P020. The Th17 cell population in the peripheral blood in patients with Crohn's disease
K. Radwan1, P. Radwan2, A. Surdacka3, C. Lozowski2, B. Skrzydlo-Radomanska2, J. Rolinski3, 1Central Clinical Hospital of Internal Affairs, Warsaw, Internal Medicine and Gastroenterology, Warsaw, Poland, 2Medical University of Lublin, Gastroenterology, Lublin, Poland, 3Medical University of Lublin, Clinical Immunology, Lublin, Poland
The prevailing dogma regarding the etiopathogenesis of Crohn's disease (CD) that T-helper (Th)1 CD4+ T cell population overreacts towards the bacterial microflora, might be dispelled by the discovery of Th17 cell population. Although it is thought to contribute to the immune-mediated disease development, its role in CD remains unclear. The aim of our study was to evaluate the percentage of IL-17-producing CD4+ and CD8+ T cells in the peripheral blood of CD patients in flare-up in comparison with healthy controls and to assess the influence of anti-TNFalpha therapy on circulating effector Th17 cells.
Patients and Methods: We evaluated CD4+IL-17+ and CD8+/IL-17+ T cell populations by flow cytometry in peripheral blood of 40 adult patients with active CD and 39 healthy volunteers. 20 CD patients were studied before and 6 weeks after the beginning of anti-TNFalpha therapy. The results were expressed as percentage of CD4+/IL-17+ and CD8+/IL-17+ Tcells of total Tcells. Disease activity was evaluated with the use of of CDAI score and C-reactive protein (CRP) levels.
The median percentages of both CD4+/IL-17+ and CD8+/IL-17+ T cells were significantly increased in peripheral blood in patients with active CD as compared to healthy controls (respectively, p < 0.0001, p < 0.005). We have also found the significant positive correlation between the disease activity assessed by CDAI as well as CRP level and CD4+/IL-17+ T cell percentage (respectively; r = 0.53, p < 0.001; r = 0.698, p < 0.0001). Moreover, the percentage of CD4+/IL-17+ T cells was significantly decreased in CD patients after anti-TNFalpha therapy compared to baseline by Wilcoxon signed rank test for paired determination (p < 0.0001).
Our data may suggest an important contribution of effector Th17 cell in the etiopathogenesis of Crohn's disease and may implicate their role as possible therapeutic target.