The continuing search for Mycobacterium tuberculosis involvement in sarcoidosis: a study on archival biopsy specimens

Introduction: Increasing evidence indicates that mycobacteria may be involved in the aetiology and pathophysiology of sarcoidosis. Objectives: To investigate the association between Mycobacterium tuberculosis complex infection and sarcoidosis. Methods: Mediastinal lymph node biopsy specimens (formalin‐fixed, paraffin‐embedded) from 52 Danish patients with sarcoidosis, 50 patients with mediastinal lymphadenopathy of other non‐mycobacterial causes (negative controls) and 12 patients with histologically and/or culture‐verified mycobacteriosis (positive controls) were included in the study. Biopsy samples were analysed for the presence of Mycobacterium tuberculosis complex by strand displacement assay and a subset of specimens were examined for bacterial rRNA by fluorescent in situ hybridisation using an eubacterial probe with general bacterial specificity (EUB338). Results: One patient with sarcoidosis displayed a positive M. tuberculosis complex test. All negative controls were negative in the test and 5/12 patients with mycobacteriosis were positive in the test. We detected M. tuberculosis complex DNA in 10‐year‐old biopsy samples. Thirty‐six samples were tested with the eubacterial probe; of these, 67% were positive with no difference between patients and controls. Conclusion: Our results do not support the hypothesis that M. tuberculosis complex infection is involved in the pathogenesis of sarcoidosis. However, we stress the importance of excluding mycobacteriosis in the diagnostic workup of sarcoidosis patients. Please cite this paper as: Svendsen CB, Milman N, Rasmussen EM, Thomsen VØ, Andersen CB and Krogfelt KA. The continuing search for Mycobacterium tuberculosis involvement in sarcoidosis: a study on archival biopsy specimens. Clin Respir J 2011; 5: 99–104.     

The impact of alcohol on BCG-induced immunity against Mycobacterium tuberculosis

Background: Alcoholics are at heightened risk for developing active tuberculosis. This study evaluates chronic alcohol consumption in a murine model of vaccination with Mycobacterium bovis Bacille Calmette–Guèrin (BCG) and subsequent pulmonary infection with virulent Mycobacterium tuberculosis. Methods: BALB/c mice were administered the Lieber–DeCarli liquid ethanol diet or pair‐fed the liquid control diet for 3 weeks either before or after subcutaneous vaccination with M. bovis BCG. At least 3 weeks after BCG vaccination, groups of mice on the aforesaid diets were challenged with intratracheal infection with M. tuberculosis H37Rv. Lung mycobacterial burden, and lung and lung‐associated lymph node CD4⁺ lymphocyte production of tuberculosis‐specific interferon (IFN)‐γ were assayed. Popliteal lymph node lymphocytes from both dietary regimens undergoing BCG vaccination (in the absence of M. tuberculosis infection) were also evaluated for purified protein derivative–induced IFN‐γ production by ELISpot assay. Results: Mice begun on alcohol prior to vaccination with M. bovis BCG demonstrated impaired control of pulmonary challenge with virulent M. tuberculosis, as well as impaired lung CD4⁺ and popliteal lymph node T‐cell IFN‐γ responses. If BCG vaccination was delivered prior to initiation of alcohol feeding, the mice remained protected against a subsequent challenge with M. tuberculosis, and BCG‐induced immunity was not impaired in either the lung or the popliteal lymph nodes. Conclusions: Alcohol consumption blunts the development of the adaptive immune response to M. bovis BCG vaccination, which impairs the control of a secondary challenge with M. tuberculosis, but only if the alcohol exposure is begun prior to BCG vaccination. These results provide insight into mechanisms by which alcohol consumption impairs antimycobacterial immunity, including in response to vaccination and subsequent pathogenic challenge.     

