应用多重聚合酶链反应和Bactec 460 TB系统检测…

合成两对引物，建立了结核杆菌ＤＮＡ多重ＰＣＲ，检测分枝杆菌标准菌株，仅人型和牛型结核杆菌呈阳性，灵敏度≥７个结核杆菌呈阳性。与Ｂａｃｔｅｃ４６０ ＴＢ系统快速培养法对照检测４０例肺结核病人痰，多重ＰＣＲ法２７例阳性，Ｂａｃｔｅｃ法１９例阳性，（Ｐ〈０．０５）。有４例Ｂａｃｔｅｃ法呈阳性，一对引物ＰＣＲ法呈阴性，而多重ＰＣＲ法呈阳性。有８例Ｂａｃｔｅｃ法呈阴性，而多重ＰＣＲ法呈阳性。多重ＰＣＲ法４８     

套式/多重PCR检测疟疾感染的应用研究

目的了解标签引物-套式/多重PCR技术在检测疟疾感染中的现场应用价值。方法随机采取我省疟疾流行区有发热症状的居民及家庭成员的耳垂血79份,同时制作厚血片和滤纸血样本各1份,用标签引物-套式/多重PCR检测所采集滤纸血样本中的疟原虫,并与镜检法进行比较。结果79份样本中,用标签引物-套式/多重PCR技术检出间日疟原虫阳性6例,镜检初检出10例间日疟原虫阳性,经复查血片后有4例排除了疟疾感染。镜检复核阳性的6例样本PCR均为阳性。以镜检复核为标准,两法阳性和阴性符合率为100%。结论标签引物-套式/多重PCR检测疟疾感染具高度敏感性和特异性,对疟疾鉴别诊断和明确诊断具有重要价值。     

膜芯片技术检测泌尿生殖道沙眼衣原体、淋病奈瑟菌和3种支原体的方法学研究

目的建立和评价一个新的多重PCR．反向线点杂交技术（RIJB）快速同时检测泌尿生殖道沙眼衣原体（Ct）、淋病奈瑟菌（坛）和3种支原体感染的方法。方法分别选择Ct隐蔽质粒和Ng16SrRNA基因设计两对特异性引物，以支原体内转录间隔序列（ITS）设计一对支原体属通用引物，生物素标记下游引物。构建三重PCR同时扩增Ct、Ng、解脲脲原体（仇）、微小脲原体（跏）、人型支原体（Mh）等菌DNA，然后与固定在尼龙膜上的各特异性寡核苷酸探针杂交。并对142份经荧光定量PCR（FQ-PCR）检测0和坛的性病高危人群标本，以及45份经支原体液体培养法鉴定的标本进行检测。结果多重PCR可同时扩增Ct、Ng、Uu、Up和Mh标准菌株DNA，其PCR产物的片段长度为208～408bp。97份FQ-PCRCt阳性标本中有93份经多重PCR-RLB检测为Ct阳性，45份FQ-PCRCt阴性标本中35份多重PCR-RLB阴性。41份FQ-PCRNg阳性标本中34份多重PCR-RLBNg阳性，101份FQ-PCRNg阴性标本中98份多重PCR-RLB阴性。其中36份经多重PCR-RLB检测为混合感染。32份支原体液体培养阳性标本中28份多重PCR-RLB阳性，13份支原体培养阴性标本经多重PCR-RLB检测均为阴性。结论多重PCR-RLB可快速同时检测Ct、Ng、Uu、Up和Mh，为性传播疾病的临床诊断提供了一种可靠的方法。     

环介导等温扩增技术检测间日疟原虫方法的建立及应用分析

目的建立一种快速、简便的检测间日疟原虫的环介导等温扩增方法（LAMP）并与常规PCR方法作比较。方法根据间日疟原虫环子孢子蛋白（CSP）基因序列合成2对特异性LAMP引物,优化Mg2＋浓度、dNTPs浓度、BstDNA聚合酶添加量、反应温度、时间以及设计引物缺省试验。评估优化后的LAMP反应的特异性和灵敏性。检测133份患者血样,以显微镜检方法为金标准,比较LAMP和多重PCR法检测间日疟原虫的敏感性和特异性。结果 LAMP法检测重组质粒DNA（Pv-rDNA）的灵敏度达到10-10,为传统PCR方法的100倍。镜检确诊的68例间日疟、43例恶性疟和22例非疟疾患者中,LAMP法和多重PCR检测间日疟原虫的敏感性为98.53%和97.06%,两法基本相当（χ2=0.34,P〉0.05）;特异性为86.15%和100%,LAMP法低于多重PCR法,差异有统计学意义（χ2=9.67,P〈0.05）。LAMP法的阳性预测值和阴性预测值分别为88.16%和98.25%,多重PCR的阳性预测值和阴性预测值分别为100%和97.01%。结论 LAMP法检测间日疟原虫具有快速简便、敏感性高、设备要求低的特点,具有较好的应用前景。     

