In the preantibiotic era, TB of the skin was treated successfully with UV light. By the 1920s, pulmonary TB was being treated with regular sun exposure. During the last decade, basic laboratory research into the antimicrobial actions of vitamin D has provided new insights into these historical observations. Vitamin D has a critical role in the innate immune system through the production of antimicrobial peptides - particularly cathelicidin. Vitamin D would appear to have an important role in respiratory tract, skin and potentially gut health. A number of autoimmune diseases, including multiple sclerosis, Type I diabetes, systemic lupus erythematosus and rheumatoid arthritis, are associated with vitamin D deficiency. Vitamin D could have an important role in the prevention and possible treatment of these conditions; however, much of the current evidence relates to basic science and epidemiological research. In many situations, appropriate double-blind, randomized controlled trial data to guide clinicians treating infectious and autoimmune disease is still lacking.

Introduction: At the turn of the twentieth century, ultraviolet light was successfully used to treat tuberculosis of the skin. Upper respiratory tract infections had been inversely associated with sun exposure. During the last decade, basic scientific research demonstrated that vitamin D has an important anti-infective role.Method: Review of the relevant literature on the influence of vitamin D on innate immunity and respiratory tract infection.Results: Vitamin D is involved in the production of defensins and cathelicidin – antimicrobial peptides that provide a natural defence against potential microbiological pathogens. Vitamin D supplementation increases cathelicidin production. Low vitamin D levels are associated with an increased incidence of upper respiratory tract infections.Conclusions: Vitamin D appears to play an important role in the regulation of innate immunity in the upper respiratory tract. Optimal vitamin D levels and appropriate dosing schedules have yet to be determined.

Despite the occurrence of the nasal cycle being well documented, the functional purpose of this phenomenon is not well understood. This investigation seeks to better understand the physiological objective of the nasal cycle in terms of airway health through the use of a computational nasal air-conditioning model. A new state-variable heat and water mass transfer model is developed to predict airway surface liquid (ASL) hydration status within each nasal airway. Nasal geometry, based on in-vivo magnetic resonance imaging (MRI) data is used to apportion inter-nasal air flow. The results demonstrate that the airway conducting the majority of the airflow also experiences a degree of ASL dehydration, as a consequence of undertaking the bulk of the heat and water mass transfer duties. In contrast, the reduced air conditioning demand within the other airway allows its ASL layer to remain sufficiently hydrated so as to support continuous mucociliary clearance. It is quantitatively demonstrated in this work how the nasal cycle enables the upper airway to accommodate the contrasting roles of air conditioning and the removal of entrapped contaminants through fluctuation in airflow partitioning between each airway.

Bacterial biofilms have been implicated in the pathogenesis of chronic rhinosinusitis. In the laboratory setting, ultrasound is effective in disrupting such biofilms; however, few clinical studies have evaluated the role of therapeutic ultrasound in chronic rhinosinusitis. This study was performed to investigate the short-term effectiveness of therapeutic ultrasound as a treatment modality for chronic rhinosinusitis. Twenty-two patients with a positive history of chronic rhinosinusitis, according to the criteria set out by the Rhinosinusitis Task Force, together with a previous computed tomography scan compatible with a diagnosis of chronic rhinosinusitis, and who had failed previous, aggressive medical management, were treated with therapeutic pulsed ultrasound at 1 MHz two to three days per week for six sessions. Patients completed an assessment of individual sinus symptom severity and the 20-Item Sino-Nasal Outcome Test questionnaire before treatment, prior to session four and after completion of session six. Two patients were unable to complete the study protocol. After completion of session six, 18 patients had experienced improvement in symptoms, while two patients noted a worsening of symptoms. Median percentage improvement of the total overall symptom score was 16.7 per cent (Wilcoxon signed rank, p < 0.001). The 20-Item Sino-Nasal Outcome Test score improved by 34.1 per cent (Wilcoxon signed rank, p < 0.0001). This study demonstrated a significant improvement in chronic rhinosinusitis symptoms after a six-session course of pulsed ultrasound therapy. Treatment with ultrasound alone or combined with antibiotics may provide a strategy to target biofilms on the sinus mucosa. Therapeutic ultrasound warrants further investigation as a potential treatment modality for chronic rhinosinusitis.