These included a history for Sjögren syndrome (n = 4), a history of malignancy (n = 2), prior and concomitant therapy with disease-modifying anti-rheumatic drugs with established risk for PML (Molloy and Calabrese 2012) (n = 9; the most common of which was MTX), and treatment with ≥ 2 prior TNF inhibitors (n = 4). This evidence concerns the gene TNF and progressive multifocal leukoencephalopathy.