Procalcitonin and Proinflammatory Cytokines in Early Diagnosis of Bacterial Infections after Bronchoscopy

BACKGROUND: Fiberoptic bronchoscopy (FOB) guided bronchoalveolar lavage (BAL) remains as the chief diagnostic tool in respiratory disorders. 1.2-16% of patients frequently experience fever after bronchoscopy. To exclude the need for multiple antibiotic prescribing in patients with post-bronchoscopy fever, the presence of the self-limiting inflammatory responses should be excluded. AIM: The current study was conducted to test the serum of patients undergoing bronchoscopy for some proinflammatory cytokines including Tumor Necrosis Factor-alpha (TNF-ɑ), Interleukin-1beta (IL-1β), Interleukin-8 (IL-8) and Interleukin-6 (IL-6) and the value of Procalcitonin (PCT). MATERIAL AND METHODS: Current case-control study was conducted at the National Research Institute of Tuberculosis and Lung Disease in Iran. Nineteen patients (48.72%) that attended with a reasonable sign for a diagnostic bronchoscopy from January 2016 to December 2017 were included in the case group. The control group consisted of 20 patients who underwent a simple bronchoscopy and without FOB-BAL. The laboratory findings for PCT concentrations and cytokine levels in the three serum samples (before FOB-BAL (t0), after 6 hr. (t1), and at 24 hr. past (t2) FOB-BAL) were compared between two groups. RESULTS: The frequency of post-bronchoscopy fever was 5.12, and the prevalence of post-bronchoscopy infectious fever was 2.56%. PCT level was considerably higher in the patient with a confirmed bacterial infection when compared to other participants (p-value < 0. 05). Interestingly, IL-8 level in the bacterial infection proven fever patient was higher than in other patients (p < 0.001). IL-8 levels displayed a specificity of 72.7% and a sensitivity of 100%, at the threshold point of 5.820 pg/ml. PCT levels had a specificity of 84% and a sensitivity of 81%, at the threshold point of 0.5 ng/ml. CONCLUSION: The present findings show that in patients with fever after bronchoscopy, PCT levels and IL-8 levels are valuable indicators for antibiotic therapy, proving adequate proof for bacterial infection. The current findings also illustrate that to monitor the serum levels of PCT and proinflammatory cytokines in the patients undergoing FOB-BAL, the best time is the 24-hour postoperative bronchoscopy.