Immunological Diagnosis of Active and Latent TB

Immunological diagnosis of tuberculosis (TB) is based on the immune responses against Mycobacterium tuberculosis (MTB). Immunological diagnosis can detect both active and latent TB, and can detect not only pulmonary TB but also extra-pulmonary TB. Compared to conventional diagnosis, immunological diagnostic tests have eminent advantages. On the other hand, there are still some limitations. As is known, various mycobacteria share homologous proteins, that lead to immunological cross reaction. To correctly detect TB infection, we need to choose a method that initiates the anti-MTB immune response properly. Human immunodeficiency virus (HIV) infection weakens the immune response, which may lead to false-negative results. HIV infection accompanied by TB is another urgent issue in global health. In this chapter, we will explain the immunological responses to MTB and the immunological interaction between HIV and TB. We will then introduce each diagnosis from the immunological point of view, and describe novel assays which we are now developing.