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

Abstract

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-alpha) and anti-inflammatory (IL-10) cytokines in IBS-D patients. 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-alpha and IL-10 were measured in all subjects using ELISA. 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 +/- 12.01 pg/ml) was significantly higher (p < 0.001) than in controls (7.48 +/- 2.55 pg/ml). The levels of TNF-alpha 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). Our results indicate that mild inflammation is involved in IBS-D patients as proinflammatory cytokines were increased although no difference in anti-inflammatory cytokine was observed.