ESAT-6 and CFP-10 can be combined to reduce the cost of testing for Mycobacterium tuberculosis infection, but CFP-10 responses associate with active disease

Commercial tests measuring IFN-gamma responses to ESAT-6 and CFP-10 are available for diagnosing Mycobacterium tuberculosis infection. Measures that minimize cost and complexity will facilitate their application in less-developed countries. We investigated whether overlapping peptides representing both ESAT-6 and CFP-10 are required to detect M. tuberculosis infection in a high TB-burden country, and whether they can be combined in a single pool. ESAT-6 and CFP-10 peptides were compared in IFN-gamma enzyme-linked immunospot (ELISPOT) in 183 HIV-negative smear-positive TB cases and 1673 HIV-negative household contacts. Separate peptide pools for each antigen were compared with a combined pool in 498 contacts. Forty per cent of responsive contacts recognized both antigens, 51% only ESAT-6 and 10% only CFP-10, whereas 56% of responsive cases recognized both antigens, 30% only ESAT-6 and 13% only CFP-10. Accordingly, CFP-10 response rates were higher for TB cases (odds ratio 2.409, P<0.001). Low purified protein derivative response rates indicated that responses to CFP-10 only were non-specific in contacts. Agreement between peptides in separate versus combined pools was good (kappa=0.758, r=0.840). Therefore a combined ESAT-6/CFP-10 peptide pool provided maximum sensitivity and efficiency, but CFP-10 was mainly required to detect active disease.     

应用酶联免疫斑点试验检测入伍新兵结核潜伏感染

目的应用酶联免疫斑点试验（ELISPOT）检测入伍新兵结核潜伏感染情况,评价ELISPOT在检测结核潜伏感染中的价值。方法以结核菌素纯蛋白衍生物 (PPD) 皮肤试验为对照,应用ELISPOT试剂盒检测366例2009年驻京部队入伍新兵外周血中分泌结核菌抗原特异性γ干扰素（IFN γ）的T淋巴细胞数。对PPD和ELISPOT均为阴性的入伍新兵接种卡介苗,10个月后再做PPD 皮肤试验和ELISPOT,比较结果。结果366例入伍新兵中,PPD皮肤试验和ELISPOT阳性率分别为44.81%和31.69%。202例PPD皮肤试验阴性和164例PPD皮肤试验阳性者中,分别有53例 （26.24%）和63例（38.41%）ELISPOT阳性,两者的一致率为57.92%（212/366）, 两者的检测结果差异具有统计学意义（χ2=14.34,P＜0.001）。在接种过卡介苗者中,PPD皮肤试验阳性率为58.53%（127/217）,ELISPOT阳性率为29.03%（63/217）,斑点形成细胞数为32.44±26.52 ;在未接种卡介苗者中,PPD皮肤试验阳性率为24.83%（37/149）,ELISPOT阳性率为35.57%（53/149）,斑点形成细胞数为41.81±30.48。110例PPD和ELISPOT均为阴性的入伍新兵接种卡介苗10个月后, PPD 皮肤试验阳转率为78.18%,而ELISPOT检测均为阴性。结论ELISPOT具有较高的特异性和敏感性,能真实反映入伍新兵的结核潜伏感染情况,可推广应用。     

