Study of upper airway inflammation in patients with obstructive sleep apnea–hypopnea syndrome

Abstract

Background Pharyngeal lavage was reported as a novel technique for noninvasive assessment of inflammation of the pharynx. Aim To study upper airway inflammation in patients with obstructive sleep apnea–hypopnea syndrome (OSAHS) and its correlation with systemic inflammation. Patients and methods A total of 36 patients with known OSAHS, admitted to the Chest Department, Alexandria Main University Hospital (group I), and 15 healthy volunteers (group II) were enrolled into the study. Informed consent was taken from all participants. The two groups underwent complete history taking, assessment of BMI, measurement of serum C-reactive protein (CRP), overnight polysomnography, and oropharyngeal lavage (OPL) analysis. Results In group I, the most prevalent cell type of OPL was lymphocytes followed by neutrophils. Compared with control group (group II), the most prevalent cell type in OPL was macrophages followed by epithelial cells. Regarding the OPL differential cell count which denotes local pharyngeal inflammation, there was a statistically significant difference between both groups (P<0.001). Similarly, CRP, a marker of systemic inflammation, showed a significant statistical difference between both groups (P<0.001). Strikingly, there was no statistically significant correlation between CRP and apnea–hypopnea index (P=0.604). Snoring, apnea–hypopnea index, and other sleep parameters correlated significantly with lymphocytic predominance in OPL (P<0.001), whereas CRP correlates significantly with neutrophils and eosinophil’s in OPL (P<0.001 and P=0.015, respectively). Conclusion Our study had provided a novel vision into the pathophysiology of OSAHS in emphasizing the existence of upper airway lymphocytic inflammation. OPL is a simple, applicable, and easy noninvasive procedure for assessment of upper airway inflammation.