CD19 and primary progressive multiple sclerosis: Our findings support the concept of CD20 antibody targeted therapy not only in bout onset MS [11,31–34], but also in PPMS [12] considering the increased levels of plasma blasts (CD19+CD138+) in the CSF of PPMS patients which express CD20 [7] and may play a role in the inflammatory process in PPMS as evidenced by the recently reported efficacy of Ocrelizumab in PPMS [12].