Obstructive sleep apnea syndrome (OSAS) represents a substantial disease of recurrent sleep fragmentation, leading to intermittent hypoxia and subsequent diseases such as cardiovascular, metabolic, or cognitive dysfunctions. In addition, OSAS is considered as low-grade systemic inflammation, which is associated with a higher incidence of cancer, severity of infections, and an overall immune dysregulation. This research project aims to comprehensively investigate the interplay of wholesome sleep and the immune functions of circulating monocytes and T cells in OSAS patients, which are known to be affected by oxidative stress. We studied the distribution of the CD14/CD16 characterized monocyte subsets in peripheral blood as well as their PD-L1 expression and complex formation with T cells. Furthermore, a detailed analysis of T cell subsets with regard to their PD-1 and PD-L1 expression was performed. Data revealed a decrease of classical monocytes accompanied by an increase of both CD16 + monocyte subsets in OSAS patients that was positively correlated with the body mass index. OSAS patients revealed an increased PD-1 and PD-L1 expression in T cells and monocytes, respectively, which was linked to the severity of monocyte subset alterations. The complex formation of monocytes and T cells was also elevated in OSAS patients, which indicates a deregulated PD-1/PD-L1 cross-talk between these cells. Our data show for the first time, to our knowledge, massive alterations of peripheral monocyte subsets in response to OSAS and its accompanying phenomena.

Superparamagnetic iron oxide nanoparticles (SPIONs) are currently under examination for magnetic particle imaging, which represents a radiation free technology for three-dimensional imaging with high sensitivity, resolution and imaging speed. SPIONs are rapidly taken up by monocytes and other phagocytes which carry them to the site of inflammation. Therefore, the SPION biocompatibility is an essential parameter for a widespread MPI usage. Many improvements are expected from SPION development and its applications for cell visualization, but the impact of MPI optimized dextran coated SPIONs on the cellular characteristics of monocytic cells has been poorly studied up to now. THP-1 monocytes, monocyte-derived macrophages (MDM) as well as peripheral blood monocytes were incubated with MPI-optimized dextran-coated SPIONs of a size between 83.5 and 86 nm. SPION uptake was measured by FITC fluorescence of labeled SPIONs and Prussian blue staining. The activation of monocytes and MDMs was evaluated by CD14, CD11b and CD86 in flow cytometry. The secretion of IL-1β, and IL-10 was analyzed in supernatants. SPIONs were rapidly taken up by monocytes and monocyte-derived macrophages while no decrease in cell viability was observed. Expression patterns of CD11b, CD14, and CD86 were not affected in THP-1 monocytes and MDMs. Monocyte differentiation in macrophages was hindered during SPION uptake. THP-1 monocytes as well as monocyte-derived macrophages showed significantly increased IL-1β and decreased IL-10 secretion by tendency after SPION treatment. Dextran-coated SPIONs showed a low cytotoxicity on monocytes but exert undesirable inflammatory side effects that have to be considered for imaging applications.

Obstructive sleep apnea (OSA) is characterized by nocturnal breathing intermissions resulting in oxidative stress and eventually, a low-grade systemic inflammation. The study aimed to investigate the impact of positive airway pressure (PAP) therapy on the inflammatory milieu as measured by monocyte and T cell phenotypic alterations. Participants were assessed for their OSA severity before PAP therapy and about six months later, including patient-reported outcome and therapy usage by telemetry readout. The distributions of the CD14/CD16-characterized monocyte subsets as well as the CD4/CD8-characterized effector T cell subsets with regard to their PD-1 and PD-L1 expression were analyzed by flow cytometry from blood samples. Data of 25 patients revealed a significant reconstitution of the monocyte subset distribution and a decrease in PD-L1 expression on pan-monocytes and CD8+ T cells without an association to initial AHI and overweight. The PD-1 expression was still increased on T cell subsets, especially on CD4+ TH17/22 cells. We conclude that PAP therapy might have a rapid effect on the monocyte phenotype and overall PD-L1 expression levels. However, T cell immune alterations especially on TH17/22 cells persist longer, indicating an ongoing disturbance of the adaptive immune system.

Head and neck squamous cell carcinoma (HNSCC) represents a heterogeneous malignant disease of the oral cavity, pharynx, and larynx. Although cigarette smoking, alcohol abuse, and aging are well-established associated factors for HNSCC, their respective influence on immunologic alterations of monocyte subsets or T-cell compositions in the peripheral blood has not yet been fully unveiled. Using flow cytometry, whole blood measurements of CD14/CD16 monocyte subsets and analyses of T-cell subsets in isolated PBMC fractions were carried out in 64 HNSCC patients in view of their tobacco and alcohol consumption, as well as their age, in comparison to healthy volunteers. Flow cytometric analysis revealed significantly increased expression of monocytic CD11b, as well as significantly decreased expression levels of CX3CR1 on classical and intermediate monocyte subsets in smoking-related and in alcohol-related HNSCC patients compared to healthy donors. Peripheral monocytes revealed an age-correlated significant decrease in PD-L1 within the entirety of the HNSCC cohort. Furthermore, we observed significantly decreased abundances of CD8+ effector memory T cells in active-smoking HNSCC patients and significantly increased percentages of CD8+ effector T cells in alcohol-abusing patients compared to the non-smoking/non-drinking patient cohort. Our data indicate an enhanced influence of smoking and alcohol abuse on the dynamics and characteristics of circulating monocyte subsets and CD4/CD8 T-cell subset proportions, as well as an age-related weakened immunosuppression in head and neck cancer patients.

This paper provides a brief historical background of saline nasal irrigation (SNI), main modes of SARS-COV-2 transmission and entry, and anti-infective properties of saline. It reviews the protective evidence associated with SNI and gargling against viral upper respiratory tract infection (URTI). SARS-CoV-2 presents as an URTI transmitted mainly via respiratory droplets and aerosols to the oro-nasal mucosa and indirectly after touching these entry sites from contaminated fomites. It can potentially be transmitted from the conjunctival mucosa to the nasal mucosa or from resuspension and inhalation from the facial area around the nose. SNI has antiviral, anti-inflammatory and mucociliary restorative properties. Numerous randomized controlled trials have reported that SNI, with and without gargling, prevents and treats viral URTI. Based on biological rationale and anecdotal evidence we suggest a protocol: Soap and Water to the Hands and Face-Eye Rinse Nasal Irrigation and Gargling with Saline (SWHF-ERNIGS) may limit the transmission SARS-CoV-2, and prevent and treat COVID-19 infection. Clinical considerations of the protocol are presented. The protocol is safe, straightforward and can be easily performed by healthcare workers and the general public; it uses readily available salt, water and soap. Formal studies of effectiveness and application of the protocol are warranted.