HBsAg阴性孕妇血清中HBV-DNA检测的临床意义

目的检测乙型肝炎表面抗原（HBsAg）阴性孕妇血清中HBV-DNA存在情况。方法用荧光定量PCR方法检测HBsAg阴性孕妇血清中HBV-DNA。结果检测680例HBsAg阴性孕妇血清HBV-DNA,阳性53例,阳性率7.8%。结论HBsAg阴性孕妇血液中有相当一部分人存在乙型肝炎病毒（HBV）,使用PCR法对HBsAg阴性孕妇进行血清中HBV-DNA检测筛查,有利于对HBV-DNA阳性孕妇早期进行免疫阻断,以减少宫内感染、阻断HBV母婴垂直传播有重要意义。     

登革热病毒多重荧光PCR检测及基因分型方法的研究

目的建立一种登革热病毒双靶基因多重荧光PCR检测方法,用于登革热病毒的实验室诊断和基因分型。方法选取登革热病毒Ⅰ-Ⅳ型病毒保守区设计型特异性引物探针和通用型引物探针。评估多重荧光PCR检测方法的特异性、重复性和检测限;并对20份阳性样本进行检测。结果20个登革热阳性核酸标本在通用型检测全部为阳性,特异性型别检测发现登革热病毒Ⅰ型10例、登革热病毒Ⅱ型3例、登革热病毒Ⅲ型3例、登革热病毒Ⅳ型4例;20名正常无症状人群标本提取的核酸和HIV、HCV和HEV通用型和特异性型别检测全部为阴性。梯度检测的变异系数均小于5％。对登革热Ⅰ-Ⅳ型病毒检测最低检测限达10^3 eopies／ml。结论本研究建立的登革热病毒双靶基因多重荧光PCR检测及分型方法具有特异性好、重复性好、快速易操作等优点,可用于登革热病毒的快速检测和基因分型鉴定。     

ELISA法和RT-PCR法在麻疹病毒检测中的应用比较分析

目的 探讨酶联免疫吸附试验(enzyme linked immunosorbent assay,ELISA)和实时荧光定量PCR(quantitative real-time PCR,RT-PCR)对疑似麻疹病例的麻疹病毒的检测,为疾病的尽早确诊及治疗提供实验依据.方法 以上海市宝山区2014年4月至2015年12月的250例疑似麻疹病例为研究对象,采集其血清标本和咽拭子标本,分别应用ELISA法检测患者血清中的麻疹特异性的免疫球蛋白M(immunoglobulin M,IgM)抗体和RT-PCR法检测咽拭子中麻疹病毒的核酸.结果 250例疑似麻疹病例,排除风疹病毒阳性的34例病例,其中麻疹病毒(measles virus,MV) IgM抗体呈阳性的有80例,阳性率为37.04％;MV RT-PCR呈阳性的有128例,阳性率为59.26％.RT-PCR的检测阳性率显著高于IgM检测(x2=41.14,P＜0.001).结论 RT-PCR法可快速诊断麻疹病毒的病原学,且对出疹初期麻疹IgM呈阴性的病例可进～步确诊,是一种有效可靠的方法.     

聚合酶链反应和免疫学方法检测乙型肝炎病毒为比较

本文应用聚合酶链反应(PCR)检测30例至少有一项免疫学指标(HBsAg、HBsAb、HBcAb、HBeAg 和 HNeAb)阳性的乙肝病人血清中的乙型肝炎病毒 DNA.结果表明,在30例血清中有18例 PCR 呈阳性反应,并且在14份 HBeAg 阳性的血清中有11份 PCR 阳性,两者呈平行关系.PCR 检测乙肝病毒 DNA有突出的敏感性和特异性;并且 PCR 检测的是乙肝病毒 DNA 本身,可反映出乙型肝炎病毒是否处于复制状态,这对临床治疗具有很重要的指导意义.     

