Tuberculosis (TB) is an airborne and contagious-infectious disease caused by Mycobacterium tuberculosis bacilli (MTB), ranked as the one of causes of morbidity worldwide and requires long-term management. It infected approximately one-third of the world’s population , resulting in 2 million deaths each year. MTB, usually establishes its infection in the lungs and known as pulmonary tuberculosis(PTB) also can affect other organs and known as extrapulmonary tuberculosis (EPTB). TB is a major global  public health problem for both developed and developing countries, is the second lethal disease cause of death in worldwide ,after the human immunodeficiency virus (HIV) .In 2014,World Health Organization (WHO) estimated  the  burden of TB disease was  9.6 million new cases worldwide and 1.5 million deaths were estimated TB resumption again is mainly a consequence  due to onset of the AIDS pandemic and  emergence of  drug resistant strains MDR.


Tuberculosis (TB) is the second leading cause of human mortality from infectious diseases worldwide. WHO reported 1.3 million deaths and 8.6 million new cases of TB in 2012 . One-third of the world's human population is latently infected with Mycobacterium tuberculosis (M. tb), and adult tuberculosis (TB) is largely caused by the resuscitation of latent M. TB. Multidrug-resistant (MDR) TB is caused by strains of Mycobacterium tuberculosis (M. tb) resistant to isoniazid and rifampin, the backbone of first-line antitubercular treatment. MDR TB affects an estimated 500,000 new patients annually. Genetic analysis of drug-resistant MDR-TB showed that airborne transmission of undetected and untreated strains played a major role in disease outbreaks .

 Smear Negative pulmonary TB:

Diagnosis of smear-negative  pulmonary TB is still a clinical challenge due to low of the paucibacillary. Previous clinical  studies  indicated  that  sputum  smear  grading  at  the  time  of diagnosis  (negative,  scanty, 1+, 2+, or 3+)  is  predictive  of  diagnosis, relapse  and recurrence  of  TB  disease. Some studies suggested that different cytokine expression profiles in active PTB  are associated with the bacterial loads.Therefore, immunity of an individual to TB sometimes reflected the bacterial load. During the end of the last century, different human and animal researches were carried out on cytokine as immunological biomarkers that result  from the immune response to M. tuberculosis infection.Thus measuring of multiple pro- and anti-inflammatory cytokine specific to TB will give insight into the pathogenesis mechanism of Mtb infection, also provide the opportunity to identify candidate immunologic biomarkers for TB disease and infection.

 Drug discovery for TB: