Immunogenicity of Whole / 生物医学与环境科学（英文）

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Characteristic profile of antibody responses to PPD, ESAT-6, and CFP-10 of Mycobacterium tuberculosis in pulmonary tuberculosis suspected cases in Surabaya, Indonesia

Abstract Accurate and rapid diagnostic tools are important aspects of managing tuberculosis (TB) cases appropriately. However, the sensitivity and specificity of diagnostic kits based on immune response such as the tuberculin skin test (TST) and interferon gamma release assay (IGRA) are still debated. Thus, the exploration and assessment of specific biomarker-targeted antibodies are needed for the development of an accurate and rapid diagnostic tool. The present study was conducted in patients with a respiratory problem suspected to be TB at Dr. Soetomo Hospital, Surabaya, Indonesia. Among 102 patients tested by GeneXpert and AFB, 59 serum samples were from cases retrospectively determined to have active TB. A total of 102 serum of healthy controls (HC) was also collected. The PPD antigen and the recombinant CFP-10 and ESAT-6 proteins were prepared. Antibody responses against these proteins were evaluated by ELISA. All samples were also screened for the possibility of Mycobacterium avium-intracellulare complex (MAC) infection using Capilla MaC kit. The results showed that TB patients had a significantly higher concentration of IgG antibody in response to PPD than the HC. In addition, the receiver operating characteristic (ROC) curve analysis showed that PPD was acceptable for diagnostic purposes with an AUC value of 0.835 (95% CI 0.770-0.900, p < 0.0001). However, ESAT-6 and CFP-10 had low AUCs, and 32 samples from both groups showed a low concentration of IgA antibody against all antigens. The MAC detection results also showed that the concentration of IgA in the HC group was the highest. The current results indicate that PPD is a better antigen for antibody-based detection of TB than ESAT-6 and CFP-10. Based on the MAC detection assay, 53 people in the HC group were probably infected with rapidly growing nontuberculous mycobacteria (NTM), although antibody response to PPD was low.

Preservation of cytotoxic granule production in response to mycobacterial antigens by T-lymphocytes from vertically HIV-infected Brazilian youth on effective combined antiretroviral therapy

ABSTRACT Background: HIV infection harms adaptive cellular immunity mechanisms. Long-term virological control by combined antiretroviral therapy (cART) reduces the risk of mycobacterial infections. Thus, we aimed to study cellular responses to mycobacterial antigens in 20 HIV-infected adolescents with at least one year of virological control (HIV-RNA <40 copies/mL) and 20 healthy adolescents. Methods: We evaluated CD8 and γδ T-cell degranulation by measurement of CD107a membrane expression after stimulation with lysates from BCG (10 µg/mL) and H37RA Mycobacterium tuberculosis (Mtb, 10 µg/mL). Immune activation and antigen-presenting ability were also assessed by determination of HLA-DR, CD80, and CD86 markers. Results: TCR γδ T-cell CD107a expression was similar between groups in response to mycobacterial antigens, and lower in the HIV-infected group in response to mitogen. Higher baseline HLA-DR expression and lower mycobacterial-stimulated expression was found within the HIV-infected group. Conclusions: Similar degranulation in stimulated CD8+ and TCR γδ T-cells from HIV-infected adolescents, when compared to healthy controls suggests long-term immunological preservation with immune reconstitution under successful cART. However, differences in HLA-DR expression may represent ongoing inflammation and lower specific responses in HIV-infected youth. These features may be relevant in the context of the precocity and severity of vertically acquired HIV infection.

Evaluation of the transcriptional immune biomarkers in peripheral blood from warao indigenous associate with the infection by mycobacterium tuberculosis

