Graft versus host disease: New insights into A(2A) receptor agonist therapy

Allogeneic transplantation can cure many disorders, including sickle cell disease, chronic granulomatous disease (CGD), severe combined immunodeficiency (SCID) and many types of cancers. However, there are several associated risks that can result in severe immunological reactions and, in some cases, death. Much of this morbidity is related to graft versus host disease (GVHD) [1]. GVHD is an immune mediated reaction in which donor T cells recognize the host as antigenically foreign, causing donor T cells to expand and attack host tissues. The current method of treating recent transplant patients with immunosuppressants to prevent this reaction has met with only partial success, emphasizing a need for new methods of GVHD treatment and prevention. Recently, a novel strategy has emerged targeting adenosine A(2A) receptors (A(2A)R) through the use of adenosine agonists. These agonists have been shown in vitro to increase the TGFβ-induced generation of FoxP3(+) regulatory T cells (T(regs)) and in vivo to improve weight gain and mortality as well as inhibit the release of pro-inflammatory cytokines in GVHD murine models [2,3]. Positive results involving A(2A)R agonists in vitro and in vivo are promising, suggesting that A(2A)R agonists should be a part of the management of clinical GvHD.