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TB disease and infection: Do we have real news? Martina Sester Department of Transplant and Infection Immunology Saarland University; Germany

Overview – Facts and news…* Worldwide epidemiology of tuberculosis M. tuberculosis infection: continuum from latency to active disease Implications for diagnosis of M. tuberculosis infection Host-pathogen interactions Role of innate immunity The vaccine pipeline *an immunologist´s view on 2011´s news…

Tuberculosis – the facts 7. position of leading causes of deaths 1/3 of the world's population could be infected > 80% can be cured prevention can be > 90% effective Global tuberculosis control: WHO report 2011

Tuberculosis – the facts 1.45 million people died in 2010 due to TB equally to 3800 deaths per day 8.8 million new cases of TB in 2010 Global incidence rate of 128/100 000 Most cases occurred in Asia (59%) and Africa (26%) WHO report 2011

Estimated TB incidence rates 2010 WHO report 2011

The global burden of TB in 2010 in relation to HIV co-infection Estimated number of cases Estimated number of deaths All forms of TB 8.8 Mio (8.5–9.2 Mio) 1.45 Mio (1.2–1.5 Mio) HIV-associated TB 1.1 Mio (13%)* (1.0–1.3 Mio) 0.35 Mio (0.32–0.39 Mio) The proportion of TB cases coinfected with HIV is highest in countries in the African Region (Figure 2.4); overall, the African Region accounted for 82% of TB cases among people living with HIV. *82% of TB cases among people living with HIV originate from the African region WHO report 2011

Estimated HIV prevalence in new TB cases 2010 WHO report 2011

Trends in TB incidence rates Lawn and Zumla (2011) Lancet 378: 57

Overview – Facts and news… Worldwide epidemiology of tuberculosis M. tuberculosis infection: continuum from latency to active disease Implications for diagnosis of M. tuberculosis infection Host-pathogen interactions Role of innate immunity The vaccine pipeline

Infection cycle of M. tuberculosis from: Ulrichs und Kaufmann 2006 Monatsschrift Kinderheilkd 154: 133

TB disease and infection - definitions Detection of M. tuberculosis and/or clinical symptoms compatible with tuberculosis Latent infection with M. tuberculosis (LTBI) Presence of an immune response in a skin test or an IFN-g release assay (IGRA) Absence of clinical symptoms

Natural course of M. tuberculosis infection Immunosuppression exposure Progression 1% TB disease Recent contacts High TB prevalence Old healed TB Years after contact Low TB prevalence Successful TB/LTBI treatment Latency 5% 2-5% Latency 5% 2-5% Latency 5% 2-5% infection Illustrate effect of MTB prevalence, illustrate effect of LTBI treatment in the various situations LTBI Protective immunity Latency 90% Never TB Bacterium extinguished? Live bacilli? Chemoprophylaxis efficient Chemoprophylaxis not necessary

Prevalence of latent infection with M Prevalence of latent infection with M. tuberculosis and risk for progression Prevalence of positive immune responses and relative risk for tuberculosis Horsburg and Rubin (2011) N Engl J Med 364:1441

Immunodiagnosis of latent M. tuberculosis infection APC T cell antigens/ peptides IGRA IFN-g release assay PPD ESAT-6/CFP-10/TB7.7 Negative controls Positive controls, i.e. mitogens PHA/SEB activation/ cytokine induction cytokine induction cytokine induction cytokine induction Skin test ELISA ELISPOT assay Flow-cytometry cytokine activation marker T.SPOT.TB QuantiFERON TB gold

PPV and NPV of immune-based assays for the development of tuberculosis Test PPV NPV TST 2.3-3.3 99.7 QFT-G-IT 2.8-14.3 99.8 T-SPOT.TB 3.3-10.0 97.8 Diel et al. (2011) Eur Respir J 37: 88 16

Sensitivity and specificity of immune-based assays to diagnose active TB Test Sensitivity Specificity TST 0.65 0.75 QFT-G-IT blood 0.80 0.79 extrasang. 0.48 0.82 T-SPOT.TB 0.81 0.59 0.88 summary of pooled values Sester, Sotgiu et al. Eur Respir J (2011), 37: 100 17

New experimental tests LTBI Antigen different from the commercial RD1 peptides Markers different from IFN-g Readouts different from ELISA or ELISPOT Biological sample different from blood More details in the following talk: IGRA testing to diagnose TB disease and infection. What is new in clinical practice and for programmatic management? - D. Goletti, M Sester

Diagnosis of active tuberculosis Patient history Chest X-ray Culture Acid-fast bacilli staining Nucleic acid amplification testing

