Dispenzieri Angela, Zhang Lijun, Katzmann Jerry A, Snyder Melissa, Blood Emily, Degoey Roberta, Henderson Kimberly, Kyle Robert A, Oken Martin M, Bradwell Arthur R, Greipp Philip R
Departments of Hematology, Mayo Clinic, Rochester, MN, USA.
Blood. 2008 May 15;111(10):4908-15. doi: 10.1182/blood-2008-02-138602. Epub 2008 Mar 25.
The immunoglobulin free light chain (FLC) assay is an invaluable tool for following patients with oligosecretory plasma cell dyscrasia. Baseline values have also been shown to be prognostic in all plasma cell disorders tested. A looming question, however, is the role it should play in following myeloma patients with disease that is measurable using serum and urine electrophoresis. We used the data and stored samples from a mature Eastern Cooperative Oncology Group clinical trial (E9486) to assess serum levels of FLC at baseline and after 2 months of alkylator-based therapy. For serial determinations, the absolute level of involved serum FLC or the difference of the involved and uninvolved FLC is preferred over the ratio of involved to uninvolved FLC. FLC response after 2 months of therapy was superior to early M-protein measurement to predict overall response. The ideal cut-point for FLC change appears to be between 40% and 50% reduction. The correlation between serial measurements of serum FLC and urine M-protein is inadequate to abolish the serial 24-hour urine protein. Although baseline values of FLC are prognostic in newly diagnosed myeloma patients, serial measurements do not appear to have added value in patients who have M-proteins measurable by electrophoresis.
免疫球蛋白游离轻链（FLC）检测是跟踪寡分泌性浆细胞发育异常患者的一项重要工具。在所有接受检测的浆细胞疾病中，基线值也显示出具有预后价值。然而，一个亟待解决的问题是，在跟踪骨髓瘤患者时，对于可通过血清和尿电泳检测出疾病的患者，该检测应发挥何种作用。我们利用来自一项成熟的东部肿瘤协作组临床试验（E9486）的数据和储存样本，评估了基于烷化剂治疗2个月前后的血清FLC水平。对于连续测定，受累血清FLC的绝对水平或受累与未受累FLC的差值比受累与未受累FLC的比值更可取。治疗2个月后的FLC反应在预测总体反应方面优于早期M蛋白测量。FLC变化的理想切点似乎在降低40%至50%之间。血清FLC连续测量值与尿M蛋白之间的相关性不足以取消连续24小时尿蛋白检测。虽然FLC基线值对新诊断的骨髓瘤患者具有预后价值，但对于可通过电泳检测出M蛋白的患者，连续测量似乎没有额外价值。
