MicroRNA miR-155 and miR-21 as Biomarkers in Active PulmonaryTuberculosis and the Healing Process: A Mini Review

Pulmonary tuberculosis (TB) caused by Mycobacterium tuberculosis is still a great challengein the public health domain to this day. Sputum collection from TB patients followed by anexamination of acid-fast bacilli (AFB) is a common diagnostic tool routinely done; however, itcould lead to false negative results when the patient excretes saliva instead of sputum. Meanwhile,bacterial culture, which is the gold standard, is time- and labor-consuming. MicroRNAs (miRNAs)are a type of RNA that is small (18-25 nucleotides) and controls the function of messengerRNA (mRNA). MicroRNA is the 6th and most recent cell communication pathway discovered, asthe secreted miRNAs are encased in exosomes and can circulate throughout the body and can befound in any body fluids including sputum. MiRNAs in TB patients associated with TB infectioncan be expressed as increased or decreased according to the severity of the infection. MiRNA-155and 21 are miRNAs with increased expression in active pulmonary TB and decrease in the healingprocess, so both miRNAs hold the potency to be used as biomarkers to monitor the level of diseaseactivity and the healing process.