The profile of the key pro-inflammatory cytokines in the serum of patients with CD and their association with the disease severity and activity

BACKGROUND: The epidemiology of Crohn’s disease (CD) has changed over the past decades, demonstrating a trend toward increased prevalence in developing countries, while in developed countries, its incidence has stabilized. The study aimed to examine the profile of the key pro-inflammatory cytokines in the serum of patients with CD and establish their association with the severity and activity of the disease. METHODS: A total of 61 patients (29 women (47.5%), 32 men (52.5%) aged from 18 to 40 years (mean age (30.42 ± 2.51) years) with the verified diagnosis of CD in the active phase were examined. The control group consisted of 30 healthy people of corresponding age. RESULTS: CD is characterized by a reliable increase of pro-inflammatory cytokines in blood compared to healthy people: tumor necrosis factor-α (TNF-α) – by 4.45 times (137.46 ± 9.72 vs. 30.88 ± 2.08 pg/ml in healthy people, p < 0,001), interleukin-1α (IL-1α) – by 5.08 times (51.55 ± 4.36 vs. 10.14 ± 0.93 pg/ml, p < 0.001), interleukin-6 (IL-6) – by 2.16 times (20.03 ± 1.81 vs. 9.27 ± 0.52 pg/ml, p < 0.001), interleukin-8 (IL-8) – by 2.04 times (25.74 ± 2.05 vs. 12.62 ± 1.16 pg/ml, p < 0.001), and interferon-γ (IFN-γ) – by 5.30 times (208.63 ± 14.29 vs. 39.35 ± 2.40 pg/ml, p < 0.001). The authors have established direct correlations between the Crohn's disease activity index and blood content of TNF-α (r = 0.84, p < 0.013), INF-γ (r = 0.61, p < 0.028); between TNF-α and INF-γ content (r = 0.67, p < 0.023), IL-1α (r = 0.49, p < 0.042), IL-6 (r = 0.40, p < 0.045), and IL-8 (r = 0.51, p < 0.033); INF-γ and IL-1α (r = 0.53, p < 0.040), IL-6 (r = 0.37, p < 0.039), IL-8 (r = 0.44, p < 0.040). CONCLUSIONS: Patients with CD were found to have multiple cytokines (TNF-α, IL-1α, IL-6, IL-8, and IFN-γ,). The content of cytokines correlated positively with the CD activity index.