Th1 and Th17 immune responses to viable Propionibacterium acnes in patients with sarcoidosis

BackgroundPropionibacterium acnes and Mycobacterium tuberculosis have emerged as probable candidates responsible for sarcoidosis. This study was conducted to investigate the Th1/Th17 responses elicited by these pathogens in sarcoidosis and to clarify the causative role of these pathogens.MethodsPeripheral blood mononuclear cells (PBMCs) obtained from patients with sarcoidosis and from healthy volunteers were, respectively, co-cultured with viable P. acnes, with Bacille de Calmette et Guérin (BCG) as a viable M. tuberculosis complex, and with the early secretory antigenic target (ESAT)-6. Th1 cytokine production was measured using RT-PCR and enzyme-linked immunospot (ELISPOT) assays, and interleukin (IL)-17 mRNA expression was measured by RT-PCR.ResultsIL-2 secretion from PBMCs after stimulation with P. acnes was significantly higher in patients with sarcoidosis than in the controls. Similarly, IL-2 and IL-12 mRNA expression after stimulation with P. acnes was significantly higher in PBMCs from patients with sarcoidosis than in PBMCs from controls. In contrast, IL-17 mRNA expression was significantly lower in PBMCs from patients with sarcoidosis than in PBMCs from controls. No significant differences between the groups were observed in the responses to stimulation with BCG or ESAT-6.ConclusionSarcoidosis may arise from an imbalance of Th1/Th17 immune responses against viable P. acnes, but not M. tuberculosis complex.     

Impact of a Mycobacterium tuberculosis-specific interferon-γ release assay in bronchoalveolar lavage fluid for a rapid diagnosis of tuberculosis

Abstract. Jafari C, Kessler P, Sotgiu G, Ernst M, Lange C (Research Center Borstel, Borstel, Germany; Hygiene and Preventive Medicine Institute, University Sassari, Sassari, Italy; Research Center Borstel, Borstel, Germany). Impact of a Mycobacterium tuberculosis‐specific interferon‐γ release assay in bronchoalveolar lavage fluid for a rapid diagnosis of tuberculosis. J Intern Med 2011; 270 : 254–262. Objectives. Evaluation of different methods for an initial treatment decision in individuals with suspected pulmonary tuberculosis. Background. Recently, important advances regarding the diagnosis of pulmonary tuberculosis have been introduced, which influence the decision to initiate anti‐tuberculosis treatment. Methods. To evaluate the impact of different methods for the presumed diagnosis of tuberculosis, individuals with suspected tuberculosis were prospectively enrolled following a specific algorithm including initial smear microscopy and Mycobacterium tuberculosis‐specific nucleic acid amplification (NAAT) from sputum. In cases of negative initial test results, tuberculin skin testing, bronchoscopy with transbronchial biopsies and interferon‐γ release assays (IGRAs) in peripheral blood and bronchoalveolar lavage (BAL) fluid were performed. Results. Amongst 135 individuals with suspected tuberculosis, 42 had tuberculosis, 10 had nontuberculous mycobacteria pulmonary infection/colonization (one had both tuberculosis and nontuberculous mycobacteria pulmonary infection/colonization) and 84 had an alternative final diagnosis. The sensitivity and specificity were 41% and 99% [positive likelihood ratio (LR+) = 40] for sputum microscopy and 31% and 98% (LR+ = 16) for BAL nucleic acid amplification, respectively. In patients with acid‐fast bacilli smear‐negative tuberculosis (25/42, 59.5%), M. tuberculosis‐specific BAL fluid IGRA was 92% sensitive and 87% specific (LR+ = 7) for the diagnosis of tuberculosis. Conclusion. None of the microbiological or immunological methods that aim to provide a rapid diagnosis of tuberculosis whilst waiting the confirmation of the M. tuberculosis culture results is on its own accurate enough to diagnose or exclude pulmonary tuberculosis. Negative sputum microscopy and M. tuberculosis‐specific NAAT results should prompt bronchoscopy including BAL for M. tuberculosis‐specific IGRA in individuals with suspected pulmonary tuberculosis.     