New experimental tests active tuberculosis Assays for childhood tuberculosis Assays for smear negative tuberculosis Faster assays Improved NAAT tests (i.e. Xpert MTB/RIF assay) More details in the following talk: The new horizons of molecular diagnosis: do we still need conventional microbiology? - D. Cirillo

Overview – Facts and news… Worldwide epidemiology of tuberculosis M. tuberculosis infection: continuum from latency to active disease Implications for diagnosis of M. tuberculosis infection Host-pathogen interactions Role of innate immunity The vaccine pipeline

Pathogenesis and immune effector mechanisms Kaufmann (2010) Immunity 33: 567

Pathogenesis and immune effector mechanisms Macrophage activation Interplay IFN-g/VitD signaling Apoptosis/necrosis of Macrophages affects bacterial growth and T-cell priming Immuno-pathogenesis of IRIS Kaufmann (2010) Immunity 33: 567

Role of innate immunity Controlling early pathogen growth Instructing adaptive immunity without innate immunity without adaptive immunity M. tuberculosis load normal immunity infection time

Role of innate immunity Controlling early pathogen growth Instructing adaptive immunity Fremond et al. (2004) J Clin Invest 114: 1790; Feng et al. (2005) J Immunol 174: 4185

Apoptosis versus necrosis Apoptotic macrophages decrease bacterial load and accelerate T-cell priming Necrotic macrophages increase bacterial load and slow down T-cell priming Divangahi et al. (2010) Nat Immunol 11: 751; Divangahi et al. (2009) Nat Immunol 10: 899

Apoptosis versus necrosis Apoptotic macrophages decrease bacterial load and accelerate T-cell priming Necrotic macrophages increase bacterial load and slow down T-cell priming Divangahi et al. (2010) Nat Immunol 11: 751; Divangahi et al. (2009) Nat Immunol 10: 899

Suppression of apoptosis as innate defence mechanism of virulent strains Interference with plasma membrane repair Decreased bacterial load Accelerated T-cell priming Increased bacterial load Delay in T-cell priming Divangahi et al. (2010) Nat Immunol 11: 751; Divangahi et al. (2009) Nat Immunol 10: 899; Behar et al. (2010) Nat Rev Microbiol 8: 668

Pathogenesis and immune effector mechanisms Macrophage activation Interplay IFN-g/VitD signaling Kaufmann (2010) Immunity 33: 567

Vitamin D deficiency and susceptibility to tuberculosis Vitamin D3 at start of antimicrobial treatment, and after 14, 28, and 42 days Martineau et al. (2011) Lancet 377: 242

Vitamin D deficiency and susceptibility to tuberculosis Median time to culture conversion 36·0 days in the intervention group and 43·5 days in the placebo group Adjusted hazard ratio 1·39, 95% CI 0·90–2·16; p=0.14. Vitamin D3 at start of antimicrobial treatment, and after 14, 28, and 42 days Martineau et al. (2011) Lancet 377: 242

Vitamin D deficiency and susceptibility to tuberculosis Effect of TaqI genotype Enhanced response with tt genotype (8.09, 95% CI 1.36–48.01; p=0.02) Tt genotype (0.85, 95% CI 0.45–1.63; p=0.63) TT genotype (1.13, 95% CI 0.60–2.10; p=0.71) Median time to sputum culture conversion 36·0 days - intervention group 43·5 days - placebo group Adjusted hazard ratio 1·39, 95% CI 0·90–2·16; p=0.14. Martineau et al. (2011) Lancet 377: 242

Active TB is associated with vitamin D deficiency Patients from Cape Town For the 75 nmol/L threshold for serum 25(OH)D concentration, proposed by some to denote optimal vitamin D status (23), a similar association was seen for HIV-infected participants (P = 0.001) but not for those without HIV infection (P = 0.45) Effect of vitamin D deficiency is more pronounced in HIV infected patients Martineau et al. (2011) Proc Natl Acad Sci U S A 108: 19013

Seasonal variation in vitamin D status and tuberculosis notifications Martineau et al. (2011) Proc Natl Acad Sci U S A 108: 19013

Antimicrobial effect of vitamin D and T-cell derived IFN-g Fabri et al. (2011) Sci Transl Med 3: 104ra102

Antimicrobial effect of vitamin D and T-cell derived IFN-g Induction of autophagy Fabri et al. (2011) Sci Transl Med 3: 104ra102

Antimicrobial effect of vitamin D and T-cell derived IFN-g Induction of antimicrobial peptides Fabri et al. (2011) Sci Transl Med 3: 104ra102

Mechanistic link - vitamin D deficiency and HIV-induced immunodeficiency Antimicrobial effect via induction of antimicrobial peptides and autophagy Martineau et al. (2011) Proc Natl Acad Sci U S A 108: 19013 Fabri et al. (2011) Sci Transl Med 3: 104ra102

Pathogenesis and immune effector mechanisms Immuno-pathogenesis of IRIS Kaufmann (2010) Immunity 33: 567

HIV-associated IRIS Immune reconstitution inflammatory syndrome May occur in up to 30% of HIV infected patients after start of ART Tissue destructive inflammation Microbial co-infections as risk factor Recovering CD4 T cells as immediate effectors? Pathological T cell responses?

