The role of memory T cells in type 1 diabetes: Phenotypes, mechanisms, and therapeutic implications

Type 1 diabetes (T1D) is a chronic autoimmune disease characterized by the loss of insulin-producing cells in the pancreatic islets. Patients with T1D have autoreactive CD4⁺ and CD8⁺ T cells that show specific features, indicating previous exposure to self-antigens. Despite that memory T cells are vital components of the adaptive immune system, providing enduring protection against pathogens; individuals with T1D have a higher proportion of memory T cells compared to healthy individuals with naїve phenotypes. Targeting memory T cells in newly diagnosed T1D patients has shown promising results, providing evidence for the significant role of memory T cells in this disease. There are various types of memory T cells, each with unique characteristics and functions. Recent advancements in understanding the complexity and heterogeneity of T cell subpopulations have shown that T1D cannot be fully understood through simple categorization. This review aims to discuss various types of memory T cells in the immunopathogenesis of T1D, focusing on their phenotypes and frequencies, as well as epigenetic and metabolic alterations. Additionally, it will address novel immunotherapeutic approaches targeting memory T cell subsets in T1D.