Laboratoire de Biochimie, CHRU Montpellier, Univ Montpellier 1, Montpellier F-34000, France.
Clin Biochem. 2013 Nov;46(16-17):1764-6. doi: 10.1016/j.clinbiochem.2013.08.024. Epub 2013 Sep 9.
Transplant patients have an increased incidence of lymphoproliferative disorders. The development of a sensitive immunoassay for serum free light chain (sFLC) determination has improved the diagnosis of monoclonal gammapathy. However, metabolism of FLC largely depends on renal function which could lead to misinterpretation of results. The aim of this study was to assess polyclonal FLC in kidney transplant recipients in relation to markers of renal function.
97 renal transplant patients (median transplantation follow-up of 2.2 years) were included in this study. Kappa FLC, lambda FLC and cystatin C were measured by particle-enhanced turbidimetric immunoassay (PETIA) using kits from a Binding Site (Birmingham, UK) SPAPLUS(®) analyzer. Glomerular filtration rate was measured using urinary clearance of (99m)Tc-DTPA and estimated using CKD-EPI creatinine 2009, CKD-EPI cystatin C 2012 and CKD-EPI creatinine-cystatin C 2012.
Serum kappa FLC was 22.38 [6.39-68.91] mg/L and serum lambda FLC was 15.66 [7.29-50.81] mg/L. Both levels of kappa and lambda were correlated with renal function. Median κ/λ ratio was 1.34 [0.57 to 2.67] leaving 19.6% of renal transplant patients outside the normal reference range [0.26-1.65]. However, using a reference interval normalized by renal function [0.37-3.1], none of our patients was classified as abnormal.
κ/λ ratio should be cautiously analyzed in renal transplantation and renal function, estimated by creatinine/cystatin C equations should be taken into account.
移植患者淋巴增生性疾病的发病率增加。用于血清游离轻链 (sFLC) 测定的灵敏免疫分析法的发展提高了单克隆丙种球蛋白病的诊断。然而，FLC 的代谢在很大程度上取决于肾功能，这可能导致结果的误读。本研究旨在评估肾移植受者的多克隆 FLC 与肾功能标志物的关系。
本研究纳入了 97 例肾移植患者（中位移植随访时间为 2.2 年）。采用Binding Site（英国伯明翰）SPAPLUS(®)分析仪上的试剂盒，通过颗粒增强比浊免疫分析法（PETIA）测量κFLC、λFLC 和胱抑素 C。使用（99m）Tc-DTPA 的尿清除率测量肾小球滤过率，并使用 CKD-EPI 肌酐 2009、CKD-EPI 胱抑素 C 2012 和 CKD-EPI 肌酐-胱抑素 C 2012 进行估算。
血清κFLC 为 22.38[6.39-68.91]mg/L，血清λFLC 为 15.66[7.29-50.81]mg/L。κ 和 λ 的水平均与肾功能相关。κ/λ 比值中位数为 1.34[0.57 至 2.67]，19.6%的肾移植患者超出正常参考范围[0.26-1.65]。然而，使用通过肾功能[0.37-3.1] 进行归一化的参考区间，我们的患者中没有一个被归类为异常。
在肾移植中应谨慎分析 κ/λ 比值，并应考虑使用肌酐/胱抑素 C 方程估算的肾功能。