Abstract INTRODUCTION: Biomarkers are critical tools for finding new approaches for controlling the spread of tuberculosis (TB), including for predicting the development of TB therapeutics, vaccines, and diagnostic tools. METHODS: Expression of immune biomarkers was analyzed in peripheral blood cells stimulated and non-stimulated with M. tuberculosis antigens ESAT-6, CFP10 and TB7.7. in Warao indigenous individuals. These biomarkers may be able to differentiate TB states, such as active tuberculosis (ATB) cases and latent tuberculosis infection (LTBI) from non-infected controls (NIC). A real-time reverse transcription polymerase chain reaction (RT-qPCR) assay was performed on 100 blood samples under non-stimulation or direct ex vivo conditions (NS=50) and stimulation conditions (S=50). RESULTS: The findings are shown as the median and interquartile range (IQR) of relative gene expression levels of IFN-γ, CD14, MMP9, CCR5, CCL11, CXCL9/MIG, and uPAR/PLAUR immune biomarkers. MMP9 levels were significantly higher in the LTBI-NS and LTBI-S groups compared with the NIC-NS and NIC-S groups. However, CCR5 levels were significantly lower in the LTBI-S group compared with both NIC-NS and NIC-S groups. CCL11 levels were significantly lower in the LTBI-S group compared with the NIC-NS group. CONCLUSIONS: Preliminary findings showed that MMP9 immune biomarkers separated LTBI indigenous individuals from NIC indigenous individuals, while CCR5, CCL11, CD14, and IFN-γ did not differentiate TB states from NIC. MMP9 may be useful as a potential biomarker for LTBI and new infected case detection among Warao indigenous individuals at high risk of developing the disease. It may also be used to halt the epidemic, which will require further validation in larger studies.

Assessing and screening for T-cell epitopes from Mycobacterium tuberculosis RD2 proteins for the diagnosis of active tuberculosis

ABSTRACT The Region of D eletion 2 (RD2) of Mycobacterium tuberculosis encodes reserved antigens that contribute to bacterial virulence. Among these antigens, Rv1983, Rv1986, Rv1987, and Rv1989c have been shown to be immunodominant in infected cattle; however, their diagnostic utility has not been evaluated in humans.In this study, we screened 87 overlapping synthetic peptides encoded by five RD2 proteins for diagnosing tuberculosis epitopes in 50 active tuberculosis (TB) cases, 31 non-tuberculosis patients and 36 healthy individuals. A pool of promising epitopes was then assessed for their diagnostic value in 233 suspected TB patients using a whole blood IFN-γ release assay.Only 10 peptides were recognized by more than 10% of active tuberculosis patients. The IFN-γ release responses to Rv1986-P9, P15, P16, Rv1988-P4, P11, and Rv1987-P11 were significantly higher in the active TB group than in the control groups (p < 0.05). The whole blood IFN-γ release assay based on these epitopes yielded a sensitivity of 51% and a specificity of 85% in diagnosing active tuberculosis, and the corresponding results using the T-SPOT.TB assay were 76% and 75%, respectively.In conclusion, these results suggest that the six epitopes from the RD2 of M. tuberculosis have potential diagnostic value in TB.

Current use and acceptability of novel diagnostic tests for active tuberculosis: a worldwide survey / Uso atual e aceitabilidade de novos testes diagnósticos para tuberculose ativa: um inquérito mundial

ABSTRACT Objective: To determine the current use and potential acceptance (by tuberculosis experts worldwide) of novel rapid tests for the diagnosis of tuberculosis that are in line with World Health Organization target product profiles. Methods: A multilingual survey was disseminated online between July and November of 2016. Results: A total of 723 individuals from 114 countries responded to the survey. Smear microscopy was the most commonly used rapid tuberculosis test (available to 90.9% of the respondents), followed by molecular assays (available to 70.7%). Only a small proportion of the respondents in middle- and low-income countries had access to interferon-gamma-release assays. Serological and lateral flow immunoassays were used by more than a quarter (25.4%) of the respondents. Among the respondents who had access to molecular tests, 46.7% were using the Xpert assay overall, that proportion being higher in lower middle-income countries (55.6%) and low-income countries (76.6%). The data also suggest that there was some alignment of pricing for molecular assays. Respondents stated they would accept novel rapid tuberculosis tests if available, including molecular assays (acceptable to 86.0%) or biomarker-based serological assays (acceptable to 81.7%). Simple biomarker-based assays were more commonly deemed acceptable in middle- and low-income countries. Conclusions: Second-generation molecular assays have become more widely available in high- and low-resource settings. However, the development of novel rapid tuberculosis tests continues to be considered important by tuberculosis experts. Our data also underscore the need for additional training and education of end users.

