Pharyngeal Lavage Lymphocytosis in Patients with Obstructive Sleep Apnea: A Preliminary Observation

Background: Upper airway inflammation has been previously demonstrated in obstructive sleep apnea (OSA). However, investigation has been hampered by the necessity of invasive tissue biopsies. Objective: To evaluate the pharyngeal lavage (PHAL) as a new tool to analyze mucosal inflammation in the pharynx of patients with sleep-related disordered breathing. Patients and Methods: 36 patients with a diagnosis of OSA, 14 patients with heavy snorer syndrome (HS) or body position dependent OSA (bd-OSA), and 14 healthy volunteers underwent PHAL. Inflammatory cell counts were compared. Results: Neutrophils were the predominant cells in PHAL in all groups (94.3%60.7%, 98.5%60.6%, 94.3%60.7%, and 96.2%61.4%). OSA patients had significantly increased numbers of lymphocytes (3.2%60.4%) compared to bd-OSA/HS and controls group (0.5%60.1 % and 0.6%60.2%, respectively; P,0.05). Patients with moderate to severe OSA had significantly higher numbers of lymphocytes compared to patients with mild OSA (P,0.05). Conclusions: Data from this study suggest that PHAL is a feasible tool to investigate upper airway inflammation in OSA. In addition, PHAL demonstrates lymphocytic inflammation of the pharynx in OSA patients. Future studies are warranted to evaluate whether PHAL can be used to monitor disease and whether lymphocytic inflammation is affected by OSA treatment

Microscopy of pharyngeal lavage showing neutrophils (A) and squamous cells and lymphocytes (B).

<p>Hemacolor fats stain. Original magnification x400.</p

Demographic characteristics of patient groups and controls.

<p>OSA: Obstructive sleep apnea. Bd-OSA: body-dependent OSA. HS: heavy snorer. RDI: respiratory distress index. ODI: oxygen desaturation index. ESS: Epworth sleepiness scale.</p><p>*: P<0.05 vs OSA.</p

Numbers of lymphocytes according to severity of OSA.

<p>Dots represent individual values. Lines represent mean values. *: P<0.05 vs mild OSA. +: P<0.05 vs mild, moderate and sever OSA.</p