ESAT-6/CFP-10融合蛋白的抗原性分析及其对诊断结核临床应用价值

目的 分析ESAT-6/CFP-10融合蛋白作为结核抗原的特性,并探讨以其作为抗原的酶联免疫斑点实验(ELISPOT)在结核诊断中的应用价值.方法 以ESAT-6/CFP- 10融合蛋白为刺激抗原的EIISPOT法(ESAT-6/CFP-10-ELISPOT)检测经结核特异性抗原刺激后分泌γ干扰素的效应T淋巴细胞数量方法,测定65例单纯结核病患者,16例HIV/结核双重感染患者,20例HIV感染患者,32例非结核呼吸道疾病患者,30名健康体检者外周血单个核细胞中结核菌抗原特异的T淋巴细胞的频率.结果 ESAT-6/CFP- 10-ELISPOT与结核菌素皮肤试验(TST)在所有81例结核患者中的比较,ESAT-6/CFP- 10-ELISPOT阳性率98.8％,TST阳性率为56.8％;ESAT-6/CFP-10-ELISPOT在涂阳结核组、涂阴结核组、HIV/结核双重感染组阳性率分别为100.0％、97.1％、100.0％,其敏感性远高于痰涂片检查,且各组结果差异无统计学意义;20例HIV感染组有1例阳性,非结核呼吸道疾病患者组与健康对照组均为阴性,提示ESAT-6/CFP- 10-ELISPOT方法的特异度为98.8％.结论 ESAT-6/CFP-10融合蛋白可以很好的刺激效应T淋巴细胞分泌γ干扰素,适合作为结核诊断中的特异性抗原,因而可以用于ELISPOT的检测,ESAT-6/CFP- 10-ELISPOT对结核诊断有应用价值.     

2007—2011年莱芜市涂阳肺结核患者密切接触者筛查情况分析

目的了解对涂阳肺结核患者密切接触者进行筛查的意义。方法对莱芜市2007—2011年间登记的2 487例涂阳患者密切接触者,均进行痰涂片(夜间痰、晨痰和即时痰)检查和X线胸部拍片检查,对年龄≤15岁者进行PPD试验。结果 2 487例密切接触者发现活动性肺结核19例,检出率0.764%。密切接触者中患活动性肺结核的几率与所接触的涂阳患者的排菌量呈正相关关系。结论对涂阳患者密切接触者进行痰涂片和X线胸片检查,有助于肺结核患者的发现,对此人群开展结核病预防工作具有重要意义。     

优化T-SPOT. TB在区分脊柱结核与其他脊柱感染中的诊断效能

目的 探讨结核感染T细胞斑点试验(T-SPOT.TB)在脊柱结核(STB)鉴别诊断中的效能,并通过受试者工作特征(ROC)曲线最佳截断值优化诊断效能。方法 收集2010年1月—2019年5月某院脊柱感染患者的临床资料,包括术前T-SPOT.TB检测结果、白细胞计数、C-反应蛋白、血沉、降钙素原和结核抗体等相关数据,根据诊断标准进行临床诊断,分析T-SPOT.TB在术前诊断STB与其他脊柱感染中的灵敏度和特异度,评价优化后的T-SPOT.TB指标的诊断效能。结果 共纳入132例患者,其中78例(59.09%)为STB,54例(40.91%)为非结核脊柱感染。T-SPOT.TB在鉴别诊断STB方面的灵敏度为67.68%,特异度为66.67%。单因素logistic回归分析显示,与非结核脊柱感染比较,T-SPOT.TB检测诊断STB的OR值为4.188(95%CI:1.847～9.974,P<0.001)。优化T-SPOT.TB评价指标,通过绘制ROC曲线,确定ESAT-6、CFP-10、CFP-10+ESAT-6在STB和非结核脊柱感染鉴别诊断中的最佳截断值,分别为12.5、19.5...     

结核感染T淋巴细胞γ干扰素释放试验在骨关节结核诊断中的应用

目的探讨结核感染T淋巴细胞γ干扰素释放试验(斑点试验,T-SPOT.TB)在骨关节结核中的应用价值。 方法回顾性分析2016年1月至2018年3月在我院骨外科行T-SPOT.TB检测的127疑似骨关节结核感染病例,分析T-SPOT.TB在骨关节结核中的诊断性能;比较在不同部位骨关节结核的阳性率差异;同时比较以早期分泌抗原靶6 (early secreted antigenic target 6,ESAT-6)和培养滤液蛋白10 (culture filtrate protein 10,CFP-10)诊断骨关节结核的阳性率差异。 结果T-SPOT.TB检测的正确率、灵敏度、特异度、阳性预测值、阴性预测值分别为86.61%(110/127)、83.33%(35/42)、88.24%(75/85)、77.78%(35/45)、91.46%(75/82);且在不同类型骨关节结核的阳性率差别无统计学意义(χ²=1.72,P>0.05);单独以ESAT-6和CFP-10抗原的点数诊断骨关节结核阳性率为69.04%、61.90%,差异无统计学意义(χ²=0.27,P>0.05),两者联合诊断阳性率(83.33%)均高于ESAT-6和CFP-10抗原单独诊断的阳性率,差异有统计学意义(χ²=4.16、7.11,P<0.05)。 结论T-SPOT.TB在骨关节结核诊断中具有重要的应用价值,值得临床推广。     

