Ascaris lumbricoides coinfection reduces tissue damage by decreasing IL-6 levels without altering clinical evolution of pulmonary tuberculosis or Th1/Th2/Th17 cytokine profile

Abstract INTRODUCTION: Immunological control of Mycobacterium tuberculosis infection is dependent on the cellular immune response, mediated predominantly by Th1 type CD4+ T cells. Polarization of the immune response to Th2 can inhibit the host immune protection against pathogens. Patients with tuberculosis coinfected with helminths demonstrate more severe pulmonary symptoms, a deficiency in the immune response against tuberculosis, and an impaired response to anti-tuberculosis therapy. METHODS: We evaluated the cellular immune response and the impact of the presence of Ascaris lumbricoides on the immune and clinical response in pulmonary tuberculosis patients. Ninety-one individuals were included in the study: 38 tuberculosis patients, 11 tuberculosis patients coinfected with Ascaris lumbricoides and other helminths, 10 Ascaris lumbricoides patients, and 34 non-infected control individuals. Clinical evolution of pulmonary tuberculosis was studied on 0, 30, 60, and 90 days post-diagnosis of Mycobacterium tuberculosis and Ascaris lumbricoides. Furthermore, immune cells and plasma cytokine profiles were examined in mono/coinfection by Mycobacterium tuberculosis and Ascaris lumbricoides using flow cytometry. RESULTS: There were no statistical differences in any of the evaluated parameters and the results indicated that Ascaris lumbricoides infection does not lead to significant clinical repercussions in the presentation and evolution of pulmonary tuberculosis. CONCLUSIONS: The association with Ascaris lumbricoides did not influence the Th1, Th2, and Th17 type responses, or the proportions of T lymphocyte subpopulations. However, higher serum levels of IL-6 in tuberculosis patients may explain the pulmonary parenchymal damage.

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.

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.

Coinfección tuberculosis pulmonar/VIH: asociación entre estado inmunológico y hallazgos radiológicos / Pulmonary Tuberculosis / HIV Infections: Association between Immune Status and Radiological Findings

Introducción: la infección por VIH afecta la inmunidad celular, por tanto aumenta la susceptibilidad del huésped a la infección por Mycobacterium tuberculosis. En la atención primaria de salud es imprescindible el papel desarrollado por el médico y la enfermera de la familia a fin de prevenir estas complicaciones en el paciente infectado. Objetivo: determinar la asociación entre el estado inmunológico y los hallazgos radiológicos en pacientes VIH/sida con TB pulmonar. Métodos: estudio descriptivo de casos clínicos. El universo estuvo constituido por 120 pacientes con VIH/sida y cultivo de esputo positivo de Mycobacterium tuberculosis, atendidos en el Hospital del Instituto de Medicina Tropical "Pedro Kourí", en el periodo comprendido entre enero de 2004 y diciembre del 2010. Resultados: los pacientes con conteo de linfocitos T CD4+ inferior a 200 cel/µL tuvieron 5,70 veces mayor oportunidad de presentar un patrón radiológico primario (OR: 5,70; IC 2,48- 13,09; p=0,00). No se encontró asociación estadísticamente significativa entre el patrón radiológico post primario y el conteo de linfocitos T CD4+. Los pacientes con conteos de linfocitos T CD4+ mayor a 200 cel/µL tuvieron 1,96 veces mayor oportunidad de presentar Rx de tórax normales, pero resultó no significativo estadísticamente. Conclusiones: el patrón radiológico de TB primaria se asoció al conteo de linfocitos T CD4+ inferior a 200 cel/µL y la ausencia de alteraciones radiológicas en pacientes con conteo de linfocitos T CD4+ superior a 200 cel/µL, no descartó la coinfección TB pulmonar/VIH(AU)

