Heterogeneity in tuberculosis

• Published in: Nature reviews. Immunology Vol. 17; no. 11; pp. 691 - 702
• Main Authors: Cadena, Anthony M., Fortune, Sarah M., Flynn, JoAnne L.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01-11-2017; Nature Publishing Group
• Subjects: 631/250/254; 631/250/255/1856; 631/326/41/2534; Animals; Antitubercular Agents - pharmacology; Antitubercular Agents - therapeutic use; B cells; Biomedicine; Development and progression; Disease Models, Animal; Disease Susceptibility; Granuloma - immunology; Granuloma - microbiology; Granuloma - pathology; Health aspects; Heterogeneity; Host-pathogen interactions; Host-Pathogen Interactions - immunology; Humans; Immune response; Immunology; Infections; Mycobacterium tuberculosis - immunology; Patient Outcome Assessment; review-article; Treatment Outcome; Tuberculosis; Tuberculosis - drug therapy; Tuberculosis - immunology; Tuberculosis - microbiology; Tuberculosis - pathology
• ISSN: 1474-1733; 1474-1741
• DOI: 10.1038/nri.2017.69

Key Points
Tuberculosis (TB) is a highly complex and variable disease that presents along a spectrum of infection outcomes.
The TB granuloma is a primary contributor to the biological heterogeneity of TB.
Local inflammation, the immune response and bacterial state all contribute to the outcome of a granuloma, and thus there are multiple pathways by which to either achieve control or promote dissemination.
The failure of one or a few granulomas is sufficient to initiate disease progression and influence the clinical status of the host.
Tuberculosis (TB) is a heterogeneous disease: most infections are asymptomatic, but some infected individuals develop active symptomatic disease. This Review describes how features of the host immune response, granulomas and the mycobacteria contribute to the varied outcomes of TB infection.
Infection with
Mycobacterium tuberculosis
, the causative agent of tuberculosis (TB), results in a range of clinical presentations in humans. Most infections manifest as a clinically asymptomatic, contained state that is termed latent TB infection (LTBI); a smaller subset of infected individuals present with symptomatic, active TB. Within these two seemingly binary states, there is a spectrum of host outcomes that have varying symptoms, microbiologies, immune responses and pathologies. Recently, it has become apparent that there is diversity of infection even within a single individual. A good understanding of the heterogeneity that is intrinsic to TB — at both the population level and the individual level — is crucial to inform the development of intervention strategies that account for and target the unique, complex and independent nature of the local host–pathogen interactions that occur in this infection. In this Review, we draw on model systems and human data to discuss multiple facets of TB biology and their relationship to the overall heterogeneity observed in the human disease.