The restoration of deficient counts of B cells expressing a “regulatory” phenotype (CD19+CD24hiCD38hi and CD19+PD-L1hi) in the peripheral blood of relapsing MS patients was observed during the first year following alemtuzumab (47) Values of the naïve B “regulatory” phenotype CD19+CD20+CD27-CD24hiCD38hi were significantly increased compared with baseline up to month 36 following treatment in another study, with a marked decrease in the ratio of total memory B cells to naïve “regulatory” cells (49). This evidence concerns the gene CD19 and myeloid sarcoma.