Vitamin D and its role in allergic disease

Evaluation of the Impact of Serum Vitamin D Levels on the Scoring Atopic Dermatitis Index in Pediatric Atopic Dermatitis

Atopic dermatitis (AD) is a chronic and recurrent inflammatory skin condition characterized by itching, eczematous plaques, and dry skin. Despite ongoing research, its exact cause remains elusive. In this study, we aimed to explore the factors that influence the severity of AD in children and assess the relationship between serum vitamin D levels and the disease's severity. We enrolled 96 AD patients in our investigation, evaluated their clinical condition using the Scoring Atopic Dermatitis (SCORAD) index, and compared them to a group of 90 healthy controls. Our analysis revealed that serum vitamin D levels and eosinophil counts significantly impacted the SCORAD index (p < 0.001). According to standardized regression coefficients, for each incremental unit in serum vitamin D levels, the SCORAD index exhibited a decrease of 0.449 units. Similarly, a one-unit increase in eosinophil count resulted in a 0.009 unit increase in the SCORAD index. It is worth noting that the influence of serum vitamin D levels on disease severity surpasses that of eosinophil counts and atopic conditions. In our patient cohort, we uncovered a negative correlation (r = -0.419, p < 0.001) between serum vitamin D levels and the SCORAD index. Our findings suggest that low serum vitamin D levels may have a more substantial impact on AD severity than atopic conditions and eosinophilia. Furthermore, we observed a negative association between the severity of AD and serum 25(OH)D3 levels.

Treating allergies via skin - Recent advances in cutaneous allergen immunotherapy

Subcutaneous allergen immunotherapy has been practiced clinically for decades to treat airborne allergies. Recently, the cutaneous route, which exploits the immunocompetence of the skin has received attention, which is evident from attempts to use it to treat peanut allergy. Delivery of allergens into the skin is inherently impeded by the barrier imposed by stratum corneum, the top layer of the skin. While the stratum corneum barrier must be overcome for efficient allergen delivery, excessive disruption of this layer can predispose to development of allergic inflammation. Thus, the most desirable allergen delivery approach must provide a balance between the level of skin disruption and the amount of allergen delivered. Such an approach should aim to achieve high allergen delivery efficiency across various skin types independent of age and ethnicity, and optimize variables such as safety profile, allergen dosage, treatment frequency, application time and patient compliance. The ability to precisely quantify the amount of allergen being delivered into the skin is crucial since it can allow for allergen dose optimization and can promote consistency and reproducibility in treatment response. In this work we review prominent cutaneous delivery approaches, and offer a perspective on further improvisation in cutaneous allergen-specific immunotherapy.

The Effect of Serum Vitamin D Level on Allergic Rhinitis Symptoms in Children

Background: Allergic rhinitis (AR) is a chronic disease that is becoming increasingly common worldwide and has a negative impact on school performance, work performance, and quality of life. The aim of this study was to investigate the effect of vitamin D on the symptoms of AR in children. Methods: Serum vitamin D levels of children with AR and age-matched healthy controls were compared using the high-pressure liquid chromatography method. The relationship between serum vitamin D levels and symptoms and severity of AR was then examined. Results: The study included 137 patients diagnosed with AR (76 males, 61 females; median age: 11 years). Serum vitamin D levels were lower in the patient group than in the control group (P = 0.001), lower in all aeroallergen groups (mites, pollen, and multiple inhalants) than in the healthy control group (P = 0.001), and lower in both the perennial AR group and the seasonal AR group than in the control group (P = 0.001). Spearman correlation analysis showed that there was no correlation between symptom score and vitamin D level (r_s = -0.099; P = 0.25). Conclusions: We found no correlation between serum vitamin D level and symptoms and severity of AR. Serum vitamin D levels were lower in children with AR than in healthy children.

Maternal serum 25-hydroxyvitamin D levels and infant atopic dermatitis: A prospective cohort study

BACKGROUND

Maternal vitamin D status during pregnancy has been linked with the risk of atopic dermatitis (AD) in children, while the results were inconsistent. The objective of this study was to assess the potential association.

METHODS

Serum 25-hydroxyvitamin D (25(OH)D) levels were measured in pregnant women from the birth cohort MKFOAD. Infant AD was diagnosed according to Williams' criteria. Multivariate logistic regression model was used to examine the association of maternal serum 25(OH)D levels in the first, second, and third trimester of gestation with the risk of infant AD at first year of age.

RESULTS

In total, 121 (26.5%) of 456 infants developed AD prior to 1 year of age. In general, higher maternal serum 25(OH)D levels throughout pregnancy were associated with increased risks of AD in infants prior to 1 year of age in multivariate logistic regression models, with borderline statistical significance in the first (per ln unit increase: adjusted OR = 1.93, 95% CI: 0.96, 3.88) and second (per ln unit increase: adjusted OR = 1.72, 95% CI: 0.93, 3.19) trimester. Multivariate logistic regression models using categorical variables of maternal 25(OH)D levels by tertiles showed similar results: Infants born to mothers with serum 25(OH)D levels in the highest tertile had higher risk of AD than those with 25(OH)D in the lowest tertile.

