Diabetes and the immune system

Presentation of β-cell peptides by antigen-presenting cell (APCs). APCs bearing these autoantigens interact with autoreactive CD4+ T lymphocytes, which in turn mediate the activation of autoreactive CD8+T cells. CD8+ T cells return to the islet and lyse β cells expressing immunogenic self-antigens on major histocompatibility complex class I surface molecules.β-cell destruction is exacerbated by the release of proinflammatory cytokines and reactive oxygen species from  macrophages, natural killer cells, and neutrophils. This process is amplified by defects in regulatory T lymphocytes. Activated T cells  stimulate B lymphocytes to produce autoantibodies against β-cell proteins. These autoantibodies  are considered a defining biomarker of type 1 diabetes.