Although most patients with type 1 diabetes (T1D) retain some functional insulin-producing islet β cells at the time of diagnosis, the rate of further β cell loss varies across individuals. It is not clear what drives this differential progression rate. CD8+ T cells have been implicated in the autoimmune destruction of β cells. Here, we addressed whether the phenotype and function of autoreactive CD8+ T cells influence disease progression. We identified islet-specific CD8+ T cells using high-content, single-cell mass cytometry in combination with peptide-loaded MHC tetramer staining. We applied a new analytical method, DISCOV-R, to characterize these rare subsets. Autoreactive T cells were phenotypically heterogeneous, and their phenotype differed by rate of disease progression. Activated islet-specific CD8+ memory T cells were prevalent in subjects with T1D who experienced rapid loss of C-peptide; in contrast, slow disease progression was associated with an exhaustion-like profile, with expression of multiple inhibitory receptors, limited cytokine production, and reduced proliferative capacity. This relationship between properties of autoreactive CD8+ T cells and the rate of T1D disease progression after onset make these phenotypes attractive putative biomarkers of disease trajectory and treatment response and reveal potential targets for therapeutic intervention.
Alice E. Wiedeman, Virginia S. Muir, Mario G. Rosasco, Hannah A. DeBerg, Scott Presnell, Bertrand Haas, Matthew J. Dufort, Cate Speake, Carla J. Greenbaum, Elisavet Serti, Gerald T. Nepom, Gabriele Blahnik, Anna M. Kus, Eddie A. James, Peter S. Linsley, S. Alice Long
Islet-specific CD8+ T cells are dominated by three CXCR3+ memory phenotypes across subjects with T1D.