The olfactory function in patients with common variable immunodeficiency

Evaluation and treatment of rhinosinusitis with primary antibody deficiency in adults: Evidence-based review with recommendations

BACKGROUND

There is clear evidence that the prevalence of primary antibody deficiency (PAD) is higher in patients with recurrent and chronic rhinosinusitis (CRS) than in the general population. The purpose of this multi-institutional and multidisciplinary evidence-based review with recommendations (EBRR) is to thoroughly review the literature on rhinosinusitis with PAD, summarize the existing evidence, and provide recommendations on the evaluation and management of rhinosinusitis in patients with PAD.

METHODS

The PubMed, EMBASE, and Cochrane databases were systematically reviewed from inception through August 2022. Studies on the evaluation and management of rhinosinusitis in PAD patients were included. An iterative review process was utilized in accordance with EBRR guidelines. Levels of evidence and recommendations on the evaluation and management principles for PAD were generated.

RESULTS

A total of 42 studies were included in this evidence-based review. These studies were evaluated on incidence of PAD in rhinosinusitis patients, incidence of rhinosinusitis in PAD patients, and on the different treatment modalities used and their outcome. The aggregate quality of evidence was varied across reviewed domains.

CONCLUSION

Based on the currently available evidence, PAD can occur in up to 50% of patients with recalcitrant CRS. Despite the presence of multiple studies addressing rhinosinusitis and PAD, the level of evidence supporting different treatment options continues to be lacking. Optimal management requires a multidisciplinary approach through collaboration with clinical immunology. There is need for higher-level studies that compare different treatments in patients with PAD and rhinosinusitis.

Modulation of olfactory signal detection in the olfactory epithelium: focus on the internal and external environment, and the emerging role of the immune system

Detection and discrimination of odorants by the olfactory system plays a pivotal role in animal survival. Olfactory-based behaviors must be adapted to an ever-changing environment. Part of these adaptations includes changes of odorant detection by olfactory sensory neurons localized in the olfactory epithelium. It is now well established that internal signals such as hormones, neurotransmitters, or paracrine signals directly affect the electric activity of olfactory neurons. Furthermore, recent data have shown that activity-dependent survival of olfactory neurons is important in the olfactory epithelium. Finally, as olfactory neurons are directly exposed to environmental toxicants and pathogens, the olfactory epithelium also interacts closely with the immune system leading to neuroimmune modulations. Here, we review how detection of odorants can be modulated in the vertebrate olfactory epithelium. We choose to focus on three cellular types of the olfactory epithelium (the olfactory sensory neuron, the sustentacular and microvillar cells) to present the diversity of modulation of the detection of odorant in the olfactory epithelium. We also present some of the growing literature on the importance of immune cells in the functioning of the olfactory epithelium, although their impact on odorant detection is only just beginning to be unravelled.

Olfactory function in patients with obstructive sleep apnea: a meta-analysis study

PURPOSE

This meta-analysis study was designed to analyze the olfactory function in obstructive sleep apnea patients (OSA).

METHODS

A comprehensive review of the English language literature regarding OSA patients and olfactory function/dysfunction was performed. The papers assessing olfactory dysfunction with Sniffin' Sticks test were taken into consideration.

RESULTS

A total of 420 OSA patients were judged eligible for the study. The average TDI score was found to be 24.3 ± 5.6. The olfactory identification (OD), the olfactory discrimination (OD), and the olfactory threshold (OT) average values were calculated resulting 9.9 ± 2.1, 9.8 ± 1.5, and 5.3 ± 2, respectively. There were 161 healthy control subjects in this meta-analysis. The average TDI of the control group was 30.7 ± 6.0 showing a statistical difference with the group of OSA patients (p = 0.03). A linear correlation between Apnea-Hypopnea Index (AHI) increase and TDI decrease (R² = 0.1, p = 0.05) was detected. Finally, the average values of TDI of 151 patients classified as mild-moderate OSA and 159 patients considered as severe OSA were calculated. The difference between these two groups resulted not statistically significant (p = 0.3).

CONCLUSION

The comparison between OSA patients and healthy subjects using Sniffin' Sticks test showed lower values of the various olfactory parameters. Although a linear correlation between AHI increase and olfactory dysfunction was observed, no statistical difference between mild-moderate and severe OSA patients in terms of the severity of olfactory dysfunction could be proved.