Utility of dual skin tests to evaluate tuberculin skin test reactions of 10 to 14 mm in healthcare workers.

OBJECTIVE: To define the utility of 10- to 14-mm reactions to a Mycobacterium tuberculosis purified protein derivative (PPD) skin test for healthcare workers (HCWs). DESIGN: Blinded dual skin testing, using PPD and M. avium sensitin, of HCWs at a single medical center who had a 10- to 14-mm reaction to PPD when tested by personnel from the Occupational Health Department as part of routine annual screening. SETTING: A single tertiary-care academic medical center. PARTICIPANTS: Employees of the medical center who underwent routine annual PPD screening and were identified by the Occupational Health Department as having a reaction of 10 to 14 mm to PPD. RESULTS: Nineteen employees were identified as candidates and 11 underwent dual skin testing. Only 4 (36%) had repeat results for PPD in the 10- to 14-mm range, whether read by Occupational Health Department personnel or study investigators. For only 5 (45%) of the subjects did the Occupational Health Department personnel and study investigators concur (+/- 3 mm) on the size of the PPD reaction. Two of the 4 subjects with reactions of 10 to 14 mm as measured by the study investigators were M. avium sensitin dominant, 1 was PPD dominant, and 1 was nondominant. CONCLUSION: A reaction of 10 to 14 mm to PPD should not be used as an indication for the treatment of latent tuberculosis (TB) infection in healthy HCWs born in the United States with no known exposure to TB.     

应用酶联免疫斑点法快速诊断儿童结核分枝杆菌感染的研究

目的:探讨基于ESAT-6和CFP-10抗原肽的酶联免疫斑点技术(Enzyme-link immunospot essay,ELISPOT)在临床实践中诊断儿童结核分枝杆菌感染的临床价值。方法:应用ELISPOT技术检测14例确诊的儿童肺结核病例和16例健康儿童对照的外周血单个核细胞的INF-γ,同时对所有研究对象实施结核菌素皮肤实验(Tuberculin Skin Test,TST),探讨ELIS-POT技术在快速诊断儿童结核分枝杆菌感染的临床应用价值。结果:ELISPOT灵敏度为85.7%(95%CI:60.1～95.0),特异度为93.8%(95%CI:71.7～98.9)。TST灵敏度为71.4%(95%CI:45.4～88.3),特异度为56.3%(95%CI:33.2～76.9)。ELISPOT的灵敏度高于TST,但无统计学意义(P>0.05)。ELISPOT的特异度显著高于TST(P<0.05)。ELISPOT和TST检测结果总一致性较差(κ=0.35)。在活动型结核病组中,ELISPOT和TST一致性较差(κ=0.18),类似地,在对照组中,ELIS-POT和TST一致性也较差(κ=0.16)。不一致的检测结果在病例组中常见ELISPOT阳性而TST阴性(3例),而在对照组中常见于ELISPOT阴性而TST阳性(7例)。结论:ELISPOT诊断儿童活动性结核病准确性高于TST。ELISPOT具有较高的诊断灵敏度和特异度,其特异度不受儿童的卡介苗接种的影响,适合作为临床诊断儿童结核分枝杆菌感染的辅助诊断技术,有助于感染的儿童得到更快速的诊断和治疗。     

