Targeting of the A2A adenosine receptor counteracts immunosuppression in vivo in a mouse model of chronic lymphocytic leukemia.

Tumor immunosuppression is a major cause for treatment failure and disease relapse, both in solid tumors and leukemia. Local hypoxia is among the conditions that cause immunosuppression, acting at least in part through the upregulation of extracellular adenosine levels, which potently suppress T cell responses and skew macrophages towards an M2 phenotype. Hence, there is intense investigation to identify drugs that target this axis.

Immune Response Dysfunction in Chronic Lymphocytic Leukemia: Dissecting Molecular Mechanisms and Microenvironmental Conditions.

Representing the major cause of morbidity and mortality for chronic lymphocytic leukemia (CLL) patients, immunosuppression is a common feature of the disease. Effectors of the innate and the adaptive immune response show marked dysfunction and skewing towards the generation of a tolerant environment that favors disease expansion. Major deregulations are found in the T lymphocyte compartment, with inhibition of CD8 cytotoxic and CD4 activated effector T cells, replaced by exhausted and more tolerogenic subsets.