RESUMO Objetivo: Determinar o uso atual e a aceitação potencial (por especialistas em tuberculose em todo o mundo) de novos testes rápidos para o diagnóstico de tuberculose que estão alinhados com os perfis de produtos alvo da Organização Mundial da Saúde. Métodos: Um inquérito multilingue foi divulgado on-line entre julho e novembro de 2016. Resultados: Um total de 723 indivíduos de 114 países respondeu ao inquérito. A baciloscopia foi o teste rápido para tuberculose mais utilizado (disponível para 90,9% dos entrevistados), seguida de ensaios moleculares (disponível para 70,7%). Apenas uma pequena proporção dos entrevistados de países de renda média e baixa tinha acesso a ensaios de liberação de IFN-γ. Imunoensaios de fluxo lateral e testes sorológicos eram utilizados por mais de um quarto dos entrevistados (25,4%). Entre os entrevistados que tinham acesso a testes moleculares, 46,7% utilizavam o teste Xpert de forma geral, sendo essa proporção maior em países de renda média baixa (55,6%) e renda baixa (76,6%). Os dados também sugerem que houve algum alinhamento de preços para testes moleculares. Os entrevistados afirmaram que aceitariam novos testes rápidos para tuberculose, se disponíveis, incluindo testes moleculares (aceitáveis para 86,0%) ou testes sorológicos baseados em biomarcadores (aceitáveis para 81,7%). Testes simples baseados em biomarcadores foram mais comumente considerados aceitáveis nos países de renda média e baixa. Conclusões: Os testes moleculares de segunda geração tornaram-se mais amplamente disponíveis em locais tanto com poucos quanto com muitos recursos. No entanto, o desenvolvimento de novos testes rápidos para tuberculose continua a ser considerado importante por especialistas em tuberculose. Nossos dados também ressaltam a necessidade de maior formação e educação dos usuários finais.

Cordyceps sinensis promotes immune regulation and enhances bacteriostatic activity of PA-824 via IL-10 in Mycobacterium tuberculosis disease

PA-824 is a novel bicyclic nitroimidazole anti-tuberculosis (TB) drug. Cordyceps sinensis (Berk.) Sacc. (CS) was proven to be a good immunomodulatory compound. This research aimed to investigate the effect of CS on PA-824 in Mycobacterium tuberculosis (M.tb) infected mice (female CBA/J mice, 6 to 8 weeks of age and 20±2 g of weight). Mice were randomly assigned to 4 groups: PA-824, CS, PA-824+CS, and control. To verify the effect of PA-824 and CS on M.tb, after drug administration, mice lungs were harvested and bacterial colony formations were measured. Cells were isolated from infected lungs and spleens to analyze the percentage of CD4+ T cells (CD11a positive). Lung cells were cultured to detect the secretion of interferon-γ (IFN-γ) and interleukin-10 (IL-10) by ELISA. IFN-γ and IL-10 double-positive CD4+ cells in peripheral blood were measured by flow cytometry. The expression levels of IL-2 and IL-10 in mice lungs were analyzed by real-time PCR and western blot. Results showed that PA-824 combined with CS led to the lowest lung colony-forming units (CFU) counts among treated groups. Furthermore, this beneficial outcome might be associated with the decreased CD11a on CD4+ cells in mice lungs and spleens. Moreover, the suppressed secretion of IFN-γ and IL-10, and IL-10 expressions, as well as the decreased IFN-γ and IL-10 double-positive CD4+ cells in blood, could also be associated with the positive effect. However, no significant effect on IL-2 production was found. The combination of PA-824 and CS had more effective bacteriostatic and immunomodulatory effects on M.tb infected mice than PA-824 alone. In conclusion, CS has the potential to be an effective adjuvant in TB treatment.