学校涂阳肺结核密切接触者筛查及预防性服药效果分析

目的对学校涂阳肺结核疫情发生后密切接触者进行筛查,并观察预防性服药的效果。方法选取2008-2012年嵊州市6起学校涂阳肺结核,疫情发生后密切接触者和一般接触者进行结核菌素试验（PPD试验）,PPD强阳性胸片未见异常者建议给予抗结核预防性服药,并随访观察预防性服药的效果。结果6起学校肺结核疫情共确诊肺结核34例,密切接触者710人,一般接触者190人。密切接触者中179名PPD筛查呈强阳性,其中86名开展预防性服药,随访1年无人发病;93名未服药的学生随访1年后,23人（24．73％）发病。预防性服药过程中,4人出现轻度的胃肠道反应,3人出现肝功能异常,停药好转后继续治疗,无严重不良反应发生。结论通过PPD试验筛查,掌握密切接触者结核分枝杆菌感染状况,有针对性地进行预防性服药,能有效控制结核病扩散。     

Immunogenicity and efficacy analyses of EPC002, ECA006, and EPCP009 protein subunit combinations as tuberculosis vaccine candidates

Tuberculosis (TB) is the leading cause of death from infectious diseases worldwide, and developing a new TB vaccine is a priority for TB control. Combining multiple immunodominant antigens to form a novel multicomponent vaccine with broad-spectrum antigens to induce protective immune responses is a trend in TB vaccine development. In this study, we used T-cell epitope-rich protein subunits to construct three antigenic combinations: EPC002, ECA006, and EPCP009. Fusion expression of purified protein EPC002f (CFP-10-linker-ESAT-6-linker-nPPE18), ECA006f (CFP-10-linker-ESAT-6-linker-Ag85B), and EPCP009f (CFP-10-linker-ESAT-6-linker-nPPE18-linker-nPstS1) and recombinant purified protein mixtures EPC002m (mix of CFP-10, ESAT-6, and nPPE18), ECA006m (mix of CFP-10, ESAT-6, and Ag85B), and EPCP009m (mix of CFP-10, ESAT-6, nPPE18, and nPstS1) were used as antigens, formulated with alum adjuvant, and the immunogenicity and efficacy were analyzed using immunity experiments with BALB/c mice. All protein-immunized groups elicited higher levels of humoral immunity, including IgG and IgG1. The IgG2a/IgG1 ratio of the EPCP009m-immunized group was the highest, followed by that of the EPCP009f-immunized group, which was significantly higher than the ratios of the other four groups. The multiplex microsphere-based cytokine immunoassay revealed that EPCP009f and EPCP009m induced the production of a wider range of cytokines than EPC002f, EPC002m, ECA006f, and ECA006m, which included Th1-type (IL-2, IFN-γ, TNF-α), Th2-type (IL-4, IL-6, IL-10), Th17-type (IL-17), and other proinflammatory cytokines (GM-CSF, IL-12). The enzyme-linked immunospot assays demonstrated that the EPCP009f- and EPCP009m-immunized groups had significantly higher amounts of IFN-γ than the other four groups. The in vitro mycobacterial growth inhibition assay demonstrated that EPCP009m inhibited Mycobacterium tuberculosis (Mtb) growth most strongly, followed by EPCP009f, which was significantly better than that of the other four vaccine candidates. These results indicated that EPCP009m containing four immunodominant antigens exhibited better immunogenicity and Mtb growth inhibition in vitro and may be a promising candidate vaccine for the control of TB.     

