ABSTRACT
Progressive multifocal leukoencephalopathy (PML) is a rare and lethal central nervous demyelinating disease caused by JC polyomavirus (JCV), particularly in patients with impaired immune system. The variation of JCV plays an important role in the pathogenesis of PML, including the recombination of non-coding regulatory region (NCCR), which is closely related to binding sites of transcription factors and affect the level of gene transcription. Nucleotide mutations in VP1 region determine the antigenicity and receptor specificity of JCV, play an important role in cell adsorption, immune-mediation and pathogenicity. In addition, immune cells are also involved in the pathogenesis of PML. T lymphocytes can recognize virus antigens, clear JCV, which are directly related to the prognosis of PML. B lymphocytes can serve as latent sites of JCV, and participate in viral transmission, replication, and coordination of the expression of transcription factors. This paper summarizes the roles of JCV variation and immune cells in pathogenesis of PML.