酶联免疫法检测PAF受体RNA的聚合酶链反应产物

目的：建立PCR—ELISA法检测附受体RNA。方法：提取20例银屑病病人和20例正常对照组血液单个核细胞标本中的总RNA，用双标记的PAF—R(Biotion与Digoxin标记)及β-actin(Biotin或Fluorescein标记)引物进行RT-PCR，用ELISA检测PCR产物，用传统的琼脂糖凝胶电泳对照。结果；ELISA法和琼脂糖凝胶电泳法对β-actin检测结果均为阳性；ELISA法检测PAF-R，20例病人标本均为阳性，20例对照组16例阳性；琼脂糖凝胶电泳法检测PAF—R，20例病人标本18例阳性，20例对照组16例阳性。结论：PCR-ELISA引物双标记法检测PAF—R操作简单，有较高的敏感性。     

酶联免疫吸附试验检测肉毒中毒婴儿粪便中肉毒杆菌A型与B型毒素

本文评价了酶联免疫吸附试验(ELISA)检出肉毒杆菌A型,B型毒素诊断婴儿肉毒中毒的准确性。该法对常规法(包括鼠致死性试验和粪便培养)确诊的22例病人检测全为阳性。5例粪便标本经培养呈阳性,但小白鼠致死性生物学测定法或为阴性,或因不能被特异性抗毒素中和,毒性判断为非特异性。上述标本ELISA检测的阳性结果表明,对某些病例来说,该法较小鼠生物学测定法可能更为可靠。21例可疑食物传播该菌的粪便,其中2份以小鼠生物学测定法及ELISA均证实含有肉毒毒素,从特异性上看,应用小鼠生物学测定法A、B型肉毒毒素检查呈阴性的35倒粪便标本和19例可疑食物媒介的病例,ELISA检测也均阴性。仅2例粪便标本小白鼠生物学测定法为阴性而ELISA呈阳性,说明该法用于从临床标本中检出肉毒杆菌毒素的筛选试验。     

Rapid detection of smear-negative Mycobacterium tuberculosis by PCR and sequencing for rifampin resistance with DNA extracted directly from slides

Conventional methods for identification of Mycobacterium tuberculosis from culture can take 6 weeks. To facilitate the rapid detection of M. tuberculosis and to assess the risks of drug resistance, we developed a technique of eluting DNA directly from sputum slides and performing PCR for the detection of M. tuberculosis DNA, followed by sequencing the rpoB gene to detect rifampin resistance. This entire process requires only 48 h. Forty-seven sputum specimens submitted for microscopy for detection of acid-fast bacilli (AFB) and for mycobacterial culture and susceptibility testing were assessed after elution from the slides and extraction. M. tuberculosis-specific DNA was amplified in a nested PCR with previously described primers (primers rpo95-rpo293 and rpo105-rpo273), followed by analysis on a 4% agarose gel for a 168-bp product. Automated sequencing was performed, and the sequences were aligned against a database for detection of anomalies in the rpoB gene (codons 511 to 533) which indicate rifampin resistance. Of the 47 sputum specimens tested, 51% (24 of 47) were culture positive (time to positive culture, 2 to 6 weeks). Smears for AFB were positive for 58% (14 of 24) of the specimens and were negative for 42% (10 of 24) of the specimens. All 24 culture-positive sputum specimens (14 microscopy-positive and 10 microscopy-negative sputum specimens) were positive by PCR with eluates from the smears. Forty-nine percent (23 of 47) of the sputum specimens were negative for M. tuberculosis by smear, culture, and PCR. Of the isolates from the culture-positive samples, five were rifampin resistant by sequencing; all five were also rifampin resistant by in vitro susceptibility testing. Of these rifampin-resistant M. tuberculosis isolates, two were microscopy negative for AFB. Patients who are negative for AFB and culture positive for M. tuberculosis can now be identified within a day, allowing institution of therapy and reducing isolation time and medical costs.     

Use of polymerase chain reaction for early identification of Mycobacterium tuberculosis in positive cultures.

