Interplay Between Dysregulated Immune System and the Footprints of Blood-Borne miRNAs in Treatment Naive Crohn's Disease and Ulcerative Colitis Patients.

Dysregulated T-cell-mediated immune responses are a hallmark of inflammatory bowel diseases (IBD), including Crohn's disease (CD) and ulcerative colitis (UC). MicroRNAs (miRNAs) regulate various biological processes and play a significant role in the pathophysiology of numerous diseases. In this study, we aim to clarify the relationship between dysregulated immune response and altered miRNA signatures in patients with IBD. Our goal is to identify differentially expressed miRNAs that could potentially serve as diagnostic markers to differentiate between CD and UC. To quantify circulating miRNAs, we employed small RNA sequencing. To describe immune dysregulation, we determined the levels of circulating T-cell-related cytokines and the distribution of T-cell subpopulations in both circulation and in tissue samples. Our analysis revealed that 14 miRNAs exhibited significant expression differences between IBD patients and control subjects. These miRNAs may also implicate pathways associated with colitis-related colorectal carcinogenesis, suggesting their value in early risk assessment. Furthermore, we found that five miRNAs demonstrated a strong ability to discriminate between CD and UC patients. Additionally, levels of IL-22 and IFN-γ were significantly elevated in individuals with IBD. Notably, miRNA levels showed strong correlations with cytokine levels and T-cell subset distribution in both blood and tissue samples, exhibiting disease-specific patterns. In conclusion, we identified differentially expressed miRNAs in IBD patient groups, and a subset of these miRNAs might exhibit diagnostic potential to distinguish between CD and UC. Analyzing miRNAs in the blood of IBD patients may provide valuable insights into the underlying immune dysfunction.