The current article highlights the role of mitochondrial function in three aspects of ‘autoimmune’ disorders, namely: (1) intercellular interactions leading to dyshomeostasis in a given microenvironment within different tissues and organs; (2) the attraction and activation of cytolytic cells, including NK cells and CD8+ T cells; (3) the regulation of B-cell function, phenotypes and antibody production, as shown in Figure 4 (see Figure 6). This evidence concerns the gene CD8A and autoimmune disease.