The correlation between serum IL-17 and TNF-A concentration sanddisease activity in ankylosing spondylitis patients

GOAL: Ankylosingspondylitis is a prototype disease for chronic progressiv einflammatory spondylo arthro pathies whiche specially effect the spine and sacroiliac joints with unknow netiology. Th17 cell sare characterized by proinflammatory cytokine production (IL-17, IL-16,IL-22, TNF-a). In this study we aimed to determine how IL-17 and TNF-a affect the pathogenesis of AS, how they influence the disease activity and the ircorrelation with diseaseduration, type of treatment and when to start treatment. METHOD: We enrolled fort his study 91 AS patients, 9 RA patientsand 31 healthy volunteers. RESULTS: Comparingall the groups in this study we have found a statisticall ysignificant difference betwwen IL-17 and TNF-a levels in RA patients. IL-17 levels were much lower than other groups (p=0,012). TNF-a levels in AS patients recieving conventional treatmentand RA patients were lower than healthy volunteersand AS patients recieving anti TNF (p=0,009). There were nostatistically significant difference between BasFi, ESR, CRP, IL-17, TNF-a levels when comparing AS patients recieving conventional the rapyto AS patients taking anti-TNF therapy. In contrast BasDa ipoints were lower in anti-TNF therapy group (p=0,036). When we compare patients who recieved late anti TNF therapy to conventional the rapy group, the former had higher IL-17 levels(p=0,010). Between TNF-a level sand BasDai points of anti Tnf recieving AS patients we established aweak, negatively directed correlation which is statistically significant. Patients with low TNF-a levels had higher BasDai points (r=-0,294, p=0,020). Wehavefound a positivelydirected, statisticallysignificant, moderate correlation between CRP levelsand BASDAI points of AS patients recieving conventional therapy( Table 13). Patients with high CRP levels had also high BASDAI points (r=0,434, P=0,019). We established a weak, statisticall ysignificantand a positive correlation between IL-17 level sand BASDAI points in AS patients recieving conventional therapy. Patients with high IL-17 levels had alsohigh BASDAI points (r=0,374; p=0,046) CONCLUSION: We have concluded that IL-17 level sare significantly high in patients wh orecieved anti TNFtherapy late. Because IL-17 is a crucial component in inflammation pathogenesis of sponylo arthropaties, it is reasonable to think that chronic inflammation is more severe in patients who started the anti TNF therapy late.