Host Biomarkers in Tuberculosis.

Host-derived biomarkers are high-priority targets for development and could play important roles in diagnosis of various states of Mycobacterium tuberculosis (Mtb) infection and disease, prediction of outcomes, and might guide vaccine and drug regimen evaluation. We discuss the need for priority tuberculosis (TB) biomarkers, including markers of immune sensitization, prediction of progression, diagnosis of asymptomatic and symptomatic TB, including extrapulmonary TB, and treatment monitoring. The focus of the review is on ex vivo transcriptomic and proteomic markers as these are amenable to the development of field-near test formats, which are the most appropriate tests for future incorporation into TB management programs in resource-scarce settings, where the need for new tools is the greatest. The performance of candidate markers is measured against World Health Organization (Target Product Profiles for Tuberculosis Screening Tests, www.who.int/publications/i/item/9789240113572)-devised target product profiles, and challenges for harmonized research approaches to secure strong clinical data, coupled with sample repositories, and biomedical resources are discussed.