MacNamara E M, Whicher J T
Department of Chemical Pathology, Old Medical School, University of Leeds, England.
Electrophoresis. 1990 May;11(5):376-81. doi: 10.1002/elps.1150110506.
About 15% of monoclonal components or paraproteins are associated with malignancy when detected by simple electrophoresis on cellulose acetate membranes or agarose gel followed by protein staining. More sensitive methods for detecting monoclonal components result in a lower frequency of association with recognisable underlying disease. The sensitivity is dependent on the system used. Isoelectric focusing is 10 to 40 times more sensitive than simple electrophoresis at detecting monoclonal components. Electrophoretically separated bands may be quantitated densitometrically and at the present time this is the most satisfactory method for measuring monoclonal component concentration. Immunochemical methods for quantitating monoclonal components are limited by failure to react in a similar manner to polyclonal standards and giving problems of antigen excess resulting both in falsely elevated and low results. Electrophoretic methods must always be used in conjunction with these. The normal polyclonal ratio of immunoglobulin kappa:lambda light chain is disturbed by the presence of a monoclonal component. In 260 patients with myeloma we found that serum electrophoresis alone detected 90% while a disturbance in the kappa:lambda ratio detected 98%. However, 50% of monoclonal components less than 3 g/L were missed. Log kappa:lambda ratio correlates well with the densitometric scan of monoclonal components, both in vitro and in patients being monitored for treatment response in myeloma. This approach may complement or even replace densitometry for this purpose in the future.
当通过在醋酸纤维素膜或琼脂糖凝胶上进行简单电泳然后进行蛋白质染色来检测时，约15%的单克隆成分或副蛋白与恶性肿瘤相关。检测单克隆成分的更灵敏方法会使与可识别的潜在疾病的关联频率降低。灵敏度取决于所使用的系统。等电聚焦在检测单克隆成分方面比简单电泳灵敏10至40倍。电泳分离的条带可以通过光密度法进行定量，目前这是测量单克隆成分浓度最令人满意的方法。定量单克隆成分的免疫化学方法受到与多克隆标准品反应方式不同以及抗原过量问题的限制，导致结果出现假性升高和降低。电泳方法必须始终与这些方法结合使用。单克隆成分的存在会扰乱免疫球蛋白κ链与λ链的正常多克隆比例。在260例骨髓瘤患者中，我们发现仅血清电泳检测出90%，而κ:λ比例的紊乱检测出98%。然而，50%小于3g/L的单克隆成分被漏检。对数κ:λ比例与单克隆成分的光密度扫描在体外以及在骨髓瘤治疗反应监测患者中都有很好的相关性。这种方法未来可能会补充甚至取代光密度法用于此目的。
