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    Invariant Natural Killer T Cell Deficiency and Functional Impairment in Sleep Apnea: Links to Cancer Comorbidity


    Gaoatswe, Gadintshware and Kent, Brian D. and Corrigan, Michelle and Nolan, Geraldine and Hogan, Andrew and McNicholas, Walter and O'Shea, Donal (2015) Invariant Natural Killer T Cell Deficiency and Functional Impairment in Sleep Apnea: Links to Cancer Comorbidity. Sleep, 38 (10). pp. 1629-1634. ISSN 0161-8105

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    Abstract

    Study Objectives: Emerging evidence links obstructive sleep apnea (OSA) with increased cancer incidence and mortality. Invariant natural killer T (iNKT) cells play an important role in cancer immunity. We hypothesized that patients with OSA have low number of circulating invariant natural killer T (iNKT) cells, which may also be functionally impaired. This study aims to evaluate the frequency of circulating iNKT cells in OSA. Design: We evaluated the frequency of circulating iNKT cells by flow cytometry in 33 snorers being assessed for possible OSA. Using iNKT cell lines, we also evaluated the effect of exposure to hypoxia over 24 hours on apoptosis, cytotoxicity, and cytokine production. Setting: Teaching hospital based sleep unit and research laboratory. Patients: Thirty-three snorers were evaluated: 9 with no OSA (apnea-hypopnea frequency [AHI] < 5/h), 12 with mild-moderate OSA (AHI 5–30) and 12 with severe OSA (AHI > 30). Measurements and Results: Patients with severe OSA had considerably fewer iNKT cells (0.18%) compared to patients with mild-moderate (0.24%) or no OSA (0.35%), P = 0.0026. The frequency of iNKT cells correlated negatively with apnea-hypopnea index (r = −0.58, P = 0.001), oxygen desaturation index (r = −0.58, P = 0.0003), and SpO2% < 90% (r = −0.5407, P = 0.005). The frequency of iNKT cells increased following 12 months of nCPAP therapy (P = 0.015). Hypoxia resulted in increased apoptosis (P = 0.016) and impaired cytotoxicity (P = 0.035). Conclusion: Patients with obstructive sleep apnea (OSA) have significantly reduced levels of circulating invariant natural killer T (iNKT) cells and hypoxia leads to impaired iNKT cell function. These observations may partly explain the increased cancer risk reported in patients with OSA.

    Item Type: Article
    Keywords: obstructive sleep apnea; invariant natural killer T cells; cancer; cytotoxicity;
    Academic Unit: Faculty of Science and Engineering > Biology
    Item ID: 12411
    Identification Number: https://doi.org/10.5665/sleep.5062
    Depositing User: Andrew Hogan
    Date Deposited: 13 Feb 2020 12:09
    Journal or Publication Title: Sleep
    Publisher: Oxford University Press
    Refereed: Yes
    URI:

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