Delineating the Significance of Several Inflammatory Markers in a Lung Tuberculosis Cohort During the Active and Post-Tuberculosis Stages of the Disease: An Observational Study in Cape Town, South Africa (2019 to 2024)

Background Pulmonary tuberculosis (TB) frequently leads to long-term lung complications that contribute to increased mortality. Understanding the pathogenesis of post-TB lung impairments is crucial for improving long-term outcomes in TB patients; yet this area remains poorly researched. Methods Our study assessed circulatory inflammatory markers in patients who completed TB treatment more than one year before enrolment (population 1) and patients receiving in-hospital treatment for active drug-sensitive TB (population 2). Results IL-6 was seven times higher in both populations compared to the normal range. IL-8 was below the limit of detection (LOD) in population 1, while it was approximately 2.5 times higher in population 2 compared to the normal range. TNF-α was 21 times higher in population 1 and 19 times higher in population 2 compared to the normal range. CRP was almost 49 times higher in both populations, and IL-1Ra was below the LOD in population 1, while it was ~1.5 times higher in population 2 compared to the normal range. Conclusions These inflammatory biomarkers correlated well with lung function in the post-TB state, and their high levels suggest a persistent pro-inflammatory state post-TB, which may contribute to post-TB lung disease. More research is warranted to better understand this phenomenon, but these findings may highlight a need to consider anti-inflammatory therapy for patients with post-TB lung disease, especially since these high levels of cytokines can directly contribute to lung damage.