Serum 25-hydroxyvitamin D concentrations and waning pneumococcal antibody titers among individuals with atopy

Vitamin D receptor and STAT6 interactome governs oesophageal epithelial barrier responses to IL-13 signalling

OBJECTIVE

The contribution of vitamin D (VD) deficiency to the pathogenesis of allergic diseases remains elusive. We aimed to define the impact of VD on oesophageal allergic inflammation.

DESIGN

We assessed the genomic distribution and function of VD receptor (VDR) and STAT6 using histology, molecular imaging, motif discovery and metagenomic analysis. We examined the role of VD supplementation in oesophageal epithelial cells, in a preclinical model of IL-13-induced oesophageal allergic inflammation and in human subjects with eosinophilic oesophagitis (EoE).

RESULTS

VDR response elements were enriched in oesophageal epithelium, suggesting enhanced VDR binding to functional gene enhancer and promoter regions. Metagenomic analysis showed that VD supplementation reversed dysregulation of up to 70% of the transcriptome and epigenetic modifications (H3K27Ac) induced by IL-13 in VD-deficient cells, including genes encoding the transcription factors HIF1A and SMAD3, endopeptidases (SERPINB3) and epithelial-mesenchymal transition mediators (TGFBR1, TIAM1, SRC, ROBO1, CDH1). Molecular imaging and chromatin immunoprecipitation showed VDR and STAT6 colocalisation within the regulatory regions of the affected genes, suggesting that VDR and STAT6 interactome governs epithelial tissue responses to IL-13 signalling. Indeed, VD supplementation reversed IL-13-induced epithelial hyperproliferation, reduced dilated intercellular spaces and barrier permeability, and improved differentiation marker expression (filaggrin, involucrin). In a preclinical model of IL-13-mediated oesophageal allergic inflammation and in human EoE, VD levels inversely associated with severity of oesophageal eosinophilia and epithelial histopathology.

CONCLUSIONS

Collectively, these findings identify VD as a natural IL-13 antagonist with capacity to regulate the oesophageal epithelial barrier functions, providing a novel therapeutic entry point for type 2 immunity-related diseases.

Relationship between asthma status and antibody response pattern to 23-valent pneumococcal vaccination

Objective: Asthma poses an increased risk for serious pneumococcal disease, but little is known about the influence of asthma status on the 23-valent serotype-specific pneumococcal antibody response. We examined differences in antibody titers between pre- and post-vaccination with 23-valent pneumococcal polysaccharide vaccine (PPSV-23) in relation to asthma status. Methods: Asthma status was retrospectively ascertained by the Predetermined Asthma Criteria in an existing vaccine cohort through comprehensive medical record review. Twenty-three serotype-specific pneumococcal antibody titers measured at baseline and 4-6 weeks post-vaccination were analyzed. Vaccine responses to PPSV-23 were calculated from pre- to post-vaccine titers for each of the serotypes. Results: Of the 64 eligible and enrolled subjects, 18 (28%) had asthma. Controls (i.e., subjects without asthma) demonstrated a statistically significant fold change response compared to their baseline for all serotypes, while those with asthma did not mount a significant response to serotypes 7F, 22F, and 23F. The overall vaccine response as measured by fold change over baseline was lower in subjects with asthma than controls. Conclusions: Poorer humoral immune responses to PPSV-23 as measured by fold change were more likely to be observed in subjects with asthma compared to controls. We recommend the consideration of asthma status when interpreting vaccine response for immune competence workup through larger studies. Further studies are warranted to replicate these findings.

Is Nasal Polyposis Related to Levels of Serum Vitamin D and Vitamin D Receptor Gene Expression?

BACKGROUND Nasal polyposis (NP) is the most frequent cause of nasal masses. Despite considerable research on the subject, its etiology has not been fully elucidated, and effective treatment methods have not been developed. Some etiological factors causing low or high expression of genes in genetically predisposed individuals may play a role in the pathogenesis of the disease. The purpose of this study was to assess the relation between levels of vitamin D receptor (VDR) gene expression and serum vitamin D with NP. MATERIAL AND METHODS The study included 46 subjects with NP (NP group) and 40 volunteers (control group). Nasal polyp tissue samples were taken from the NP group and nasal mucosa samples were taken from the control group. Levels of VDR gene expression in the tissue samples were assessed using the real-time polymerase chain reaction (RT-PCR) method. RESULTS Mean serum 25(OH)D levels were 13.38±14.08 ng/ml in the NP group and 10.57±6.44 ng/ml in the control group (p=0.249). VDR gene expression was present in 17.5% of the NP group and 3.3% of the control group, and the difference between the 2 groups was statistically significant (likelihood ratio χ²=3.887; p=0.049). CONCLUSIONS This is the first study to assess levels of VDR gene expression in subjects with NP. Our results suggest that VDR gene expression may be associated with the pathogenesis or progression of NP.

Plasma vitamin D levels of patients with allergic rhino-conjunctivitis with positive skin prick test

BACKGROUND

Allergic rhino-conjunctivitis (ARC) and allergic rhinitis are inflammatory diseases that develop through immunoglobulin E in the rhino-ocular mucosa due to allergy. The main symptoms are runny nose, nasal congestion, sneezing, itchy nose, and conjunctivitis.

