Latency in Pulmonary Tuberculosis

This study is currently recruiting participants.
Verified June 2011 by Tuberculosis Research Centre, India
Sponsor:
Collaborator:
Information provided by:
Tuberculosis Research Centre, India
ClinicalTrials.gov Identifier:
NCT01154959
First received: June 30, 2010
Last updated: June 15, 2011
Last verified: June 2011

June 30, 2010
June 15, 2011
February 2010
February 2013   (final data collection date for primary outcome measure)
The immune response to crude antigens - PPD and CFA and defined antigens - ESAT-6 and CFP-10 as well as positive controls- SEB and anti-CD3. [ Time Frame: 2 years ] [ Designated as safety issue: No ]
Same as current
Complete list of historical versions of study NCT01154959 on ClinicalTrials.gov Archive Site
Determining the correlation of increase in regulatory factors with the development of relapse in treated TB patients. [ Time Frame: 2 years ] [ Designated as safety issue: No ]
Same as current
Not Provided
Not Provided
 
Latency in Pulmonary Tuberculosis
Characterization of Immune Responses in Treatment-induced Latency in Pulmonary Tuberculosis

The immune responses in latent tuberculosis are poorly understood. While it is difficult to define the onset of latency during natural infection, patients undergoing treatment for tuberculosis are driven into a state of latency or cure. The present study on the effect of 3 and 4 month regimens containing moxifloxacin in sputum smear and culture positive pulmonary tuberculosis (TRC Study number 24) offers us the opportunity to study definitive immune responses pre and post treatment. We will evaluate a variety of innate and adaptive immune responses in patients before and after treatment and our study will compare the differences in immuno-phenotype (eg. Markers of T, B and NK cell activation, proliferation and regulatory phenotype) and function (eg. Production of cytokines, proliferative responses to TB antigens) at different time points following treatment. In addition, since a small percentage of patients will undergo relapse following treatment, the kinetics of immune responses in these patients will used to assess immunological predictors of relapse in tuberculosis.

Although Mycobacterium tuberculosis (Mtb) infects approximately 2 billion people worldwide, 90% of Mtb infected individuals are able to resist overt disease (active tuberculosis) development and manifest only latent infection. Latent tuberculosis (TB) is defined as the persistent presence of live Mtb within an infected host without causing disease. It is characterized by a delayed type hypersensitivity response to purified protein derivative (PPD) mediated by mycobacteria specific T cells. During latency, Mtb is contained in localized granulomas where the mycobacteria reside in macrophages and in which growth and replication appears to be constrained. Maintenance of the granulomatous lesion is mediated by CD4+ and CD8+ T cells. Based on murine models, immunity to Mtb requires Th1 responses and (to a lesser extent) Th17 responses. Thus, IL 12, IFN gamma, and TNF alpha (and IL 17 and IL 23) all play important roles in induction and maintenance of protective immune responses against tuberculous disease. Although CD4+ T lymphocytes of Th1 type are critical for protective immunity, evidence exists that CD8+ T cells as well as unconventional T cells (gamma-delta T cells and CD 1 restricted T cells) contribute to optimum protection in susceptible animal models. Aside from producing cytokines that activate macrophages and initiate granuloma formation, T cells also have direct mycobactericidal activities through the concerted actions of perforins and granulysins.

T cell differentiation into Th1 and Th2 lineages based on their cytokine profile and transcription factor expression has served as the basis of our understanding the pathogenesis of a variety of infectious and allergic diseases. With the advent of newer techniques, T cell differentiation has expanded into several subsets, including Tregs, Th17 cells, and polyfunctional T cells, among others. Th1 cells are absolutely essential for resistance to TB both in mice and humans. Deficiencies in the IL 12 IFN gamma Stat1 pathway leads to disseminated mycobacterial infection in humans and to abrogation of resistance in mice. In addition, TNF alpha, another Th1 cytokine, is of almost equal importance, as treatment with biologics (e.g., anti TNF alpha antibodies) for inflammatory disorders such as rheumatoid arthritis has caused reactivation of TB in some individuals.

Latent TB can be maintained for the lifetime of the individual unless the immunological balance between the host and the pathogen is perturbed, resulting in reactivation of Mtb and active disease. The host and environmental factors involved in compromising the ability to contain latent infection are human immunodeficiency virus co infection, malnutrition, aging, stress, Type 2 diabetes, use of immunosuppressive agents, and other genetic factors. On the pathogen side, latency is thought to reflect a transition from replicating to nonreplicating dormant bacilli, with this transition being influenced by a variety of factors including oxygen deprivation and nitric oxide. The use of in vitro and in vivo models of latency combined with genome wide transcriptome profiling has led to the identification of Mtb genes highly expressed during latency called dosR or devR (dormancy) genes; however, each of the host and pathogen related factors controlling resistance and/or susceptibility to TB awaits complete elucidation.

