Association Study Between IL-33with Its Receptor ST2in The Regulation Of Th2Immune Response And Ankylosing Spondylitis

Objective IL-33is a novel member of the IL-1family, which promotes Th2responsesand inflammation through the ST2receptor. The aim of this study was to further explorethe correlation between IL-33and AS, through investigating the expression of IL-33,ST2and Th2-associated cytokines (IL-13, IL-4, IL-5) in patients with AS, andexamining the correlation between serum cytokines levels and disease activity andlaboratory parameters.Methods A total of43AS patients were selected from the first affiliated hospital ofAnhui Medical University. According to the disease activity we divided the AS patientsinto disease activity group and stable condition group.40healthy people from physicalexamination were selected as controls during the same period, in43AS samples andcompared with27age-and sex-matched healthy controls. Sandwich enzyme-linkedimmunosorbnent assay (ELISA) was used to measure the levels of IL-33, IL-13, IL-4and IL-5in serum, and compared with that of healthy control. And we further analyzedthe correlation between these cytokines and clinical indicators. The mRNA expressionlevels of IL-33and ST2were quantified by real time quantitative PCR (RT-qPCR).Results Serum IL-33, IL-4and IL-13levels were increased significantly in AS patientscompared with controls (P<0.01); moreover, serum IL-33and IL-13levels weresignificantly higher in patients with active AS than those with inactive AS (P<0.05).The serum levels of IL-5showed no significant difference between AS patients andcontrols (P>0.05). Serum IL-33levels were positively correlated with both IL-13 (r=0.306, P<0.01) and IL-4levels (r=0.432, P<0.01). Moreover, Serum IL-33levelswere positively correlated with both BASDAI and CRP, but there was no correlationwith ESR. The mRNA levels of IL-33and ST2were significantly different between ASpatients and controls (P<0.01), but not between active and inactive AS patients.Conclusion IL-33levels were elevated in patients with AS, and correlated with diseaseactivity. IL-33/ST2signaling might play an important role in the pathogenesis of AS.