Introduction: HIV infection affects cellular immunity, thus increasing host susceptibility to infection by Mycobacterium tuberculosis. In primary health care the role played by the family physician and the family nurse is essential to prevent these complications in infected patients. Objective: Determine the association between immune status and radiological findings in HIV / AIDS patients with pulmonary TB. Methods: Descriptive study of clinical cases. A hundred twenty patients with HIV / AIDS and positive sputum culture for Mycobacterium tuberculosis were the universe of our study. These patients were treated at the Hospital of Pedro Kouri Institute of Tropical Medicine from January 2004 to December 2010. Results: Patients with T CD4+ counts below 200 cel/µL had 5.70 times higher chance of presenting a primary radiological pattern (OR: 5.70; CI 2, 48- 13,09; p = 0.00 ). No statistically significant association between the radiological post primary pattern and T CD4+ count was found. Patients with T CD4+ counts above 200 cel/µL had 1.96 times higher chance of presenting normal chest Rx, but it was not statistically significant. Conclusions: The radiographic pattern of primary TB is associated with T CD4+ count below 200 cells / uL and the absence of radiographic abnormalities in patients with counts of TCD4 + above 200 cells / uL, did not rule out pulmonary TB / HIV co- infection(AU)

Infección por Mycobacterium tuberculosis en una niña sometida a trasplante de progenitores hematopoyéticos / Mycobacterium tuberculosis infection in a pediatric patient who underwent a hematopoietic stem cell transplant

We report the case of a 10 year old girl with a relapsed acute lymphoblastic leukemia, who underwent a haploidentical hematopoietic stem cell transplant (HSCT), with grade II skin and digestive graft versus host disease, treated with corticosteroids and cyclosporine. On day + 54, she presented fever, with no other remarkable clinical findings. Imaging study showed the presence of lung and liver nodules, liver biopsy was performed. The study included histology, staining and culture for bacteria and fungi, and the preservation of a piece of tissue at -20°C for future prospective studies. Ziehl Nielsen stain was positive, and study for Mycobacterium infection was performed. Microbiological smears of tracheal and gastric aspirate, and bronchial fluid obtained by bronchoalveolar lavage (BAL) were positive. The final report confirmed Mycobacterium tuberculosis in gastric content, sputum, BAL and liver tissue, susceptible to rifampin, isoniazid, streptomycin and ethambutol, with determination of mutations for genes rpoβ and kat G (-). Tuberculosis (TB) diagnosis was confirmed. The girl received daily therapy for two months and then she continued on three times per week therapy for 9 months. Controlled by the transplant, infectious diseases and respiratory teams, the patient remained in good general condition, with radiologic resolution of pulmonary and liver involvement and negative smears. We conclude that Mycobacterium tuberculosis infection should be part of differential diagnosis of febrile illness in patients undergoing HSCT, and biopsy should be a standard practice of early diagnosis in these patients.

Se presenta el caso clínico de una niña de 10 años, con una leucemia linfoblástica aguda en recaída, sometida a un trasplante de progenitores hematopoyéticos (TPH) haploidéntico, con enfermedad injerto contra hospedero cutánea y digestiva grado II, en tratamiento con corti-costeroides y ciclosporina, que presentó el día +54 posttrasplante fiebre y compromiso de estado general. Dentro del estudio de su cuadro febril se practicaron imágenes que mostraron presencia de nódulos pulmonares y hepáticos. Se realizó una biopsia hepática cuyo estudio incluyó histología, tinciones y cultivo para bacterias y hongos. La tinción de Ziehl Nielsen de tejido hepático, así como las baciloscopias de contenido gástrico, aspirado traqueal y de fluido bronquial obtenido por lavado broncoalveolar (LBA) fueron positivas. El informe definitivo de cultivo confirmó Mycobacterium tuberculosis en contenido gástrico, esputo, LBA y tejido hepático, sensible a rifampicina, isoniazida, estreptomicina y etambutol, con determinación de mutaciones de genes rpoβ y kat G (-). Se confirmó el diagnóstico de tuberculosis, por lo que recibió tratamiento diario con cuatro fármacos por dos meses y luego terapia trisemanal con rifampicina, isoniazida y etambutol por nueve meses. Controlada por los equipos de trasplante, infectología y broncopulmonar, la paciente se mantiene actualmente en buenas condiciones generales, con imágenes con resolución del compromiso hepático y pulmonar y baciloscopias negativas. La infección por M. tuberculosis debe formar parte del diagnóstico diferencial de los cuadros febriles en los pacientes sometidos a TPH, y la toma de biopsia debe ser una práctica habitual y precoz en el enfrentamiento diagnóstico de estos pacientes.

