Role of serum procalcitonin in the diagnosis and monitoring of treatment response in treatment-naive subjects with chronic pulmonary aspergillosis

Background: Interferon-gamma (IFN-gamma) down-regulates plasma procalcitonin (PCT), marker of inflammation. Chronic pulmonary aspergillosis (CPA) is associated with low IFN-gamma levels. Thus, plasma PCT may be elevated in CPA and could have a role in diagnosing and monitoring treatment response in CPA. Herein, we investigate the diagnostic performance of plasma PCT in CPA. Methods: We extracted the demographic, clinical, radiological, treatment outcomes, and plasma PCT levels of CPA subjects and controls (previously treated pulmonary tuberculosis with radiological abnormalities on CT chest [diseased controls] and treatment naive active pulmonary tuberculosis [PTB]). We treated CPA subjects with six months of oral itraconazole. We took 0.25 ng/mL as a cut-off value for PCT. The study's primary objective was to ascertain the diagnostic performance of PCT in diagnosing CPA. The key secondary outcome was to study the change in the plasma PCT levels after itraconazole therapy. Results: We included 190 CPA cases and 40 controls (diseased controls [n = 20] and active PTB [n = 20]). PCT was elevated (>= 0.25 ng/mL) in only 7 (3.7%) subjects with CPA. The sensitivity and specificity of PCT (>= 0.25 ng/mL) were 3.7% (1.5-7.4%) and 100 (91.2-100%), respectively. The area under the curve for plasma PCT was 0.48 (95% confidence interval, 0.39-0.58). The plasma PCT values were available in 93 subjects at six months. There was a significant decline in the median plasma levels of PCT after treatment; however, the PCT levels either increased or remained the same in 45% of the subjects.

Automated summary

This study investigated the diagnostic performance of plasma procalcitonin (PCT) in chronic pulmonary aspergillosis (CPA). The results showed that the proportion of elevated PCT in CPA patients was very low, with a sensitivity of only 3.7% and a specificity of 100%. After treatment, the plasma PCT levels decreased in some patients, but 45% of the patients had an increase or no change in PCT levels.