Xuemei Xie, MD PhD: No financial relationships to disclose
Introduction/Rationale: Subsets of T cells have been shown to home to atherosclerotic plaque in atherosclerosis patients. In mice, CXCR6 and CCR5 play roles in mediating T cell recruitment to atherosclerotic lesions. We hypothesized that human T cell subsets possess the capacity to traffic between blood and atherosclerotic plaque. CD4+ regulatory T cells (Tregs) are known to give rise to exTregs, but their differentiation in atherosclerosis remains unclear. To address these gaps, we integrated CITE-seq datasets of PBMC and plaque from patients, focusing on αβ CD4⁺ T cells composition, migratory signatures, and differentiation between blood and plaque.
Methods: We analyzed CITE-seq datasets from a total of 12 patients aged over 69 years (6 PBMCs and 6 plaque). Data was integrated using LIGER. αβ CD4⁺ T cells were subset for re-clustering. TCR-seq data was used to assess clonal expansion across CD4⁺ T cell subsets. Trajectory analyses were used to infer differentiation relationships. pySCENIC was preformed to infer transcription factor activity.
Results: Integrated analysis showed enrichment of mast cells and NKT cells in plaque, while NK cells, classical monocytes, and CD4⁺ T cells predominated in blood. CD4⁺ T cell re-clustering identified naive, effector, memory, cytotoxic, and regulatory subsets. Naive and effector CD4⁺ T cells were blood-enriched, whereas cytotoxic effector memory CD4⁺ T cells and FoxP3hi Tregs were enriched in plaque. Cytotoxic CD4⁺ T cells expressed CCL5, GZMA, and GZMK, consistent with cytotoxic exTregs. FoxP3hi Tregs showed an activated phenotype distinct from FoxP3low Tregs. CXCR6 and CCR5 marked plaque-homing CD4⁺ T cells, with CCR7 supporting inter-compartment trafficking; CCR6 emerged as an additional pathway. Trajectory and TCR analyses supported differentiation from naive CD4⁺ T cells through unstable Tregs toward cytotoxic states, driven by ETV7 and GFI1 regulons.
Conclusion: Our study showed CD4⁺ T cell subset composition and differentiation between blood and plaque.
