POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal protein [M-protein], and skin changes) is a rare systemic disorder characterized by various symptoms caused by underlying plasma cell (PC) dyscrasia. Detection of monoclonal PCs is mandatory for the diagnosis of POEMS syndrome; however, the usefulness of EuroFlow-based next-generation flow cytometry (EuroFlow-NGF) in POEMS syndrome for detecting monoclonal PCs in bone marrow (BM) and the gating strategy suitable for flow cytometry study of POEMS syndrome remain unknown. We employed EuroFlow-NGF-based single-tube eight-color multiparameter flow cytometry (MM-flow) and established a new gating strategy (POEMS-flow) to detect the monoclonal PCs in POEMS syndrome, gating CD38 broadly from dim to bright and CD45 narrowly from negative to dim compared to MM-flow. MM-flow detected monoclonal PCs in 9/25 (36.0%) cases, including 2/2 immunofixation electrophoresis (IFE)-negative cases (100%). However, POEMS-flow detected monoclonal PCs in 18/25 cases (72.0%), including 2/2 IFE-negative cases (100%). POEMS-flow detected monoclonal PCs with immunophenotypes of CD19⁻ in 17/18 (94.4%). In six cases where post-treatment samples were available, the size of the clones was significantly reduced after the treatment (P = 0.031). POEMS-flow can enhance the identification rate of monoclonal PCs in POEMS syndrome and become a valuable tool for the diagnosis of POEMS syndrome.

POEMS 综合征（多发性神经病、器官肿大、内分泌病、单克隆蛋白 [M 蛋白] 和皮肤变化）是一种罕见的全身性疾病，其特征是由潜在浆细胞 (PC) 恶液质引起的各种症状。 POEMS 综合征的诊断必须检测单克隆 PC；然而，基于 EuroFlow 的下一代流式细胞术 (EuroFlow-NGF) 在 POEMS 综合征中检测骨髓 (BM) 中单克隆 PC 的有用性以及适合 POEMS 综合征流式细胞术研究的门控策略仍然未知。我们采用基于 EuroFlow-NGF 的单管八色多参数流式细胞仪 (MM-flow) 并建立了新的门控策略 (POEMS-flow) 来检测 POEMS 综合征中的单克隆 PC，对 CD38 从暗到亮进行广泛门控，对 CD45 进行门控。与 MM 流相比，从负到暗淡的范围很窄。 MM-flow 在 9/25 (36.0%) 病例中检测到单克隆 PC，其中包括 2/2 免疫固定电泳 (IFE) 阴性病例 (100%)。然而，POEMS-flow 在 18/25 例 (72.0%) 中检测到单克隆 PC，其中包括 2/2 IFE 阴性病例 (100%)。 POEMS-flow 在 17/18 (94.4%) 中检测到具有 CD19 ⁻免疫表型的单克隆 PC。在可获得治疗后样本的六例中，治疗后克隆的大小显着减小（ P = 0.031）。 POEMS-flow可以提高POEMS综合征中单克隆PC的识别率，成为诊断POEMS综合征的有价值的工具。