RESUMO
Background: Vitamin D3 (VitD3) is known to have immunomodulatory functions, and VitD3 deficiency is associated with more severe asthma. Objective: We aimed to assess the immunoregulatory effects of VitD3 food supplementation on asthma manifestation, with particular focus on T cells and type 2 innate lymphoid cells. Methods: Preschool children and adult asthmatic cohorts were analyzed in the context of VitD3 supplementation and serum levels. In a murine model of ovalbumin-induced asthma, effects of diet VitD3 sufficiency and deficiency on T cells and type 2 innate lymphoid cells immune mechanisms were investigated. Results: We found less severe and better-controlled asthma phenotypes along with reduced need for steroid medication in preschool children and asthmatic adults with VitD3 supplementation. VitD3 serum levels correlated with B lymphocyte-induced maturation protein 1 (Blimp-1) expression in blood peripheral mononuclear cells. VitD3-supplement-fed mice showed decreased asthmatic traits, with a decrease in IgE serum levels, reduced airway mucus, and increased IL-10 production by lung cells. Furthermore, we discovered an upregulation of effector T cells and Blimp-1+ lung tissue-resident memory T cells as well as induction of anti-inflammatory Blimp-1+ lung innate lymphoid cells producing IL-10. Conclusion: Supplementing VitD3 resulted in amelioration of clinical asthma manifestations in human studies as well as in experimental allergic asthma, indicating that VitD3 shifts proinflammatory immune responses to anti-inflammatory immune responses via upregulating Blimp-1 in lung innate lymphoid cells and tissue-resident memory cells.
RESUMO
BACKGROUND: Investigation of preschool asthma is important since not all children outgrow their illness during this age. Data are scarce on the role of rhinovirus (RV) infections in this patient group. OBJECTIVES: To investigate the role of RV infections in preschool asthma: (i) susceptibility factors, (ii) clinical course, and (iii) medium-term outcome. METHODS: A total of 130 asthmatic children aged 4-6 years from the multinational PreDicta cohort were prospectively followed for a 12-month period. Allergy tests and a standard health questionnaire were carried out at study entry. Respiratory virus presence in nasopharyngeal washes was studied at illness visits and at 3 scheduled visits. RESULTS: At study entry, mean age of the children was 5.3 years. Of 571 visits, 54% were positive for any virus and 39% for RV. Patient characteristics were only assessed with RV infection due to low number of other viruses. The use of supplementary vitamin D was inversely associated with RV infection (P < .05). RV infection was associated with more severe course of acute illness in terms of more severe nighttime coughing, more sleep disturbances, and more days with runny nose (all P < .05). RV infection was also associated with more severe disease course during the 12-month follow-up in terms of more nights with awakenings and more days of exercise-related symptoms (both P < .05). CONCLUSIONS: Vitamin D supplementation may have an anti-rhinovirus effect. Both short- and medium-term outcomes suggest RV infection to be an important clinical marker of instable preschool asthma.