Comparison of the tine and Mantoux tuberculin tests. Report of the Tuberculin Subcommittee of the Researched Committee of the British Thoracic Association.

Intracutaneous (Mantoux 5 TU) and tine tuberculin tests were performed on the opposite arms of 307 people. The results of each test were read by two independent observers at either 48 or 72 hours. Positive readings were recorded in 59% of the Mantoux tests; induration was 10 mm or more in 34.7% of cases. Positive readings were recorded for 3.9% of the tine tests, and a further 15.5% were recorded in the doubtful category. The tine test is unsuitable for epidemiological use because of the high proportion of negative and doubtful results in people positive on the Mantoux test. For the same reasons its usefulness in clinical practice is very limited.     

Tuberculin Test in Children with Malnutrition

Tuberculin tests with Heaf''s multiple-puncture method, as well as intradermal tests with varying strengths of old tuberculin, were carried out on 402 children with severe malnutrition. From the radiological and bacteriological findings 51 children (12.5%) were considered to have active tuberculosis. The Heaf test was positive in only 11 of these children, but the intradermal test using 100 tuberculin units was positive in a further 18. This confirms previous findings that tuberculin sensitivity is impaired in malnourished children, and suggests that a higher dose of tuberculin is more likely to elicit a positive response.     

Vaccination with Freeze-Dried BCG

Sixty first-year medical students, negative to 1:2000 and 1:100 dilutions of old tuberculin (OT), were vaccinated with freezedried BCG vaccine. At six months, 98.3% were found to be positive reactors as ascertained by the intracutaneous (Mantoux) method, using 1:2000 and 1:100 dilutions of OT, and 73.7% as ascertained by the Heaf test, using a tuberculin PPD solution containing 100,000 T.U. per ml.     

Prevalence of Mycobacterium tuberculosis infection among injection drug users in Toronto

BACKGROUND: Injection drug users are at increased risk of Mycobacterium tuberculosis infection and active tuberculosis (TB). The primary objective of this study was to determine the prevalence of M. tuberculosis infection among injection drug users in Toronto, as indicated by a positive tuberculin skin test result. An additional objective was to identify predictors of a positive skin test result in this population. METHODS: A cross-sectional study was carried out involving self-selected injection drug users in the city of Toronto. A total of 171 participants were recruited through a downtown Toronto needle-exchange program from June 1 to Oct. 31, 1996. RESULTS: Of 167 subjects tested, 155 (92.8%) returned for interpretation of their skin test result within the designated timeframe (48 to 72 hours). Using a 5-mm cut-off, the prevalence rate of positive tuberculin skin test results was 31.0% (95% confidence interval 23.8% to 38.9%). Birth outside of Canada and increasing age were both predictive of a positive result. INTERPRETATION: There is a high burden of M. tuberculosis infection in this population of injection drug users. The compliance observed with returning for interpretation of skin test results indicates that successful TB screening is possible among injection drug users.     

A New Approach in Dispensing Tuberculin PPD and in Performing a Multi-Puncture Tuberculin Test

A simple and low-cost kit for single-dose tuberculin testing is described. For those who perform occasional tuberculin tests only, this kit is proposed as a substitute for the Heaf apparatus used in carrying out a multi-puncture test. No difference in the tuberculin skin reactions could be observed when the needle multi-puncture test was compared with the Heaf test in BCG-sensitized guinea pigs and in 12 volunteers. A comparative study on 37 student nurses, using the needle multi-puncture method and the intracutaneous method (Mantoux test), showed that with the needle multi-puncture method more positive reactors were detected than with the Mantoux test using 1:2000 dilution of OT. However, more positive reactors were obtained with the Mantoux test using 1:100 dilution of OT. It is felt that the singledose kit can be a valuable asset when only few skin tests are performed.     

Cell-mediated response to BCG investigated by leukocyte migration test from an agarose droplet

The modified leukocyte migration test (LMT) from an agarose droplet with the antigen stimulation (by BCG) is proposed in the present work. The BCG concentrations ranging from 1.25 up to 130 mg/l were used to examine 20 tuberculin (PPD) skin test negative and 10 PPD positive patients, which suffered from lung diseases. The optimal concentrations were 6.25 and 25.0 mg/l. The mean index values of a 20 membered control group ranged from 0.7 up to 0.88 when stimulated with the lower BCG concentration, and they were of 0.53 up to 0.69 at higher BCG concentration. In spite of its suitable indicatory properties as to ascertain cell mediated immunity state, the LMT with the BCG were of no use as a tuberculin skin test correlate.     