The subsets of CD4+ T cells constitute an ever expanding repertoire, classified by their discrete cytokine profiles and often by expression of prototypical transcription factors and/or cell surface molecules. Two relatively newly emerging CD4+ T cell subsets of importance are Th17 cells, characterized by production of IL 17 family of cytokines, and regulatory T cells (Tregs), characterized by surface expression of CD25 and the transcription factor FoxP3. Little is known about the role of these two subsets in latent TB. The mechanism by which Mtb subverts immune responses to establish chronic, latent infection is also not well understood. Recently, a number of regulatory factors, including Tregs, IL 10, TGF-beta, CTLA 4, and PD 1, have been implicated in the establishment of chronic viral, bacterial, and parasitic infections.

The role of T, B and NK cells in the evolution of the immune response following therapy in Mycobacterium tuberculosis infection has to be elucidated. The development of cellular immune responses in TB-infected patients post-chemotherapy to delineate the cellular arms of immunity in response to crude and defined TB antigens in treated patients needs to be studied.

Interventional
Phase 3
Allocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Treatment
Pulmonary Tuberculosis
Drug: Moxifloxacin, Isoniazid, Rifampicin Pyrazinamide, Ethambutol
Moxifloxacin (400mg), Isoniazid (300mg daily, 600mg thrice weekly), Rifampicin (450mg, and 600mg for patients weighing 60kg or more), Pyrazinamide (1500mg), Ethambutol (800mg)
  • Experimental: Regimen 1
    Rifampicin, isoniazid, pyrazinamide, ethambutol and moxifloxacin daily for 3 months (3RHZEM)
    Intervention: Drug: Moxifloxacin, Isoniazid, Rifampicin Pyrazinamide, Ethambutol
  • Experimental: Regimen 2
    Rifampicin, isoniazid, pyrazinamide, ethambutol and moxifloxacin daily for 2 months followed by rifampicin, isoniazid, and moxifloxacin daily for 2 months (2 RHZEM daily / 2 RHM daily)
    Intervention: Drug: Moxifloxacin, Isoniazid, Rifampicin Pyrazinamide, Ethambutol
  • Experimental: Regimen 3
    Rifampicin, isoniazid, pyrazinamide, ethambutol and moxifloxacin daily for 2 months followed by rifampicin, isoniazid, and moxifloxacin thrice weekly for 2 months (2 RHZEM daily / 2RHM thrice weekly)
    Intervention: Drug: Moxifloxacin, Isoniazid, Rifampicin Pyrazinamide, Ethambutol
  • Experimental: Regimen 4
    Rifampicin, isoniazid, pyrazinamide, ethambutol and moxifloxacin daily for 2 months followed by rifampicin, isoniazid, ethambutol and moxifloxacin thrice weekly for 2 months (2 RHZEM daily / 2 RHEM thrice weekly)
    Intervention: Drug: Moxifloxacin, Isoniazid, Rifampicin Pyrazinamide, Ethambutol
  • Active Comparator: Control Regimen
    Rifampicin, isoniazid, pyrazinamide and ethambutol thrice weekly for 2 months followed by rifampicin and isoniazid thrice weekly for 4 months (2 RHZE thrice weekly / 4 RH thrice weekly)
    Intervention: Drug: Moxifloxacin, Isoniazid, Rifampicin Pyrazinamide, Ethambutol

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Recruiting
200
February 2015
February 2013   (final data collection date for primary outcome measure)

Inclusion Criteria:

  • Age 18 years and above
  • Residing in or around Chennai or Madurai
  • No anti-TB treatment in the past or should have had less than one month of treatment (but less than one week in the preceding one month before enrollment in the study)
  • At least two sputum smears should be positive for tubercle bacilli by fluorescent microscopy
  • Express willingness to attend the treatment centre for supervised treatment
  • Express willingness for home visits by the staff of the centre
  • Express willingness to give written informed consent

Exclusion Criteria:

  • Body weight less than 30 kg
  • Hepatic or renal disease as evidenced by clinical or biochemical abnormalities
  • Diabetes mellitus
  • A history of seizure or loss of consciousness
  • Psychiatric illness
  • An abnormal electrocardiogram or anti-arrhythmic medication
  • Those in a moribund state
  • Sero-positive for HIV antibodies
  • Pregnancy or lactation
  • Visual disorders other than refractory error
Both
18 Years and older
No
Contact: Subash Babu, MBBS, PhD 91-44-28369711 sbabu@niaid.nih.gov
Contact: Pavan Kumar, MSc 91-44-28369766 pavankumarn@trcchennai.in
India
 
NCT01154959
LTB01
No
Dr. S. Subash Babu, Tuberculosis Research Centre (ICMR)
Tuberculosis Research Centre, India
National Institutes of Health (NIH)
Principal Investigator: Subash Babu, MBBS, PhD Tuberculosis Research Centre, India
Tuberculosis Research Centre, India
June 2011

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP