Pheripheral Blood B Cells In Patients With Neuromyelitis Optica Spectrum Disorders

ObjectivesNeuromyelitis Optica Spectrum Disorders(NMOSD) is a kind of autoantibody mediated astrocytopathy in central nervous system, which is one of the many serious diseases leading to disability of young adults in our country. The study aimed to analyze the changes of B cells and subtypes including regulatory B cells(Bregs), B cells secreting interleukin 10(B10s), memory B cells(Bmems), plasma cells in patients with NMOSD in acute phase and after high dose methylprednisolone( HDMP) therapy. To evaluate the efficiency of reduced dosage of rituximab(RTX)and the proper time initiating this therapy. To find out wether antirituximab antibody(ARA) was related with clinical response and its influence.MethodsThirteen patients with NMOSD in acute phase and 10 age- and gender- matched healthy controls(HCs) were recruited, peripheral blood monouclear cells(PBMC)were collected then portion and amount of B cell and subtypes were measured and analyzed with flow cytometry. Changes of B cells were evaluated in the 13 patients receiving HDMP. Sixteen patients with NMOSD receiving reduced dosage RTX were recruited and the clinical response were analyzed. Enzyme linked immunosorbent assay(ELISA) was used to evaluated the ARA and B cells were dynamically monitored in 6 of them.Results1.No difference was found in the CD19+B cell number and proportion in patients with NMOSD and HCs. Number and proportion of CD19+CD24hi CD38 hi Bregs and CD19+IL-10+B10s were lower and CD19+CD138+plasma cells higher in acute phase in NMOSD patients than HCs(p < 0.05). No difference were found of the number and proportion of CD19+CD27+Bmems in acute phase of NMOSD patients compared with HCs.2. Number and proportion of CD19+CD24hiCD38hiBregs and CD19+CD138+plasma cells of patients with NMOSD in their acute phasedeclined and Bmems raised after HDMP treatment(p < 0.05). CD19+IL-10+B10s number and proportion of patients with NMOSD in their acute phase showed no significant changes after HDMP treatment(p > 0.05).3.Repeated reduced dosage of RTX therapy significantly decreased the relapse times,annual relapse rate(ARR), EDSS of patients with NMOSD(p < 0.05). There’s no significant difference in the clinical benefit between patients starting RTX therapy within 1 years of onset or after 1 year of onset. Patients starting RTX in remission phase presented less replase times, less ARR, and lower EDSS scores than in acute phase(p < 0.05). No matter patients with higher or lower EDSS, they could all benifit from RTX.4.Number and proportion of CD19+CD24hi CD38 hi Bregs was found no significant difference before and after repeated reduced dosage RTX treatment in 6 patients with NMOSD. While number and proportion of Bregs in patients who responded well to RTX rebounded earlier than whom didn’t(p < 0.05). CD19+CD27+Bmems number and proportion declined after RTX(p < 0.05). But no significant difference on Bmems deletion nor rebounding was found between patients respond well or not.5. 3 of 16 patients who received RTX were ARA positive in sera. ARA negative patients showed lower relapse before or after treatment than ARA positive patients(p< 0.05).Conclusion1. Though no significant difference was found in CD19+ B cells between patients with NMOSD in acute phase and HCs, CD19+CD24hi CD38 hi Bregs and CD19+IL-10+B10s were lower in patients than HCs, mentioning the injury of regulatory function of B cells. No changes were found between patients and HCs in CD19+CD27+Bmems.While CD19+CD138+ plasma cells were significantly higher suggesting the pathogenic function through secreting autoantibodies.2.B cells subtypes responsed differently after HDMP therapy in patients with NMOSD, suggesting the diverse roles of them. CD19+CD24hi CD38 hi Bregs were lower after HDMP while CD19+IL-10+B10s had no changes, though HDMP might inhibit CD19+CD24hi CD38 hi Bregs, the number of B cells secreting IL-10 might be free of HDMP. CD19+CD27+Bmems raised after HDMP, seggesting the inaction of HDMP to Bmems. CD19+CD138+ decreased after HDMP, inhibiting pathogenic autoantibodies production. Low dosage glucocorticoid could not inhibit Bmems and plasma cells, single using low dosage glucocorticoid might not control NMOSD relapse.3.Reduced dosage of RTX was effective in preventing NMOSD relapse. Patients would benefit from reduced dosage RTX, whether RTX was used in early phase or late phase, EDSS high or low. Starting in remission phase would be better. Bregs rebounding speed might related with RTX effect, when reduced dosage RTX was applied to NMOSD patient. Decrease of Bmems after RTX was not related with RTX effect.4. ARA existed in patients receiving reduced dosage RTX and ARA negative patients respond more positively. Presence of ARA might not influence the drug function but could reduce the effect of RTX. ARA might relate with side effects.