MS4A1 and myeloid sarcoma: In a cohort of PP-MS patients, the percentage of CSF CD4+CD20+, but not of CD8+CD20+ memory, T cells showed a positive correlation with age (r = 0.6799, p = 0.0150), whereas the latter was inversely correlated with the frequency of CSF B cells (r = −0.6603, p = 0.0140) [33].