OBJECTIVETo detect memory B lymphocyte (Bm) in peripheral blood (PB) of immune-related pancytopenia (IRP).

METHODS86 patients with IRP and 11 health volunteers were enrolled in this study. Bm (CD5⁺ CD19⁺ CD27⁺) and bone marrow mononucleated cell antibodies (BMMNC-Ab) were determined via fluorescence-activated cell sorting, and clinical outcomes of these patients were analyzed.

RESULTS(1)43 initial patients achieved obvious remission in all 52 initial cases after conventional immunosuppression therapy. 16 relapsed patients with IRP received Rituximab (RTX) and 14 cases achieved obvious remission, among which 7 cases were refractory to conventional immunosuppression therapy, 5 cases exhibited obvious remission, and 2 cases did not respond. Other 18 relapsed cases received conventional immunosuppression therapy and 13 cases achieved obvious remission. (1)The level of Bm in PB in 52 initial patients with IRP was(1.81 ± 0.97)%, and no significant difference was observed between the initial patients and health volunteers (1.75 ± 0.55)% (P>0.05). The level of Bm in PB in 34 relapsed patients with IRP was obviously higher than that in the initial IRP patients and health volunteers (P<0.05). Significant difference was observed in the level of Bm in PB in 16 relapsed IRP patients between pre-therapy and post-therapy with RTX (P<0.05). No statistical difference was found between the remission and no-response groups in relapsed patients treated with RTX. RTX regimen produced more effective outcome than conventional immunosuppression therapy, which better eliminated Bm than the latter (P<0.05). Initial patients with IRP who relapsed within a two-year follow-up period had a lower level of Bm in PB compared with un-relapsed patients (P<0.05). Majority of BMMNC- Ab antibodies in relapsed patients were IgG (82.4%) and IgM (69.2%) autoantibodies in patients with initial IRP.

CONCLUSIONThe level of Bm in PB was associated with relapsed patients with IRP. Bm did not respond to conventional immunosuppression therapy,but responded to RTX.