Cladribine is a deoxyadenosine analog that exhibits immunosuppressive and anticancer chemotherapeutic activities. Cladribine is used clinically to treat hairy cell leukemia and has shown mixed results as a potential treatment for multiple sclerosis. Cladribine induces apoptosis in monocyte-derived dendritic cells. Across many cellular models, this compound decreases levels of circulating B and T lymphocytes and inhibits growth of both proliferating and quiescent cells. As a nucleoside analog, cladribine inhibits DNA polymerase and ribonucleotide reductase, suppressing DNA repair and synthesis.