Influence of rs7372209 in MicroRNA-26a and Interferon Gamma expression of tuberculosis patients

Background: MicroRNA-26a (miR-26a) and interferon-gamma (IFN-γ) play regulatory roles in the immune response to Mycobacterium tuberculosis (Mtb). Genetic polymorphisms such as miR-26a rs7372209 (C>T) may affect cytokine expression and influence tuberculosis (TB) susceptibility. Aim: This study aimed to determine the association between miR-26a rs7372209 (C>T) polymorphism and tuberculosis susceptibility among Iraqi patients, and to evaluate the relationship between genotypes and the expression levels of miR-26a and IFN-γ. Methods: A hospital-based case–control study was conducted at the Tuberculosis Health Centre and Baghdad Teaching Hospital (Iraq) between December 2024 and May 2025. One hundred pulmonary TB patients and fifty healthy controls were enrolled. Genotyping of miR-26a rs7372209 was performed by PCR and Sanger sequencing, and expression levels of miR-26a and IFN-γ were quantified using qRT-PCR. Data were analyzed using χ² tests and ANOVA (SPSS v25). Results: The CT genotype (52% in patients vs 34% in controls; p < 0.01) and T allele (53% vs 47%; OR = 2.07, 95% CI 1.27–3.75, p = 0.0001) were significantly associated with elevated TB risk. Expression of miR-26a was highest in TT carriers (4.16 ± 1.07-fold, p < 0.05), followed by CT and CC genotypes. Likewise, IFN-γ expression was increased in TT genotype patients (2.41 ± 1.13-fold, p < 0.01), indicating genotype-dependent regulation. Conclusion: The miR-26a rs7372209 T allele and CT/TT genotypes are linked to higher TB susceptibility and upregulated miR-26a and IFN-γ expression. These findings suggest that miR-26a may serve as a molecular adjunct to current TB diagnostic and prognostic tools, aiding in personalized infection management.