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

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.

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.

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).

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.