MS4A1 and myeloid sarcoma: Palanichamy et al. [7] were among the first to identify CD3+CD20+ T cells in the peripheral blood and cerebrospinal fluid (CSF) of MS patients, describing their enhanced production of pro-inflammatory cytokines (e.g., IFN-γ and IL-17) and their depletion following anti-CD20 therapy (RTX), thereby implicating a potential pathogenic role.