MS4A1 and myeloid sarcoma: Further validation was generated by an independent scRNA-seq dataset including TCR data of paired blood and CSF samples from five MS patients and six healthy controls42: Expanded TRB clonotypes showed higher proportion of MS4A1 expressing cells both in blood and CSF (Figure S5D), and MS4A1-expressing, expanded clonotypes showed sequence overlap from blood to CSF (Figure S5E).