两种γ干扰素释放试验及PPD试验结果在结核感染诊断中的比较

The results comparison of two methods of Interferon-γ release assays with PPD skin test in TB infection diagnosis

目的研究2种γ干扰素（IFN7）释放试验（interferon-γ releaseassays，IGRA）和PPD试验在结核感染诊断中的相关性及应用价值。方法对2010年178名驻京部队河南籍入伍新兵进行PPD试验，用结核分枝杆菌特异性重组培养滤液蛋白10（culturefiltrateprotein10，CFP10）-早期分泌性靶抗原6（earlysecretoryantigenictarget6，ESAT6）融合蛋白（重组CFPl0-ESAT6融合蛋白）-酶联免疫斑点试验（enzymelinked-immunospotassay，EUSPOT）检测新兵外周血释放IFN-γ的效应T淋巴细胞，并用结核分枝杆菌CFP10-ESAT6重组蛋白-化学发光酶免疫法（chemiluminescenceenzymeimmunoassay，CLEIA）检测其全血中IFN-γ水平。结果178名入伍新兵中，PPD试验、ELISPOT和CLEIA的阳性率分别为39．89％（71／178）、31．46％（56／178）和21．35％（38／178）。前者阳性率显著高于后二者（χ^2=14．3663，P〈0．01），ELISPOT法阳性率也显著高于CLEIA法（χ^2=4．6834，P〈0．05）。在107名PPD试验阴性者中，ELISPOT、CLEIA法检测阳性者分别为33例（30．84％）、14例（13．08％），前者阳性率显著高于后者（χ^2=9．8425，P〈0．01）。在71例PPD阳性者中，ELISPOT、CLEIA法检测阳性者分别为23例（32．39％）、24例（33．80％），两者差异无统计学意义（χ^2=0．0318，P〉0．05）。ELISPOT法和PPD试验的一致率为54．49％（97／178，U=0．218，P〉0．05）；CLEIA法和PPD试验的一致率为65．73％（117／178，U=3．227，P〈0．01），ELISPOT和CLEIA法的一致率为66．29％（118／178，U=1．885，P〉0．05）；PPD试验、ELISPOT和CLEIA检测方法的一致率为42．70％（76／178）。ELISPOT法检测的斑点数与PPD试验反应的硬结平均直径之间缺乏相关性（r=0．13851，P〉0．05）；CLEIA法检测的IFN-γ水平与PPD试验反应的硬结平均直径之间有低的相关性（r=0．25244，P〈0．01）；ELISPOT检测的斑点数与CLEIA检测的IFN-γ水平之间也有低的相关性（r=0．2755，P〈0．01）。在卡介苗接种者中，PPD试验检测的阳性率为50．00％（48／96），ELISPOT为22．92％（22／96），CLEIA为23．96％（23／96）；在无卡介苗接种者中，PPD试验检测的阳性率为28．05％（23／82），ELISPOT为47．56％（39／82），CLEIA为17．07％（14／82）。结论两种IGRA方法与PPD试验之间的一致性差、相关性低，用IGRA方法能够有效地筛查结核感染，而ELISPOT检测的阳性率高于CLEIA。

Objective To analyze the relevance and application value of 2 kinds of interferon gamma （IFN- gamma） release test （IGRA） and purified protein derivative （PPD） skin test. Methods A total of 178 new recruits to the army from Henan province received intradermally injected with purified protein derivative PPD skin test and to detect IFN-γ t lymphocytes in peripheral blood with enzyme linked-immunospot assay （ELISPOT） assay and IFN-γin whole blood with chemiluminescence enzyme immunoassay （CLEIA） with recombinant CFP-10/ESAT-6 fusion protein （rCFP-10/ESAT-6） as a stimulus. Results The prevalence of Latent TB infection （LTBT）, as estimated by PPD skin test, ELISPOT assay and CLEIA, was 39.89% （71/178）, 31.46% （56/178） and 21.35% （38/178） of new recruits, respectively. The positive rate by PPD skin test is significant higher than that by two methods of IGRA （X2 14. 3663, P〈0. 01）, the positive rate by ELISPOT is significant higher than that by CLEIA （X2 = 4. 6834,P〈0. 05）. Of 107 PPD-negative volunteers, 33 （30.84%） were ELISPOT-positive and 14 （13.08%） were CLEIA positive, respectively, the positive rate by ELISPOT is higher than that by CLEIA （Z2 =9. 8425 ,P〈0.01）. OF 71 PPDpositive volunteers, 23 （32.39%） were ELISPOT positive and 24 （33.80%） were CLEIA-positive, re- spectively, there was no statistically significant difference （X2 =0. 0318,P〉0.05）. Agreement between PPD skin test and ELISPOT assay was 54.49% （97/178, U=0. 218, P〉0. 05）; agreement between PPD skin test and CLEIA was 65.73% （ 117/178, U =3. 227, P〈0.01 ） ; agreement between ELISPOT assay and CEEIA was 66.29 （118/178, U=1. 885, P〉0.05）. Overall agreement among three tests was 42.70% （76/178）. There was no cor- relation between spot formation cells detected by ELISPOT with average diameter detected by PPD skin test （r=0. 138 51, P〉0.05）. There are low correlation between IFN-γ level detected by CLEIA with average diameter de- tected by PPD skin test（r=0. 252 44,P〈0.01） ; There are low correlation between spot formation ceils detected by ELISPOT with IFN-＇/level detected CLEIA （r=0. 2755, P〈0. 01）. 50.00% （48/96） of PPD-positive new re~ cruits, 22.92% （22/96） of ELISPOT-positive new recruits and 23.96% （23/96） oFCLE1A-positive new recruits found the IK2G vaccination scars on their arms; while 28.05%（23/82） of PPD-positive new recruits, 47.56% （39/82） of ELISPOT-positive new recruits and 17.07% （14/82） of CLEIA-positive new recruits had not BCG scars. Conclusion There was low correlation and poor agreement between two methods of IGRA assays and PPD skin test, but IGRA may be more accurate methods for screening TB infection in countries with high coverage of BCG vaccination, the sensitivity of ELISPOT is higher than that of CLEIA.