CONCLUSIONS

The present study found some evidence supporting that higher maternal 25(OH)D levels during pregnancy increased the risk of infant AD. However, the clinical implication of the findings should be limited for those with blood levels over the recommendations.

Dietary Vitamin D Supplementation Is Ineffective in Preventing Murine Cow's Milk Allergy, Irrespective of the Presence of Nondigestible Oligosaccharides

INTRODUCTION

Cow's milk allergy (CMA) is one of the most common food allergies especially early in life. A mixture of nondigestible short-chain galacto-oligosaccharides, long-chain fructo-oligosaccharides, and pectin-derived acidic-oligosaccharides (GFA) may reduce allergy development and allergic symptoms in murine CMA. Recently, vitamin D (VitD) has been suggested to have beneficial effects in reducing allergy as well.

OBJECTIVE

In this study, the immune modulatory effect on allergy prevention using the combination of GFA and VitD was investigated.

METHODS

Female C3H/HeOuJ mice were fed a control or GFA-containing diet with depleted, standard (1,000 IU/kg), or supplemented (5,000 IU/kg) VitD content for 2 weeks before and during whey sensitization (n = 10-15). Mice were sensitized 5 times intragastrically with PBS as a control, whey as cow's milk allergen, and/or cholera toxin as adjuvant on a weekly interval. One week after the last sensitization, mice were intradermally challenged in both ear pinnae and orally with whey, subsequently the acute allergic skin response and shock symptoms were measured. After 18 h, terminal blood samples, mesenteric lymph nodes, and spleens were collected. Whey-specific immunoglobulin (Ig) E and IgG1 levels were measured by means of ELISA. T cell subsets and dendritic cells (DCs) were studied using flow cytometry.

RESULTS

Additional VitD supplementation did not lower the allergic symptoms compared to the standard VitD diet. CMA mice fed the GFA diet supplemented with VitD (GFA VitD+) significantly decreased the acute allergic skin response of whey sensitized mice when compared to the CMA mice fed VitD (VitD+) group (p < 0.05). The effect of GFA was not improved by extra VitD supplementation even though the CMA mice fed the GFA VitD+ diet had a significantly increased percentage of CD103+ DCs compared to the VitD+ group (p < 0.05). The VitD-deprived mice showed a high percentage of severe shock and many reached the humane endpoint; therefore, these groups were not further analyzed.

CONCLUSIONS

High-dose VitD supplementation in mice does not protect against CMA development in the presence or absence of GFA.

Serum Vitamin D Level and Body Mass Index in Children with Vernal Keratoconjunctivitis

OBJECTIVES

The purpose of this study was to evaluate the body mass index (BMI) value and serum 25-hydroxyvitamin D [25(OH)D3] level in children with vernal keratoconjunctivitis (VKC).

METHODS

A total of 40 healthy, non-atopic children (control group) and 46 children with VKC (study group) were included in the study. The serum vitamin D [25(OH)D3] levels and BMI values were measured and compared between the 2 groups.

RESULTS

The mean vitamin D level measured in the healthy children (mean: 19.01±5.66 ng/mL, range: 9-33.09 ng/mL) was significantly different from the mean vitamin D level in the VKC-affected children (mean: 14.06±5.02 ng/mL, range 4.37-31 ng/mL) (p<0.001). The mean BMI in the VKC group (17.1±2.5 kg/m²) was significantly higher than the mean BMI of the healthy children (mean: 16.5±2.3 kg/m²; p=0.046). A negative correlation (Spearman's rho=-0.275; p=0.01) was observed between the vitamin D level and the BMI value.

CONCLUSION

The results indicated that children with VKC had a lower serum vitamin D level and a higher BMI value compared with healthy, age- and sex-matched children.

Budesonide up-regulates vitamin D receptor expression in human bronchial fibroblasts and enhances the inhibitory effect of calcitriol on airway remodeling

INTRODUCTION AND OBJECTIVES

Transforming growth factor β1 (TGFβ1) and dysregulated microRNA-21 (miR-21) expression is associated with TGFβ/Smad signaling pathway activation and fibrosis. While calcitriol has been shown to improve airway remodeling in asthmatic mice, its mechanism remains unknown. In this study, the effect of calcitriol on the TGFβ/Smad signaling pathway and miR-21 expression in human bronchial fibroblasts was investigated to explore the mechanism of action of calcitriol and the inhaled glucocorticoid, budesonide, in airway remodeling.

MATERIALS AND METHODS

Human bronchial fibroblasts were pretreated with budesonide, calcitriol, or budesonide plus calcitriol, and stimulated with TGFβ1 for 48h. Quantitative real-time PCR was used to determine the expression of miR-21. Western blot was used to determine airway remodeling-related proteins, TGFβ/Smad signaling pathway-related proteins, glucocorticoid receptor, and vitamin D receptor (VDR) expression.

