Sintilimab for treating progressive multifocal leukoencephalopathy caused by human polyomavirus 2 virus infection following allogeneic hematopoietic cell transplantation: a case report

Background: Progressive multifocal leukoencephalopathy (PML) is characterized by demyelination in the central nervous system. It is caused by infection with human polyomavirus 2 and has a poor prognosis. Therapeutic strategies involve restoring immune function and/or discontinuing immunosuppressive treatment. Immune checkpoint inhibitors such as those targeting programmed death receptor-1 (PD-1) can alleviate PML by restoring T cell function. There are no case reports on the use of the PD-1 inhibitor, Sintilimab, for treating PML. Here, we report a case of successful treatment of PML with sintilimab following allogeneic hematopoietic stem cell transplantation.