Waldenström Macroglobulinemia (WM) is a lymphoplasmacytic lymphoma with bone marrow (BM) involvement and IgM monoclonal gammopathy. To date, no studies have focused specifically on peripheral blood (PB) involvement. In this study, 100 patients diagnosed with WM according to the World Health Organization (WHO) criteria were included based on the demonstration ofMYD88mut in BM and the availability of PB multiparametric flow cytometry (MFC) analysis. Leukemic involvement by MFC was detected in 50/100 patients. A low percentage of mature small lymphocytes in PB smears was observed in only 15 cases.MYD88mut by AS-qPCR was detected in PB in 65/100 cases. In cases with leukemic expression by MFC,MYD88mut was detected in all cases, and IGH was rearranged in 44/49 cases. In 21/50 patients without PB involvement by MFC, molecular data were consistent with circulating disease (MYD88mut by AS-qPCR 3/50, IGH rearranged 6/50, both 12/50). Therefore, PB involvement by standard techniques was detected in 71/100 patients.MYD88mut was detected in PB by dPCR in 9/29 triple negative cases. Overall, 80% of the patients presented PB involvement by any technique. Our findings support the role of PB MFC in the evaluation of patients with IgM monoclonal gammopathy and provide reliable information on correlation with molecular features. The development of a feasible MFC assay may stand as an objective tool in the classification of mature B cell neoplasms presenting with IgM monoclonal gammopathy.
华氏巨球蛋白血症（WM）是一种伴有骨髓（BM）受累及IgM单克隆丙种球蛋白病的淋巴浆细胞淋巴瘤。迄今为止，尚无研究专门关注外周血（PB）受累情况。本研究依据世界卫生组织（WHO）诊断标准，纳入100例确诊WM患者，所有病例均经骨髓MYD88突变证实并具备PB多参数流式细胞术（MFC）检测数据。MFC检测发现50/100例患者存在白血病性受累，而PB涂片仅15例观察到少量成熟小淋巴细胞。通过等位基因特异性定量PCR（AS-qPCR）在65/100例患者PB中检出MYD88突变。在MFC显示白血病性表达的病例中，所有病例均检出MYD88突变，且44/49例存在IGH基因重排。在21/50例MFC未显示PB受累的患者中，分子学数据提示存在循环疾病（AS-qPCR检出MYD88突变3/50例，IGH重排6/50例，两者兼具12/50例）。因此，通过标准技术共在71/100例患者中检测到PB受累。通过数字PCR（dPCR）在9/29例三重阴性病例的PB中检出MYD88突变。总体而言，80%的患者经任何技术检测均显示PB受累。本研究结果支持PB MFC在IgM单克隆丙种球蛋白病患者评估中的作用，并提供了与分子特征相关性的可靠信息。开发可行的MFC检测方法，可作为伴IgM单克隆丙种球蛋白病的成熟B细胞肿瘤分类的客观工具。
Leukemic Involvement Is a Common Feature in Waldenström Macroglobulinemia at Diagnosis
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