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.

Avaliação da associação de polimorfismos de base única em região promotora de genes das citocinas fator de necrose tumoral (TNF) e Interleucina-10 (IL-10) com a susceptibilidade ou resistência a tuberculose pulmonar / Evaluation of the association of single nucleotide polymorphisms in the promoter region of genes of cytokines tumor necrosis factor alpha (TNF) and interleukin-10 (IL-10) with susceptibility or resistance to pulmonary tuberculosis

Polimorfismos de base única (SNPs) em regiões promotoras de genes das citocinas TNF-alfa e IL-10 influenciam a resposta imunológica e podem estar envolvidos na resistência ou susceptibilidade a tuberculose. Este trabalho objetivou avaliar a associação entre os SNPs funcionais dos genes das citocinas TNF-alfa (-308G/A) e IL-10 (-1082A/G) com a resistência ou susceptibilidade a tuberculose pulmonar ativa em pacientes oriundos do estado de Pernambuco. Participaram 282 indivíduos, distribuídos em grupos de estudo de acordo com achados clínicos, radiológicos e exames laboratoriais. O grupo caso foi formado por 71 pacientes com tuberculose pulmonar ativa; controle 1: 53 pacientes sintomáticos respiratórios com tuberculose latente; controle 2: 57 pacientes sintomáticos respiratórios portadores de infecções pulmonares inespecíficas e o controle 3 por 101 indivíduos clinicamente saudáveis, de serviços públicos de saúde. Foram coletados 5-10mL de escarro e 4,5mL de sangue periférico, realizada extração de DNA genômico e determinação do polimorfismo genético através de qPCR. A análise polimórfica comparativa entre os grupos de estudo demonstrou que o alelo mutante -1082G [p<0.0001; OR=3.90 [2.45- 6.59] e os genótipos -1082GA [p<0.0001; OR=2.90 [1.42- 5.95] e -1082GG [p<0.0001; OR=15.50 [5.18- 1.62] estava associado com o risco de desenvolvimento da tuberculose pulmonar quando o grupo caso foi comparado com o controle 3. O genótipo heterozigoto -308AG [p=0.005; OR=0.374 [0.17–0.76] apresentou associação estatística significante entre o grupo caso e o controle 3

Não houve diferença estatística significante na análise de associação dos SNP´s -308G/A e -1082A/G na comparação entre o grupo caso e os controles 1 e 2. Portanto, portadores do alelo mutante -1082G, equivalente a níveis protéicos aumentados de IL-10 podem estar influenciando a resposta imune contra o M. tuberculosis. Entretanto, portadores do genótipo heterozigoto -308GA, demonstrou um fator de proteção ao desenvolvimento da doença. O estudo demonstrou que os SNPs apresentaram um importante papel na susceptibilidade ou resistência a tuberculose pulmonar na população pernambucana estudada

Polimorfismo gênico de receptores TLRs e citocinas: papel na resposta imune em pacientes com tuberculose pulmonar / Genomic polymorphism of TLR s and cytokine receptors: role in immune response in patients with pulmonary tuberculosis

It is estimated that one-third of the total world population is latently infected with M. tuberculosis and only 5-10% of the infected individuals will develop active TB disease during their life-time. The reason why some infected individuals develop active disease, while others do not is not yet entirely understood. Given the central role of TLR-2 in the incitement of inflammation, polymorphisms in its gene might be involved in both infectious and inflammatory diseases. The aim of this study was to evaluate the influence of TLR2 - 16934A/T and GT repeat polymorphisms on the immune response of PTB patients undergoing anti-TB treatment at different time points of anti-tuberculosis treatment: T1 (beginning), T2 (3 months) and T3 (end). For this we genotyped TLR2 -16934 and (GT)n repeats polymorphisms and evaluated the immune response of pulmonary tuberculosis patients during the time of anti-tuberculosis treatment. The present study suggests that TLR2 - 16934A/T and GT repeats polymorphisms can influence differential TLR-2, NF-κB and cytokine levels during anti-TB treatment. We also suggest that PTB patients with TLR2 - 16934 AA genotype may have a worst outcome of the disease, since they have a lower IFN-γ, cytokine essential to initiate the protective immunity to active TB. This association could not be made in our study due to the low number of patients evaluated. Since TLR-2 play a major role in initiating immune response against M...

