Objective: To investigate the clinical characteristics, responses, and prognosis of immunoglobulin M multiple myeloma (IgM MM) . Methods: The clinical characteristics, laboratory results, bone marrow biopsy results, response, and prognosis of six cases of IgM MM in the Blood Diseases Hospital, Chinese Academy of Medical Sciences, from December 18, 2009 to October 29, 2020 were collected and analyzed. Results: All six cases met the diagnosis criteria of IgM MM. There were four males and two females. The median age at first diagnosis was 70 (59-81) years. According to Durie-Salmon (DS) staging, 2 cases were in ⅠA, and 4 cases were in ⅢA. According to the International Staging System (ISS) , 4 cases were in Ⅱ, and 2 cases were in Ⅲ. The initial symptoms were as follows: 4 cases of bone pain, 3 cases of hyperviscosity, and 2 cases of lymphadenopathy or hepatosplenomegaly. Laboratory results showed the following: median blood M protein: 39.11 (3.61-75.56) g/L; median serum IgM: 69.35 (4.35-137.00) g/L; median hemoglobin: 87.0 (70-131) g/L; median blood creatinine: 83.6 (53.0-129.6) μmol/L; median blood calcium: 2.12 (2.11-2.50) mmol/L. The median ratio of bone marrow plasma cells was 0.390 (0.255-0.590) , and in four cases, plasma cells were observed in blood smears. Karyotype analysis and fluorescence in situ hybridization (FISH) examination showed the following: 1 case of hypodiploidy, 2 cases of P53 gene deletion, 1 case of 1q21 amplification positive, and 4 cases of RB-1 gene deletion positive. The immunoglobulin heavy chain (IgH) rearrangement was positive in all cases, of which 3 cases were CCND1/IgH fusion gene-positive identified with t (11;14) rearrangement. Immunophenotyping revealed that all cases were positive for CD38, CD138, and monoclonal light chain and four cases were weakly positive for CD20. All cases accepted proteasome inhibitor-based regimens and attained the response of partial remission to strict complete remission. Conclusion: In addition to the typical clinical manifestations of myeloma, IgM MM is also characterized by hyperviscosity, lymphadenopathy, or hepatosplenomegaly, and t (11;14) is the most frequent cytogenetics aberration. Furthermore, the response and prognosis of IgM MM are similar to other common myeloma subtypes.
目的： 探究IgM型多发性骨髓瘤（MM）患者的临床特征、疗效及预后。 方法： 收集中国医学科学院血液病医院2009年12月18日至2020年10月29日收治的6例IgM型MM患者临床资料，对其临床特点、实验室检查结果、骨髓检查结果、疗效及预后进行总结、分析。 结果： 6例患者均符合IgM型MM的诊断标准。男4例，女2例，初次诊断中位年龄为70（59~81）岁。Durie-Salmon（DS）分期：ⅠA期2例，ⅢA期4例；国际分期系统（ISS）分期：Ⅱ期4例，Ⅲ期2例。初发症状：骨痛4例，高黏滞血症3例，淋巴结肿大或肝脾大2例。实验室检查：中位血清M蛋白39.11（3.61~75.56）g/L，中位血清IgM 69.35（4.35~137.00）g/L，中位HGB 87（70~131）g/L，中位血清肌酐83.6（53.0~129.6）μmol/L，中位血清钙2.12（2.11~2.50）mmol/L。中位骨髓浆细胞比例为0.390（0.255~0.590），4例患者外周血细胞形态学可见浆细胞。染色体核型分析：低二倍体1例。FISH检查：2例P53基因缺失，1例1q21扩增阳性，4例RB-1基因缺失阳性；6例患者IgH重排均阳性，其中3例CCND1/IgH融合基因阳性，明确为t（11;14）重排改变。免疫表型：CD38、CD138、单克隆轻链表达均阳性，4例CD20个别阳性。6例患者均接受蛋白酶体抑制剂为主的方案治疗，达到部分缓解至严格意义的完全缓解，治疗敏感性尚可。 结论： IgM型MM除骨髓瘤典型临床表现外，可伴高黏滞血症、淋巴结肿大或肝脾大等特征性表现，细胞遗传学以t（11;14）多见治疗反应及预后与常见骨髓瘤亚型无明显区别。.
Keywords: Hyperviscosity; Immunoglobulin M; Multiple myeloma.