Kitaaki Shoko, Hayashi Nobuhide, Sato Itsuko, Watanabe Katsunori, Saegusa Jun, Kawano Seiji
Rinsho Byori. 2015 Apr;63(4):427-34.
Measurement of matrix metalloproteinase-3(MMP-3), a marker for rheumatoid arthritis, by means of latex agglutination turbidimetric immunoassay (LTIA), has come to replace ELISA kit, but pre-improvement LTIA kit S(Sekisui Medical) frequently shows false values resulting from non-specific reactions. We analyzed factors influencing the frequency of non-specific reactions for MMP-3 detection using various methods.
Serum MMP-3 levels were measured in 1,214 routine samples or 57 panels with various immunoserological abnormalities by means of pre-improvement and improved kit S, LTIA kit E (Eiken Chemical) and ELISA kit. Non-specific reaction samples were selected either from the routine samples based on the results of correlativity tests between the kits and of dilution linearity tests, or from 57 panels with immunoserological abnormalities based on the results of recovery tests. To explore the factors causing non- specific reactions, titers of rheumatoid factor (RF), immunoglobulins and four heterophil antibodies were measured in these samples. In addition, changes in findings as a result of reduction treatment or IgM absorption were examined in selected samples to clarify the effect of heterophil antibodies.
Samples which showed suspected false values probably due to non-specific reaction numbered 75, 15, 5 and 17 as measured with pre-improvement kit S, improved kit S, kit E and ELISA kit, respectively. Kit S also showed high rate of deviation in recovery tests on panels with immunoserological abnormalities. Rate of RF titer in samples with non-specific reactions was higher than that of other factors. Non-specific reaction could be inhibited in two samples as a result of reduction treatment or absorption of IgM subtype.
Pre-improvement kit S showed a higher rate of non-specific reactions than other kits. The most common cause of non-specific reactions is thought to be high RF titer, but high levels of IgM, including heterophil antibodies, may also affect the values of MMP-3.
通过乳胶凝集比浊免疫测定法（LTIA）检测类风湿关节炎标志物基质金属蛋白酶-3（MMP-3）已逐渐取代酶联免疫吸附测定（ELISA）试剂盒，但改进前的LTIA试剂盒S（积水医疗株式会社）经常因非特异性反应出现错误值。我们使用多种方法分析了影响MMP-3检测中非特异性反应频率的因素。
采用改进前和改进后的试剂盒S、LTIA试剂盒E（荣化学工业株式会社）和ELISA试剂盒，对1214份常规样本或57份具有各种免疫血清学异常的样本组进行血清MMP-3水平检测。根据试剂盒间相关性测试和稀释线性测试结果，从常规样本中选择非特异性反应样本；根据回收测试结果，从57份具有免疫血清学异常的样本组中选择非特异性反应样本。为探究引起非特异性反应的因素，检测这些样本中的类风湿因子（RF）、免疫球蛋白和四种嗜异性抗体的滴度。此外，对选定样本进行还原处理或IgM吸附后的结果变化进行检查，以阐明嗜异性抗体的作用。
使用改进前试剂盒S、改进后试剂盒S、试剂盒E和ELISA试剂盒检测时，疑似因非特异性反应导致错误值的样本分别为75、15、5和17份。试剂盒S在免疫血清学异常样本组的回收测试中也显示出较高的偏差率。非特异性反应样本中RF滴度高于其他因素。通过还原处理或IgM亚型吸附，两份样本中的非特异性反应得到抑制。
改进前的试剂盒S比其他试剂盒显示出更高的非特异性反应率。非特异性反应最常见的原因被认为是高RF滴度，但包括嗜异性抗体在内的高水平IgM也可能影响MMP-3的值。
