In Reply We thank Taylor and Irani for their valuable insights and Kim’s inquiries about serial B-cell levels, plasma cell counts, and the maintenance of efficacy, as well as the safety of our recent report on bortezomib treatment in more severe neuromyelitis optica spectrum disorder (NMOSD) cases.
We appreciate this opportunity to show our analysis of the kinetics of peripheral blood B cells and plasma cells by ﬂow cytometry before and after bortezomib treatment in all 5 patients. CD19+ B cells decrease signiﬁcantly on proteasome inhibition from a median of 230 (interquartile range, 175-390) counts/μL (to convert to ×109 per liter, multiply by 0.001) at baseline, to 107 (67-131) counts/μL at 3 months and 41 (21-158) counts/μL at 12 months (Figure, A). Similarly, numbers of CD138+ plasma cells significantly decreased with bortezomib treatment to 3 (2-5) counts/μL at 3 months and 2 (1-3) counts/μL at 12 months compared with the baseline 7 (6-13) counts/μL (Figure, B). As expected, the numbers of both peripheral B cells and plasma cells slightly recovered after 18 months, increasing to 136 (66-223) counts/μL and 4 (4-7) counts/μL, respectively.
Chao Zhang, Fu-Dong Shi. Bortezomib for Neuromyelitis Optica Spectrum DisorderA New Therapeutic Option for the More Severe Forms?—Reply. JAMA Neurol. Published online November 20, 2017. doi:10.1001/jamaneurol.2017.3450
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