Interferon-gamma gene+874T-A polymorphism is associated with tuberculosis and gamma interferon response

Interferon-gamma is the most important cytokine in resistance to mycobacterial diseases and common variants of interferon-gamma gene could be related to tuberculosis susceptibility. We tested the hypothesis that the interferon-gamma+874T-A polymorphism is associated with tuberculosis disease, and affects the interferon-gamma response. We determined by pyrosequencing the distribution of the interferon-gamma+874T-A polymorphism in a Turkish population of 319 patients with pulmonary tuberculosis, 42 children with severe forms of tuberculosis and 115 healthy donors. We also analysed whether any correlation exists between this polymorphism and interferon-gamma response to Mycobacterium tuberculosis antigens by ELISPOT in 58 pulmonary tuberculosis cases, and the results were analysed according to the genotypes. We found that the minor allele (T) frequency was significantly lower in patients with pulmonary tuberculosis when compared to controls (P=0.024, OR=0.7), a similarly significant decrease in the frequency of TT genotype was observed in patients with pulmonary tuberculosis, compared to the control group (P=0.02, OR=0.49). IFN-gamma responses to PPD antigen in TT genotype was found to be significantly higher than the AA group (P>0.001). Non-parametric correlation analysis of ELISPOT data showed significant reverse correlation in PPD, CFP10 and ESAT6 values and IFN-gamma +874 genotypes. These results show that the IFN-gamma +874T-A polymorphism is related to the IFN-gamma response and the magnitude of the response decreases during transition from TT- to TA and to AA genotypes. Our data suggest that similar to various Caucasian populations, in a Turkish population the IFN-gamma+874 T-A polymorphism is also associated with tuberculosis disease and affects the magnitude of the IFN-gamma response.     

Differentiation of sarcoidosis from tuberculosis by use of electron capture gas-liquid chromatography

To explore further the possible etiologic role of mycobacteria in the development of sarcoidosis, we measured free, nonbound tuberculostearic acid (TSA, 10-methyloctadecanoic), a component of mycobacteria, in the sera of subjects with sarcoidosis or active untreated pulmonary tuberculosis and in healthy controls by use of frequency-pulsed electron capture gas-liquid chromatography (FPEC-GLC). The selective analytic system is capable of measuring as little as 15-fmol quantities of free, nonbound TSA in serum and cerebral spinal fluid. We found that TSA was present in the sera of all subjects with Mycobacterium tuberculosis (n = 10) but was undetectable in subjects with sarcoidosis (n = 15) and in healthy controls (n = 15), thereby suggesting that if sarcoidosis is caused by a mycobacterial organism, TSA is not produced or does not gain access to the systemic circulation in quantities sufficient for measurement. However, in the course of the studies we found that a peak, designated p11, was elevated in the sera of all subjects with acute sarcoidosis (n = 4). Also, a peak designated p3 was reduced significantly in all subjects with acute and chronic sarcoidosis and absent in subjects with M. tuberculosis compared with healthy controls. Both peaks were later shown by chemical analysis and mass spectral studies to be carboxylic acids not previously associated with specific disease entities. Follow-up detailed studies will be needed to determine if quantitation of these unique carboxylic acids will be useful in differentiating sarcoidosis from other disorders.     

CFP10/ESAT6融合蛋白-ELISPOT方法的建立及其在结核分枝杆菌感染诊断中的应用价值

目的建立应用酶联免疫斑点试验(Enzyme Linked-Immunospot Assay,ELISPOT)检测结核分枝杆菌感染的方法 ,评价CFP10/ESAT6融合蛋白抗原在检测结核分枝杆菌感染中的应用价值。方法通过比较不同的实验条件确定ELIS-POT检测结核分枝杆菌感染方法的最佳细胞浓度、孵育时间、蛋白抗原浓度等,建立ELISPOT方法。以PPD皮肤试验作对照。结果 ELISPOT方法的最佳实验条件为:每孔细胞浓度2×105,CFP10/ESAT6融合蛋白抗原浓度20~40μg/mL,细胞孵育时间20h。应用PPD皮试检测30例健康体检者、38例非结核疾病患者和40例结核病患者的阳性率分别为40.0%、0%、72.5%,而ELISPOT检测的阳性率分别为20.0%、10.5%、92.5%。应用ELISPOT检测40例结核病痰菌阳性组和阴性组的灵敏度分别为94.4%、90.9%。结论应用CFP10/ESAT6融合蛋白作为抗原建立的ELISPOT方法可初步应用于诊断结核分枝杆菌感染、辅助结核病诊断。     

The immune response to Mycobacterium tuberculosis in HIV-infected and uninfected adults in Uganda: application of a whole blood cytokine assay in an epidemiological study.

