Background
Identification of proinflammatory factors responding to Mycobacterium tuberculosis is important to reduce long-term sequelae of pulmonary tuberculosis (TB).
Methods
We examined the association between plasma biomarkers, the fraction of exhaled nitric oxide (FeNO), and lung function among a prospective cohort of 105 newly diagnosed TB/HIV adults in South Africa. Participants were followed for 48 weeks from ART initiation with serial assessments of plasma biomarkers, FeNO, lung function, and respiratory symptoms. Linear regression and generalized estimating equations were used to examine the associations at baseline and over the course of TB treatment, respectively.
Results
At baseline, higher FeNO levels were associated with preserved lung function, while greater respiratory symptoms and higher interleukin (IL)-6 plasma levels were associated with worse lung function. After ART and TB treatment initiation, improvements in lung function were associated with increases in FeNO (rate ratio [RR]=86mL, 95% Confidence Interval [CI]=34,139) and decreases in IL-6 (-118mL, 95%CI=-193, -43) and VEGF (-178mL, 95%CI=-314, -43).
Conclusions
Circulating IL-6, VEGF and FeNO are associated with lung function in adults being treated for TB/HIV. These biomarkers may help identify individuals at higher risk for post-TB lung disease and elucidate targetable pathways to modify the risk of chronic lung impairment among TB survivors.