Clin Chem Lab Med. 2016 Jun 1;54(6):991-5. doi: 10.1515/cclm-2015-0689.
Multiple myeloma (MM) is characterized, in about 80% of cases, by the production of monoclonal intact immunoglobulin and more than 95% of them have elevated concentrations of involved (i.e. of the same class of intact immunoglobulin) free light chain (FLC). The introduction of novel therapeutic strategies has changed the natural history of the disease, leading to new manifestations of relapse. Light chain escape (LCE) is a pattern of relapse in which the FLC increase is not accompanied by a concomitant raise of the original monoclonal component (MC). Here we present a case of a 55-year-old man with an IgG kappa MM stage III diagnosed in September 2007. At presentation an IgG kappa MC and urine Bence Jones protein (BJP) kappa were present. Bone marrow biopsy (BMB) showed the presence of 80% monotypic kappa plasma cells (PCs). The patient received bortezomib, thalidomide, dexamethasone before undergoing a double autologous stem cell transplantation (ASCT) in October 2008 and April 2009. In May 2011 he relapsed showing the same pattern of presentation and treatment with lenalidomide and dexamethasone was started. ln May 2013 serum and urine immunofixation and FLC became negative. In September 2014, an increase of kappa FLC was observed, while serum and urine immunofixations remained negative until January 2015, when urine immunofixation became positive. Eventually, in February 2015, serum immunofixation revealed the presence of a free kappa MC. After a new BMB showing 80% of monotypic kappa PCs, a LCE relapse was diagnosed and the patient started the treatment with bendamustine, bortezomib and dexamethasone. In the present case, the increase of kappa FLC has indicated relapse 4 and 5 months earlier than urine and serum IFE, respectively. Our observation confirms that it is advisable to routinely perform FLC or BJP during follow up of MM patients undergoing ASCT and/or treatment with biological drugs to ensure that LCE is not missed.
多发性骨髓瘤（MM）的特征是，约 80%的病例产生单克隆完整免疫球蛋白，超过 95%的病例游离轻链（FLC）浓度升高，涉及（即同一完整免疫球蛋白类别的）。新型治疗策略的引入改变了疾病的自然史，导致新的复发表现。轻链逃逸（LCE）是一种复发模式，其中 FLC 的增加不伴有原始单克隆成分（MC）的相应升高。在这里，我们报告了一名 55 岁男性的病例，他于 2007 年 9 月被诊断为 III 期 IgG kappa MM。初诊时存在 IgG kappa MC 和尿 Bence Jones 蛋白（BJP）kappa。骨髓活检（BMB）显示存在 80%单型 kappa 浆细胞（PC）。该患者在 2008 年 10 月和 2009 年 4 月接受了两次自体干细胞移植（ASCT）之前接受了硼替佐米、沙利度胺、地塞米松治疗。2011 年 5 月，他复发，表现出相同的发病模式，并开始接受来那度胺和地塞米松治疗。2013 年 5 月，血清和尿液免疫固定电泳和 FLC 转为阴性。2014 年 9 月，观察到 kappa FLC 增加，而血清和尿液免疫固定电泳一直为阴性，直到 2015 年 1 月，尿液免疫固定电泳转为阳性。最终，2015 年 2 月，血清免疫固定电泳显示存在游离 kappa MC。新的 BMB 显示 80%的单型 kappa PC 后，诊断为 LCE 复发，患者开始接受苯达莫司汀、硼替佐米和地塞米松治疗。在本例中，kappa FLC 的增加比尿液和血清 IFE 分别早 4 个月和 5 个月提示复发。我们的观察结果证实，在接受 ASCT 和/或生物药物治疗的 MM 患者的随访中，常规进行 FLC 或 BJP 检测以确保不遗漏 LCE 是明智的。
