[Mycobacterium tuberculosis. From the gene to the diagnosis].

Pulmonary tuberculosis still in on the list of the world major health problems. Tuberculosis has not been eradicated yet, from developing countries. Furthermore, its incidence is increasing in the industrialized world, due to the human immunodeficiency virus (HIV) epidemic. In this regard, atypical clinical presentation of tuberculosis in individuals who have a deficient immune system, such as those at risk of tuberculosis because of HIV infection, makes the diagnostic process more difficult. Tuberculosis cases are often diagnosed later in HIV individuals compared to non-HIV individuals. The ensuing greater risk of contagion thus requires rapid and sensitive diagnostic protocols. In this context, several biotechnological tools have been developed that can be applied to the diagnosis of tuberculosis. M. tuberculosis genes have been cloned, monoclonal antibodies against pure proteins have been produced, thus enabling researchers to generate molecular and biochemical probes. As a consequence, DNA hybridization and DNA amplification techniques have been applied to the detection of mycobacteria, and ELISA kits of high sensitivity are been already made available. In regard to the latter, it is likely that monospecific and highly sensitive immunoassays will be developed that are directed against "active disease" immunodominant antigens. It may thus be expected that future new technologies will supplement the traditional tools for the diagnosis of tuberculosis and rapid diagnosis protocols will be available to chest clinicians in a foreseeable future.