Correlation of tuberculin-induced lymphocyte transformation with skin test reactivity and with clinical manifestations of sarcoidosis

In vitro lymphocyte reactivity to tuberculin (PPD) was studied in buffy coat cultures from 87 patients with sarcoidosis and from 64 controls. A strong correlation was found between PPD-induced lymphocyte transformation and skin reactivity. No significant differences were found in the in vitro response of lymphocytes from skin test positive patients with sarcoidosis and from controls with the same degree of skin test reactivity. In patients with sarcoidosis negative to 100 TU, tuberculin sensitivity could be demonstrated in vitro significantly more often than in comparison subjects. Both in vivo and in vitro tuberculin sensitivity and “spontaneous” transformation were significantly more frequent in patients with erythema nodosum.     

Skin reactivity to mycobacterial antigens in children living in an area of Mycobacterium xenopi endemicity

Intradermal skin tests with a 2TU dose of PPD-RT 23 prepared from M. tuberculosis and 0.1 ug/0.1 ml of PPD-RS 631 from M. xenopi were simultaneously carried out in 378 7-year-old children from two localities in North-Bohemian region's capital Ustí n. Lab., a focus of M. xenopi endemicity repeatedly confirmed since its disclosure in 1980 by positive M. xenopi isolations from humans and public water supply network. A further group 157 children serving as controls was from Prague district 4 where no presence of M. xenopi strains was ever recorded. All of these children had received routine immunization at birth with Czech BCG vaccine. The children from the two endemic localities were found to give a positive 6 mm or greater reaction to M. xenopi mycobacterin in 43.3% and 22.3%, to human tuberculin in 12.8% and 12.6%, respectively. The frequency histogram clearly separated a group of reactors with 8-18 mm indurations from a group of nonreactors showing a skin induration of 4-8 mm. The higher reactivity of this exposed child population was also reflected in a larger proportion of reactions greater to M. xenopi PPD than to human tuberculin antigen: the reactions greater by 1-5 mm accounted, respectively, for 25.1% and 20.6%, reactions greater by 6 mm or more for 23.7% and 15.9%. Among a group of children from Prague district 4, 6.4% had medium-sized and 3.8% large-sized reactions to M. xenopi antigen; the proportion of reactions greater to M. xenopi antigen than to human tuberculin accounted for only 5.1%, reactions greater to tuberculin than to sensitin were here in slight predominance. The evidenced skin sensitization to M. xenopi mycobacterin is suggested to result from the different degrees of exposure to infection by environmental mycobacteria.     

Immunological Pregnancy Diagnosis in the Mare

An immunological gel-diffusion test for the diagnosis of pregnancy in the mare is described. 56 blood samples from 50 different mares were tested. Control tests were made both by the Ashheim-Zondek method and by clinical examination. The accuracy of the immunological method was 96.4 %. No false positive reactions were observed. It is recommended to draw the blood sample at approximately 45 days or more after the last service. The immunological method is simple, cheap and accurate and is recommended as a routine test for the diagnosis of pregnancy in mares.     

Detection of Mycobacterium bovis in bovine tissue samples by the Abbott LCx Mycobacterium tuberculosis assay and comparison with culture methods.

A ligase chain reaction (LCR) DNA amplification method for the molecular diagnosis of Mycobacterium tuberculosis complex (Abbott LCx MTB) was evaluated in comparison with solid (Lowenstein Jensen), liquid (7H12, Bactec 460 system) phase culture and microscopic examination (ME) on 86 tissue samples collected from 86 intradermal tuberculin positive cattle and one pool from 4 guinea pigs experimentally infected with M. bovis. Overall, 48 samples (58.81%) were culturally positive for mycobacteria, and on the basis of biochemical characters, all the isolates were identified as M. bovis. Sensitivity was 83.92% for LCx, 53.57% for LJ, 85.71% for Bactec and 41.07% for ME. In 3 out of 25 "no visible lesion" tissue samples, M. bovis was detected only by LCx and Bactec but not by LJ and ME. The concordance in the determination of positives and negatives among the methods observed in pairs was calculated according to Cohen's K concordance coefficient and showed 81.1% of concordance of LCx vs Bactec, 68.8% LCx vs LJ, 72.2% LCx vs ME, 80.0% Bactec vs LJ, 66.7% Bactec vs ME, 85.5% LJ vs ME. Despite a certain variability in concordance rates, both Cohen's K concordance coefficients or standardized (Zk) values were statistically significant. Both LCx and Bactec appear not alternative but subsidiary to the other methods traditionally applied for direct diagnosis of bovine tuberculosis on tissue samples from cattle reacting to intradermal tuberculin test.     

