The grand majority (35 patients; 76,1 %) chose to discontinue NAT due to high titer JCV positivity or seroconversion during the therapy, thus the elevated risk of progressive multifocal leukoencephalopathy (PML); 4 patients stopped the therapy due to inefficacy, of which 2 patients were proven to have NAT-neutralizing antibodies. Here, BRD2 is linked to progressive multifocal leukoencephalopathy.