RESULTS

Both budesonide and calcitriol down-regulated miR-21 expression in human bronchial fibroblasts, up-regulated Smad7 expression, and inhibited the expression of airway remodeling-related proteins. Both budesonide and calcitriol up-regulated the low expression of VDR induced by TGFβ1 in human bronchial fibroblasts. The expression of VDR in the combined treatment group (budesonide plus calcitriol) was significantly higher than that in the calcitriol treatment group. The expression of collagen type I in the combined treatment group was significantly lower than that in the calcitriol treatment group.

CONCLUSIONS

Calcitriol can up-regulate the expression of VDR in human bronchial fibroblasts and exert an anti-airway remodeling effect. Budesonide can up-regulate the expression of VDR in human bronchial fibroblasts and enhance the inhibitory effect of calcitriol on airway remodeling.

The unpredictability of seasonal variations in serum vitamin D levels in children with asthma and/or rhinitis

BACKGROUND

Some studies have showed that seasonality is an important determinant of vitamin D (vitD) status.

OBJECTIVE

We evaluated whether there are differences in individual trends of serum vitD level over one year in asthmatic and rhinitic children.

MATERIALS AND METHODS

Ninety-two asthmatic and rhinitic paediatric patients were followed up for one year and their serum vitD level was detected at three-month intervals, once in each season.

RESULTS

We observed higher vitD levels at the end of summer and lower at the end of winter. However, the individual seasonal trend was very variable and unpredictable. If it is true that in a given season the majority of patients followed one direction (increase or decrease of serum vitD levels), nevertheless a substantial percentage behaved differently and unpredictably. For example, at the end of spring, 70% of patients showed an increase in serum vitD levels, but 30% showed a decrease. In addition, five individuals had a value ≥50ng/ml in September and showed serum vitD levels ≥30ng/ml throughout the year; 16 patients presented vitD value ≥40ng/ml in September and always had ≥20ng/ml in the other months.

CONCLUSIONS

The wide and unpredictable variability of the individual trend of serum vitD levels should be taken into account before deciding whether or not a drug supplementation is appropriate.

Dose-response association between vitamin D deficiency and atopic dermatitis in children, and effect modification by gender: a case-control study

BACKGROUND

Vitamin D is a regulatory factor for immunity and skin barrier functions. It is hypothesized to be linked to atopic dermatitis (AD) which is characterized by interaction between epidermal barrier dysfunction and dysregulation of skin immune functions.

METHODS

One hundred AD patients and one hundred and one normal controls were collected from outpatient clinic based on their clinical condition, both had measurement of 25-hydroxyvitamin D [25(OH)D]. We assessed the relationship between 25(OH)D deficiency and AD prevalence using adjusted Poisson regression model.

RESULTS

Serum 25(OH)D levels were significantly lower in cases than controls (mean 35.1 versus 22.6 ng/mL, p < .001). The unadjusted prevalence ratios (PRs) (95% CI) for AD for comparing participants with intermediate and deficient vitamin D levels to those with optimal levels were 3.11 (1.91, 5.06) and 4.77 (2.99, 7.60), respectively. The association did not materially change after adjusting for potential confounders. In the fully adjusted analysis stratified by gender, PRs for AD for comparing male participants with intermediate and deficient vitamin D levels to those with optimal levels were 3.38 (1.21, 9.40) and 5.20 (1.91, 14.13), respectively, whereas in the female participants were 1.32 (0.96, 1.83) and 1.49 (1.04, 2.14), respectively (p-interaction <.001).

CONCLUSION

In this case-control study in children, we found a statistically significant dose-response association between vitamin D deficiency and AD. We also observed a statistically significant effect modification of this association by gender. Further research is recommended to study this association longitudinally, and to examine whether treating vitamin D deficiency may potentially improve AD. Key points Question: Can atopic dermatitis be associated with vitamin D deficiency? Finding: Serum 25(OH)D levels were significantly lower in cases with AD than in controls. Prevalence ratios for comparing male participants with intermediate and deficient vitamin D levels to those with optimal levels were 3.38 (1.21, 9.40) and 5.20 (1.91, 14.13), respectively, whereas in the female participants were 1.32 (0.96, 1.83) and 1.49 (1.04, 2.14), respectively (p-interaction <.001). Meaning: vitamin D deficiency is associated with AD in children, effect modification of this association by gender was also observed.

Vitamin D status of very low birth weight infants at birth and the effects of generally recommended supplementation on their vitamin D levels at discharge

Purpose: To evaluate vitamin D status in mothers and their very low birth weight infants (VLBW) at birth (umbilical cord blood) and at discharge with currently recommended supplementation of vitamin D.Methods: Ninety-four infants with birth weight less than 1500 g completed the study. The total daily vitamin D intake was 800-1000 IU. We examined 25-hydroxyvitamin-D [25(OH)D] levels in maternal serum before labor, in cord blood, and in infants' serum at discharge.Results: Median (IQR) serum 25(OH)D was 21 (14-36) nmol/l [8 (6-15) ng/ml] in cord blood, and 46 (37-60) nmol/l [18 (15-24) ng/ml] at discharge. Serum 25(OH)D was <50 nmol/L in 71.3% of mothers, in 91.5% of cord blood samples, and in almost 60% of preterm newborns at discharge (after 8 weeks of supplementation). Serum 25(OH)D was <75 nmol/L in 88.3% of mothers, in 97.9% of cord blood samples, and in 91.4% of preterm newborns at discharge.Conclusions: In our cohort, we found that due to the very high prevalence of 25(OH)D deficiency among mothers, the current generally recommended dose of vitamin D (800-1000 IU per day) for VLBW infants was unable to improve vitamin D levels above the desired 50 or even 75 nmol/L before discharge.

