Exploring tumor necrosis factor-alpha as a biomarker for post-tuberculosis pulmonary fibrosis: A case-control study

Post-tuberculosis lung disease (PTLD), particularly pulmonary fibrosis, affects up to 50 % of TB survivors, contributing to chronic respiratory morbidity. This study investigates tumor necrosis factor-alpha (TNF-α) as a biomarker for post-tubercular sequelae (fibrosis) in patients cured of drug-sensitive pulmonary TB (DS-PTB).

A case-control study included 76 DS-PTB patients who completed treatment within one year. Cases (n = 38) had chest X-ray evidence of fibrosis, while controls (n = 38) had no fibrosis. Fibrosis extent was assessed using a chest X-ray scoring system (0-20). Serum TNF-α levels were measured using ELISA. Statistical analysis included generalized linear models and receiver operating characteristic (ROC) curves to evaluate associations and discriminative performance.

Patients with fibrosis were older, predominantly male, and had significantly higher TNF-α levels (3242.7 ± 750.0 ng/L) compared to controls (262.8 ± 93.8 ng/L, p < 0.001). ROC curve analysis revealed an area under the curve (AUC) of 0.79, indicating good discriminative ability for PTLD. A TNF-α threshold of 2787.3750 ng/L yielded a sensitivity for predicting the number of zones was 86.7 % (specificity: 16.4 %), and for CXR severity, it was 83.3 % (specificity: 20.3 %), indicating strong discriminative capacity but low specificity.

Elevated TNF-α levels are associated with post-TB pulmonary fibrosis and have the potential to serve as a biomarker for its identification. Further studies are warranted to validate these findings and explore TNF-α's role in guiding management strategies for PTLD.