间接免疫荧光试验检测登革IgG的应用

Application of Indirect Immunofluorescent Assay for Detecting IgG of Dengue Virus

１９９５年广东省番禺等市发生登革热流行，应用间接免疫荧光试验检测５８份待测登革ＩｇＧ的标本，３８份阳性，阳性率６５．５２％（３８／５８）；检测疑似登革热患者早期血标本５１份，用Ｃ６／３６细胞分离出２８株登革Ｉ型病毒，阳性率５４．９０％（２８／５１）．证实本次流行是登革Ｉ型病毒所引起，二者检出率差异无显著性（Ｘ２＝１．２８，Ｐ＞０．０５）。ＩｇＧ最早检出于发病后第三天，一周后达高峰，患者血清中各型登革ＩｇＧ呈高度交叉反应，不能分型，其平均几何滴度在１：１００以上。此外，ＩＥＡ检测确诊登革病人血清９份。ＩｇＧ阳性率为１００％，滴度范围为１：１６０－１：１２８０：检测非登革血清３３６份，滴度１：４０有１５份，１：８０有１份，阳性率为４．７６％。此法检测登革ＩｇＧ，方法简单、敏感、快速、经济。结果表明：病后一周取检，ＩｇＧ抗体滴度达１：８０以上，对诊断为登革热感染有参考意义。

Dengue fever was prevalence in Panyu and other cities of Guangdong Province in 1995.Indirect Immunofluorescent assay(IFA) was carried out for detecting anti dengue virus IgG.Of 58 sera specimens tested,38 were positive and the positive rate was 65.52%(38/58).C6/36 cell culture was used for virus isolation.Of 51 serum samples of early phase blood,type Idengue virus was isolated in 28 specimens and the positive rate was 54.90%(28/51).It verified that type I dengue Virus was the cause of this epidemic.There was significant difference between the two positive rates (X 2=1.28,P>0.05).IgG was first detected on the third day and its positive rate reached peak in a week after onset.Patients'sera were not able to type because of the high cross-reaction among 4 types and the mean geometric titres of IgG were all above 1∶100.In addition,the specificity of IFA in the detection of antidengue virus IgG was established.9 sera samples of confirmed dengue fever patients were tested,the positive rate of IgG was 100%and their titres were 1∶160-1∶1280.Of 336 samples of sera other than dengue fever patients,16 were positive (15 samples 1∶40;1 sample,1∶80) and the positive rate was 4.76%.The results showed that if the IgG titre reached 1∶80 or above,it was helpful in the diagnosis of dengue virus infection,but the diagnosis should be confirmed by virus isolation.The authors concluded that this assay was simple,sensitive,rapid and economical.