[Expression and clinical significance of CXCR3 on effector T cells in the peripheral blood of patients with Alzheimer's disease].

<b>Objective:</b> This study investigated the expression of C-X-C motif chemokine receptor 3 (CXCR3) on CD45RO⁺ T cells in the peripheral blood of patients with Alzheimer's disease (AD) and its association with clinical features. <b>Methods:</b> A total of 41 AD patients and 30 age-and sex-matched healthy controls (HCs) were recruited from the Department of Neurology at the Medical Division of PLA General Hospital between September 2022 and March 2024. Flow cytometry was used to quantify CXCR3 expression on CD45RO⁺ T cell subsets in peripheral blood. Dementia severity in AD patients was assessed using the Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA). Spearman correlation analysis examined the relationship between CD45RO⁺CXCR3⁺ T cell levels and cognitive function in the AD group. Receiver operating characteristic (ROC) curve analysis determined the predictive utility of CD45RO⁺CXCR3⁺ T cells for AD, quantified by the area under the curve (AUC). <b>Results:</b> Compared to healthy controls, AD patients exhibited significantly elevated levels of CD8⁺CD45RO⁺CXCR3⁺ T cells [17.8% (7.2%, 40.3%) vs. 8.2% (5.1%, 12.3%), <i>Z</i>=-2.59, <i>P</i><0.05]. However, no significant differences were observed for CD4⁺CD45RO⁺CXCR3⁺ T cells, CD4⁺CD45RO⁻CXCR3⁺ T cells, or CD8⁺CD45RO⁻CXCR3⁺ T cells (<i>P</i>>0.05). Spearman correlation analysis revealed a negative correlation between CD8⁺CD45RO⁺CXCR3⁺ T cell levels and cognitive scores (MMSE: <i>r</i>=-0.72, <i>P</i><0.05; MoCA: <i>r</i>=-0.70, <i>P</i><0.05). ROC analysis demonstrated an AUC of 0.81 for CD8⁺CD45RO⁺CXCR3⁺ T cells in predicting AD, with a sensitivity of 59.0% and specificity of 93.3%. <b>Conclusions:</b> CXCR3 expression is significantly upregulated on CD8⁺CD45RO⁺ T cells in AD patients, and its levels correlate with cognitive impairment severity. These findings suggest that CD8⁺CD45RO⁺CXCR3⁺ T cells may serve as a potential biomarker for AD diagnosis and progression monitoring.