Tuberculosis (TB) is a leading infectious cause of death worldwide. Current strategies for monitoring TB treatment response are culture dependent and insensitive. New methods of assessing treatment response in vivo could inform new drug development and other treatment strategies. Cell-free DNA (cfDNA) - small circulating fragments of DNA - is widely used in maternofetal medicine and oncology for diagnosis and assessment of treatment response. This study aims to investigate whether pathogen derived Mycobacterium tuberculosis-specific cfDNA (Mtb-cfDNA) can be used to monitor TB treatment response.

This feasibility study will take place at Mae RaMat TB Center in Thailand and includes two study groups:

1. Assay Development and Validation
2. Longitudinal Assessment of Mtb-cfDNA levels

This study is funded by the Wellcome Trust; grant reference number: 223099/Z/21/Z

Inclusion Criteria:

Participants with a new diagnosis of tuberculosis

• Aged ≥ 18 years old
• Newly microbiologically confirmed (culture or nucleic acid amplification test) diagnosis of Mycobacterium tuberculosis (Mtb.) infection (of any site)
• Has not yet commenced antituberculosis therapy
• Able to understand study procedures and requirements and is able to give informed consent

For healthy volunteers:

• Aged ≥ 18 years old
• Healthy as judged by a responsible physician
• Able to understand study procedures and requirements and is able to give informed consent

Exclusion Criteria:

Participants with a new diagnosis of tuberculosis

• Exposure to antituberculosis treatment in the last 8 weeks (or Mycobacterium tuberculosis (Mtb.) active fluoroquinolone)
• Known history of underlying malignancy
• Pregnancy
• Transfusion dependent anaemia

For healthy volunteers:

• History of tuberculosis infection or latent tuberculosis infection
• Household, or other close contact, of a person living with tuberculosis disease
• Chest radiograph (CXR) changes suggestive of pulmonary tuberculosis
• Presence of symptoms which would otherwise indicate screening for tuberculosis (cough > 2 weeks duration, fever, weight loss, night sweats)
• Other major medical comorbidity
• Pregnancy
• Known malignancy

Group 1: Assay development and validation. In this group, sampling will be performed at tuberculosis diagnosis. Tuberculosis participants (n = 20) will have blood sampling performed at day 0. Healthy participants (n = 20) without clinical evidence of tuberculosis will have blood sampling performed at a single timepoint.

Group 2: Longitudinal Assessment. In this group, tuberculosis participants (n= 120) will have longitudinal sampling performed from diagnosis to the end of treatment. This will help to establish the feasibility of dynamic Mtb-cfDNA measurements.

The data generated in this study belongs to the study group as a whole. The final database will be shared amongst the PI and key members of the research team.

With participant's consent, clinical data and results from blood analyses stored in the database may be shared with researchers not directly involved in this study but only after the main paper has been published and in accordance with MORU guidelines on data sharing.

The results of the study will be summarised in lay language, in both English and the language(s) commonly spoken at the study site, and disseminated to participants and the community.

The Investigators will be involved in reviewing drafts of the manuscripts, abstracts, press releases and any other publications arising from the study. Authorship will be determined in accordance with the International Committee of Medical Journal Editors (ICMJE) guidelines and other contributors will be acknowledged.