Background Takayasu's arteritis (TA) is a granulomatous large vessel vasculitis predominantly affecting the aorta and its major division branches. Over the past decades, cell-mediated autoimmunity has been implicated in the pathogenesis of TA. Studies have shown that the cellular infiltration in TA contains about 15% of CD4+ and 15% of CD8+ T cells respectively. These cells play a key role in the pathogenesis of large-vessel vasculitides. Newly discovered Interleukin (IL)-9–producing CD4+ helper T cells (Th9 cells) have been reported to contribute to doing tissue inflammation and immune responses, preferentially produces IL-9 and that appears to be distinct from Th2 cells, has been reported to provide a unique role to immune responses2,3.
Objectives To identify changes and possible functions of IL-9 and IL-9-producing T cells in the pathogenesis of TA.
Methods Peripheral blood samples were taken from 20 TA patients and 10 healthy donors. Flow cytometry was used to analyze the subsets of Th9 cells (CD4+IL-9+PU.1+) in peripheral blood from 12 TA patients and 10 health controls. Cytometric Bead Array Flex Set was used to analyze the proinflammatory cytokines production in sera of TA patients and healthy donors.
Results We detected the serum proinflammatory cytokines production in TA patients and in healthy donors, our study found that proinflammatory cytokine IL-9 levels were significantly higher in TA patients (10.29±4.46) pg/ml than that of healthy donor group (2.97±1.95) pg/ml (P<0.05) (Fig 1A). Percentage of CD4+IL-9+T cells in PBMC were 8.32%, CD4+PU.1+ T cells in PBMC were 4.26% and IL-9+PU.1+ T cells in CD4+ T cells (Th9 cells) were 7.98% in the peripheral blood of 12 TA patients, and we did not found CD4+IL-9+ T cells, CD4+PU.1+ T cells and CD4+IL-9+PU.1+ T cells in donor group (Fig 1B). Statistical analysis showed no correlation between the percentage of Th9 cells and clinical indexes such as erythrocyte sedimentation rate and C-reactive protein.
Conclusions IL-9 producing T cells especially Th9 cells may play a crucial role in pathogenesis in TA. The role in Th9 cells in disease activity of TA remain to clarify by further studies.
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Disclosure of Interest None declared