2007--2008年石家庄市涂阳肺结核病人密切接触者筛查结果分析

目的了解涂阳肺结核病人密切接触者的发病情况。方法对新登记的涂阳肺结核病人的密切接触者先进行症状筛查,对有症状的密切接触者进行免费的x线胸片、查痰、结核菌素试验等检查。结果2007—2008年石家庄市涂阳病人的非家庭密切接触者较家庭的密切接触者更容易发病,非家庭密切接触者的发病率为1643／10万远远高于家庭的密切接触者的发病率317／10万。结论在结核病的防治工作中,涂阳病人的非家庭密切接触者更应受到关注,如学校、监狱等人员密集的特殊场所,更要加强结核病的防治工作。     

Evaluation of Mycobacterium tuberculosis Early Secreted Antigenic Target 6 Recombinant Protein as a Diagnostic Marker in Skin Test

Objectives

Tuberculosis (TB) is the leading infectious disease in the developing world. Delayed-type hypersensitivity skin test diagnoses TB using tuberculin purified protein derivative (PPD), but this test is incapable of distinguishing Mycobacterium tuberculosis (MTB) infection from bacillus Calmette–Guérin (BCG) vaccination or an infection caused by nontuberculous mycobacteria (NTM). This study was performed to evaluate the use of recombinant early secretory antigenic target 6 (rESAT-6), a secretory protein found only in MTB, Mycobacterium bovis, and few other mycobacterial species, as a skin marker for MTB in guinea pigs.

Methods

We prepared recombinant MTB ESAT-6 and evaluated its use as a specific antigen for MTB in guinea pigs.

Results

Our results show that the purified MTB rESAT-6 antigen is capable of inducing a positive reaction only in guinea pigs sensitized to MTB. No such reaction was observed in the animals sensitized to M. bovis, BCG vaccination, or NTM (Mycobacterium avium).

Conclusion

Our study results confirm that the ESAT-6 antigen is more specific to MTB infection than PPD and could be used in more specific skin tests for detection of MTB in large animals and in humans.     

Survey for tuberculosis in an indigenous population of Amazonia: the Suruí of Rondônia, Brazil

A cross-sectional survey was carried out in 2003 to investigate the epidemiology of tuberculosis (TB) among the Suruí Indians, Brazilian Amazon. A total of 736 subjects (50.7% females) were examined (80% of the total population). TB suspects underwent standardised evaluation for the presence of signs and/or symptoms of active TB, including chest radiography, PPD skin test, sputum microscopy examination for acid-fast bacilli and mycobacterial culture. A Bacillus Calmette-Guerin vaccine scar was detected in 699 individuals (95.0%). Of all the individuals examined, 120 (16.3%) had undergone previous TB treatment (46.7% females). One hundred and nine individuals were assessed as TB suspects (52.3% females). The survey identified six new cases of TB in the Suruí (three men and three women). Five of the six cases came from only two of the ten villages. Mycobacterium tuberculosis colonies grew from 5 (4.6%) samples (only two of which were also smear-positive) and mycobacteria other than M. tuberculosis were isolated from 14 (12.8%) samples. Diagnosis of TB based exclusively on clinical grounds was established only in the case of a 4-year-old girl. Based on this survey, the prevalence of active TB in the sampled group (N=736) was 815.2 per 100000. This study highlights the urgent need to review and strengthen control strategies directed at indigenous peoples in the country, taking into consideration their social, cultural and environmental differences.     

Analysis of complex formation and immune response of CFP-10 and ESAT-6 mutants

ESAT-6 and CFP-10 form a 1:1 heterodimeric complex which contributes to the virulence of Mycobacterium tuberculosis H37Rv. Based on the structure of CFP-10-ESAT-6 complex, we have selected four point mutations each of CFP-10 and ESAT-6 and have analyzed complex formation for the 25 possible combinations between wild-type and mutant CFP-10 and ESAT-6 proteins. We observed that the mutations L25R or F58R of CFP-10 and L29D or L65D of ESAT-6 lead to disruption of complex formation. We have evaluated the immunogenic responses of the wild-type and mutant CFP-10 and ESAT-6 proteins, the wild-type CFP-10-ESAT-6 complex, six complex-forming and two non-complex-forming combinations of wild-type/mutant CFP-10 and ESAT-6 proteins. CFP-10 mutants I21R, L25R, and W43R were found to have better immunogenic potential than wt-CFP-10, while none of the ESAT-6 mutants were better than wt-ESAT-6. Very interestingly, we have discovered that the non-complex-forming mixture of CFP-10-I21R and ESAT-6-L29D gives a strong immunogenic response.     

