Summary Tuberculosis (TB) is one of the most important infectious diseases around the world. Several studies have focused on the identification of correlates of protection against TB. Most of them ...have concentrated on the study of IFN-γ due to its robust association with protection against TB. However, given the complexity of the immune response elicited after Mtb infection, other cytokines should also be considered. In the present study, we evaluated Th1 and Th17 responses and their association with the protection or development of active disease. Therefore, non infected individuals (nonTBi), latently infected individuals (LTBi) and patients with active TB (ATB) were studied. The evaluation of the number of cytokine producing cells by ELISPOT showed a higher number of IFN-γ-producing cells in ATB patients, but no differences were found regarding the number of IL-17 producing cells among studied groups. The evaluation of IFN-γ, IL-2, TNF-α and IL-17 producing CD4+ and CD8+ T cells at 1 day and 6 days of stimulation with mycobacterial antigens suggests the presence of functional signatures associated with latency or active TB. The results presented herein suggest the possible use of the evaluation of Th1-type cytokines, such as IFN-γ and/or TNF-α, as a correlate of protection against TB; however, these results need to be validated for other groups.
Summary Regulatory T cells (Tregs) play an essential role in immune homeostasis. In infectious diseases Tregs may inhibit protective responses facilitating pathogen multiplication and dissemination, ...but they may also limit the inflammatory response diminishing tissue damage. Although there is experimental and clinical evidence that Tregs are induced during Mycobacterium tuberculosis infection, their role in the immunopathogenesis of tuberculosis is still not completely understood. In this study, the phenotype, frequency and activity of circulating Tregs in active and latent tuberculosis were evaluated. Phenotypic analysis showed that Tregs were CD4+ CD25high FOXP3+ CD45RO+ CD127- . High levels of circulating Tregs were found in patients with active pulmonary tuberculosis, compared to individuals with latent infection. Treg activity was evaluated by ELISPOT by determining the effect of CD25+ cell depletion on the frequency of IFN-γ and IL-17 producing cells after in vitro stimulation with ESAT-6, CFP-10 and PPD. Treg depletion increased the frequency of IFN-γ producing cells, without affecting the frequency of IL-17 producing cells, in both active and latent tuberculosis, irrespective of the antigen used. Neutralization of IL-10 did not have any effect on the frequency of IFN-γ and IL-17 producing cells. Altogether, these results suggest that during active tuberculosis Tregs inhibit protective Th1 responses, but not the proinflammatory Th17 responses, facilitating mycobacterial replication and tissue damage.
Alterations of monocyte/macrophages have been reported in patients with tuberculosis (TB), but their significance is poorly understood. Blood mononuclear cells from patients with different clinical ...forms of TB, at various times of anti-TB treatment, and healthy tuberculin positive individuals, were double-stained for CD14 plus CD206, TLR-2, IFN-γR1, CD40, HLA-DR, CD36 and CD163, and analyzed by flow cytometry. Monocytes were infected with
Mycobacterium tuberculosis H37Rv and 24
h later the phenotype, induction of necrosis and apoptosis and production of tumor necrosis factor TNFα, interleukin (IL)-10 and IL-12p40 were determined. TB patients presented higher percentage of CD14
+ cells but lower percentage of CD14
+DR
+ and CD14
+CD36
+ cells. Expression of CD14, HLA-DR and CD36 was decreased in TB patients. Normal percentages and expression were restored during anti-TB treatment. Monocytes from TB patients underwent necrosis and apoptosis after
M. tuberculosis infection, whereas monocytes from healthy controls exhibited only apoptosis. Anti-TB treatment reverted necrosis. There were no differences between the various clinical forms of TB. In vitro
M. tuberculosis infection decreased expression of the membrane molecules studied. HLA-DR and CD36 inhibition correlated with induction of apoptosis. Restoration of monocyte alterations during anti-TB treatment suggests that such alterations may be caused by the high
