The miRNA involvement in mycobacterial infections has strengthened hope for a better understanding of pathogenesis, the development of a new class of predictive and diagnostic biomarkers, and the provision of novel treatments for tuberculosis (TB). This period of studies is in its infancy and requires further attention and ongoing efforts to understand the complex regulation of miRNA in TB and wide applications to augment a rational plan for effective control and management of TB. Accordingly, the purpose of this study was to investigate the miR-21 expression level in the patients infected with mycobacterium tuberculosis. The serum samples were collected from 200 samples during a three-year period in hospitals of Kerman in Iran. The expression level of extracted miR-21 was analyzed using real-time PCR technique. In this study, there was no significant difference in the serum miR-21 gene expression in the symptomatic patients with negative smear and negative PPD (tuberculin skin test). However, the patients with positive smear and positive PPD showed a significant increase in the miR-21 gene expression (P < 0.05). These results confirm the need for more accurate diagnostic methods, especially molecular techniques, to detect M. tuberculosis infection, as late detection of infection can eliminate the possibility of effective treatment and endanger the lives of individuals. Due to the correlation between miR-21 and this infection, the miR-21 inhibitors can also be used in the treatment of the disease.

mycobacterium tuberculosis, miR-21, real time PCR.