SETTING: Out-patient clinic, Entebbe, Uganda. BACKGROUND: It has been proposed that 'type 1' cytokines are essential in protective immunity to Mycobacterium tuberculosis and that suppression of 'type 1' or a switch to a 'type 2' profile is deleterious. We employed a simple assay to examine whether the dependence of the immunological responses to mycobacterial antigens on a range of explanatory factors could be determined in a population where tuberculosis is endemic. OBJECTIVE: To determine the relationship between the tuberculin skin test response and cytokine profile, and the effect of human immunodeficiency virus (HIV) infection. DESIGN: A cross-sectional study of 97 Ugandan adults (22 HIV-positive, 75 HIV-negative). Whole blood was stimulated in vitro using mycobacterial antigens (purified protein derivative [PPD] and culture filtrate proteins [CFP]). 'Type 1' cytokines (gamma interferon [IFN-gamma] and interleukin-2 [IL-2]), 'type 2' cytokines (IL-5 and IL-10) and tumour necrosis factor alpha (TNF-alpha) were measured in culture supernatants. RESULTS: Among HIV-negative subjects, a positive tuberculin skin test was associated with type 1 or mixed (type 1 + type 2) cytokine production, but a positive IFN-gamma response also occurred in a proportion of tuberculin skin test negative subjects (36% for PPD, 17% for CFP). In association with HIV infection, IFN-gamma responses to mycobacterial antigens were profoundly impaired (odds ratio [OR] 0.10 for PPD, 0.06 for CFP, P< or =0.001), but production of IL-2, IL-5 and TNF-alpha was relatively sustained, and IL-10 increased or sustained (OR 3.97 for PPD, P = 0.01, 1.14 for CFP, P = 0.99). CONCLUSION: The type 1/type 2 cytokine balance was not defined by the tuberculin skin test response, and may have a closer relation to protective immunity. IFN-gamma production was strikingly impaired in association with HIV infection, while production of type 2 cytokines was sustained or increased. Use of a simple assay allowed a large sample of subjects to be examined, producing epidemiologically meaningful results.     

High prevalence of Mycobacterium tuberculosis DNA in biopsies from sarcoidosis patients from Catalonia, Spain

BACKGROUND: Sarcoidosis is a systemic granulomatous disease of unknown etiology. The presence of mycobacterial nucleic acid components in patients with sarcoidosis has been demonstrated with varying degrees of success. OBJECTIVES: The aim of this study was to estimate the presence of Mycobacterium tuberculosis DNA in tissues from sarcoidosis patients, in Catalonia, Spain, as well as to assess the long-term clinical course in these patients. METHODS: Fifty-eight paraffin-embedded tissue biopsies corresponding to cases of sarcoidosis (n = 23), lung neoplasm (n = 23), and lung tuberculosis (n = 12) available in 1996 were analyzed in a retrospective study by means of a nested polymerase chain reaction using primers corresponding to the insertion element IS6110 of M. tuberculosis complex. For greater sensitivity, Southern blot hybridization was performed. Clinical data were recorded prior to and after PCR analysis (follow-up reported until 2002). RESULTS: M. tuberculosis DNA was present in 9 out of 23 sarcoidosis biopsies (39%), in 1 out of 23 control patients (4%) (p < 0.01), and in all tissue samples from the 12 control patients with tuberculosis. To date, none of these sarcoidosis patients has developed tuberculosis over a mean (+/-SD) follow-up period of 11 (+/-3.4) years. CONCLUSION: In our setting, M. tuberculosis DNA is present in tissue biopsies of significantly more sarcoidosis patients than controls. However, these results do not demonstrate causality, although they may suggest a link between M. tuberculosis infection and sarcoidosis in some cases. Follow-up of these patients suggests that M. tuberculosis-DNA-positive sarcoidosis patients are not at greater risk of developing tuberculosis than M. tuberculosis-DNA-negative patients.     