一起学校聚集性肺结核疫情调查

目的了解学生聚集性结核病疫情发生的原因,为学校肺结核病防控提供依据。方法对嵊州市某学校出现病例所有班级学生进行结核菌素(PPD)试验、X线胸部摄片,可疑者CT复查,对X线胸片检查或CT复查异常者给予痰涂片检查抗酸杆菌。结果首发病例为涂阳病人,患者出现症状后在密闭空调环境中与其他同学一起学习2个月,才被明确诊断并离校治疗,增加交叉感染的发病概率。本起疫情通过因症就诊、转诊和筛查共发现肺结核病31例,均为学生病例。其中涂阳肺结核4例、涂阴肺结核25例、结核性胸膜炎2例;18例有临床症状,13例无自觉症状;3-4月份为发病高峰。第1例阳性病例发现时间晚、就诊延误、持续接触、通风不良和学校分班是造成本次聚集性疫情的主要原因。结论应加强学校对传染病的管理,落实晨检和症状监测,以及时发现和隔离结核病病人,预防服药是聚集性肺结核疫情中密切接触者的有效预防手段。     

Contact tracing and population screening for tuberculosis--who should be assessed?

BACKGROUND: The aim of the study was to investigate the relative effectiveness of four strategies in detecting and preventing tuberculosis: contact tracing of smear-positive pulmonary disease, of smear-negative pulmonary disease and of non-pulmonary disease, and screening new entrants. METHODS: An analysis of patient records and a TB database was carried out for an NHS Trust-based tuberculosis service in a socio-economically deprived area. Subjects were contacts of all patients treated for TB between 1997 and 1999. New entrants were screened in 1999. Outcomes measured were numbers of cases of active tuberculosis detected and numbers of those screened given chemoprophylaxis. RESULTS: A total of 643 contacts of 227 cases of active TB were seen, and 322 new entrants to the United Kingdom. The highest proportion of contacts requiring full treatment or chemoprophylaxis were contacts of smear-positive index cases (33 out of 263 contacts; 12.5 per cent). Tracing contacts of those with smear-negative pulmonary tuberculosis (12 out of 156; 7.7 per cent) and non-pulmonary disease (14 out of 277; 6.2 per cent) was significantly more effective in identifying individuals requiring intervention (full treatment or chemoprophylaxis) than routine screening of new entrants (10 out of 322; 3.1 per cent). CONCLUSIONS: Screening for TB of new entrants to the United Kingdom is part of the national programme for control and prevention of TB, whereas tracing contacts of those with smear-negative and non-pulmonary disease is not. This study demonstrates that, in our population, the contact-tracing strategy is more effective than new entrant screening. It is not likely that the contacts have caught their disease from the index case, but rather that in high-incidence areas such as ours such tracing selects extended families or communities at particularly high risk.     

北京市昌平区某高校大学新生结核潜伏感染调查

目的 调查大学新生结核潜伏感染情况,以便采取预防性措施。 方法 2010年10月随机纳入北京市昌平区某高校入学新生TST≥10 mm的健康受试者420例,应用ELISPOT检测经抗原刺激后分泌IFN-γ的效应T淋巴细胞(即斑点形成细胞,SFCs)数量,并对ELISPOT阳性者进行为期3年的结核感染发病情况监测。 结果 ELISPOT检测LTBI总的阳性率为41.2%,在BCG接种(阳性率41.5%)和未接种(阳性率40.0%)中差异无统计学意义(χ²=0.064, P=0.447),在TST直径10~14、15~19和≥20 mm组间(37.6%、45.4%和64.3%)差异有统计学意义(χ²=8.408, P=0.015),173例未治疗的 ELISPOT+/TST+者经3年的ATB监测,发病率为0。 结论 北京市昌平区某高校大学新生LTBI比率高,但仅以ELISPOT和TST双阳性者为预防性治疗指标,尚不足够。     