The mc2-CMX vaccine induces an enhanced immune response against Mycobacterium tuberculosis compared to Bacillus Calmette-Guérin but with similar lung inflammatory effects

Although the attenuated Mycobacterium bovis Bacillus Calmette-Guérin (BCG) vaccine has been used since 1921, tuberculosis (TB) control still proceeds at a slow pace. The main reason is the variable efficacy of BCG protection against TB among adults, which ranges from 0-80%. Subsequently, the mc2-CMX vaccine was developed with promising results. Nonetheless, this recombinant vaccine needs to be compared to the standard BCG vaccine. The objective of this study was to evaluate the immune response induced by mc2-CMX and compare it to the response generated by BCG. BALB/c mice were immunised with both vaccines and challenged withMycobacterium tuberculosis (Mtb). The immune and inflammatory responses were evaluated by ELISA, flow cytometry, and histopathology. Mice vaccinated with mc2-CMX and challenged with Mtb induced an increase in the IgG1 and IgG2 levels against CMX as well as recalled specific CD4+ T-cells that produced T-helper 1 cytokines in the lungs and spleen compared with BCG vaccinated and challenged mice. Both vaccines reduced the lung inflammatory pathology induced by the Mtb infection. The mc2-CMX vaccine induces a humoral and cellular response that is superior to BCG and is efficiently recalled after challenge with Mtb, although both vaccines induced similar inflammatory reductions.

Evaluation of the role of Mycobacterium tuberculosis pili (MTP) as an adhesin, invasin, and cytokine inducer of epithelial cells

Abstract This study was undertaken in order to assess the involvement of Mycobacterium tuberculosis pili (MTP) as an adhesin, invasin, and cytokine inducer in the M. tuberculosis-epithelial cell interaction. A MTP-deficient strain of M. tuberculosis demonstrated a significant reduction of 69.39% (p = 0.047) and 56.20% (p = 0.033) in its ability to adhere to and invade A549 pulmonary epithelial cells, respectively, in comparison with the wild-type strain. Complementation of the MTP-deficient mutant restored its adhesion and invasion capacity back to the wild-type levels. Overall, it was found that similar concentrations of IL-1β, IL-4, IL-6, IL-8, G-CSF, IFN-γ, MCP-1, and TNF-α were induced in A549 cells infected with the MTP-proficient and MTP-deficient strains. However, at 48 h post-infection, the MTP-deficient mutant induced significantly lower levels of TNF-α than the wild-type strain (p = 0.033). Furthermore, at 72 h post-infection, the mutant induced significantly higher levels of IL-8 than the wild-type (p = 0.005). We conclude that MTP is an adhesin/invasin of epithelial cells and, while playing a role in M. tuberculosis entry, they do not appear to largely influence the epithelial cell cytokine response.

Interferon-gamma release assay versus tuberculin skin test for latent tuberculosis infection among HIV patients in Brazil

Abstract Setting Patients HIV+ attending in a reference clinic, Southern Brazil. Objective To compare the interferon-gamma-release assay (IGRA – QuantiFERON® TB Gold In-Tube) with the tuberculin skin test (TST – PPD-Rt 23) for latent tuberculosis infection (LTBI) in patients with HIV. Design Cohort study. Patients were simultaneously submitted to the TST and blood collection for the IGRA. Results A total of 140 subjects were included. Nine (6.4%) were IGRA+/TST+, 12 (8.6%) were IGRA+/TST−, 4 (3%) were IGRA−/TST+, and 115 (82%) IGRA−/TST−. There was poor agreement between tests (kappa = 0.2), and no correlation between these results and CD4+ T lymphocyte counts. During follow-up, one patient with negative results on both tests died from sepsis, and another with discordant results (IGRA+/TST−) exhibited TST seroconversion. Compared to the TST, IGRA showed a sensitivity and specificity of 69% and 90%, respectively. The IGRA detected 8% more positive results than the TST. All patients were followed up for 2 years. Conclusion The higher accuracy of the IGRA would result in LTBI treatments being administered to patients who would have otherwise been overlooked, decreasing the number of active tuberculosis cases. The long-term survival of HIV carriers requires further evaluation.

Challenging Mycobacterium tuberculosi s dormancy mechanisms and their immunodiagnostic potential

ABSTRACT Mycobacterium tuberculosis is the etiologic agent of tuberculosis, one of the world's greatest cause of morbidity and mortality due to infectious disease. Many evolutionary mechanisms have contributed to its high level of adaptation as a host pathogen. Prior to become dormant, a group of about 50 genes related to metabolic changes are transcribed by the DosR regulon, one of the most complex and important systems of host-pathogen interaction. This genetic mechanism allows the mycobacteria to persist during long time periods, establishing the so-called latent infection. Even in the presence of a competent immune response, the host cannot eliminate the pathogen, only managing to keep it surrounded by an unfavorable microenvironment for its growth. However, conditions such as immunosuppression may reestablish optimal conditions for bacterial growth, culminating in the onset of active disease. The interactions between the pathogen and its host are still not completely elucidated. Nonetheless, many studies are being carried out in order to clarify this complex relationship, thus creating new possibilities for patient approach and laboratory screening.

