Sex-specific impact of obstructive sleep apnea on peripheral blood mononuclear cells

Purpose: Experimental sleep disruption in healthy adults is more deleterious to immune function in females relative to males; however, it remains unknown if this translates to patients with obstructive sleep apnea (OSA). Thus, this study explored sex differences in peripheral blood mononuclear cells (PBMCs) from patients with untreated OSA.

Methods: Participants completed sleep studies to identify the presence of OSA via the apnea-hypopnea index (AHI). PBMCs were isolated, cryopreserved, and batch phenotyped via mass cytometry.

Results: Females with (n = 6, AHI = 25.9 ± 21.4 events/hr, age = 37 ± 14yrs, BMI = 30.5 ± 7.4 kg/m²) and without (n = 9, AHI = 2.6 ± 1.6 events/hr, age = 35 ± 10yrs, BMI = 29.2 ± 6.3 kg/m²) OSA were compared to males with (n = 7, AHI = 13.7 ± 8.5 events/hr, age = 33 ± 11yrs, BMI = 30.0 ± 4.8 kg/m²) and without (n = 7, AHI = 2.6 ± 1.6 events/hr, age = 33 ± 10yrs, BMI = 28.9 ± 3.8 kg/m²) OSA. No significant group-by-sex interactions were observed in CD3 T cells (p = 0.273), CD8 T cells (p = 0.656), B cells (p = 0.190), monocytes (p = 0.638), nor granulocytes (p = 0.267) expressed as a percent of their respective parent population. While the percentage of total NK cells did not differ between groups (group-by-sex p = 0.822), females with OSA had fewer CD57^- (42.4 ± 14.7 vs. 62.4 ± 10.4%) and more CD57⁺ (57.6 ± 14.7 vs. 37.6 ± 10.4%) NK cells than females without OSA (p < 0.050). No differences in CD57^- (53.6 ± 18.1 vs. 44.9 ± 16.8%) and CD57⁺ (46.4 ± 18.1 vs. 55.2 ± 19.8%) NK cells were observed between males (p = 0.283). Tregs were more prevalent in females with vs. females without OSA (2.17 ± 0.64 vs. 1.31 ± 0.41%, p = 0.006) with no difference between males (1.55 ± 0.50 vs. 1.71 ± 0.71%, p = 0.601).

Conclusions: Our data suggest that OSA increases the prevalence of cytotoxic NK cells and Tregs in females. The causes and downstream effects of these changes remain undetermined.