Reinsberg J, Nocke W
Zentrum für Frauenheilkunde und Geburtshilfe, Universität Bonn, Germany.
Eur J Clin Chem Clin Biochem. 1993 May;31(5):323-7. doi: 10.1515/cclm.1993.31.5.323.
We investigated a one-step immunometric CA 125 assay, which employs new anti-CA 125 antibodies as capture antibodies and OC125 antibodies for detection, for interference due to antibodies induced by repeated administration of F(ab')2 fragments of the anti-CA 125 antibody OC125. Testing 33 samples, obtained from 13 patients treated with OC125 fragments, we found falsely high CA 125 concentrations only in samples with exceptionally high concentrations of both anti-idiotypic antibodies and non-specific human anti-mouse antibodies. In contrast, the recovery of added CA 125 was already diminished in the presence of low anti-idiotypic antibody concentrations. Both interferences disappeared after removal of serum IgG. It was possible to eliminate the falsely high results, but not the reduction in recovery rate, by adding non-specific murine IgG. When the binding of the detector antibodies was performed in a separate incubation step, no reduction in recovery rate was observed. Our results suggest that non-specific human anti-mouse antibodies are responsible for falsely high results. The reduction in the recovery rate is obviously due to an inhibition of the binding of OC125 detector antibodies by anti-idiotypic antibodies. In patients receiving OC125 antibodies CA 125 can be measured using OC125 detector antibodies if a two-step assay is performed. An increase in CA 125 following OC125 infusion should be confirmed after the addition of non-specific murine IgG.
我们研究了一种一步免疫测定CA 125的方法，该方法采用新的抗CA 125抗体作为捕获抗体，并用OC125抗体进行检测，以评估因反复注射抗CA 125抗体OC125的F(ab')2片段所诱导的抗体导致的干扰。对从13例接受OC125片段治疗的患者中获取的33份样本进行检测，我们发现只有在抗独特型抗体和非特异性人抗鼠抗体浓度都异常高的样本中，CA 125浓度才会出现假性升高。相反，在抗独特型抗体浓度较低时，添加的CA 125的回收率就已经降低。去除血清IgG后，这两种干扰都消失了。通过添加非特异性鼠IgG，可以消除假性高值结果，但无法消除回收率的降低。当在单独的孵育步骤中进行检测抗体的结合时，未观察到回收率降低。我们的结果表明，非特异性人抗鼠抗体是导致假性高值结果的原因。回收率降低显然是由于抗独特型抗体抑制了OC125检测抗体的结合。在接受OC125抗体治疗的患者中，如果采用两步法测定，可用OC125检测抗体来检测CA 125。在输注OC125后CA 125升高的情况，应在添加非特异性鼠IgG后加以确认。
