ANXA1 and progressive multifocal leukoencephalopathy: In fact, one of the key treatments for Multiple Sclerosis—Natalizumab is a humanized monoclonal antibody against α4β1 integrin with the aim to prevent T-cell infiltration into the brain parenchyma thus suggesting the potential for exploiting ANXA1 as a therapeutic particularly as Natalizumab carries the risk of developing progressive multifocal leukoencephalopathy (PML) as a side effect [141].