γδ T cells response to Mycobacterium tuberculosis in pulmonary tuberculosis patients using preponderant complementary determinant region 3 sequence.

Background & objectives: The unique immunological functions of γδ T lymphocytes to contribute immunity against Mycobacterium tuberculosis attracted interest of researchers. However, little is known about the specificity of γδ Τ cell in tuberculosis patients and the lack of exact tuberculosis antigen recognized by γδ T cells limited its application. The analysis of complementary determinant region (CDR)3 sequence characteristic in γδ T cells of tuberculosis patients would contribute to understand the distribution specificity of γδ T cell. In present study, we investigated the diversity of the γ9/δ2 T cell immunorepertoire and analysed the specificity of the expressed CDR3 in pulmonary tuberculosis patients. Methods: The total RNA in peripheral blood mononuclear cell of 50 pulmonary tuberculosis patients and 10 healthy controls was extracted. The polymerase chain reaction was used to specifically amplify the CDR3 region of γ9 and δ2 chain. The PCR products were ligated into the pGEM-T easy vector. The plasmid DNA was sequenced using the ABI3700 and the T7 primer. Results: Our findings showed that predominant CDR3 sequence of δ2 chain in pulmonary tuberculosis patients was CACDTLVSTDKLIFGKG. The sequence specifically exists in almost all pulmonary tuberculosis patients. The conserved hydrophobic acid residue in 97 positions is present in the γδ T cell reactive to M. tuberculosis. The length of δ2 CDR3 in pulmonary tuberculosis patients has no relation with the disease progress. Interpretation & conclusions: Our results suggest that γδ T cells appear to use CDR3 sequence to recognise M. tuberculosis antigen. γδ T cells reactive to M. tuberculosis were diverse and polyclonal.

Co-infection and risk factors of tuberculosis in a Mexican HIV+ population / Coinfecção e fatores de risco de tuberculose em uma população Mexicana com HIV+

INTRODUCTION: The situation of tuberculosis (TB) is being modified by the human immunodeficiency virus (HIV), which is increasing the occurrence of new cases and the generation of drug resistant strains, affecting not only the people infected with HIV, but also their close contacts and the general population, conforming a serious public health concern. However, the magnitudes of the factors associated to this co-infection differ considerably in relation to the population groups and geographical areas. METHODS: In order to evaluate the prevalence and risk factors for the co-infection of tuberculosis (TB) in a population with human immunodeficiency virus (HIV+) in the Southeast of Mexico, we made the analysis of clinical and epidemiological variables and the diagnosis of tuberculosis by isolation of mycobacteria from respiratory samples. RESULTS: From the 147 HIV+ individuals analyzed, 12 were culture positive; this shows a prevalence of 8 percent for the co-infection. The only variable found with statistical significance for the co-infection was the number of CD4-T < 200 cells/mm³, OR 13 (95 percent, CI 2-106 vs 12-109). CONCLUSIONS: To our knowledge this is the first report describing the factors associated with tuberculosis co -infection with HIV in a population from Southern Mexico. The low number of CD4 T-cells was the only variable associated with the TB co-infection and the rest of the variables provide scenarios that require specific and particular interventions for this population group.

