Diagnostic value of miR-155, miR-29a and lncRNAs (NEAT1, GAS5 and COX2) in HIV, tuberculosis, and HIV/TB co-infection.

Tuberculosis (TB) and human immunodeficiency virus (HIV) co-infection remain leading causes of mortality, especially in source-limited settings where diagnostic challenges impede timely management. Non-coding RNAs (ncRNAs) are emerging as non-invasive biomarkers for infectious diseases due to their role in immune regulation. However, the diagnostic potential of ncRNAs in distinguishing TB monoinfection, HIV monoinfection, and TB/HIV co-infection remains unclear. In this study, we examined the expression of miR-155, miR-29a, and lncRNAs (lncRNA-COX2, lncRNA-NEAT1, lncRNA-GAS5) by qRT-PCR in peripheral blood mononuclear cells (PBMCs) from 95 participants: 25 with HIV monoinfection, 20 with TB monoinfection, 25 with TB/HIV co-infection, and 25 healthy controls. Statistical analyses, including Spearman's rank correlation and receiver operating characteristic (ROC) curves, were used to evaluate diagnostic performance. miR-155 was significantly downregulated in HIV+ (P&#x2009;=&#x2009;0.0004) and TB+ (P&#x2009;=&#x2009;0.02) groups compared to controls, but not in TB/HIV+ (P&#x2009;=&#x2009;0.3). miR-29a was upregulated in TB+ (P&#x2009;=&#x2009;0.03) but not significantly altered in other infected groups. lncRNA-COX2 was upregulated in HIV+ (P&#x2009;=&#x2009;0.03) compared to controls, with non-significant trends in TB&#x2009;+&#x2009;and TB/HIV+. lncRNA-NEAT1 was upregulated in HIV+ (P&#x2009;=&#x2009;0.0002) and TB+ (P&#x2009;<&#x2009;0.0001), but not in TB/HIV+ (P&#x2009;=&#x2009;0.3). lncRNA-GAS5 was downregulated in HIV+ (P&#x2009;<&#x2009;0.0001), with no significant changes in TB+ (P&#x2009;=&#x2009;0.4) or TB/HIV+ (P&#x2009;=&#x2009;0.1). These group-specific patterns are detailed in Table&#xa0;2 with fold-changes. Both lncRNA-COX2 and lncRNA-NEAT1 were upregulated across all infected groups compared to controls, while lncRNA-GAS5 was increased in TB&#x2009;+&#x2009;and TB/HIV&#x2009;+&#x2009;groups but decreased in HIV&#x2009;+&#x2009;alone. Notably, lncRNA-COX2 exhibited the highest expression levels in TB&#x2009;+&#x2009;and TB/HIV&#x2009;+&#x2009;groups, indicating an inflammatory response related to TB. Similarly, elevated lncRNA-GAS5 levels in TB&#x2009;+&#x2009;and TB/HIV&#x2009;+&#x2009;suggest its role in TB-associated pathology and co-infection effects. lncRNA-GAS5 and lncRNA-NEAT1 demonstrated high diagnostic accuracy for TB (AUC&#x2009;=&#x2009;0.79 and 0.85, respectively). Selective biomarkers enhanced diagnostic performance, with a combination of miR-29a, lncRNA-NEAT1, and lncRNA-GAS5 achieving an AUC of 0.98 for TB. These findings suggest that multiplex ncRNA profiles provide a powerful diagnostic tool for TB/HIV co-infection, offering a robust, blood-based alternative for early detection in high-burden regions.