The Role of Interleukine-33and s ST2 in inflammatory Bowel Disease

The inflammatory bowel disease,Crohn’s disease and ulcerative colitis are heterogenous chronic inflammatory disorders of the gastrointestinal (GI) tract.The most widely accepted etiopathogenic hypothesis for these disorders suggests an immune mediated process originates from an inappropriate response of mucosal immune system to the normal enteric flora in a genetically susceptible individual
This study was performed to evaluate the role of IL-33and sST2 in pathogenesis of IBD and to correlate their levels with the disease activity and/or severity, and with serumlevels of high sensitivity C-reactive protein (CRP), per nuclear antineutrophil
cytoplasmic antibodies (pANCA) and anti-saccharomyces cerevisiae antibodies (ASCA). Fifty five subjects with IBD (41 UC patients and 14 CD patients) their ages range from 16-65 years and 25 volunteers their ages and sexes were matched with the patients were participated in this study. Blood samples were collected from all patients and controls to assess serum concentrations of IL-33, sST2, hs-CRP, pANCA and ASCA by enzyme-linked immune-sorbent assay.
The present data revealed that there was significant elevation (P<0.05) in serum levels of IL-33 in UC and CD patients as compared with control group, whereas
serum level of sST2 was significantly increase in UC patients (P<0.01), but in CD patients there was no significant differences when compared to control group
(p>0.05). Moreover, there were no significant differences (p>0.05) in the mean ratio of IL-33/ST2 in the study groups. Other results in the present study were the high frequencies of pANCA in UC patients and ASCA in CD patients(p<0.001) when compared with healthy control group. However; this prevalence of pANCA was significantly higher (p<0.001) among UC patients when compared with CD
VIII patients, while seroprevalence of ASCA in UC patients was significantly lower (p<0.001) than those in CDpatients. Furthermore, significant increase of serum hs- CRP level was showed in both disease groups UC and CD with highly statistical significant difference (p<0.001)than control group.Concerning the correlation between serum levels of (IL-33 and sST2)with clinical parameters, the current study revealed positive correlation between serum
IL-33 and sST2 with the disease activity in UC (P=0.41, <0.001) respectively.As regards to disease location,IL-33 was significantly higher (P<0.001) in UC patients with pan-colitis (E3) as compared to those patients with E1 and E2.Meanwhile,serum level of sST2 did not show any significant differences
(p>0.05) in UC patients with proctitis disease (E1) and left side of colon (E2) or pan-colitis (E3). On the other hand the correlation among immunological
parameters in this study indicate that there was significant positive linear IL-33 and hs-CRP in CD (r=0.659, P=0.010). Whereas in UC, IL-33 level was positively correlated with each of sST2, hs-CRP and pANCA (r= 0.408, P= 0.008; r=0.392, P=0.011; r=0.355, P=0.023) respectively. This study indicated that IL-33 and its receptor (sST2) might be a crucial mediator in pathogenesis of IBD. In addition, the increased serum level of IL33 and sST2 correlated with activity and location of UC could predict the response to therapy and possibly reflect an acute-phase response due to inflammation.