Evaluation of cell-mediated immune responses to two BCG vaccination regimes in young children in South Korea

Children in South Korea are vaccinated with either BCG Pasteur vaccine intradermally (ID), or with BCG Tokyo vaccine given by multipuncture device (MP). Data from a recent national survey indicated that in children under 6 years old, 31.1% had received the ID vaccine and 64.5% the MP vaccine. To compare the T cell responses induced by the two vaccines, children aged 3-7 were recruited and tested for tuberculin skin test reactivity and for in vitro IFN-γ responses to mycobacterial antigens. DTH responses were not significantly different in children vaccinated by either the ID or MP vaccines. PPD-induced IFN-γ was measured in supernatants of 6-day diluted whole blood cultures. IFN-γ production to PPD was not significantly different in the two vaccine groups, although there is a trend that the MP group gives a higher proportion of IFN-γ positivity than the ID group. In addition, when IFN-γ responses to the antigens ESAT-6 and CFP-10 were assessed in the 6-7 year old group, there was no significant difference between the two vaccine groups. Thus, there was no evidence that the increasing use of MP vaccination has reduced protection against M. tuberculosis in young children in South Korea, based on immunogenicity as assessed by DTH and IFN-γ responses to PPD, and also equivalent frequency of responses to ESAT-6 and CFP-10.     

Screening for tuberculosis among orphans in a developing country

BACKGROUND: There has been a recent resurgence of tuberculosis (TB) as a worldwide public health concern. It is a well-documented health problem in Haiti, where the reported prevalence is 123.9 per 100,000 population. While the Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO) policy papers for the eradication of TB recommend screening in shelters, prisons, and other congregate-living facilities, screening in institutional orphanages is not specifically mentioned. METHODS: A total of 445 orphans with no documentation of Bacillus Calmette-Guerin (BCG) vaccine at six orphanages representing urban, suburban, and rural Haiti were screened for TB using standardized purified protein derivative (PPD). An inoculum of 0.1 cc was introduced intradermally, with site checks for induration at 48-72 hours after inoculation. Induration >5 mm was recorded as positive. Active cases of TB were defined by symptoms such as fever, night sweats, cough greater than 1 month, or signs of extrapulmonary TB (like scrofula or Pott's disease). RESULTS: The number of positive PPD tests was 170 of the 445 children tested, or 38,202 per 100,000; there were 10 active cases. The overall prevalence of tuberculin positivity in the three orphanages with one or more active cases was 44%, compared to 13% in the three with no identified active cases. CONCLUSIONS: The data indicate that TB prevalence among the orphans screened was 1123 per 100,000. This is substantially greater than that reported for the general Haitian population. These data thus suggest children living in orphanages as a previously unidentified high-risk group for TB infection. Further investigation of TB is recommended for orphans in developing countries.     

T细胞酶联免疫斑点法对艾滋病合并结核病患者的诊断价值研究

目的探讨T细胞酶联免疫斑点法(T.SPOT-TB)在艾滋病合并结核病患者中的诊断价值。方法应用T.SPOT-TB对57例诊断明确的艾滋病合并结核病患者的血液样本进行检测并分析不同因素对T.SPOT-TB诊断价值的影响,同时对所有患者做结核菌素皮试(TST)试验进行比较。结果在艾滋病合并结核病的所有患者、肺结核组、肺外结核组、肺结核初治组、肺结核复治组的各组患者中,T.SPOT-TB的阳性检出率分别为80.70%、77.41%、88.46%、72.73%、80.00%;而TST试验的阳性检出率分别为22.81%、25.81%、19.23%、54.54%、10.00%。在患者总体、肺结核组、肺外结核组、复治组中,T.SPOT-TB检测的阳性检出率均高于TST试验(P0.05)。结论对于MTB/HIV双重感染患者,T.SPOT-TB检测的敏感性高于目前常用的TST试验,且不受结核发病部位和初复治类型的影响,适用于我国艾滋病合并结核病的快速诊断。