Host Immune Responses Differ between M. africanum- and M. tuberculosis-Infected Patients following Standard Anti-tuberculosis Treatment

PLoS Negl Trop Dis. 2016 May 18;10(5):e0004701. doi: 10.1371/journal.pntd.0004701. eCollection 2016 May.

Abstract

Epidemiological differences exist between Mycobacterium africanum (Maf)- and Mycobacterium tuberculosis (Mtb)-infected patients, but to date, contributing host factors have not been characterised. We analysed clinical outcomes, as well as soluble markers and gene expression profiles in unstimulated, and ESAT6/CFP-10-, whole-Maf- and Mtb-stimulated blood samples of 26 Maf- and 49 Mtb-HIV-negative tuberculosis patients before, and after 2 and 6 months of anti-tuberculosis therapy. Before treatment, both groups had similar clinical parameters, but differed in few cytokines concentration and gene expression profiles. Following treatment the body mass index, skinfold thickness and chest X-ray scores showed greater improvement in the Mtb- compared to Maf-infected patients, after adjusting for age, sex and ethnicity (p = 0.02; 0.04 and 0.007, respectively). In addition, in unstimulated blood, IL-12p70, IL12A and TLR9 were significantly higher in Maf-infected patients, while IL-15, IL-8 and MIP-1α were higher in Mtb-infected patients. Overnight stimulation with ESAT-6/CFP-10 induced significantly higher levels of IFN-γ and TNF-α production, as well as gene expression of CCL4, IL1B and TLR4 in Mtb- compared to Maf-infected patients. Our study confirms differences in clinical features and immune genes expression and concentration of proteins associated with inflammatory processes between Mtb- and Maf-infected patients following anti-tuberculosis treatment These findings have public health implications for treatment regimens, and biomarkers for tuberculosis diagnosis and susceptibility.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Antigens, Bacterial / immunology
  • Antitubercular Agents / therapeutic use*
  • Biomarkers / blood
  • Cytokines / blood*
  • Female
  • Gambia
  • Gene Expression
  • Host-Pathogen Interactions
  • Humans
  • Interferon-gamma / blood
  • Interleukin-5 / blood
  • Interleukin-8 / blood
  • Male
  • Middle Aged
  • Mycobacterium / drug effects
  • Mycobacterium / immunology*
  • Mycobacterium / isolation & purification
  • Mycobacterium tuberculosis / drug effects
  • Mycobacterium tuberculosis / immunology*
  • Mycobacterium tuberculosis / isolation & purification
  • Tuberculosis / drug therapy*
  • Tuberculosis / ethnology
  • Tuberculosis / immunology*
  • Tuberculosis / microbiology
  • Tumor Necrosis Factor-alpha / drug effects
  • Young Adult

Substances

  • Antigens, Bacterial
  • Antitubercular Agents
  • Biomarkers
  • Cytokines
  • ESAT-6 antigen, Mycobacterium leprae
  • IL5 protein, human
  • Interleukin-5
  • Interleukin-8
  • Tumor Necrosis Factor-alpha
  • Interferon-gamma