Sthaneshwar Pavai, Nadarajan Veerasekaran, Maniam Jayaranee A S, Nordin Nani, Gin Gin Gan
Department of Pathology, University of Malaya, Kuala Lumpur, Malaya.
Clin Chem Lab Med. 2009;47(9):1101-7. doi: 10.1515/CCLM.2009.260.
Measurement of serum free light chains (FLCs) has recently become available for the diagnosis and monitoring of patients with plasma cell dyscrasias. The aim of this study was to investigate the performance of the serum FLC assay as a tumour marker by comparing FLC concentrations with serum protein electrophoresis (PE) results in the diagnosis of multiple myeloma (MM). In addition, we also evaluated the prognostic value of the baseline serum FLC ratio in patients with MM.
We measured FLC concentrations and calculated the kappa/lambda (kappa/lambda) FLC ratios for three groups (control, polyclonal gammopathy and MM).
The FLC ratio at a cut-off threshold of 2.0 showed higher sensitivity and specificity compared with serum electrophoresis for the diagnosis of MM. We used the median FLC ratio of >57.5 and <0.04 for kappa and lambda secretors, respectively, for assessing survival. Survival was 30 months in patients with the kappa/lambda ratio of >57.5 and <0.04 compared to 47 months in patients with the ratio <57.5 and >0.04, indicating that more abnormal serum FLC ratios are associated with poorer survival (p<0.011).
Despite the limitations of the assay, the results of our study indicate that the FLC assay in combination with serum PE has an increased sensitivity in the diagnosis of MM. Also, baseline measurement of the kappa/lambda ratio provides prognostic information in these same patients.
血清游离轻链（FLC）检测最近已可用于浆细胞异常增殖症患者的诊断和监测。本研究的目的是通过比较FLC浓度与血清蛋白电泳（PE）结果在多发性骨髓瘤（MM）诊断中的表现，来研究血清FLC检测作为肿瘤标志物的性能。此外，我们还评估了MM患者基线血清FLC比值的预后价值。
我们测量了三组（对照组、多克隆丙种球蛋白病组和MM组）的FLC浓度，并计算了κ/λ（kappa/lambda）FLC比值。
在诊断MM时，与血清电泳相比，FLC比值在截断阈值为2.0时显示出更高的敏感性和特异性。我们分别使用κ和λ分泌型患者中FLC比值中位数>57.5和<0.04来评估生存情况。κ/λ比值>57.5且<0.04的患者生存时间为30个月，而比值<57.5且>0.04的患者生存时间为47个月，这表明血清FLC比值越异常，生存情况越差（p<0.011）。
尽管该检测存在局限性，但我们的研究结果表明，FLC检测与血清PE相结合在MM诊断中具有更高的敏感性。此外，κ/λ比值的基线测量可为这些患者提供预后信息。
