Rituximab therapy reduces activated B cells in both the peripheral blood and bone marrow of @entity1 with XXXX : depletion of memory B cells correlates with clinical response.

@entity1 @entity1075 @entity2225 @entity7211 @entity2731 @entity309
INTRODUCTION: Bone marrow (BM) is an immunologically privileged site where activated autoantibody-producing B cells may survive for prolonged periods. We investigated the effect of rituximab (anti- @entity2225 mAb) in peripheral blood (PB) and BM B-cell and T-cell populations in active @entity309 ( @entity309 ) @entity1 . METHODS: Active @entity309 @entity1 received rituximab (1,000 mg) on days 1 and 15. PB (n = 11) and BM (n = 8) aspirates were collected at baseline and at 3 months. We assessed B-cell and T-cell populations using triple-color flow cytometry. RESULTS: Rituximab therapy decreased PB (from a mean 2% to 0.9%, P = 0.022) but not BM (from 4.6% to 3.8%, P = 0.273) @entity1075 + B cells, associated with a significant reduction in the activated @entity1075 +HLA-DR+ subset both in PB (from 55% to 19%, P = 0.007) and in BM (from 68% to 19%, P = 0.007). Response to rituximab was preceded by a significant decrease in PB and BM @entity1075 + @entity2731 + memory B cells (P = 0.022). These effects were specific to rituximab since anti-TNF therapy did not reduce total or activated B cells. Rituximab therapy did not alter the number of activated CD4+HLA-DR+ and CD4+ @entity7211 + T cells. CONCLUSIONS: Rituximab therapy preferentially depletes activated @entity1075 +HLA-DR+ B cells in the PB and BM of active @entity309 @entity1 . Clinical response to rituximab is associated with depletion of @entity1075 + @entity2731 + memory B cells in PB and BM of @entity309 @entity1 .
