BRD2 and progressive multifocal leukoencephalopathy: The mean percentage of TRB perturbations, measured at the PML onset in the 5 PML patients, was similar to that of a group of 30 untreated MS patients (that included PML-NAT#1, PML-NAT#2 and MS#1-5 analyzed before natalizumab first infusion), but was significantly higher than in HC (Fig. 2).