M. tuberculosis load present during active disease.
Tuberculosis (TB) has different clinical presentations. Pulmonary TB affects only the lungs and exhibits variable anti-mycobacterial immune responses. Pleural TB is a localized disease with a strong ...immune response. Miliary TB is a disseminated form with poor immune response. Cytokines play a pivotal role in anti-mycobacterial response and may determine the type of TB. Thus, gene polymorphisms associated with cytokine production may be associated with clinical presentations of TB. In this study, 54 tuberculin-negative healthy controls, 81 tuberculin-positive healthy controls, 140 patients with pulmonary TB, 30 with pleural TB and 20 with miliary TB were studied. Single nucleotide polymorphisms were typed for tumour necrosis factor-α, interferon-γ (IFN-
γ), transforming growth factor-
β1, interleukin-10 (IL-10) and interleukin-6 by sequence-specific primer polymerase chain reaction (SSP-PCR). Allelic, genotypic and haplotypic associations with clinical forms of TB were evaluated. IL-10 −1082 A/A genotype and IFN
γ+874 T allele were associated with pleural TB. Seventy-five extended genotypes were found; two differed between patients and controls, and two between groups of patients. Results suggest that IL-10 low-producer polymorphism and IFN-
γ high-producer polymorphism are associated with pleural TB.
Objectives Household contacts (HHCs) of pulmonary tuberculosis patients are at high risk of Mycobacterium tuberculosis infection and early disease development. Identification of individuals at risk ...of tuberculosis disease is a desirable goal for tuberculosis control. Interferon-gamma release assays (IGRAs) using specific M. tuberculosis antigens provide an alternative to tuberculin skin testing (TST) for infection detection. Additionally, the levels of IFNγ produced in response to these antigens may have prognostic value. We estimated the prevalence of M. tuberculosis infection by IGRA and TST in HHCs and their source population (SP), and assessed whether IFNγ levels in HHCs correlate with tuberculosis development. Methods A cohort of 2060 HHCs was followed for 2–3 years after exposure to a tuberculosis case. Besides TST, IFNγ responses to mycobacterial antigens: CFP, CFP-10, HspX and Ag85A were assessed in 7-days whole blood cultures and compared to 766 individuals from the SP in Medellín, Colombia. Isoniazid prophylaxis was not offered to child contacts because Colombian tuberculosis regulations consider it only in children under 5 years, TST positive without BCG vaccination. Results Using TST 65.9% of HHCs and 42.7% subjects from the SP were positive (OR 2.60, p<0.0001). IFNγ response to CFP-10, a biomarker of M. tuberculosis infection, tested positive in 66.3% HHCs and 24.3% from the SP (OR = 6.07, p<0.0001). Tuberculosis incidence rate was 7.0/1000 person years. Children <5 years accounted for 21.6% of incident cases. No significant difference was found between positive and negative IFNγ responders to CFP-10 (HR 1.82 95% CI 0.79–4.20 p = 0.16). However, a significant trend for tuberculosis development amongst high HHC IFNγ producers was observed (trend Log rank p = 0.007). Discussion CFP-10-induced IFNγ production is useful to establish tuberculosis infection prevalence amongst HHC and identify those at highest risk of disease. The high tuberculosis incidence amongst children supports administration of chemoprohylaxis to child contacts regardless of BCG vaccination.
Summary In the present study, we investigated whether pretransplantation HLA class I and class II antibodies and pretransplantation levels of soluble CD30 (sCD30) and IgA anti-Fab autoantibodies are ...predictive of kidney allograft survival. Pretransplantation sera of 504 deceased-donor kidney recipients were tested for IgG HLA class I and class II antibodies, sCD30, and IgA anti-Fab levels using the CTS 4 ELISA kit. Kidney graft survival was estimated by Kaplan-Meier method and multivariate Cox regression. Regardless of the presence of HLA class II antibodies, recipients with high HLA class I reactivity had lower 1-year graft survival than recipients with low reactivity ( p < 0.01). Recipients with high sCD30 had lower 5-year graft survival rate than those with low sCD30 ( p < 0.01). The sCD30 effect was observed in presensitized and nonsensitized recipients, demonstrated a synergistic effect with HLA class I antibodies ( p < 0.001), and appeared to be neutralized in recipients with no HLA class II mismatches. IgA anti-Fab did not influence kidney graft survival. Our results indicate that high pretransplantation sCD30 levels and HLA class I positivity increase the risk of kidney graft loss regardless of other factors. Consequently, such determinations should be routinely performed to estimate recipients’ risks of graft rejection before transplantation.
