B cell depleting therapies permit immunosuppressive drug withdrawal and maintain remission in patients with frequently relapsing nephrotic syndrome (FRNS) or steroid–dependent nephrotic syndrome (SDNS), but lack of biomarkers for treatment failure. Post-depletion immune cell reconstitution may identify relapsing patients, but previous characterizations suffered from methodological limitations of flow cytometry. Time-of-flight mass cytometry (CyTOF) is a comprehensive analytic modality that simultaneously quantifies over 40 cellular markers. Herein, we report CyTOF-enabled immune cell comparisons over a 12-month period from 30 children with SDNS receiving B cell depleting therapy who either relapsed (n = 17) or remained stable (n = 13). Anti-CD20 treatment depleted all B cells subsets and CD20 depleting agent choice (rituximab vs ofatumumab) did not affect B cell subset recovery. Despite equal total numbers of B cells, 5 subsets of B cells were significantly higher in relapsing individuals; all identified subsets of B cells were class-switched. T cell subsets (including T follicular helper cells and regulatory T cells) and other major immune compartments were largely unaffected by B cell depletion, and similar between relapsing and stable children. In conclusion, CyTOF analysis of immune cells from anti-CD20 antibody treated patients identifies class-switched B cells as the main subset whose expansion associates with disease relapse. Our findings set the basis for future studies exploring how identified subsets can be used to monitor treatment response and improve our understanding of the pathogenesis of the disease.

B 细胞耗竭疗法允许频繁复发性肾病综合征 (FRNS) 或类固醇依赖性肾病综合征 (SDNS) 患者停用免疫抑制药物并维持缓解，但缺乏治疗失败的生物标志物。消耗后免疫细胞重建可以识别复发患者，但之前的表征受到流式细胞术方法学上的限制。飞行时间质谱流式细胞术 (CyTOF) 是一种综合分析模式，可同时量化 40 多种细胞标记物。在此，我们报告了 30 名接受 B 细胞耗竭治疗的 SDNS 儿童在 12 个月内对 CyTOF 启用的免疫细胞进行的比较，这些儿童要么复发（n = 17），要么保持稳定（n = 13）。抗 CD20 治疗消耗了所有 B 细胞亚群和 CD20 消耗剂选择（利妥昔单抗对比ofatumumab) 不影响 B 细胞亚群的恢复。尽管 B 细胞总数相同，但在复发个体中，5 个 B 细胞亚群显着更高；所有已识别的 B 细胞亚群都进行了类别转换。T 细胞亚群（包括 T 滤泡辅助细胞和调节性 T 细胞）和其他主要免疫区室在很大程度上不受 B 细胞耗竭的影响，复发和稳定儿童之间也相似。总之，来自抗 CD20 抗体治疗患者的免疫细胞的 CyTOF 分析将类别转换的 B 细胞确定为主要亚群，其扩增与疾病复发相关。我们的研究结果为未来的研究奠定了基础，探索如何使用已识别的子集来监测治疗反应并提高我们对疾病发病机制的理解。