Genetic polymorphisms in <Emphasis Type="Italic">TNF</Emphasis>genes and tuberculosis in North Indians

Background  

Pulmonary tuberculosis, the most common clinical form of mycobacterial diseases, is a granulomatous disease of the lungs caused by Mycobaterium tuberculosis. A number of genes have been identified in studies of diverse origins to be important in tuberculosis. Of these, both tumor necrosis factor α (TNF-α) and lymphotoxin α (LT-α) play important immunoregulatory roles.     

Disseminated Mycobacterium haemophilum skeletal disease in a patient with interferon‐gamma deficiency

Disseminated non‐tuberculous mycobacterial (NTM) infection is rare in immunocompetent adults. Anti‐interferon‐gamma (IFN‐γ) autoantibodies have recently been associated with NTM infections, particularly in patients of Asian ethnicity. We describe a case of disseminated Mycobacterium haemophilum skeletal infection due to anti IFN‐γ autoantibodies in a 71‐year‐old Cambodian man. He responded to a combination of anti‐mycobacterial antibiotics without requirement for immunomodulator therapy. Testing for acquired IFN‐γ deficiency due to IFN‐γ autoantibodies should be considered when standard tests for immunodeficiency are negative in patients with unusual or severe opportunistic infections, including NTM.     

Specific in Vitro Proliferative Immune Responses and Lymphokine Production in Ethiopian Children with and without Tuberculosis

Summary We investigated the profile of some in vitro parameters of cellular immune responses in non-HIV-infected Ethiopian children and young adults with and without tuberculosis (TB) as compared to healthy Ethiopian and non-Ethiopian controls. The in vitro proliferative responses of peripheral blood mononuclear cells (PBMC) to purified protein derivative (PPD) were determined in 15 Ethiopian children and young adults with TB, 12 healthy Ethiopian children who were contacts of TB patients, 20 Ethiopian children without contact with TB and ten non-Ethiopian controls. All TB patients and contacts had a positive Mantoux skin test. The PBMC proliverative response to PPD of the Ethiopian children with TB was significantly higher than that of the Ethiopian children without TB, while all Ethiopian children demonstrated stronger proliferative response as compared to non-Ethiopian healthy controls. Interleukin 2 (IL-2), interferon gamma (IFN-γ), interleukin 4 (IL-4) and interleukin 6 (IL-6) were measured by ELISA assays performed on the supernatant of PPD-stimulated and non-stimulated PBMC cultures of seven Ethiopian children with TB, ten Ethiopian children without TB and eight non-Ethiopian controls. IFN-γ and IL-4 were undetectable and IL-2 levels in unstimulated supernatants were low in all groups. PPD stimulation induced a significant rise in IL-2 levels in Ethiopians with TB as compared to all other groups. There was no increase above baseline in IL-6 levels in any group studied. Conclusions: Ethiopian children with TB exhibit a strong cellular immune response as expressed by Mantoux tests and lack of stimulation of IL-4 and IL-6 production. This pattern suggests a Th1 type effective cellular immune response to mycobacteria in a cohort of young Ethiopians with TB. Received: December 3, 1998 · Revision accepted: December 4, 1999     

Evaluation of DPPD, a single recombinant Mycobacterium tuberculosis protein as an alternative antigen for the Mantoux test