An evaluation of vitamin D levels in children with seasonal allergic rhinitis during pollen season

BACKGROUND

Serum vitamin D levels have not been studied in children with seasonal allergic rhinitis (SAR). The aim of this study was to evaluate the vitamin D levels of children with SAR and to compare them to levels in healthy children during pollen season.

METHODS

This study was conducted in 100 children with SAR and 100 healthy controls. Clinical and laboratory evaluations and vitamin D analyses of all the participants were performed between the months of April and July. Pollen sensitization was detected in the patient group using a skin prick test. 25(OH)D₃ levels were compared between the patient and control groups. Associations among the patient 25(OH)D₃ levels and their demographic, clinical, and laboratory characteristics were analyzed.

RESULTS

Overall, 72% of the patients were male, the median age was 12.35 years (range: 6-17.8 years), and the median body mass index value was 19.15 (range: 13.6-27.8). There were no differences between the patients and healthy controls in terms of gender, age, or body mass index. The mean levels of 25(OH)D₃ (20.78±6) in patients were higher than those of the controls (17.92±4). In the patient group, no associations were found among 25(OH)D₃ levels, demographic characteristics, atopy test results, atopy history, severity of rhinitis, and the total four symptoms score (all P>.05).

CONCLUSIONS

During pollen season, children with SAR may have higher vitamin D levels than healthy controls. The presence of asthma and/or atopic dermatitis in addition to SAR did not change this result.

Towards evidence-based vitamin D supplementation in infants: vitamin D intervention in infants (VIDI) - study design and methods of a randomised controlled double-blinded intervention study

BACKGROUND

Vitamin D is important for bone mass accrual during growth. Additionally, it is considered a requirement for a multitude of processes associated with, for example, the development of immunity. Many countries apply vitamin D supplementation strategies in infants, but the guidelines are not based on scientific evidence and aim at prevention of rickets. It remains unclear whether the recommended doses are sufficient for the wide array of other effects of vitamin D. The VIDI trial performed in Finland is the first large randomised controlled study for evaluation of the effects of different vitamin D supplemental doses in infancy on: 1. bone strength 2. infections and immunity 3. allergy, atopy and asthma 4. cognitive development 5. genetic regulation of mineral homeostasis METHODS/DESIGN: VIDI, a randomised controlled double-blinded single-centre intervention study is conducted in infants from the age of 2 weeks to 24 months. Participants, recruited at Helsinki Maternity Hospital, are randomised to receive daily either 10 μg (400 IU) or 30 μg (1 200 IU) of vitamin D3 supplementation. Both groups are assessed at 6 months of age for calcium homeostasis, and at 12 and 24 months of age for parameters associated with bone strength, growth, developmental milestones, infections, immunity, atopy-related diseases, and genetic factors involved in these functions.

DISCUSSION

The study enables evaluation of short and long term effects of supplemental vitamin D on growth, immune functions and skeletal and developmental parameters in infants, and the effects of genetic factors therein. The results enable institution of evidence-based guidelines for vitamin D supplementation in infancy.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01723852 , registration date 6.11.2012.

Vitamin D regulates immunoglobulin mucin domain molecule-4 expression in dendritic cells

BACKGROUND

Dendritic cell (DC)-derived immunoglobulin domain molecule (TIM)4 plays a critical role in the initiation of T helper (Th)2 polarization. Vitamin D (VitD) involves the regulation of a number of immune responses.

OBJECTIVES

This study tests a hypothesis that VitD regulates TIM4 expression in DCs.

METHODS

Peripheral blood samples were collected from patients with allergic rhinitis (AR) and healthy subjects. DCs were isolated from the samples and analyzed for the expression of TIM4.

RESULTS

We observed that the levels of calcitriol, the active form of VitD3, in the sera of AR patients were lower than that in healthy subjects. The peripheral DC expressed higher levels of TIM4 and lower levels of VDR. A negative correlation was identified between the data of serum calcitriol and TIM4 in DCs. Exposure DCs to calcitriol in the culture increased the expression of VDR. We also found that VDR bound to the TIM4 promoter locus in DCs to repress the TIM4 gene transcription and expression.

CONCLUSIONS AND CLINICAL RELEVANCE

VitD deficiency may contribute to the pathogenesis of AR by increasing the TIM4 expression. The results suggest that to regulate the serum calcitriol levels and the expression of VDR in DCs may be necessary to be taken into account in the treatment of AR.

World Allergy Organization-McMaster University Guidelines for Allergic Disease Prevention (GLAD-P): Vitamin D

BACKGROUND

The prevalence of allergic diseases is approximately 10 % in infants whose parents and siblings do not have allergic diseases and 20-30 % in those with an allergic first-degree relative. Vitamin D is involved in the regulation of the immune system and it may play a role in the development, severity and course of asthma and other allergic diseases.

