选用细胞因子ＩＬ４ 为靶基因， 以β肌动蛋白（βａｃｔｉｎ） 基因作为内参照， 将两者在同一ＰＣＲ体系中扩增， 分析ＰＣＲ扩增的动力学， 内参照βａｃｔｉｎ 的引物于ＰＣＲ扩增中的滞后加入， 弥补了ＩＬ４ 与ＲＴＰＣＲ模板量的差异， 使二者的扩增同时处于指数扩增期， 其扩增产物均可在溴乙锭染色的聚丙烯酰胺胶上检测出， 从而可求出ＩＬ４ 的ｃＤＮＡ 拷贝数占βａｃｔｉｎ拷贝数的百分比。重复实验的ＣＶ 值在１０％ 以内， 表明此半定量ＲＴＰＣＲ 方法的可靠性。 The selection of cytokines IL 4 as a target gene, β actin (β actin) gene as an internal reference, both in the same PCR amplification, analysis of PCR amplification kinetics, internal reference β actin Of the primers in the PCR amplification lag added to make up for the IL  4 and RT  PCR template amount of the difference between the two amplification at the same time in the exponential amplification period of its amplification products are in ethidium bromide staining Polyacrylamide gel detected, which can be obtained IL  4 cDNA copy number accounted for β  actin copy number percentage. CV value of repeated experiments within 10%, indicating the reliability of this semi-quantitative RT PCR method.