Although the tuberculin test has aided in the diagnosis of tuberculosis for more than 85 years, its interpretation is difficult particularly because sensitization with non-tuberculous mycobacteria leads to false positive tests. Using the guinea pig model of tuberculosis, we have recently described a recombinant antigen (DPPD) that could circumvent this problem. The DPPD gene is unique to the M. tuberculosis complex organisms and is absent in the organisms representative of all other members of the Mycobacterium genus. Moreover, DPPD induced strong DTH in 100% of the guinea pigs infected with M. tuberculosis and in none of the guinea pigs immunized with nine different species of Mycobacterium. Here we present results of a clinical investigation using DPPD. Mantoux test using both PPD and DPPD was initially performed in 26 patients with confirmed pulmonary tuberculosis and in 25 healthy PPD negative individuals. The results indicated that both PPD and DPPD elicited DTH in 24 out of the 26 patients. No DTH was observed in any of the PPD negative individuals. In addition, a small clinical trial was performed in a population of 270 clinically healthy and randomly selected individuals. DPPD produced a bimodal histogram of skin reaction size and PPD produced a skewed histogram. Because the DPPD gene is not present in non-tuberculous bacilli, these results suggest that this molecule can be an additional tool for a more specific diagnosis of tuberculosis.     

Recombinant and synthetic peptides to identify Mycobacterium tuberculosis antigens and epitopes of diagnostic and vaccine relevance

The failures of Bacillus Calmette Guerin (BCG) as a vaccine and purified protein derivative as a diagnostic reagent in controlling the worldwide prevalence of tuberculosis (TB) have accelerated the research to identify Mycobacterium tuberculosis-specific antigens that could be useful as new vaccines and diagnostic reagents against TB. In the recent years, the comparative analyses of M. tuberculosis genome with the genomes of other mycobacteria have led to the identification of several genomic regions of M. tuberculosis that are deleted in BCG and other mycobacteria. These deleted regions (RDs) are predicted to encode over 100 proteins. If found immunologically reactive, the proteins encoded by M. tuberculosis-specific RDs could be useful in the specific diagnosis of TB and developing new vaccines. Among the approaches available for immunological characterization of the predicted M. tuberculosis-specific proteins are the evaluations of recombinant proteins and/or overlapping synthetic peptides, covering the sequence of each protein, for antibody and/or Th1 cell reactivity. These approaches have resulted into the identification of several antigenic proteins of M. tuberculosis encoded by genes located in RD1 with potentials in specific diagnosis of TB in low endemic areas and/or development of new vaccines, e.g. ORF14, ESAT6, CFP10, PE, PPE proteins, etc. In addition, prediction programs to identify peptides that could bind several HLA molecules, and presented to T-cells in a promiscuous manner, have been developed. These programs have been used, on a limited scale, to identify the promiscuous peptides encoded by the genes spanning the M. tuberculosis-specific sequence. The promiscuous antigens/peptides recognized by T-cells in cell mediated immunity assays may have potentials in developing peptide-based vaccines and diagnostic reagents against TB.     

Antigen-specific multifunctional T-cells in sarcoidosis patients with Lofgren's syndrome

Sarcoidosis is a granulomatous disease of unknown aetiology, mainly affecting the lungs. Recently, T-cell responses towards a specific mycobacterial protein, catalase-peroxidase (mKatG), were observed in sarcoidosis patients. Bronchoalveolar lavage (BAL) fluid and peripheral blood were obtained from a total of 23 sarcoidosis patients, of whom 13 had L?fgren's syndrome and lung accumulations of T-cell receptor AV2S3+ T-cells. Using six-colour flow cytometry in combination with intracellular cytokine staining, T-cell subsets were studied with regard to interferon (IFN)-γ, tumour necrosis factor (TNF) and interleukin-2 production, after stimulation with mKatG or Mycobacterium tuberculosis purified protein derivate (PPD). Stimulation with mKatG resulted in higher simultaneous IFN-γ and TNF production, but less single IFN-γ production, from total BAL fluid CD4+ T-cells of L?fgren's syndrome patients, when compared with non-L?fgren's patients. In contrast, PPD stimulation gave rise to largely similar cytokine responses in both patient subgroups. Furthermore, mKatG stimulated higher IFN-γ production in BAL fluid and blood AV2S3+ T-cells than AV2S3- T-cells, whereas the opposite was seen in BAL fluid with PPD stimulation. Our finding that patients with L?fgren's syndrome exhibited a more pronounced multifunctional cytokine profile (simultaneous IFN-γ and TNF production) towards the mycobacterial protein mKatG may help to explain the distinct disease presentation in this patient subgroup.     