Análisis molecular del cáncer de colon esporádico / Molecular analysis of sporadic colon cancer

Background: In Chile, colorectal cancer (CRC) is often diagnosed in late stages. Thus, surgical treatment must be complemented with chemotherapy. KRAS mutations and microsatellite instability have been detected in these tumors. However, the response to treatment in patients without KRAS mutations varies and requires a better understanding. Aim: To determine the frequency and distribution of somatic point mutations in KRAS, BRAF and PIK3CA genes and microsatellite instability status (MSI) in patients with colon cancer (CC). Material and Methods: A prospective observational study of patients undergoing surgery for colon cancer. Tumor-derived DNA was analyzed by polymerase chain reaction (PCR) for the most frequent mutations of KRAS, BRAF and PIK3CA. PCR was also used to analyze MSI. Results: Fifty-eight patients with sporadic CC were analyzed, 16 showed KRAS mutations (G12R, G12D, G12V, G13D) and out of the 42 patients that did not show any mutation, 10 had mutations in BRAF (V600E) and PIK3CA (E542K, E545D, E545K, Q546E, H1047R). BRAF mutations alone or in combination with PIK3CA mutations were observed in 27% of high MSI tumors and in 2% of tumors without instability (p < 0.049). A higher percentage of high MSI tumors were located in the right colon (p < 0.001), and showed BRAF mutation (p < 0.020). Conclusions: The highest percentage of high MSI and BRAF mutations was observed in the right colon. Therefore, this study suggests the presence of different molecular features between right and left colon tumors that should be considered when defining the therapeutic management.

Mycobacterium tuberculosis epitope-specific interferon-g production in healthy Brazilians reactive and non-reactive to tuberculin skin test

The interferon (IFN)-γ response to peptides can be a useful diagnostic marker of Mycobacterium tuberculosis (MTB) latent infection. We identified promiscuous and potentially protective CD4+ T-cell epitopes from the most conserved regions of MTB antigenic proteins by scanning the MTB antigenic proteins GroEL2, phosphate-binding protein 1 precursor and 19 kDa antigen with the TEPITOPE algorithm. Seven peptide sequences predicted to bind to multiple human leukocyte antigen (HLA)-DR molecules were synthesised and tested with IFN-γ enzyme-linked immunospot (ELISPOT) assays using peripheral blood mononuclear cells (PBMCs) from 16 Mantoux tuberculin skin test (TST)-positive and 16 TST-negative healthy donors. Eighty-eight percent of TST-positive donors responded to at least one of the peptides, compared to 25% of TST-negative donors. Each individual peptide induced IFN-γ production by PBMCs from at least 31% of the TST-positive donors. The magnitude of the response against all peptides was 182 ± 230 x 106 IFN-γ spot forming cells (SFC) among TST-positive donors and 36 ± 62 x 106 SFC among TST-negative donors (p = 0.007). The response to GroEL2 (463-477) was only observed in the TST-positive group. This combination of novel MTB CD4 T-cell epitopes should be tested in a larger cohort of individuals with latent tuberculosis (TB) to evaluate its potential to diagnose latent TB and it may be included in ELISPOT-based IFN-γ assays to identify individuals with this condition.

Assessment of phagosomes infected with Mycobacterium tuberculosis as a vaccine candidate against tuberculosis.

The present study describes a novel and simple vaccination strategy that involve culturing of M. tuberculosis in the macrophage cells. Isolation of phagosome from macrophage (cell line J774) infected with M. tuberculosis (H37) and M. bovis (BCG) at early and late phase of infection was done ensuing the identification and characterization of these phagosome. In vitro study of apoptosis induced by phagosome infected with (H37) and (BCG) was performed. The vaccine candidate with H37 MOI- 1:10 at 3 h, MOI- 1:20 at 1, 1.5, 2.5 and 3 h and BCG MOI- 1:20 at 3.5 h showed percentage apoptosis as 38.64, 39.93, 34.66, 22.56,34.59 and 37.81% respectively. The results designates that macrophages provide cellular niche during infection and illustrate considerable immunogenic property. Novel antigens expressed or secreted by H37 in infected macrophages can provide evidence to be a successful vaccine candidate as it endures enhanced immune response than BCG.