OBJECTIVE

The World Allergy Organization (WAO) convened a guideline panel to develop evidence-based recommendations addressing the use of vitamin D in primary prevention of allergic diseases.

METHODS

Our WAO guideline panel identified the most relevant clinical questions and performed a systematic review of randomized controlled trials and non-randomized studies (NRS), specifically cohort and case-control studies, of vitamin D supplementation for the prevention of allergic diseases. We also reviewed the evidence about values and preferences, and resource requirements (up to January 2015, with an update on January 30, 2016). We followed the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to develop recommendations.

RESULTS

Having reviewed the currently available evidence, the WAO guideline panel found no support for the hypothesis that vitamin D supplementation reduces the risk of developing allergic diseases in children. The WAO guideline panel suggest not using vitamin D in pregnant women, breastfeeding mothers, or healthy term infants as a means of preventing the development of allergic diseases. This recommendation does not apply to those mothers and infants who have other indications for prophylactic or therapeutic use of vitamin D. The panel's recommendations are conditional and supported by very low certainty evidence.

CONCLUSIONS

WAO recommendations about vitamin D supplementation for the prevention of allergic diseases support parents, clinicians and other health care professionals in their decisions whether or not to use vitamin D in preventing allergic diseases in healthy, term infants.

Serum Vitamin D Levels Not Associated with Atopic Dermatitis Severity

BACKGOUND/OBJECTIVES

The objective of the current study was to determine the relationship between serum vitamin D levels and the severity of atopic dermatitis (AD) in a Brazilian population.

METHODS

This was a cross-sectional study of patients younger than 14 years of age seen from April to November 2013. All patients fulfilled the Hanifin and Rajka Diagnostic Criteria for AD diagnosis. Disease severity was determined using the SCORing Atopic Dermatitis index and classified as mild (<25), moderate (25-50), or severe (>50). Serum vitamin D levels were classified as sufficient (≥30 ng/mL), insufficient (29-21 ng/mL), or deficient (≤20 ng/mL).

RESULTS

A total of 105 patients met the inclusion criteria. Mild AD was diagnosed in 58 (55.2%) children, moderate in 24 (22.8%), and severe in 23 (21.9%). Vitamin D deficiency was observed in 45 individuals (42.9%). Of these, 24 (53.3%) had mild AD, 13 (28.9%) moderate, and 8 (17.7%) severe. Insufficient vitamin D levels were found in 45 (42.9%) individuals; 24 (53.3%) had mild AD, 9 (20.0%) moderate, and 12 (26.7%) severe. Of the 15 individuals (14.2%) with sufficient vitamin D levels, 10 (60.7%) had mild AD, 2 (13.3%) moderate, and 3 (20.0%) severe. The mean vitamin D level was 22.1 ± 7.3 ng/mL in individuals with mild AD, 20.8 ± 6.5 ng/mL in those with moderate AD, and 21.9 ± 9.3 ng/mL in those with severe AD. Variables such as sex, age, skin phototype, season of the year, and bacterial infection were not significantly associated with vitamin D levels.

CONCLUSION

Levels of 25-hydroxyvitamin D were deficient or insufficient in 85% of the children, but serum vitamin D concentrations were not significantly related to AD severity.

Vitamin D serum levels in children with allergic and vasomotor rhinitis

Purpose

In addition to regulating calcium and phosphorus homeostasis and bone metabolism, vitamin D is known as an immune modulator. Recently, there has been increased worldwide interest in the association between low levels of vitamin D and allergic diseases. The purpose of this study was to assess the relationship between serum vitamin D levels and allergic/vasomotor rhinitis (AR/VR) in children.

Methods

This study included 164 patients. The sample included 59 patients with AR, 42 patients with VR, and 63 controls. Their ages ranged from 0 to 16 years. We examined the levels of 25-hydroxyvitamin D, Immunoglobulin E, specific IgE, and eosinophil cationic protein; peripheral blood eosinophil count; and the results of a skin prick test.

Results

Serum 25-hydroxyvitamin D levels were 19.0±8.5 ng/mL in the AR group, 25.5±10.9 ng/mL in the VR group, and 26.9±10.7 ng/mL in the control group. After adjustment for body mass index and season at the time of blood sampling, vitamin D levels in the AR group were lower than those of the VR group (P=0.003) and control group (P<0.001). Vitamin D levels were inversely correlated with Immunoglobulin E levels (r=-0.317, P<0.001). AR patients with food allergy or atopic dermatitis did not have lower levels of 25-hydroxyvitamin D than AR patients without these diseases.

Conclusion

This study demonstrates a possible relationship between vitamin D levels and allergic rhinitis in Korean children.

Vitamin D and the development of allergic disease: how important is it?