A common haplotype of the C-C chemokine receptor 2 gene and HLA-DRB1*0301 are independent genetic risk factors for Löfgren's syndrome

Aim. Sarcoidosis is a heterogeneous disorder with a strong genetic influence. Genetic factors are also thought to influence disease severity and outcome. We sought to determine whether polymorphisms within CCR2 gene predispose to Löfgren’s syndrome – a clinically and genetically distinct sarcoidosis phenotype – and, importantly, whether this association is independent of the known association with the HLA‐DRB1*0301 allele. Methods. We investigated 5 CCR2 variants and HLA‐DRB1*0301 by sequence‐specific primer (SSP) polymerase chain reaction (PCR) in 176 Spanish (76 Löfgren’s syndrome, 100 controls) and 387 Swedish subjects (126 Löfgren’s syndrome, 77 non‐Löfgren sarcoidosis, 184 controls). Results. One of the deduced haplotypes (CCR2 haplotype 2) was associated with Löfgren’s syndrome in both Spanish (OR: 2.03, uncorrected P = 0.02; permuted P = 0.041 vs. controls) and Swedish patients (OR: 3.02, uncorrected P = 0.0007; permuted P = 0.0027 vs. non‐Löfgren sarcoidosis; OR: 2.46, uncorrected P = 0.0005; permuted P = 0.0031 vs. controls). HLA‐DRB1*0301 allele frequency was also increased in Spanish (OR: 3.52, P = 0.0004 vs. controls) and Swedish patients with Löfgren’s syndrome (OR: 10.98, P < 0.0001 vs. non‐Löfgren sarcoidosis, OR: 7.71, P < 0.0001 vs. controls). Finally, multivariate analysis revealed that the CCR2 association was independent of HLA‐DRB1*0301 in both Spanish (P = 0.02 vs. controls) and Swedish cohorts (P = 0.002 vs. non‐Löfgren sarcoidosis, P = 0.001 vs. controls). Conclusions. This study confirms that CCR2 haplotype 2 and HLA‐DRB1*0301 are independent genetic risk factors for Löfgren’s syndrome.     

白细胞介素12对结核病患者TH1/TH2平衡的影响

目的探讨白细胞介素12(IL-12)对结核病患者外周血单个核细胞(PBMC)分泌干扰素γ(IFN-γ)、白细胞介素4(IL-4)的影响.方法随机将25例结核患者和15名健康人PBMC分为RPMI1 640组、PPD组、PPD+rhIL-12组、PPD+anti-IL-12组,采用ELISA法检测各组培养上清液中IFN-γ、IL-4的水平.结果与PPD组相比,加入rhIL-12能有效增加结核患者及健康人PBMC分泌IFN-γ(分别为321.6±87.7至452.5±111.4, 387.0±70.8至515.4±44.1), 减少IL-4的分泌(54.6±11.0至41.3±13.5,55.1±9.5至38.2±12.7);而加入anti-IL-12可抑制IFN-γ的分泌,促进IL-4合成,且结核患者各组IFN-γ水平均低于健康人各对应组,而IL-4水平无差异.复治组IFN-γ、IL-4水平均低于初治组(P<0.05).结论 IL-12通过诱导IFN-γ分泌,抑制IL-4合成,从而调节TH1/TH2平衡,对结核分支杆菌感染患者产生保护性的免疫反应.IL-12可作为结核免疫调节剂,并可用于开发结核新疫苗.     

