Loss of effector Treg signature in APOB-reactive CD4+ T cells in patients with coronary artery disease

Atherosclerosis underlies most coronary artery disease (CAD). It involves a significant autoimmune component against apolipoprotein B (APOB). In this study, we used short activation-induced marker (AIM) assays to characterize APOB-reactive CD4+ T cells in patients with angiographically verified CAD. APOB-reactive CD4+ T cells expressing CD25 and 4-1BB markers were the most abundant. Their frequency correlated positively with CAD severity. Transcriptomic analysis revealed that these cells were clonally expanded and significantly enriched in genes expressed in tissue-homing effector regulatory T (eTreg) cells. They shared signatures with CD4+ T cells in mouse and human plaques, including expression of the plaque-homing chemokine receptor CXCR6. With increasing disease severity, the Treg signature was progressively and significantly lost. Conversely, APOB-specific Treg cells from patients with severe CAD gained glycolytic and interferon response signatures. We conclude that mild CAD is associated with a regulatory program in APOB-reactive CD4+ T cells, which is replaced by a pro-inflammatory program in patients with severe CAD. By characterizing APOB-reactive CD4+ T cells in patients with atherosclerosis, Roy et al. identify effector regulatory T (eTreg) cells as the predominant autoreactive subset. These APOB-specific eTreg cells are clonally expanded, express the plaque-homing receptor CXCR6 and progressively lose their regulatory phenotype as disease severity increases.