INTRODUÇÃO: A situação da tuberculose (TB) foi modificada pelo vírus da imunodeficiência humana (HIV). Com isso, aumentou-se a ocorrência de novos casos de TB e a geração de cepas resistentes à droga, afetando não só as pessoas infectadas com HIV, mas também seus contatos próximos e da população em geral, gerando um sério problema de saúde pública. No entanto, a magnitude dos fatores associados à esta coinfecção diferem consideravelmente em relação aos grupos populacionais e áreas geográficas. MÉTODOS: Para avaliar a prevalência da comorbilidade e fatores de risco da coinfecção de tuberculose (TB) em uma população com o vírus da imunodeficiência humana (VIH+) no sudeste do México, nós fizemos a análise das variáveis clínicas e epidemiológicas e de isolamento da micobactérias através de cultura de amostras respiratórias. RESULTADOS: A partir de 147 indivíduos HIV+ analisados, 12 foram positivos na cultura, o que mostra uma prevalência de 8 por cento para a coinfecção. A única variável com significância estatística encontrada para a coinfecção foi o número de células CD4-T<200 células/mm³, OR 13 (95 por cento, CI 2-106 vs 12-109). CONCLUSÕES: Ao nosso conhecimento este é o primeiro relatório que descreve os fatores associados à coinfecção de tuberculose com HIV em uma população do sudeste do Mexico. O baixo número de células T CD4+ foi à única variável associada com a coinfecção por TB no resto das variáveis, proporcionando situações que exigem intervenções específicas e particulares para este grupo populacional.

Leukotrienes are not essential for the efficacy of a heterologous vaccine against Mycobacterium tuberculosis infection

Leukotrienes are reported to be potent proinflammatory mediators that play a role in the development of several inflammatory diseases such as asthma, rheumatoid arthritis and periodontal disease. Leukotrienes have also been associated with protection against infectious diseases. However, the role of leukotrienes in Mycobacterium tuberculosis infection is not understood. To answer this question, we studied the role of leukotrienes in the protective immune response conferred by prime-boost heterologous immunization against tuberculosis. We immunized BALB/c mice (4-11/group) with subcutaneous BCG vaccine (1 x 10(5) M. bovis BCG) (prime) followed by intramuscular DNA-HSP65 vaccine (100 µg) (boost). During the 30 days following the challenge, the animals were treated by gavage daily with MK-886 (5 mg·kg-1·day-1) to inhibit leukotriene synthesis. We showed that MK-886-treated mice were more susceptible to M. tuberculosis infection by counting the number of M. tuberculosis colony-forming units in lungs. The histopathological analysis showed an impaired influx of leukocytes to the lungs of MK-886-treated mice after infection, confirming the involvement of leukotrienes in the protective immune response against experimental tuberculosis. However, prime-boost-immunized mice treated with MK-886 remained protected after challenge with M. tuberculosis, suggesting that leukotrienes are not required for the protective effect elicited by immunization. Protection against M. tuberculosis challenge achieved by prime-boost immunization in the absence of leukotrienes was accompanied by an increase in IL-17 production in the lungs of these animals, as measured by ELISA. Therefore, these data suggest that the production of IL-17 in MK-886-treated, immunized mice could contribute to the generation of a protective immune response after infection with M. tuberculosis.

Genetic polymorphisms in vitamin D receptor, vitamin D-binding protein, Toll-like receptor 2, nitric oxide synthase 2, and interferon-γ genes and its association with susceptibility to tuberculosis: [review]

Mycobacterium tuberculosis kills more people than any other single pathogen, with an estimated one-third of the world's population being infected. Among those infected, only 10 percent will develop the disease. There are several demonstrations that susceptibility to tuberculosis is linked to host genetic factors in twins, family and associated-based case control studies. In the past years, there has been dramatic improvement in our understanding of the role of innate and adaptive immunity in the human host defense to tuberculosis. To date, attention has been paid to the role of genetic host and parasitic factors in tuberculosis pathogenesis mainly regarding innate and adaptive immune responses and their complex interactions. Many studies have focused on the candidate genes for tuberculosis susceptibility ranging from those expressed in several cells from the innate or adaptive immune system such as Toll-like receptors, cytokines (TNF-α, TGF-β, IFN-γ, IL-1b, IL-1RA, IL-12, IL-10), nitric oxide synthase and vitamin D, both nuclear receptors and their carrier, the vitamin D-binding protein (VDBP). The identification of possible genes that can promote resistance or susceptibility to tuberculosis could be the first step to understanding disease pathogenesis and can help to identify new tools for treatment and vaccine development. Thus, in this mini-review, we summarize the current state of investigation on some of the genetic determinants, such as the candidate polymorphisms of vitamin D, VDBP, Toll-like receptor, nitric oxide synthase 2 and interferon-γ genes, to generate resistance or susceptibility to M. tuberculosis infection.