HIV-associated IRIS Sester et al. (2010) Eur Respir J 36: 1242

Mouse model for lymphopenia-induced IRIS IRIS develops in context of Chronic microbial infection CD4 T cell deficiency Barber et al. (2012) Nat Rev Microbiol 10: 150

Model for IRIS involving a dysregulated innate immune response Barber et al. (2012) Nat Rev Microbiol 10: 150

Overview – Facts and news… Worldwide epidemiology of tuberculosis Infection cycle M. tuberculosis infection: continuum from latency to active disease Implications for diagnosis of M. tuberculosis infection Host-pathogen interactions Role of innate immunity The vaccine pipeline

Characteristics of successful vaccines CMV Rappuoli & Aderem (2011) Nature 473: 463

BCG vaccine Developed 1921 120 Mio doses administered/year Provides 80% protection against severe and disseminated disease in children 50% risk reduction in adults (0-80% efficacy) Genetic divergence Differences in T-cell response

Vaccine candidates Subunit and live viral vectors Antigens: ESAT-6, TB10.4, Ag85A, Ag85B, Mtb32 and 39 and fusions thereof Adjuvants: IC31, AS01, AS02, CAF01 Live viral vectors: Adenovirus, Vaccinia Live attenuated or killed bacteria rBCG M. tuberculosis M. vaccae

Adjuvants used for fusion proteins Serve to improve immunogenicity i.e. ligands for pattern recognition receptors Kaufmann (2011) Lancet Infect Dis 11: 633

Vaccines – where they should act Pre-exposure vaccination Post-exposure vaccination Therapeutic vaccination Kaufmann (2011) Lancet Infect Dis 11: 633

Therapeutic vaccine candidates

Pre-/post-exposure vaccines

Most advanced vaccine candidates 12 candidates have reached clinical trials (to replace BCG) (after BCG) Animal models: Prevention of tuberculosis, no eradication of M. tuberculosis Kaufmann (2011) Lancet Infect Dis 11: 633

Most advanced vaccine candidates 12 candidates have reached clinical trials (to replace BCG) (after BCG) Animal models: Prevention of tuberculosis, no eradication of M. tuberculosis Kaufmann (2011) Lancet Infect Dis 11: 633

Most advanced vaccine candidates 12 candidates have reached clinical trials (to replace BCG) (after BCG) Animal models: Prevention of tuberculosis, no eradication of M. tuberculosis Kaufmann (2011) Lancet Infect Dis 11: 633

Most advanced vaccine candidates 12 candidates have reached clinical trials (to replace BCG) (after BCG) Animal models: Prevention of tuberculosis, no eradication of M. tuberculosis Kaufmann (2011) Lancet Infect Dis 11: 633

Post-exposure vaccines

Effective vaccine for pre- and post-exposure H56 vaccine Early antigen Ag85B Early antigen ESAT-6 Latency antigen Rv2660c expressed during starvation Vaccination of mice Aagaard et al. (2011) Nat Med 17: 189

Effective vaccine for pre- and post-exposure H56 vaccine Pre-exposure 6 weeks after challenge 24 weeks after challenge T cells induced are polyfunctional Aagaard et al. (2011) Nat Med 17: 189

Effective vaccine for pre- and post-exposure H56 vaccine Post-exposure 35 weeks p.i. blood 35 weeks p.i. spleen Aagaard et al. (2011) Nat Med 17: 189

Effective vaccine for pre- and post-exposure H56 vaccine Post-exposure 2 vaccinations 2 vaccinations 2 vaccinations 2 vaccinations 35 weeks p.i. blood 35 weeks p.i. spleen 3 vaccinations 2 vaccinations Analysis between 23 and 43 weeks p.i. Aagaard et al. (2011) Nat Med 17: 189

Future candidates? Up to now, no vaccine candidate has achieved sterilising immunity

Future candidates? Sweeney et al. (2011) Nat Med 17: 1261

Conclusions Understanding the continuum from latency to active disease will lead to improved diagnosis of patients at risk and targeted therapy Knowledge of the role of innate immunity will lead to improved understanding of host-pathogen interactions Rationale vaccine design has achieved success, but clinical studies are still proceeding at slow pace