Pro-inflammatory and anti-inflammatory cytokine response in diarrhoea-predominant Irritable bowel syndrome patients

Background and aim: Irritable bowel syndrome (IBS) is referred to as a functional bowel disorder which is diagnosed by a number of characteristic symptoms (Rome II criteria) in the absence of detectable structural abnormalities. Low-grade inflammation of the intestine may be one of the reasons for development of diarrhoea-predominant IBS (IBS-D). We undertook this study to estimate the serum levels of pro-inflammatory (IL-6, TNF-α) and anti-inflammatory (IL-10) cytokines in IBS-D patients. Methods: A total of 108 diarrhoea patients were screened. Out of these only 63 adult IBS-D patients were enrolled. Age and sex matched 62 apparently healthy controls with no GI symptoms were also recruited. Out of 63 IBS-D patients, 37 were males while there were 32 males among the controls. The patients with IBS-D were diagnosed according to the Rome II criteria. Levels of serum IL-6, TNF-α and IL-10 were measured in all subjects using ELISA. Results: Mean (+SD) age of IBS-D patients (42.6+19.5 years) was comparable (p=0.64) to that of controls (43.5+18.7 years). The mean (+SD) levels of IL-6 in IBS-D patients (32.2+12.01pg/ ml) was significantly higher (p<0.001) than in controls (7.48+2.55pg/ml). The levels of TNF-α in IBS-D patients (16.3+5.2 pg/ml) were also significantly higher (p<0.05) than in controls (7.94+2.19 pg/ml). There was no significant difference in the serum levels of IL-10 (p=0.23) between IBS-D patients (5.75+2.1 pg/ml) and controls (5.84+1.9 pg/ml). Conclusion: Our results indicate that mild inflammation is involved in IBS-D patients as pro- inflammatory cytokines were increased although no difference in anti-inflammatory cytokine was observed.