MS4A1 and myeloid sarcoma: ATZ effectiveness on CD20+ T cells seems to persist beyond two years of treatment, as, despite partial recovery of the T cell pool, the percentage of CD20+ T cells was persistently reduced in a treated RR-MS cohort compared to untreated patients, with means of 1.99% vs. 7.73%, respectively (p < 0.0001), and this was associated with an increased CD4+/CD8+ CD20+ T cell ratio (p = 0.029) [13].