Enhanced cytotoxicity of aging associated NKG2C + CD8 + T cells in ankylosing spondylitis via HLA-B27

This study aims to explore the common mechanisms between aging and the pathogenesis of ankylosing spondylitis (AS) and to identify potential therapeutic targets. A total of 87 patients with AS and matched controls were analyzed via multidimensional flow cytometry to examine the peripheral blood immune signature. Single-cell RNA sequencing was employed to characterize T-cell subsets. The infiltration of Ly49h + cells (the murine homolog of NKG2C) was observed in a collagen-induced arthritis mouse model, and functional experiments were conducted to validate the cytotoxicity of NKG2C + CD8 + T cells. The mechanisms were further confirmed via the use of HLA-B27 transgenic mice and RNA-sequencing. The peripheral blood immune signature of AS patients exhibited dysregulation similar to that observed during aging. NKG2C + CD8 + T cells activated the PI3K‒Akt signaling pathway and increased phagocytosis in AS patients. HLA-B27 stimulation significantly increased the cytotoxicity of this subset, an effect that could be reversed by NKG2C blockade. In HLA-B27 transgenic mice, Ly49h + T cells exhibited significantly enhanced degranulation ability. RNA sequencing validated the activation of the PI3K‒Akt pathway in NKG2C + CD8 + T cells by HLA-B27. HLA-B27 drives the cytotoxicity of aging-related NKG2C + CD8 + T cells via activation of the PI3K‒Akt signaling pathway. Targeting NKG2C inhibition may represent a novel therapeutic strategy for AS. This study elucidates the association between immune aging and the pathogenesis of AS, providing theoretical evidence for clinical intervention.