Predictive T-Cell Biomarkers for Checkpoint Inhibitor Response in PML

Progressive multifocal leukoencephalopathy (PML) is a devastating brain infection caused by the JC virus following immune system failure. These sources detail how the virus transforms into a neurotropic phenotype to destroy brain tissue, specifically targeting subcortical white matter and creating distinct patterns on MRI scans. Diagnosis relies on the Berger criteria, which combine clinical symptoms, radiological evidence of tissue destruction, and viral detection in spinal fluid. Current management emphasizes immune reconstitution, ranging from adjusting antiretroviral therapy to using plasma exchange for drug-induced cases. Recent clinical research highlights immune checkpoint inhibitors, such as pembrolizumab, as a vital frontier in treatment. Specifically, the presence of virus-specific T cells before therapy serves as a critical biomarker, predicting significantly higher survival rates and improved functional recovery for patients.