Immune responses to mycobacterial antigens in sarcoidosis: a systematic review

From the time sarcoidosis has been described, there has always been a viewpoint that the disease is in some way related to tuberculosis (TB). Sarcoidosis is a granulomatous disease, which is likely a result of continued presentation of a poorly degradable antigen. Mycobacterium tuberculosis has been a very strong contender for this antigen. Besides the molecular studies demonstrating mycobacterial deoxyribonucleic acid (DNA) in the sarcoid tissue, assessment of immune responses against mycobacterial antigens provides a useful tool to study the role of mycobacteria in the pathogenesis of sarcoidosis. We reviewed the studies focussing on T-cell and B-cell responses to tubercular antigens in patients with sarcoidosis. Pooled data from various studies does provide a suggestive, though not unequivocal evidence in favour of mycobacteria as a cause of sarcoidosis. These findings not only reinforce the possible pathogenic role of mycobacterial antigens in sarcoidosis, but at the same time also limit the clinical utility of molecular and serological studies based on mycobacterial antigens in the differential diagnosis of TB from sarcoidosis, particularly in a country with high endemicity for TB.     

实时定量聚合酶链反应技术在鉴别结节病与增殖性结核病中的应用

目的利用实时定量聚合酶链反应（PCR）方法检测结节病和结核病病理组织中结核分枝杆菌DNA，以探讨结核分枝杆菌在结节病发病中的作用及本方法在结节病与增殖性结核病鉴别中的应用价值。方法以上海市肺科医院1998年1月至2003年12月住院患者76例为研究对象，其中结核病组30例、结节病组31例和正常对照组（其他疾病）15例，利用定量PCR检测用石蜡包埋的淋巴结或肺组织中结核分枝杆菌DNA，并以胎鼠肺组织作为阴性对照。结果结核病组结核分枝杆菌DNA检出的阳性率（30／30）明显高于结节病组（6／31）和正常对照组（2／15），结节病组与正常对照组结核分枝杆菌DNA检出的阳性率无明显差别。结核病组结核分枝杆菌DNA检出的绝对和相对拷贝数明显高于结节病组和正常对照组，结节病组与正常对照组无明显差别，而胎鼠肺组织中未检出结核分枝杆菌DNA。结论本研究结果不支持结核分枝杆菌感染与结节病的相关性。实时定量PCR法检测石蜡包埋病理组织中结核分枝杆菌DNA可作为鉴别增殖性结核和结节病的方法之一。     

Overexpression of peroxisome proliferator‐activated receptor γ and retinoid X receptor α in gastric carcinomatous tissue

OBJECTIVE: To investigate the expression of peroxisome proliferator‐activated receptor γ (PPAR‐γ) and retinoid X receptor α (RXR‐α) in chronic gastritis, gastric mucosal dysplasia and gastric carcinoma and to identify any correlations between PPAR‐γ and RXR‐α expression in this progression sequence. METHODS: Immunohistochemical methods (avidin? biotin?peroxidase complex) were used to examine the expression of PPAR‐γ and RXR‐α in 53 patients with gastric carcinoma, 18 with gastric mucosal dysplasia and 30 with chronic atrophic gastritis. Thirty‐one patients with chronic non‐atrophic gastritis acted as controls. RESULTS: The positive rates of PPAR‐γ and RXR‐α in gastric carcinoma were 41.5 and 54.7%, 27.8 and 38.9% in gastric mucosal dysplasia, 10.0 and 20.0% in chronic atrophic gastritis, and 6.5 and 16.1% in chronic non‐atrophic gastritis, respectively. The expression of PPAR‐γ and RXR‐α increased during the progression from chronic non‐atrophic gastritis to chronic atrophic gastritis, then to gastric carcinoma. Compared with chronic gastritis, the expression of PPAR‐γ and RXR‐α in gastric mucosal dysplasia and gastric carcinoma was significantly increased (P < 0.05, P < 0.01). In gastric carcinoma, the expression of PPAR‐γ and RXR‐α was not associated with tumor cell differentiation or metastasis in the lymph nodes (P > 0.05). There was a positive correlation between the expression of PPAR‐γ and RXR‐α in gastric carcinoma (r= 0.54, P < 0.01). CONCLUSIONS: Overexpression of PPAR‐γ and RXR‐α protein is apparent in human gastric cancer. This might be an early event in carcinogenesis, and both PPAR‐γ and RXR‐α may play independent and/or synergistic roles in the progression of gastric carcinoma.