卡介苗接种对酶联免疫斑点试验检测结核分枝杆菌感染的影响

The impact of BCG vaccination on tuberculosis infection detection with ELISPOT assay

目的研究卡介苗（BCG）接种对采用重组培养滤液蛋白10（CFPl0）-早期分泌靶抗原6（ESAT6）融合蛋白（重组CFP10-ESAT6融合蛋白）进行酶联免疫斑点试验（ELISPOT）检测结核分枝杆菌感染的影响，评价ELISPOT诊断结核分枝杆菌潜伏感染的价值。方法以结核菌素纯蛋白衍生物（PPD）皮肤试验为对照，应用重组CFPl0-ESAT6融合蛋白进行ELISPOT检测105名2013年驻京部队入伍新兵外周血中分泌结核分枝杆菌CFP10-ESAT6抗原特异性γ干扰素（IFN-7）的效应T淋巴细胞斑点数。对PPD和ELISPOT均为阴性的入伍新兵接种卡介苗，3个月后再做PPD试验和ELISPOT。应用SPSS18．0统计软件进行统计学分析处理，率的比较采用卡方检验，均数比较采用t检验，P〈0．05为差异有统计学意义。结果105名入伍新兵中，PPD试验和ELISPOT阳性率分别为59．0％（62／105）和14．3％（15／105）。43名PPD试验阴性和62例PPD试验阳性者中，分别有6例（14．0％）和9例（14．5％）ELISPOT阳性，两种方法的检测结果差异具有统计学意义（χ^2=35．86，P=0．00），两种方法的一致率为43．8％（46／105）。35名PPD试验和ELISPOT检测均为阴性的入伍新兵卡介苗接种3个月后，PPD试验阳转率为37．1％（13／35），而ELISPOT检测均为阴性，接种前斑点数[（2．6±3．1）个]与接种后斑点数[（2．6±5．0）个]比较，差异无统计学意义（t=0．52，P=0．61）。结论ELISPOT检测结核分枝杆菌感染不受卡介苗接种的影响，能更真实地反映驻京部队入伍新兵的结核潜伏感染情况。

Objective To study the impact of Bacillus Calmette-Guerin （BCG） vaccine on enzyme-linked immunospot （ELISPOT） assay using M. tuberculosis recombinant CFP10-ESAT6 protein, and evaluate the application value of ELISPOT on diagnosis of latent tuberculosis infection （LTBI）. Methods A total of 105 new recruits in Beijing in 2013 were intradermally injected with purified protein derivative （PPD）, and detected with ELISPOT assay using recombinant CFP10-ESAT6 fusion protein as a stimulus. New recruits with negative ELISPOT assay and negative PPD skin test were vaccinated by intradermal injection with BCG vaccine, and detected by PPD skin test and ELISPOT assay again 3 months later. The statistic analyses were performed using SPSS 18. 0. The Chi-square test was used to assess the difference between rates, and the T test was used to assess the difference between the averag P value 〈0.05 was considered to be significantly different. Results Of 105 new recruits, the positive rates of PPD skin test and ELISPOT assay were 59.0% （62/105） and 14.3% （15/105）, respectively. Of 43 PPD-negative and 62 PPD-positive new recruits, 6 （14.0%） and 9 （14. 5%） were ELISPOT positive, respectively. The results of these two methods had significant difference （X2 =35.86, P=0. 00）. Their agreement rate was 43.8% （46/105）. Of 35 new recruits vaccinated by BCG vaccine 3 months later, 37.1% （13/35） were PPD-positive, but all of them were ELISPOT negative. There was no statistical difference between the levels of IFN-γ before （2.6± 3.1 ） and after （2.6±5.0） BCG vaccination （t=0.52, P=0.61）. Conclusion BCG vaccination has no obvious impact on the ELISPOT assay, which is more feasible for the screening of LTBI in new recruits in Beijing.