OBJECTIVE

This study was designed to evaluate plasma 25-hydroxyvitamin D levels in patients with ARC.

STUDY DESIGN

This study was planned as a prospective and cross sectional study. This study was performed in a tertiary referral center.

METHODS

This observational study involved 42 patients with ARC and 35 consecutive, age- and sex-matched healthy subjects. Patients in both groups underwent skin-prick test. Plasma 25-hydroxyvitamin D levels of all subjects were quantified with electrochemiluminescence technique. Results were compared between the groups and p < 0.05 was considered as statistically significant.

RESULTS

Group one included 42 ARC patients (15 male, 27 female, ages between 12 and 43, average age 25.7 ± 8.6); group two included 35 healthy people (15 male, 20 female, ages between 12 and 44, average age 26.9 ± 9.1). Plasma 25-hydroxyvitamin D levels of the subjects with ARC group (7.33 ± 3.61 ng/mL, standard error mean: 0.55, range 3.17-13.68 ng/mL) were significantly lower than the control group (13.37 ± 5.42 ng/mL, standard error mean: 0.91, range 6.84-25.92 ng/mL) (p = 0.010, Independent-Samples test).

CONCLUSIONS

We found lower plasma vitamin D levels in patients with ARC when compared with the control group.

Vitamin D as an adjunctive therapy in asthma. Part 2: A review of human studies

Vitamin D deficiency (VDD) is highly prevalent worldwide, with adverse effects on bone health but also potentially other unfavorable consequences. VDD and asthma-incidence/severity share many common risk factors, including winter season, industrialization, poor diet, obesity, dark skin pigmentation, and high latitude. Multiple anatomical areas relevant to asthma contain both the enzyme responsible for producing activated vitamin D and the vitamin D receptor suggesting that activated vitamin D (1,25-dihydroxyvitamin D) may have important local effects at these sites. Emerging evidence suggests that VDD is associated with increased airway hyperresponsiveness, decreased pulmonary function, worse asthma control, and possibly decreased response to standard anti-asthma therapy. However the effect is inconsistent with preliminary evidence from different studies suggesting vitamin D is both beneficial and detrimental to asthma genesis and severity. Current evidence suggests that supplementation with moderate doses of vitamin D may be appropriate for maintenance of bone health in asthmatics, particularly steroid users. However emerging data from an increasing number of randomized, controlled, intervention studies of vitamin D supplementation in pediatric and adult asthma are becoming available and should help determine the importance, if any of vitamin D for asthma pathogenesis. The purpose of this second of a two-part review is to review the current human literature on vitamin D and asthma, discussing the possible consequences of VDD for asthma and the potential for vitamin D repletion as adjunct therapy.

Serum vitamin D levels are positively associated with varicella zoster immunity in chronic dialysis patients

Uremia results in a relatively immunocompromised status, and patients under chronic dialysis have an elevated risk of developing herpes zoster (HZ). We sought to investigate the relationship between vitamin D status and immunity to varicella-zoster virus (VZV). A multicenter prevalent hemodialysis cohort was assembled between 2012 and 2013. We assayed the biochemical parameters, 25-hydroxy- (25-OH-D) and 1,25-dihydroxyvitamin D, vitamin D-binding protein levels in the sera. VZV immunity was quantitated using VZV-specific glycoprotein IgG and IgM titers. Eighty-eight patients were enrolled and their sera were analyzed. Chronic hemodialysis patients with 25-OH-D < 30 ng/ml (insufficiency or deficiency) had significantly lower VZV-IgG than those with sufficient 25-OH-D (p = 0.04). This discrepancy became more prominent if active vitamin D users alone were analyzed (p = 0.01). Generalized additive modeling showed that those with 25-OH-D higher than 27.8 ng/ml or bioavailable 25-OH-D higher than 3.88 ng/ml had significantly higher VZV-IgG levels than those with lower values. Linear regression suggested that both total and bioavailable 25-OH-D were significantly associated with higher VZV-IgG levels (p = 0.003 [total] and 0.01 [bioavailable]), whereas patients with cancer had lower VZV-IgG. Vitamin D may therefore be a potentially useful choice for raising VZV immunity in chronic dialysis patients.

Risks for infection in patients with asthma (or other atopic conditions): is asthma more than a chronic airway disease?

Most of the research effort regarding asthma has been devoted to its causes, therapy, and prognosis. There is also evidence that the presence of asthma can influence patients' susceptibility to infections, yet research in this aspect of asthma has been limited. There is additional debate in this field, with current literature tending to view the increased risk of infection among atopic patients as caused by opportunistic infections secondary to airway inflammation, especially in patients with severe atopic diseases. However, other evidence suggests that such risk and its underlying immune dysfunction might be a phenotypic or clinical feature of atopic conditions. This review argues (1) that improved understanding of the effects of asthma or other atopic conditions on the risk of microbial infections will bring important and new perspectives to clinical practice, research, and public health concerning atopic conditions and (2) that research efforts into the causes and effects of asthma must be juxtaposed because they are likely to guide each other.