Objectives: The pathogenesis of irritable bowel syndrome (IBS) is poorly understood. One contributory factor may be low-grade mucosal inflammation, perhaps initiated by the microbiota. Toll-like receptors (TLRs) are a family of pathogen-recognition receptors of the innate immune system. The aim of this study was to evaluate the potential involvement of TLRs in IBS to further understand the involvement of the innate immune system in this complex disorder.
Methods: The expression of TLRs was investigated in colonic biopsy samples obtained from 26 IBS patients and compared with 19 healthy controls. Protein expression of TLR4, TLR7, and TLR8 was confirmed by immunofluorescence and alterations in the TLR4 protein were confirmed by western blot.
Results: Quantitative reverse transcriptase-PCR showed increased levels of TLR4 (P≤0.001) and TLR5 (P=0.0013) and decreased levels of TLR7 (P≤0.001) and TLR8 (P=0.0019) in IBS patients.
Conclusions: Our results support the presence of an immune engagement between the microbiota and the host in IBS; an interaction that involves innate immunity and could generate a low-grade inflammatory response. These findings could also offer an additional biomarker of the disease or a disease subset.