Tuberculin skin test and interferon-gamma release assay values are associated with antimicrobial peptides expression in polymorphonuclear cells during latent tuberculous infection

It has been reported that patients with progressive tuberculosis (TB) express abundant amounts of the antimicrobial peptides (AMPs) cathelicidin (LL-37) and human neutrophil peptide-1 (HNP-1) in circulating cells, whereas latent TB infected donors showed no differences when compared with purified protein derivative (PPD) and QuantiFERON®-TB Gold (QFT)-healthy individuals. The aim of this study was to determine whether LL-37 and HNP-1 production correlates with higher tuberculin skin test (TST) and QFT values in TB household contacts. Twenty-six TB household contact individuals between 26-58 years old TST and QFT positive with at last two years of latent TB infection were recruited. AMPs production by polymorphonuclear cells was determined by flow cytometry and correlation between TST and QFT values was analysed. Our results showed that there is a positive correlation between levels of HNP-1 and LL-37 production with reactivity to TST and/or QFT levels. This preliminary study suggests the potential use of the expression levels of these peptides as biomarkers for progression in latent infected individuals.

The use of Mycobacterium tuberculosis HspX and GlcB proteins to identify latent tuberculosis in rheumatoid arthritis patients

Rheumatoid arthritis (RA) is an autoimmune disease characterised by the destruction of articular cartilage and bone damage. The chronic treatment of RA patients causes a higher susceptibility to infectious diseases such as tuberculosis (TB); one-third of the world’s population is latently infected (LTBI) with Mycobacterium tuberculosis (Mtb). The tuberculin skin test is used to identify individuals LTBI, but many studies have shown that this test is not suitable for RA patients. The goal of this work was to test the specific cellular immune responses to the Mtb malate synthase (GlcB) and heat shock protein X (HspX) antigens of RA patients and to correlate those responses with LTBI status. The T-helper (Th)1, Th17 and Treg-specific immune responses to the GlcB and HspX Mtb antigens were analysed in RA patients candidates for tumour necrosis factor-α blocker treatment. Our results demonstrated that LTBI RA patients had Th1-specific immune responses to GlcB and HspX. Patients were followed up over two years and 14.3% developed active TB. After the development of active TB, RA patients had increased numbers of Th17 and Treg cells, similar to TB patients. These results demonstrate that a GlcB and HspX antigen assay can be used as a diagnostic test to identify LTBI RA patients.

Development of a Quantitative Sandwich Enzyme-Linked Immunosorbent Assay for Detecting the MPT64 Antigen of Mycobacterium tuberculosis

PURPOSE: Tuberculosis (TB) is a major infectious disease and is responsible for two million deaths annually. For the identification and quantitation of Mycobacterium tuberculosis (M. tuberculosis), a causative agent of TB, a sandwich enzyme-linked immunosorbent assay (ELISA) against the MPT64 protein of M. tuberculosis, an antigen marker of the M. tuberculosis complex, was developed. MATERIALS AND METHODS: The MPT64 protein was expressed, and anti-MPT64 monoclonal antibodies were prepared. A sandwich ELISA was established using recombinant MPT64 protein and anti-MPT64 monoclonal antibodies. The sandwich MPT64 ELISA was evaluated using reference and clinical mycobacterial strains. RESULTS: The sandwich MPT64 ELISA detected MPT64 protein from 2.1 ng/mL to 250 ng/mL (equivalent to 1.7x10(4) CFU/mL and 2.0x10(6) CFU/mL). All 389 clinical M. tuberculosis isolates tested positive in the sandwich MPT64 ELISA (sensitivity, 100%), and the assay showed no cross reactivity to any tested nontuberculous mycobacterial strain (specificity, 100%). CONCLUSION: The sandwich MPT64 ELISA is a highly sensitive and quantitative test for MPT64 protein, which can identify M. tuberculosis.