T-SPOT.TB: an in vitro diagnostic assay measuring T-cell reaction to Mycobacterium tuberculosis-specific antigens

The overall sensitivity of the RD1 ELISPOT assay (T-SPO.TB), which counts T cells sensitized to specific Mycobacterium tuberculosis peptide sequences, was 81-97% in populations with confirmed tuberculosis, in whom 39-78% had immunosuppressive conditions. In patients with confirmed tuberculosis, the respective RD1 ELISPOT versus tuberculin skin test (TST) sensitivities were 100% versus 89% in adults and 77% versus 35% in children (of whom 39% were HIV-positive). In contrast to that of the TST, the sensitivity of the RD1 ELISPOT assay was not significantly affected by age <36 months, or the immunological or nutritional status of the subjects. Specificity was 100% in two UK-based studies. Isolated false positives have been recorded in patients infected with non-tuberculous M. kansasii. A study investigating latent tuberculosis infection found no significant difference in results between HIV-positive and -negative participants for the RD1 ELISPOT assay, while the TST varied significantly with HIV status. Contact-tracing studies have demonstrated concordance between the RD1 ELISPOT assay and the TST of 65-89%. There is a significant correlation between a positive result and the degree of exposure to the index case for the RD1 ELISPOT assay, but not for the TST, in contact-tracing studies. Unlike the TST, the RD1 ELISPOT assay is not confounded by bacille Calmette-Guérin vaccination.     

结核感染T细胞斑点试验对肺外结核诊断价值探讨

目的评价结核感染T细胞斑点试验（T—SPOT．TB）在肺外结核中的诊断价值。方法采用T—SPOT．TB试剂盒对疑诊或待排结核患者外周血中特异性T淋巴细胞进行检测。结果结核感染T细胞斑点试验的对结核病的敏感度、特异度分别为76．7％、84．3％。肺外结核组与肺结核组阳性率分别为92．0％和78．2％,差异有统计学意义（P〈0．05）。该数据显著高于结核菌素试验的31．4％和结核分枝杆菌培养的19．3％,差异有统计学意义（P〈0．05）。结论结核感染T细胞斑点试验是诊断肺外结核的快速敏感方法,值得在临床中推广使用。     

利用结核分枝杆菌抗原特异性γ-IFN体外释放测定评估抗结核治疗疗效的临床应用价值

探讨利用结核分枝杆菌抗原特异性γ-IFN体外释放测定评估抗结核治疗疗效的临床应用价值。研究了66例培养阳性肺结核病人抗结核治疗过程中抗原特异性γ-IFN体外释放测定结果的变化,并与结核菌素皮试结果的变化相比较。结果,抗原特异性γ-IFN体外释放测定于抗结核治疗前期(满2个月)的阳性率显著高于后期(疗程满6个月)[55/66(83.3%)vs12/66(18.2%);P≤0.01],而PPD结素皮试于抗结核治疗前期及后期的阳性率分别为[50/66(75.8%)vs38/66(57.6%);P>0.05]。结论:结核分枝杆菌抗原特异性γ-IFN体外释放测定评估抗结核治疗疗效较PPD结素皮试临床应用价值更大。     

Development and Evaluation of a Simple Latex Agglutination Test for Diagnosis of Tuberculosis

A simple latex agglutination test (SLAT) based on modifications of existing serodiagnostic techniques, in which commercially available reagents are used, was developed for detection of antibodies against Mycobacterium tuberculosis. Tests performed on 553 serum samples from 316 individuals, including 117 bacteriologically confirmed active tuberculosis patients, showed 80% positive titers. Sera from 12 patients with arrested tuberculosis showed 91% positive titers. Nonspecific reactions were noted in 5% of 160 serums from selected normal individuals and patients with diseases other than tuberculosis. The antibodies detected by the SLAT method were found to be relatively stable when exposed to low temperatures, whereas high temperatures reduced the antibody titer considerably. Disodium ethylenediaminetetraacetic acid inactivation of serum complement was found to be satisfactory. No variation of tuberculosis antibody titer was noted in tests on multiple specimens from patients whose conditions were stabilized. However, considerable fluctuation was encountered in antibody titers obtained on recently detected individuals. Data obtained in this study indicate that the modified procedures of the SLAT method could replace the tuberculin skin test for simple screening of tuberculosis in adults.     