Infecção por Mycobacterium tuberculosis entre agentes comunitários de saúde que atuam no controle da TB / Mycobacterium tuberculosis infection among community health workers involved in TB control

OBJETIVO: Avaliar a incidência de infecção por Mycobacterium tuberculosis através da prova tuberculínica em agentes comunitários de saúde (ACS) que acompanham pacientes em tratamento de TB no município de Cachoeiro de Itapemirim (ES). MÉTODOS: Incluímos 30 ACS que atuam no Programa de Saúde da Família e 30 de seus familiares residentes no mesmo domicílio. Comparamos o resultado do teste tuberculínico de cada ACS e do membro familiar correspondente. RESULTADOS: Entre os 30 ACS, 27 (90,0 por cento) eram do sexo feminino, ao passo que entre os 30 familiares, 23 (76,7 por cento) eram do sexo feminino (p = 0,299). A idade média do grupo ACS e do grupo dos familiares foi, respectivamente, 36,8 e 39,7 anos. Não houve diferença estatística no nível de escolaridade entre os grupos estudados. Na investigação da exposição ao M. tuberculosis, o mesmo número de indivíduos nos dois grupos afirmou conhecer ou já ter tido algum contato com paciente com TB (17 indivíduos; 56,7 por cento). Houve diferença estatisticamente significativa quanto ao resultado positivo da prova tuberculínica nos dois grupos (26,7 por cento no grupo ACS e 3,3 por cento no grupo de familiares; p = 0,011). CONCLUSÕES: A infecção por M. tuberculosis entre os ACS foi significativamente maior que entre seus familiares, e isso contribui para o debate em torno do risco ocupacional envolvido nas atividades destes profissionais.

OBJECTIVE: To evaluate the incidence of Mycobacterium tuberculosis infection, using tuberculin skin test, among community health agents (CHAs) monitoring TB patients in the city of Cachoeiro de Itapemirim, Brazil. METHODS: We included 30 CHAs acting in the Family Health Program and 30 of their family members residing in the same household. The tuberculin skin test results of each CHA were compared with those of the corresponding family member. RESULTS: Of the 30 CHAs, 27 (90.0 percent) were female, compared with 23 (76.7 percent) of the 30 family members (p = 0.299). The mean age of the CHA group and of the family member group was, respectively, 36.8 and 39.7 years. No statistically significant difference was found between the groups regarding the level of education. Regarding M. tuberculosis exposure, the same number of participants in the two groups reported having known or had contact with a TB patient (17 individuals; 56.7 percent). There was a statistically significant difference regarding positive tuberculin skin test results (26.7 percent in the CHA groupand 3.3 percent in the family member group; p = 0,011). CONCLUSIONS: M. tuberculosis infection was significantly higher among CHAs than among their family members, fueling the debate on the occupational risk involved in the activities of these professionals.

A study of iga antibody response to different mycobacterium tuberculosis antigens in the diagnosis and monitoring of pulmonary tuberculosis

We evaluated the performance of the ELISA technique in the detection of IgA antibodies against different Mycobacterium tuberculosis antigenic preparations in serum samples from 49 patients with pulmonary tuberculosis collected before and after the start of specific treatment. The controls consisted of serum samples from healthy patients without any prior contact with the bacteria and serum samples from patients with other pneumopathies. Glycolipid antigen gave the best diagnostic performance, with a sensitivity of 88 percent and specificities varying from 88 to 100 percent in the control groups. These antigens constitute a powerful tool for the diagnosis and monitoring of patients with pulmonary tuberculosis.

Investigation of T cell receptors in the peripheral blood of patients with active pulmonary tuberculosis.

