Salivary proinflammatory cytokines and airway bacterial infection in Bronchiectasis

<b>Introduction:</b> Increased pulmonary proinflammatory cytokines relate to chronic airway infection in bronchiectasis. However, cytokine salivary levels and their relationship with sputum levels and bronchial infection have not been investigated before. <b>Aim:</b> To determine if proinflammatory cytokines in saliva relate to their concentration in sputum and/or the presence of airway infection in patients with bronchiectasis. <b>Methods:</b> 172 patients with clinically stable bronchiectasis (mean age 69±12, FEV1 72±23% of predicted value and Bronchiectasis Severity Index 6.4±3.7) were included in the study. Airway infection was defined by the isolation of potentially pathogenic bacteria at ≥103 cfu/ml in sputum samples. Unstimulated saliva samples were collected. At the same time, spontaneous sputum samples were processed from 68 patients. TNF-α, IL-1β, IL-8 and IL-17A levels were measured in saliva and sputum supernatants by Luminex. Salivary cytokine levels were adjusted to salivary total protein using Qubit fluorometer. <b>Results:</b> Salivary TNF-α levels were increased in patients with airway infection (0.06±0.1 vs 0.02±0.02 p=0.03), especially when P.aeruginosa was isolated compared to other pathogenic bacteria (0.09±0.02 vs 0.03±0.04 p=0.03). A weak but statistically significant association between salivary and sputum TNF-α exists (rho=0.24 p=0.04). No association between salivary IL-1β, IL-8 and IL-17A, airway bacterial infection and sputum levels was found. <b>Conclusion:</b> Salivary TNF-α may be useful to study airway bacterial infection in bronchiectasis, particularly by P.aeruginosa, albeit further studies are needed to determine the role of salivary biomarkers in bronchiectasis. <i>*Supported by SEPAR, SOCAP and FUCAP.</i>&nbsp;