Vitamin D has known effects on lung development and the immune system that may be important in the development, severity, and course of allergic diseases (asthma, eczema, and food allergy). Vitamin D deficiency is prevalent worldwide and may partly explain the increases in asthma and allergic diseases that have occurred over the last 50-60 years. In this review, we explore past and current knowledge on the effect of vitamin D on lung development and immunomodulation and present the evidence of its role in allergic conditions. While there is growing observational and experimental evidence for the role of vitamin D, well-designed and well-powered clinical trials are needed to determine whether supplementation of vitamin D should be recommended in these disorders.

Modified allergens and their potential to treat allergic disease

Allergen-specific immunotherapy is the only treatment of allergic diseases that aims at modifying the underlying immune mechanism. Current protocols are long and at risk of anaphylactic reactions. The main aim of current research is decreasing the risk of side effects and increasing efficacy, in particular targeting reduction of treatment duration. Since the advent of molecular biology, extracts can be replaced by recombinant hypo-allergens, peptides, or fusion proteins. In addition, different routes of administration are being pursued as well as the addition of new adjuvants that are targeted at skewing the immune system away from a Th2 to a more Th1 or regulatory T cell phenotype. In this review, we summarize the recent advances in this field focusing on the allergen modifications and new adjuvants.

Environmental and genetic determinants of vitamin D insufficiency in 12-month-old infants

We aimed to investigate the relationship between genetic and environmental exposure and vitamin D status at age one, stratified by ethnicity. This study included 563 12-month-old infants in the HealthNuts population-based study. DNA from participants' blood samples was genotyped using Sequenom MassARRAY MALDI-TOF system on 28 single nucleotide polymorphisms (SNPs) in six genes. Using logistic regression, we examined associations between environmental exposure and SNPs in vitamin D pathway and filaggrin genes and vitamin D insufficiency (VDI). VDI, defined as serum 25-hydroxyvitamin D3(25(OH)D3) level ≤50nmol/L, was measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Infants were stratified by ethnicity determined by parent's country of birth. Infants formula fed at 12 months were associated with reduced odds of VDI compared to infants with no current formula use at 12 months. This association differed by ethnicity (Pinteraction=0.01). The odds ratio (OR) of VDI was 0.29 for Caucasian infants (95% CI, 0.18-0.47) and 0.04 for Asian infants (95% CI, 0.006-0.23). Maternal vitamin D supplementation during pregnancy and/or breastfeeding were associated with increased odds of infants being VDI (OR, 2.39; 95% CI, 1.11-5.18 and OR, 2.5; 95% CI, 1.20-5.24 respectively). Presence of a minor allele for any GC SNP (rs17467825, rs1155563, rs2282679, rs3755967, rs4588, rs7041) was associated with increased odds of VDI. Caucasian infants homozygous (AA) for rs4588 had an OR of 2.49 of being associated with VDI (95% CI, 1.19-5.18). In a country without routine infant vitamin D supplementation or food chain fortification, formula use is strongly associated with a reduced risk of VDI regardless of ethnicity. There was borderline significance for an association between filaggrin mutations and VDI. However, polymorphisms in vitamin D pathway related genes were associated with increased likelihood of being VDI in infancy.

25-Hydroxyvitamin D, IL-31, and IL-33 in children with allergic disease of the airways

Low vitamin D is involved in allergic asthma and rhinitis. IL-31 and IL-33 correlate with Th2-associated cytokines in allergic disease. We investigated whether low vitamin D is linked with circulating IL-31 and IL-33 in children with allergic disease of the airways. 25-Hydroxyvitamin D [25(OH) Vit D], IL-31, and IL-33 plasma levels were measured in 28 controls (HC), 11 allergic rhinitis (AR) patients, and 35 allergic asthma with rhinitis (AAR) patients. We found significant lower levels of 25(OH) Vit D in AR and in AAR than in HC. IL-31 and IL-33 plasma levels significantly increased in AAR than HC. IL-31 and IL-33 positively correlated in AR and AAR. 25(OH) Vit D deficient AAR had higher levels of blood eosinophils, exacerbations, disease duration, and total IgE than patients with insufficient or sufficient 25(OH) Vit D. In AAR 25(OH) Vit D levels inversely correlated with total allergen sIgE score and total atopy index. IL-31 and IL-33 did not correlate with 25(OH) Vit D in AR and AAR. In conclusion, low levels of 25(OH) Vit D might represent a risk factor for the development of concomitant asthma and rhinitis in children with allergic disease of the airways independently of IL-31/IL-33 Th2 activity.

The association between serum vitamin D level and immunoglobulin E in Korean adolescents

OBJECTIVE

Vitamin D has immune modulatory functions, and thus its relationship with allergic disease has been evaluated in a number of studies. However, no concrete link between serum IgE level and vitamin D has been established. Thus, the purpose of study was to confirm the association of serum vitamin D level with the serum IgE (total and Dematophagoides farinae specific IgE) in Korean adolescents.

METHODS

A total of 365 subjects between 10 and 18 years of age were enrolled through the Korea National Health and Nutrition Examination Survey (KNHANES). Serum levels of vitamin D, total IgE, and Dermatophagoides farinae (Df) specific IgE were measured, and data for potential confounding variables were collected. Multivariate regression analyses were used to determine the independent effects of these variables.