Background.Mycobacterium tuberculosis and puri?ed protein derivative (PPD) induce apoptosis in murine macrophages and apoptosis and necrosis in human monocytes and alveolar epithelial cells. ...Macrophages from bronchoalveolar lavages and granulomas from patients with tuberculosis (TB) present both types of cell death; however, the significance of the type of cell death in TB remains uncertain. Methods. Monocytes from PPD-positive control subjects and from patients with TB were exposed to PPD or M. tuberculosis. Apoptosis, necrosis, and the percentage of tumor necrosis factor (TNF)-a-positive and interleukin (IL)-10-positive cells were determined cytofluorometrically. Levels of lactate dehydrogenase, TNF-α, and IL-10 were measured in culture supernatants. The role of TNF-α and IL-10 was tested by blockade experiments. Results. PPD and M. tuberculosis induced apoptosis in monocytes from PPD-positive control subjects, whereas cells from patients with TB presented apoptosis and necrosis. Cells from PPD-positive control subjects produced mainly TNF-α, whereas cells from patients with TB produced mainly IL-10. Blockade experiments suggest that TNF-α and IL-10 regulate the type of cell death occurring in response to M. tuberculosis. Conclusions. Results suggest that apoptosis of monocytes exposed to mycobacteria may partly explain the protective immune response found in PPD-positive control subjects, whereas necrosis may be determinant of the bacterial dissemination and tissue damage that occur in patients with active TB.
In a population-based case-control study, 182 human immunodeficiency virus (HIV)—positive persons and 135 healthy control subjects were enrolled from the metropolitan area of Medellin, Colombia. Four ...genotypes of the natural resistance—associated macrophage protein l (NRAMP1) gene (5′ GT repeat, 274C/T, 469+14G/T, and 823C/T) were associated with altered risk of HIV infection (P = .015, .020, and .035, respectively). Three of these markers (5′ GTn, 274C/T, 469+14G/T) are in strong linkage disequilibrium, and genotypes of these markers are associated with reduced risk of HIV infection with relative risks (RRs) of 0.35 (95% confidence interval CI, 0.14–0.91), 0.31 (CI, 0.10–0.93), and 0.24 (CI, 0.08–0.72), respectively. Conversely, heterozygosity at the fourth independent marker (823C/T) was associated with increased risk of HIV infection (RR, 2.29; CI, 1.06–4.92). These findings suggest that NRAMP1 modifies risk of HIV infection.
Household contacts (HHCs) of pulmonary tuberculosis patients are at high risk of Mycobacterium tuberculosis infection and early disease development. Identification of individuals at risk of ...tuberculosis disease is a desirable goal for tuberculosis control. Interferon-gamma release assays (IGRAs) using specific M. tuberculosis antigens provide an alternative to tuberculin skin testing (TST) for infection detection. Additionally, the levels of IFNgamma produced in response to these antigens may have prognostic value. We estimated the prevalence of M. tuberculosis infection by IGRA and TST in HHCs and their source population (SP), and assessed whether IFNgamma levels in HHCs correlate with tuberculosis development. A cohort of 2060 HHCs was followed for 2-3 years after exposure to a tuberculosis case. Besides TST, IFNgamma responses to mycobacterial antigens: CFP, CFP-10, HspX and Ag85A were assessed in 7-days whole blood cultures and compared to 766 individuals from the SP in Medellín, Colombia. Isoniazid prophylaxis was not offered to child contacts because Colombian tuberculosis regulations consider it only in children under 5 years, TST positive without BCG vaccination. Using TST 65.9% of HHCs and 42.7% subjects from the SP were positive (OR 2.60, p<0.0001). IFNgamma response to CFP-10, a biomarker of M. tuberculosis infection, tested positive in 66.3% HHCs and 24.3% from the SP (OR = 6.07, p<0.0001). Tuberculosis incidence rate was 7.0/1000 person years. Children <5 years accounted for 21.6% of incident cases. No significant difference was found between positive and negative IFNgamma responders to CFP-10 (HR 1.82 95% CI 0.79-4.20 p = 0.16). However, a significant trend for tuberculosis development amongst high HHC IFNgamma producers was observed (trend Log rank p = 0.007). CFP-10-induced IFNgamma production is useful to establish tuberculosis infection prevalence amongst HHC and identify those at highest risk of disease. The high tuberculosis incidence amongst children supports administration of chemoprohylaxis to child contacts regardless of BCG vaccination.
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