Persistently high plasma procalcitonin levels despite successful treatment of tuberculous pleuritis and tuberculous lymphadenitis patients.

In a prospective cohort study, we evaluated plasma PCT levels in 48 TB lymphadenitis (TBLN) and 41 TB pleuritis (TBPE) patients. Measurements of PCT were done in unstimulated plasma of microbiologically and clinically confirmed TBLN and TBPE patients registered for anti-TB treatment at a tertiary care hospital in Lahore, Pakistan. Plasma levels of PCT were found to be raised in 89% of the patients at baseline with a median of 1.5 ng/ml. Levels were higher (p = 0.001) in TBLN as compared to TBPE (2.69, 0.96 ng/ml). PCT levels were not related to the bacterial burden depicted by culture positivity in these patients. PCT showed a negative correlation with the severity of constitutional symptoms (rho = - 0.238, p = 0.034), and inflammatory biomarkers; ferritin (rho = - 0.43, p < 0.001), INF-γ (rho = - 0.314, p = 0.003), TNF-α (rho = - 0.220, p = 0.039), IL-6 (rho = - 0.224, p = 0.035), and several chemokines of CCL and CCXL group. Raised plasma levels of PCT did not decrease with anti-TB treatment, indicating it is not a good biomarker to monitor treatment response in TBLN and TBPE patients. More studies with a larger number of confirmed EPTB cases are needed to define the role of PCT and its interaction with other biomarkers in EPTB.