IBTK and myeloid sarcoma: Since in MS regulatory functions have been attributed to transitional and naïve B cells, while the memory B-cell pool is considered to harbor B cells responsible for the aberrant activation of T cells, the overall effects we observe of BTKi on phenotypic and functional properties of B cells suggest that treatment with BTKi both limits activation and mediates a pro-inflammatory to anti-inflammatory shift in circulating B-cell responses.