AIMS: To develop a readily applicable polymerase chain reaction (PCR) based technique which would permit the identification of Mycobacterium tuberculosis complex isolates from Bactec phials at an earlier stage than currently available methods. METHODS: Mycobacterial cells cultured in Bactec 12B medium were harvested by centrifugation. The cells were lysed by heating in distilled water. Oligonucleotide primers based on the sequence of the gene coding for the immunogenic protein MPB64 were then used to amplify a 240 base pair fragment of DNA directly from the crude cell lysate. The PCR product was visualised under ultraviolet light following electrophoresis of an aliquot in an agarose gel containing ethidium bromide. The sensitivity of the PCR was adjusted so that about 600 cfu of M tuberculosis gave a positive result. The lowest growth index at which this method of identification might be applied to Bactec phials was determined and a number of routine cultures giving a positive growth index examined. RESULTS: M tuberculosis was positively identified at the lowest growth index, as determined by the Bactec system. Of 45 routine cultures examined, with growth indexes ranging from 6 to 999, the 15 confirmed by conventional means to contain M tuberculosis were correctly identified from 1 ml of culture medium. CONCLUSIONS: The method described can be used to identify M tuberculosis isolates cultured in the Bactec system at the earliest detectable rise in growth index. It may therefore allow cultured mycobacteria to be identified at an earlier stage than conventional methods or the commercially available DNA probes adapted for use with the Bactec system.     

Multiplex polymerase chain reaction for the detection of mycobacterial DNA in cases of tuberculosis and sarcoidosis.

The aims of the present study were: (1) to design a sensitive and specific polymerase chain reaction-based method that would allow detection of most common human typical and atypical mycobacterial strains and (2) to apply the method on formalin-fixed paraffin-embedded (FFPE) tissue and sputum samples from patients with clinicopathological evidence of tuberculosis and sarcoidosis. Three sets of primers were selected. The first detects specifically members of the Mycobacterium tuberculosis (M. tuberculosis) complex, amplifying a 243 bp fragment of the gene encoding the immunogenic protein MPB 64, whereas the second traces members of the Mycobacterium avium (M. avium) complex producing a 91 bp fragment of the IS1110 element. The third pair of primers is specific for slow-growing mycobacteria, amplifying a 383 bp region of the 65 kDa mycobacterial antigen gene. Our multiplex polymerase chain reaction assay identified mycobacterial DNA of 10(-3) colony-forming units (CFU)/mL from sputum samples, 10(-5) CFU/mL from FFPE tissue samples and 10(-6) CFU/mL from pure broth cultures. By performing the method on 75 FFPE tissue samples with histological and clinical evidence of tuberculosis and 300 sputum specimens from patients suspected of tuberculosis, we found 38 M. tuberculosis complex, 7 M. avium complex, and 14 slow-growing mycobacteria positive samples in the first case and in the second we found 95 M. tuberculosis complex, 21 M. avium complex, and 35 slow-growing mycobacteria positive samples. The sensitivity of the assay was significantly higher than that of Ziehl-Neelsen and in some cases higher than culture, especially when applied on atypical mycobacteria. In addition, 25 cases histologically and clinically characterized as sarcoidosis were investigated for mycobacterial DNA sequences and in nine of these, DNA corresponding to M. tuberculosis complex was detected. The method described can be applied directly on FFPE and sputum samples and allows not only the detection of mycobacterial DNA, but also an assessment concerning the species involved.     

Direct detection of rifampin- and isoniazid-resistant Mycobacterium tuberculosis in auramine-rhodamine-positive sputum specimens by real-time PCR

Our objective was to evaluate the feasibility of a molecular assay based on a real-time PCR technique, carried out with a LightCycler instrument (Roche Biochemicals), to identify Mycobacterium tuberculosis bacilli and to detect rifampin and isoniazid resistance in DNA extracts from sputum samples. We studied three genes: rpoB, which is associated with rifampin resistance, and katG and inhA, which are associated with isoniazid resistance. A total of 205 sputum samples collected from 108 patients diagnosed with pulmonary tuberculosis with positive auramine-rhodamine-staining (AR) sputum samples, were tested. The sensitivities of the LightCycler PCR assay for the positive AR specimens was 97.5% (200 of 205) for rpoB and inhA genes and 96.5% (198 of 205) for the katG gene. For the total number of patients tested, the sensitivity was 100% (108 of 108 patients) for rifampin, whereas the sensitivity was 98.1% (106 of 108 patients) for isoniazid. Full agreement was found with the Bactec MGIT 960 method and the genotype inferred from the LightCycler data for rifampin. The phenotypic method for isoniazid reported 13 resistant strains (> or = 0.1 microg/ml). In seven (53.8%) strains there was a concordance between both methods, but we found that six (46.2%) strains reported as resistant by the phenotypic method were determined to be susceptible by real-time PCR. For the 75 strains reported as susceptible by the phenotypic method, the concordance with the LightCycler data was 100%. Our results demonstrate that rifampin-resistant M. tuberculosis could be detected in DNA extracted from auramine-rhodamine-positive sputum samples in a single-tube assay that took less than 3 h to perform for a collection of auramine-rhodamine-positive specimens obtained from patients with culture-documented pulmonary tuberculosis. Similarly, this occurs in half of the isoniazid-resistant M. tuberculosis DNA extracted from auramine-rhodamine-positive specimens.     

