One of the most important advances in biology has been the discovery that siRNA (small interfering RNA) is able to regulate the expression of genes, by a phenomenon known as RNAi (RNA interference). The discovery of RNAi, first in plants and Caenorhabditis elegans and later in mammalian cells, led to the emergence of a transformative view in biomedical research. siRNA has gained attention as a potential therapeutic reagent due to its ability to inhibit specific genes in many genetic diseases. siRNAs can be used as tools to study single gene function both in vivo and in-vitro and are an attractive new class of therapeutics, especially against undruggable targets for the treatment of cancer and other diseases. The siRNA delivery systems are categorized as non-viral and viral delivery systems. The non-viral delivery system includes polymers; Lipids; peptides etc. are the widely studied delivery systems for siRNA. Effective pharmacological use of siRNA requires ‘carriers’ that can deliver the siRNA to its intended site of action. The carriers assemble the siRNA into supramolecular complexes that display functional properties during the delivery process.

Mannose-binding lectin (MBL) is an acute phase protein which recognizes the pathogens through its carbohydrate recognition domain. It is an important part of human innate immunity. The aim of the current study was to evaluate the impact of MBL2 polymorphism on pulmonary tuberculosis in a number of patients from the southeast of Iran. In this case-control study, 2 MBL gene polymorphisms (rs1800450, rs7095891) were genotyped using PCR-RFLP method and polymerase chain reaction for detection of 34bp ins/del of MBL2 gene (rs777980157) polymorphism. The study included 170 patients with PTB (pulmonary tuberculosis) and 175 control subjects. The findings indicated that the GA (GA vs. GG: OR=0.172, 95% CI=0.107–0.275, P<0.001) (OR – odds ratio; CI – confidence interval) genotype as well as GA+AA (GA+AA vs. GG: OR=0.191, 95% CI=0.120–0.302, P<0.001) genotype of rs1800450 reduced the risk of PTB compared to GG genotype. The rs7095891 variant significantly decreased the risk of PTB in codominant (GA vs. GG: OR=0.118, 95% CI=0.054–0.258, P<0.001; and AA vs. GG: OR=0.029, 95% CI=0.01–0.082, P<0.001), dominant (GA+AA vs. GG: OR=0.095, 95% CI=0.044–0.207, P<0.001) and recessive (AA vs. GA+GG: OR=0.172, CI=0.081–0.365, P<0.001) inheritance models. No significant relationship was identified between the rs777980157 variant and PTB risk/protection. In conclusion, we found that the MBL2 rs1800450 and rs7095891 polymorphisms provide relative protection against PTB. Additional studies on larger populations with different ethnicities are required to verify our findings.