The Pathogenic Role of Expanded CD8⁺CD28 Angiogenic T Cells in ANCA-Associated Vasculitis.

Angiogenic T cells (Tang) are crucial in promoting angiogenesis, with the loss of CD28 serving as a marker for highly differentiated and senescent T cells. This study aims to investigate the characteristics and potential roles of CD8CD28 Tang in patients with ANCA-associated vasculitis (AAV). A cohort of AAV patients and matched healthy controls (HCs) were analyzed. Flow cytometry was used to assess the profiles of circulating CD8CD28 Tang. In vitro functional assays were performed to evaluate the pathogenic properties of CD8CD28 Tang. : CD8CD28 Tang levels were significantly higher in the peripheral blood of AAV patients compared to HCs, and their levels were further increased in AAV patients with MPO⁺, p-ANCA⁺, or interstitial lung disease compared to their respective control groups. Additionally, there was a positive correlation between both the percentage and absolute count of CD8CD28 Tang and the Birmingham Vasculitis Activity Score (BVAS). In patients with a good treatment response, both the percentage and absolute count of CD8CD28 Tang were significantly reduced, and this reduction was positively correlated with the decrease in BVAS scores. In vitro studies revealed that CD8CD28 Tang displayed enhanced chemotactic properties, induced apoptosis in human umbilical vein endothelial cells (HUVECs), and inhibited their proliferation, migration, and tube formation. AAV patients exhibit increased levels of circulating CD8CD28 Tang, which can be reduced following effective treatment. Furthermore, CD8CD28 Tang may contribute to the pathogenesis of AAV by promoting apoptosis and inhibiting the proliferation, migration, and tube formation of HUVECs.