67 UC patients and 21 healthy controls were enrolled. At inclusion, clinical, endoscopic, and histological disease activity were assessed using the Ulcerative Colitis Activity Index (UCAI) and the Baron and Geboes scales, respectively. Serum cytokine concentrations were analyzed with a multiplex system (Bio-Plex pro, Bio-Rad) measuring interleukin (IL)-1-β, IL-2, IL-6, IL-8, IL-10, IL-13, IL-17, interferon-gamma (IFN-γ), and tumor necrosis factor alpha (TNF-α). Multiple logistic regression was used to design a serum cytokines profile.

In the UC group the disease activity was moderate to severe based on clinical evaluation in 35 patients (52.2%), by endoscopic appearance in 45 (67.2%), and in 53 patients (81.6%) using histology. With respect to controls, the multivariate analysis identified that UC patients had higher IL-8 (odds ratio [OR] = 1.37; P = 0.002) and IL-10 concentrations (OR = 3.88; P = 0.012) with lower levels of IFN-γ (OR = 0.95; P = 0.002). The model had an accuracy of 77.3%, which increased to 94.6% when only newly diagnosed patients were considered. Patients with moderate to severe disease according to their clinical score showed a higher concentration of IL-8 (OR = 1.16; P = 0.012) and IL-10 (OR = 1.76; P = 0.039) with lower levels of IL-17 (OR = 0.97; P = 0.021). The IL-8 serum concentration was also related to endoscopic and histological severity (OR = 1.10; P = 0.026 and OR = 1.33, P = 0.017, respectively).

A serum cytokine profile may be an auxiliary tool for the diagnosis and severity assessment of UC. IL-8 seems to be a reliable biomarker, closely related to disease activity.