CD81 and myeloid sarcoma: Importantly, downregulation persisted in other B cell genes, including MS4A1 (CD20, late pro-B cells through memory cells; enhances BCR response), CD19 (member of costimulatory complex of CD21 complement receptor, CD81, and CD225), EBF1 (early B cell factor 1, regulates B cell commitment) (Figure 4A), and CD80 (costimulatory molecule increased on B cells from therapy-naïve MS patients (9); fold-change = −1.40 at 2 weeks, and − 1.35 at 6 months).