Evaluation of an enzyme-linked immunospot assay for the immunodiagnosis of atypical spinal tuberculosis (atypical clinical presentation/atypical radiographic presentation) in China

BACKGROUND: Atypical spinal tuberculosis (TB) usually presents in a slowly indolent manner with nonspecific clinical presentations making the diagnosis a great challenge for physicians. New technologies for the detection of atypical spinal TB are urgently needed. The aim of this study was to assess the diagnostic value of an enzyme-linked immunospot (ELISPOT) assay in clinically suspected cases of atypical spinal TB in China. METHODS: From March 2011 to September 2012, a total of 65 patients with suspected atypical spinal TB were enrolled. In addition to conventional tests for TB, we used ELISPOT assays to measure the IFN-I response to ESAT-γ and CFP-10 in T-cells in samples of peripheral blood mononuclear cells. Patients with suspected atypical spinal TB were classified by diagnostic category. Data on clinical characteristics of the patients and conventional laboratory results were collected. RESULTS: Out of 65 patients, 4 were excluded from the study. 18 (29.5%) subjects had cultureconfirmed TB, 11 (18.0%) subjects had probable TB, and the remaining 32 (52.5%) subjects did not have TB. Generally, the features of atypical spinal TB include the following aspects: (1) worm-eaten destruction of vertebral endplate; (2) destruction of centricity of the vertebral body or concentric collapse of vertebral body; (3) tuberculous abscess with no identifiable osseous lesion; (4) contiguous or skipped vertebral body destruction. 26 patients with atypical spinal TB had available biopsy or surgical specimens for histopathologic examination and 23 (88.5%) specimens had pathologic features consistent with TB infection. The sensitivities of the PPD skin test and ELISPOT assay for atypical spinal TB were 58.6% and 82.8%, and their specificities were 59.4% and 81.3%, respectively. Malnutrition and age were associated with ELISPOT positivity in atypical spinal TB patients. CONCLUSIONS: The ELISPOT assay is a useful adjunct to current tests for diagnosis of atypical spinal TB.

Revisiting the Rich's formula: an update about granulomas in human tuberculosis

The formula proposed by Rich in 1951 explained the formation in a tuberculous lesion in a period that was unknown cellular functions, cytokines and other immunological aspects involved in granuloma formation by tuberculosis; its components are assembled conceptually to explain the pathogenic mechanisms involved in the granulomatous lesion in tuberculosis. In this manuscript, we report an update of Rich's formula based on the new and old concepts about pathogenic mechanisms involved in the granulomatous lesion in tuberculosis. Current knowledge allows us to conclude that the balance between the characteristics of the bacillus and host protective response is necessary to indicate the outcome of pathogenesis, infection or active disease and the necrosis degree of the tuberculosis lesion.

Immunologic evaluation and validation of methods using synthetic peptides derived from Mycobacterium tuberculosis for the diagnosis of tuberculosis infection

The goal of this study was to demonstrate the usefulness of an enzyme-linked immunosorbent assay (ELISA) for the serodiagnosis of pulmonary tuberculosis (PTB) and extrapulmonary TB (EPTB). This assay used 20 amino acid-long, non-overlapped synthetic peptides that spanned the complete Mycobacterium tuberculosis ESAT-6 and Ag85A sequences. The validation cohort consisted of 1,102 individuals who were grouped into the following five diagnostic groups: 455 patients with PTB, 60 patients with EPTB, 40 individuals with non-EPTB, 33 individuals with leprosy and 514 healthy controls. For the PTB group, two ESAT-6 peptides (12033 and 12034) had the highest sensitivity levels of 96.9% and 96.2%, respectively, and an Ag85A-peptide (29878) was the most specific (97.4%) in the PTB groups. For the EPTB group, two Ag85A peptides (11005 and 11006) were observed to have a sensitivity of 98.3% and an Ag85A-peptide (29878) was also the most specific (96.4%). When combinations of peptides were used, such as 12033 and 12034 or 11005 and 11006, 99.5% and 100% sensitivities in the PTB and EPTB groups were observed, respectively. In conclusion, for a cohort that consists entirely of individuals from Venezuela, a multi-antigen immunoassay using highly sensitive ESAT-6 and Ag85A peptides alone and in combination could be used to more rapidly diagnose PTB and EPTB infection.