RESULTS

Levels of both total and Df specific IgE were positively correlated with serum concentration of vitamin D (Spearman's rho (R)=0.126, p=0.016; R=0.152, p=0.004, respectively). These results were confirmed by multivariate linear regression analysis after adjusting for sex, age, and body mass index (coefficient (B): 10.45 95% confidence interval (CI): 0.59-20.31; B: 1.06, 95% CI: 0.31-1.80, respectively). And, the association between serum vitamin D and IgE showed the different results depending on the presence or absence of Df sensitization.

CONCLUSIONS

Serum concentration of vitamin D was positively associated with levels of both total IgE and Df-specific IgE in Korean adolescents.

Vitamin D deficiency is associated with diagnosis and severity of childhood atopic dermatitis

BACKGROUND

Recent studies implicated the importance of vitamin D in innate immune defense and pathogenesis of allergic diseases. However, the impact of vitamin D deficiency on atopic dermatitis (AD) diagnosis and severity remains unclear. This case-control study investigated such relationship in Hong Kong Chinese children.

METHODS

Serum 25-hydroxyvitamin D [25(OH)D] levels of 498 AD children and 328 non-allergic controls were measured by immunoassay. Subjects were categorized into deficient (< 25 nm), insufficient (25-49.9 nm), and sufficient (≥ 50 nm) groups. Short-term and long-term AD severity was evaluated by physician-diagnosed SCORing Atopic Dermatitis (SCORAD) and Nottingham Eczema Severity Score (NESS), respectively. Atopy biomarkers were also measured for analysis.

RESULTS

The mean (s.d.) serum 25(OH)D levels in AD patients and controls were 28.9 (15.3) and 34.2 (14.5) nm, respectively (p < 0.001). More patients had serum 25(OH)D levels <25 nm than controls (47.8% vs. 26.6%). AD severity as indicated by both SCORAD and NESS showed inverse associations with serum 25(OH)D levels (respective p = 3.6 × 10(-4) and 0.004 when adjusted for age, sex, month of assessment, and immunoassay batch as covariates). Vitamin D-deficient patients (3.08 ± 0.76) had higher logarithm-transformed total IgE than those with insufficient (2.74 ± 0.69) and sufficient (2.72 ± 0.72) serum 25(OH)D levels (p < 0.001). The proportion of subjects with elevated IgE was higher in vitamin D-deficient (43.2%) than vitamin D-sufficient (20.0%) groups.

CONCLUSIONS

Vitamin D deficiency and insufficiency are prevalent in Hong Kong Chinese children. Vitamin D deficiency is associated with childhood AD and high total IgE. Serum 25(OH)D levels correlate inversely with both long- and short-term AD severity.

Vitamin D and maternal and child health: overview and implications for dietary requirements

The essentiality of vitamin D for normal growth and development has been recognized for over 80 years, and vitamin D fortification programs have been in place in the United States for more than 70 years. Despite the above, vitamin D deficiency continues to be a common finding in certain population groups. Vitamin D deficiency has been suggested as a potential risk factor for the development of preeclampsia, and vitamin D deficiency during infancy and early childhood is associated with an increased risk for numerous skeletal disorders, as well as immunological and vascular abnormalities. Vitamin D deficiency can occur through multiple mechanisms including the consumption of diets low in this vitamin and inadequate exposure to environmental ultraviolet B rays. The potential value of vitamin D supplementation in high-risk pregnancies and during infancy and early childhood is discussed. Currently, there is vigorous debate concerning what constitutes appropriate vitamin D intakes during early development as exemplified by differing recommendations from the Institute of Medicine Dietary Reference Intake report and recent recommendations by the Endocrine Society. As is discussed, a major issue that needs to be resolved is what key biological endpoint should be used when making vitamin D recommendations for the pregnant woman and her offspring.

Vitamin D supplementation reduces airway hyperresponsiveness and allergic airway inflammation in a murine model

BACKGROUND

Asthma is a chronic disease associated with airway hyperresponsiveness (AHR), airway obstruction and airway remodelling. NF-κB is a transcriptional factor that regulates and co-ordinates the expression of various inflammatory genes. The NF-κB subunits, p50 and Rel-A, are translocated to the nucleus by importin α3 and importin α4. There is growing evidence that vitamin D is a potent immunomodulator. However, the evidence for beneficial or adverse effects of vitamin D in asthma is still unclear.

OBJECTIVE

In this study, we examined the effect of vitamin D status on AHR, airway inflammation and cytokines in the bronchoalveolar lavage fluid (BALF) in a murine model of allergic asthma.

METHODS

Female BALB/c mice were fed with special vitamin D-deficient or vitamin D-sufficient (2000 IU/kg) or vitamin D-supplemented (10,000 IU/kg) diet for 13 weeks. Mice were sensitized and challenged with ovalbumin (OVA). The effect of vitamin D on lung histology, AHR, T regulatory cells (Tregs) and BALF cytokines was examined. The expression of importin-α3 and Rel-A in the lung of OVA-sensitized mice was analysed using immunofluorescence.