Use of PCR in routine diagnosis of treated and untreated pulmonary tuberculosis.

AIMS--To assess the routine use of a polymerase chain reaction (PCR) assay for the direct detection of Mycobacterium tuberculosis in expectorated sputum specimens. METHODS--A pair of primers (20-mer) were designed to amplify the 38 kilodalton protein of M tuberculosis. The specificity of the assay was evaluated in 31 M tuberculosis strains, 15 atypical mycobacterium species, and several commensal bacteria of the upper respiratory tract. The assay was subsequently applied to 519 sputum specimens from 85 inpatients of a chest hospital in Hong Kong. RESULTS--An amplified product of 239 base pairs was found in all M tuberculosis strains, standard strains of M bovis, and M africanum but not in the other bacterial strains tested. For the 51 patients with pulmonary radiographic lesions, the diagnosis of pulmonary tuberculosis was subsequently confirmed by both culture and PCR in 41 of them. Five patients who were treated before admission were positive by PCR alone. All but one patient in the control group (patients with acute exacerbation of chronic obstructive airway diseases) or those with atypical mycobacterial diseases were PCR negative. The PCR remained positive after four weeks of anti-tuberculosis treatment in 29 patients, 16 of whom had become culture negative. CONCLUSION--This PCR assay is a useful technique for the diagnosis of untreated and recently treated cases of pulmonary tuberculosis.     

Early identification of Mycobacterium tuberculosis complex in BACTEC cultures by ligase chain reaction

A total of 1431 acid-fast bacilli (AFB) in Bactec culture vials from 1427 patients was differentiated by the Bactec NAP method and tested by the LCx Mycobacterium tuberculosis ligase chain reaction system. In all, 1321 of 1325 M. tuberculosis complex (MTBC) isolates were correctly detected by the LCx assay. All the 106 non-tuberculous mycobacteria (NTM) isolates were negative by the LCx assay. No false MTBC-positive result was obtained from NTM isolates. However, the LCx assay failed to detect four MTBC isolates from one patient. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 99.7, 100%, 100% and 96.4%, respectively. These data suggest that the LCx system can be used to identify MTBC in AFB-positive Bactec broth cultures when the growth index is > or = 100. The method gives a 100% PPV and allows a faster turnaround time for MTBC than the NAP test.     

Development of antigen detection assay for diagnosis of tuberculosis using sputum samples

The rising incidence of tuberculosis worldwide means an increasing burden on diagnostic facilities, so tests simpler than Ziehl-Neelsen staining are needed. Such tests should be objective, reproducible, and have at least as good a detection limit as 10(4) bacteria/ml. A capture enzyme-linked immunosorbent assay (ELISA) was developed for detection of lipoarabinomannan (LAM) in human sputum samples. As a capture antibody, we used a murine monoclonal antibody against LAM, with rabbit antiserum against Mycobacterium tuberculosis as a source of detector antibodies. The sensitivity of the capture ELISA was evaluated by using purified LAM and M. tuberculosis whole cells. We were able to detect 1 ng of purified LAM/ml and 10(4) M. tuberculosis whole cells/ml. LAM could also be detected in culture filtrate of a 3-week-old culture of M. tuberculosis. The culture filtrate contained approximately 100 microgram of LAM/ml. The detection limit in sputum pretreated with N-acetyl-L-cysteine and proteinase K was 10(4) M. tuberculosis whole cells per ml. Thirty-one (91%) of 34 sputum samples from 18 Vietnamese patients with tuberculosis (32 smear positive and 2 smear negative) were positive in the LAM detection assay. In contrast, none of the 25 sputum samples from 21 nontuberculous patients was positive. This specific and sensitive assay for the detection of LAM in sputum is potentially useful for the diagnosis of tuberculosis.     

