Immune reconstitution and remission in CML

In a comprehensive and provocative report in this issue of Blood, with findings that were not necessarily expected, Hughes and colleagues report on the immune reconstitution that occurs as a consequence of the deepening remission achieved by patients with chronic myelogenous leukemia (CML) on tyrosine kinase inhibitors (TKIs). A significant fraction of patients with CML treated with BCR-ABL TKI achieve long-term remissions and maintain this state even after stopping the TKI. Why is this? Although the TKI itself may be contributing to this immune restoration, it is not entirely responsible as best effects are observed in those patients no longer on these drugs.