Regulatory CD8 T cells found in patients

The understanding of peripheral immune tolerance in humans has been extended through the recent contribution by Li and colleagues. In this study, KIR+CD8+ T cells showed the capacity to suppress pathogenic CD4+ T cells. That’s a similar functionality as previously described in mice for the Ly49+CD8+ cell population. Higher frequencies of those T cells were found in patients with autoimmune diseases and COVID-19. In contrast to CD4+ Tregs, these CD8+ counterparts might play a distinct role in orchestrating tolerance because of their cytotoxic capacities.

Based on the clear upregulation of cytotoxic genes, we’d love to see future FluoroSpot experiments exploring cytokine secretion in this cell subpopulation.