Rosenberg Aaron Seth, Bainbridge Scott, Pahwa Roma, Jialal Ishwarlal
Division of Hematology and Oncology, UC Davis Comprehensive Cancer Center, Sacramento, CA, United States.
Department of Pathology and Laboratory Medicine, UC Davis Medical Center, Sacramento, CA, United States.
Clin Biochem. 2016 Oct;49(15):1202-1204. doi: 10.1016/j.clinbiochem.2016.07.016. Epub 2016 Jul 28.
Recently monoclonal antibody therapy has been introduced in the treatment of multiple Myeloma (MM). One such efficacious therapy is the anti-CD38 monoclonal antibody, daratumumab (Dara). Since it is an Ig-G-kappa it can interfere with both the serum protein electrophoresis and immunofixation electrophoresis (IFE). The free light chain (FLC) assay is also useful in the diagnosis and therapeutic monitoring of MM. Hence we tested the effect of Dara on the FLC assay.
30 serum samples from patients with known IgG-kappa (n=20) and non-IgG-kappa M -proteins (n=10) were spiked with Dara at a final concentration of 1.0mg/mL and the FLC performed on samples. On a further 20 samples we performed IFE to determine the migration of Dara.
On IFE, Dara migrated in the same area of the gamma zone. In the 30 samples in which we assayed FLC there was no significant differences in levels of kappa, lambda and the ratio of kappa to lambda between untreated and Dara-spiked samples.
Whilst Dara can interfere with the IFE to determine clinical responses the FLC assay can be useful in patients who have abnormal FLC ratios prior to Dara therapy to determine responses especially in IgG-kappa Myeloma.
最近，单克隆抗体疗法已被引入多发性骨髓瘤（MM）的治疗。一种有效的疗法是抗CD38单克隆抗体达雷妥尤单抗（Dara）。由于它是一种Ig-G-κ型抗体，它会干扰血清蛋白电泳和免疫固定电泳（IFE）。游离轻链（FLC）检测在MM的诊断和治疗监测中也很有用。因此，我们测试了Dara对FLC检测的影响。
30份已知为IgG-κ型（n=20）和非IgG-κ型M蛋白（n=10）患者的血清样本加入终浓度为1.0mg/mL的Dara，然后对样本进行FLC检测。另外对20份样本进行IFE检测以确定Dara的迁移情况。
在IFE检测中，Dara在γ区的相同区域迁移。在我们检测FLC的30份样本中，未处理样本和加入Dara的样本之间，κ、λ水平以及κ与λ的比值没有显著差异。
虽然Dara会干扰IFE以确定临床反应，但FLC检测对于Dara治疗前FLC比值异常的患者确定反应可能有用，尤其是在IgG-κ型骨髓瘤患者中。
