Highton J, Hessian P
J Immunol Methods. 1984 Mar 30;68(1-2):185-92. doi: 10.1016/0022-1759(84)90149-2.
Measurement of serum C-reactive protein (CRP) concentration is useful in monitoring the progress of chronic inflammatory diseases. Rheumatoid factor, by its interaction with the Fc portion of IgG, has the potential to interfere with solid-phase immunoassays for CRP and other serum proteins. To determine the effect of RF on a solid-phase enzyme immunoassay for CRP we compared assays employing whole antisera or F(ab')2 fragments. In 92 sera with RF latex titres ranging from 1/80 to 1/81,920, no correlation was found between RF concentrations and CRP measurements. CRP concentrations measured by use of whole antisera (mean +/- standard error of the mean, 59.7 +/- 5.7 mg/l, n = 92) were lower than those measured with F(ab')2 fragments (62.5 +/- 5 mg/l), indicating that exaggeration of CRP measurements did not occur in RF containing sera under the conditions of the assay. Our results show that in the CRP-ELISA, interference from RF was precluded by the high serum dilutions employed. At lower serum dilutions RF binding was detected. Consequently, in solid-phase enzyme immunoassays at lower serum dilutions the presence of RF may lead to false positive results and exaggerated measurements.
血清C反应蛋白（CRP）浓度的测定对于监测慢性炎症性疾病的进展很有用。类风湿因子通过与IgG的Fc部分相互作用，有可能干扰CRP和其他血清蛋白的固相免疫测定。为了确定类风湿因子对CRP固相酶免疫测定的影响，我们比较了使用全抗血清或F(ab')2片段的测定方法。在92份类风湿因子乳胶滴度范围为1/80至1/81920的血清中，未发现类风湿因子浓度与CRP测量值之间存在相关性。使用全抗血清测得的CRP浓度（平均值±平均标准误差，59.7±5.7mg/l，n = 92）低于使用F(ab')2片段测得的浓度（62.5±5mg/l），这表明在该测定条件下，含类风湿因子的血清中并未出现CRP测量值夸大的情况。我们的结果表明，在CRP-ELISA中，所采用的高血清稀释度排除了类风湿因子的干扰。在较低血清稀释度下检测到了类风湿因子结合。因此，在较低血清稀释度的固相酶免疫测定中，类风湿因子的存在可能导致假阳性结果和测量值夸大。
