CD52 and myeloid sarcoma: Memory B cells and plasma blasts are predominantly detected in the CSF of MS patients and are rarely detected or undetectable in the CSF of normal donors25 Treatments that broadly target B cells, including anti-CD20 (ocrelizumab and ofatumumab), anti-CD52, and cladribine, are clinically effective in MS, while those that target naïve and plasma B cells (e.g., Atacicept) or boost memory B cells (e.g. infliximab) are deleterious 26,27.