[Biomarkers to assess different aspects of tuberculosis--from development to relapse].

Prevalence of tuberculosis (TB) has been decreased in Japan, whereas rapid increases in multi-drug resistance TB and HIV co-infection have raised serious problems in developing countries. To solve these problems, development of strong anti-TB vaccine, simple low-cost tools for diagnosis with drug sensitivity testing and new powerful anti-TB drugs is in urgent need. To evaluate new weapons against TB properly, appropriate biomarkers to assess the presence and severity of disease, response to treatment and prediction of relapse should be established. In case of TB, no relapse within two years after treatment is a gold standard to evaluate treatment outcome, but if we have a surrogate biomarker to predict relapse more quickly and accurately, clinical trials for TB drugs will be facilitated. A candidate TB vaccine may also be evaluated in a similar way. It may be further useful for individualized medicine to determine optimal dose and duration of TB treatment for each patient. I will review the current situation of biomarker studies and a new trend for development of biomarkers based on platforms of "omics" technology.