T cells have the capability of recognizing target cells through their T cell receptors (TCRs). Thus, the percentages of CD3+/gamma-delta (gammadelta) TCR+ and CD3+/alpha-beta (alphabeta) TCR+ T lymphocytes were investigated in active and inactive pulmonary tuberculosis (PT) patients and in healthy individuals. CD3+ and CD3+/alphabeta TCR+ cell percentages were significantly lower in all PT patients than in healthy subjects. Percentages of CD3+/gammadelta and CD3+/alphabeta TCR+ were not statistically different between active and inactive PT patients. It was concluded that alphabeta TCR+ T cells might have a protective role in tuberculosis infection.

Macrophage Apoptosis in Tuberculosis

Mycobacterium tuberculosis (Mtb) is an intracellular pathogen that infects alveolar macrophages following aerosol transmission. Lung macrophages provide a critical intracellular niche that is required for Mtb to establish infection in the human host. This parasitic relationship is made possible by the capacity of Mtb to block phagosome maturation following entry into the host macrophage, creating an environment that supports bacillary replication. Apoptosis is increasingly understood to play a role in host defense against intracellular pathogens including viruses, fungi, protozoa and bacteria. In the last 15 years an understanding of the role that macrophage apoptosis plays in TB has begun to emerge. Here we review the history and current state of the art of this topic and we offer a model of the macrophage-pathogen interaction that takes into the account the complexities of programmed cell death and the relationship between various death signaling pathways and host defense in TB.

CD4+ cell counts in patients with different clinical manifestations of tuberculosis

Tuberculosis is the prototype of infections that require a cellular immune response for their control. It has been shown that CD4+ T-lymphocytes are most important in the protective response against Mycobacterium tuberculosis. CD8+ T-lymphocytes are also important for effective T-cell immune response. This study compares CD4+ and CD8+ baseline values in patients with different manifestations of tuberculosis. CD4+ and CD8+ in three groups of patients with tuberculosis (pulmonary, lymphadenitis, meningitis/milliary involvement) and a group of healthy volunteers were enumerated using flowcytometry. Twenty-six patients with pulmonary tuberculosis, 10 with adenitis, 16 with meningitis or milliary tuberculosis and 16 healthy volunteers entered the study. Mean CD4 in meningitis/milliary group was significantly lower than all other groups (p<0.05). Mean CD4 counts of patients with pulmonary tuberculosis was also significantly lower than control group (p=0.01). Mean CD8 in meningitis/milliary group was significantly lower than control group (p=0.02). No relation was found between results of TSTs and CD4 values in three groups. CD4 depletion is an expectable phenomenon in patients with tuberculosis. This study shows that patients with more severe form of disease had the lowest number of both CD4 and CD8 cells which can be a sign of suppressed cellular immunity in these patients.

Comparison of serological responses in two different populations with pulmonary tuberculosis

Observational studies on the humoural immune responses of the Warao indigenous people from Delta Amacuro, an isolated area, were compared with urban residents of the Venezuelan capital. Mycobacterium tuberculosis-specific reactivities (IgM, IgE, sIgA, IgG and IgG subclasses) were measured by ELISA using PPD and 38-kDa M. tuberculosis antigens. A total of 294 individuals were studied, 162 Warao (indigenous people) and 132 Creole (non-indigenous people). The patient group consisted of 87 Warao patients and 58 Creole patients, while the control group consisted of 75 Warao controls and 74 Creole controls. Combinations among the isotypes studied were performed. The findings showed that for the Warao people, sensitivity to the combination including anti-PPD IgG and IgE was 92.0 percent, while for the Creole people, sensitivity to the combination including anti-PPD IgG but more so anti-PPD IgG1 and IgG2 was 90.0 percent. Simple tests were able to show higher specificities, which were population-specific; specificities were anti-PPD IgG3, 100.0 percent and anti-PPD IgM, 97.4 percent for the Warao and Creole peoples, respectively. In conclusion, while simple tests reached high specificity, the multi-isotype tests improved sensitivity; the latter shows this approach may be useful in diagnostic testing.