Role of CD20+ T cells in cancer, autoimmunity and obesity.

Despite the known link between obesity and insulin resistance (IR) to chronic low-grade inflammation, new markers capable of early IR detection are needed. Immune cells are components of adipose tissue's (AT) stromal vascular fraction (SVF) that regulate AT homeostasis. The altered phenotype and function of AT-infiltrating immune cells may contribute to the development and maintenance of local AT inflammation observed under obesity-induced IR conditions. Impaired AT-specific immunometabolic function may influence the whole organism. Therefore, AT-infiltrating immune cells may be important players in the development of obesity-related metabolic complications, such as type 2 diabetes mellitus (T2DM). B and T cells, particularly CD20+ T cells, play important roles in human pathology, such as autoimmune disease and cancer. However, the question remains as to whether CD20+ T cells have an important contribution to the development of obesity-related IR. While circulating CD20+ T cells are mostly of the central memory phenotype (i.e. antigen-experienced T cells with the ability to home to secondary lymphoid organs), tissues-infiltrated CD20+ T cells are predominantly of the effector memory phenotype (i.e. antigen-experienced T cells that preferentially infiltrate peripheral tissues). The latter produce pro-inflammatory cytokines, such as IFN-γ and IL-17, which play a role in obesity-related IR development. This review describes the CD20 molecule and its presence in both B and T cells, shedding light on its ontogeny and function, in health and disease, with emphasis on AT. The link between CD20+ T cell dysregulation, obesity, and IR development supports the role of CD20+ T cells as markers of adipose tissue dysmetabolism.