IL2 and progressive multifocal leukoencephalopathy: Only a handful of cases have been described showing clinical improvement in PML patients when treated with IL-2.14,35, , –38 Our results add to these previous observations by demonstrating a marked rise in HPyV-2-specific T-cells in association with resolution of HPyV-2 viremia and clinical improvement, which was not measured in the majority of prior reports.