Use of Gen-Probe and Bactec for rapid isolation and identification of mycobacteria. Correlation of probe results with growth index

Gen-Probe culture confirmation tests (Gen-Probe, San Diego, CA) for Mycobacterium tuberculosis complex and Mycobacterium avium complex were performed on 276 mycobacterial isolates. All 138 M. tuberculosis complex isolates and 79 of 80 M. avium complex isolates were identified correctly. No falsely positive test results were obtained; 58 nontuberculous mycobacteria other than M. avium complex were negative by Gen-Probe. In a second phase of testing, Gen-Probe tests were performed using concentrates from 101 patient Bactec 12B cultures. Positive results by Gen-Probe tests were correlated with the growth index (GI) reading on the day of processing as well as the accumulated GI readings. For those 51 with high (greater than or equal to 999) final GIs, 40/40 (100%) M. tuberculosis complex isolates and 9/11 M. avium complex isolates were positive by Gen-Probe, and six other mycobacteria were negative. Of the 25 with moderate final readings (400 less than or equal to GI less than 999), 12/17 M. tuberculosis complex isolates and 1/1 M. avium complex isolates were correctly identified by Gen-Probe; seven other mycobacteria were negative. Of 25 with low readings (GI less than 400), 8/24 M. tuberculosis isolates were correctly identified by Gen-Probe, and no falsely positive test results were obtained with the other probes. All true negative tests on seven other mycobacteria (not M. tuberculosis complex or M. avium complex) had less than 2% hybridization. Of the 24 falsely negative tests on M. tuberculosis complex isolates or M. avium complex isolates, 22 had greater than 2% hybridization with their respective probes. Thus, percent hybridization greater than 2% may be a useful indicator of the need for retesting.     

Significance of circulating immune complexes in pulmonary tuberculosis

In the present study we have tried to demonstrate circulating immune complexes (CIC) in sera from patients with pulmonary tuberculosis (TB) by three techniques; latex agglutination; 3.5% PEG precipitation and determination of optical density at 280 nm and RIA of CIC using bovine spermatozoa. About 40 normal control sera and 100 TB patients sera were investigated for the presence of CIC. Seventeen per cent cases of pulmonary TB were positive by latex agglutination while none of the control was positive. Levels of CIC as detected by PEG precipitation and RIA were significantly elevated in patients as compared to normal controls. While IgG, IgA and IgM were elevated in the CIC of patients, IgM immunoglobulins were detected only in patients and not in controls. Detection of CIC may at times be useful in diagnosis, prognosis and therapeutic monitoring of disease processes, but it is the characterization of immune complexes (IC) and identification of the specific components of these complexes which holds the greatest potential for better understanding of disease mechanisms. CIC were precipitated using 3.5% PEG from sera of patients suffering from TB. The specific anti-TB antibody component of complex was determined using S. aureus protein A as a solid phase, Anti-BCG antibody and 125I-labelled TB antigen. The specific TB antigen component of the IC was dissociated thermally from TB antibody and assayed by a radioimmunoassay technique developed in our laboratory. Patients were classified into two groups. Those those sputum was positive for Mycobacterium tuberculosis by smear and/or culture and those whose sputum was negative. The TB antigen concentrations of CIC was higher 19.1 +/- 2.3 ng/ml (mean +s.e.) in sputum positive cases, and 9.9 +/- 1.9 ng/ml in sputum negative cases as compared to 2.2 +/- 0.3 ng/ml in controls. Patient groups were significantly different from controls as well as from each other (P less than 0.001). Anti-TB antibody ratios were 11.7 +/- 1.48, 5.1 +/- 1.5 and 0.6 +/- 0.1 in sputum positive, sputum negative and controls. The significance of differences between the groups was P less than 0.001. The effect of treatment administered over a period of 12 weeks or more was evaluated. It was observed that in patients with persistent demonstration of M. tuberculosis in the sputum, the TB antigen and TB antibody levels of CIC were consistently high. In patients who responded to anti-tubercular drugs the TB antigen levels decreased progressively while TB antibody levels remained high.(ABSTRACT TRUNCATED AT 400 WORDS)