Immune Response to other Agents of Calves Persistently Infected with Bovine Virus Diarrhoea Virus (BVDV)

The ability of calves persistently infected (PI) with bovine virus diarrhoea virus BVDV to respond immunologically to defined antigens other than BVDV was studied. Five clinically healthy PI calves were studied together with 5 non-PI calves serving as controls. The humoral immune response was tested by measuring the serum antitoxin titre following immunization against tetanus. The cellular immune response was tested by the ability to develop a positive reaction in a cutaneous tuberculin test performed 1 month after immunization against Johne’s disease (paratuberculosis). Finally, a skin-sensitizing agent, dinitrochlorobenzene (DNCB), was employed to study whether PI calves would react by hypersensitization following skin exposure to DNCB for 7 consecutive days followed by application of DNCB to a new skin area remote from the area that had first been exposed. The response of PI calves to the various types of antigenic stimuli applied was not significantly different from that of the control calves. Thus, PI calves developed a potent antitoxin response after tetanus immunization, they showed a positive reaction to tuberculin skin test after immunization against paratuberculosis, and were skin sentitized with DNCB.     

Outbreak of tuberculosis after minimal exposure to infection.

The identification of a case of respiratory tuberculosis in a swimming-baths attendant whose sputum was smear positive was followed by intensive contact tracing of children aged 8-11 years who had visited the baths. An outbreak was discovered that otherwise might not have been detected. Out of 3764 children, 108 (2.9%) had evidence of infection: there were 16 cases of tuberculosis, of which 11 were symptomless but showed lesions on chest radiography, and a further 92 with tine test grade 3 or 4 without clinical or radiological signs. The contact of these children with the index case was apparently minimal. Early detection, isolation, and treatment of infectious cases of respiratory tuberculosis and vigorous contact tracing should be given more priority in tuberculosis control.     

猴结核病血清抗体检测方法的建立

目的目前活检猴感染结核病的检疫方法只有结核菌素试验。由于检测方法的单一性,结核菌素试验敏感性和特异性低,给灵长类结核病的管理带来困难。为此,开展了猴结核病血清抗体的检测方法。方法利用胞浆蛋白、结核菌素、Trehalose 6,6-’dimycolate(TDM)分别作为抗原建立猴结核病血清抗体ELISA检测方法,检测了28份自然感染血清和121份阴性血清,评价其应用价值。结果根据三种抗原对标本检测结果的敏感度和特异度,用受试者工作特性曲线(ROC)进行分析比较。胞浆蛋白、结核菌素、TDM三种抗原检测的敏感度分别为89.3%、75%与64.3%;特异度分别为93.4%、95.9%与88.4%。ROC曲线下面积都大于0.5(P<0.01)。结论表明三种抗原能用于抗猴结核病的ELISA检测,具有较好的准确性。其中,胞浆蛋白抗原的敏感性和特异性最高,是猴结核病血清抗体检测较好的一种抗原。     

多肽抗体谱免疫印迹法检测ENA抗体的临床应用

本文报道应用多肽抗体谱印迹法检测风湿性疾病患者的ＥＮＡ抗体,该法一次可检测７种抗体。应用本法检测ＳＬＥ８５例,其Ｓｍ抗体阳性率为２０．０％,ｕ１－ＲＮＰ抗体为４１．１％,ＳＳ－Ａ抗体为１０．５％ＳＳ－Ｂ抗体为３．５％,抗核糖体为７．０％。检测ＤＬＥ６例,其山ｕ１－ＲＮＰ抗体阳性率为３３．０％。检测ＰＭ／ＤＭ１５例,其ｕ１－ＲＮＰ抗体阳性率为１３．０％,Ｊｏ－１抗体为１４．０％。检测ＲＡ４８例,其ｕ１－ＲＮＰ抗体的阳性率为３３．３％。检测ＳＳ２１例,其ＳＳ－Ａ抗体阳性率为４３．０％,ＳＳ－Ｂ抗体为３８．０％,检测ＰＳＳ９例,其Ｓｃｌ－７０抗体阳性率为２２．０％。检测ＭＣＴＤ１０例,其ｕ１－ＲＮＰ抗体阳性率为５０．０％。健康人对照１００例,７种抗体均为阴性。显示应用多肽抗体谱印迹法检测结果与国内其它方法所测得结果基本一致,但可检测的抗体种类多于其它方法。