RESULTS

Vitamin D deficiency was associated with higher AHR in OVA-sensitized and challenged mice than those in vitamin D-sufficient mice. This was accompanied with marked signs of airway remodelling, high BALF eosinophilia, increased BALF pro-inflammatory cytokines, reduced BALF IL-10 levels, reduced blood Tregs, increased expression of importin-α3 and Rel-A in the lung tissue. Vitamin D supplementation attenuated the pro-inflammatory effects, but did not completely reverse the features of allergic airway inflammation.

CONCLUSION AND CLINICAL RELEVANCE

Vitamin D could be beneficial as an adjunct therapy in the treatment of allergic asthma.

Two neglected biologic risk factors in bone grafting and implantology: high low-density lipoprotein cholesterol and low serum vitamin D

Following a failure of a bone graft or an implant placement, the hypothesis of a biological abnormality is rarely considered as a possible cause. A systematic search of peer-reviewed literature for dyslipidemia or vitamin D deficiency may explain this lack of consideration. Excess low-density lipoprotein cholesterol (dyslipidemia) is responsible for a slower bone metabolism or lower dental implant osseointegration. In addition, vitamin D is a key factor for linking innate and adaptive immunity. Both of these factors are compromised under the conditions of vitamin D deficiency. Therefore, vitamin D deficiency slows implant osseointegration and increases the risk of graft infection. Vitamin D is also involved in immune function and therefore allergic reactions.

Higher vitamin D intake in preterm infants fed an isocaloric, protein- and mineral-enriched postdischarge formula is associated with increased bone accretion

During the first half of infancy, bone accretion in preterm infants fed an isocaloric, protein- and mineral-enriched postdischarge formula (PDF) is higher compared with those fed term formula (TF) or human milk (HM). This may be related to higher protein, calcium, phosphorus, and vitamin D intakes. This study investigated serum calcium, phosphate, and 25-hydroxyvitamin D [25(OH)D] in relation to bone mineral content (BMC) in PDF-, TF-, and HM-fed preterm infants between term age (40 wk postmenstrual age) and 6 mo corrected age (CA). Between term age and 6 mo CA, 52 preterm infants were fed PDF (per 100 mL: 67 kcal, 1.7 g protein, 65 mg calcium, 38 mg phosphorus, 56 IU vitamin D), 41 were fed TF (per 100 mL: 67 kcal, 1.47 g protein, 50 mg calcium, 30 mg phosphorus, 48 IU vitamin D), and 46 were fed HM. Serum calcium, phosphorus, and 25(OH)D were measured at term age and at 3 and 6 mo CA. BMC (g) was measured by whole-body dual-energy X-ray absorptiometry at term age and at 6 mo CA. Between term age and 6 mo CA, intakes of calcium, phosphorus, and vitamin D were significantly higher in PDF- compared with TF-fed infants, and PDF-fed infants reached significantly higher serum 25(OH)D concentrations at 6 mo CA (103 ± 24.3 vs. 92.8 ± 15.5 nmol/L, P = 0.003). Between term age and 6 mo CA, increases in serum 25(OH)D were associated with an increase in BMC (β = 0.001; 95% CI: 0.00, 0.003; P = 0.046). In conclusion, during the first 6 mo postterm, higher vitamin D intake and greater increase in serum 25(OH)D concentration in PDF-fed preterm infants were associated with increased bone accretion.

Longitudinal trajectory of vitamin D status from birth to early childhood in the development of food sensitization

BACKGROUND

Increasing evidence supports the immunomodulatory effect of vitamin D on allergic diseases. The combined role of prenatal and postnatal vitamin D status in the development of food sensitization (FS) and food allergy remains understudied.

METHODS

Plasma 25-hydroxyvitamin D (25(OH)D) levels of 460 children in the Boston Birth Cohort (BBC) were measured at birth and early childhood, and the subjects were genotyped for rs2243250 (C-590T) in the IL4 gene. We defined FS as specific IgE levels of ≥0.35 kUA/l to any of eight common food allergens; we defined persistently low vitamin D status as cord blood 25(OH)D <11 ng/ml and postnatal 25(OH)D <30 ng/ml.

RESULTS

We observed a moderate correlation between cord blood 25(OH)D at birth and venous blood 25(OH)D measured at 2-3 y (r = 0.63), but a weak correlation at <1 y (r = 0.28). There was no association between low vitamin D status and FS at any single time point alone. However, in combination, persistence of low vitamin D status at birth and in early childhood increased the risk of FS (odds ratio (OR) = 2.03, 95% confidence interval (CI): 1.02-4.04), particularly among children carrying the C allele of rs2243250 (OR = 3.23, 95% CI: 1.37-7.60).

CONCLUSION

Prenatal and early postnatal vitamin D levels, along with individual genetic susceptibility, should be considered in assessing the role of vitamin D in the development of FS and food allergy.

The pathophysiology of the hygiene hypothesis

There has been a considerable increase in the diagnosis of allergic diseases over the last decades. Prevalence of allergies in high-income countries and urban areas appears higher than in rural environments. While environmental factors like pollution or nutrition can be important, it is more likely that in the end they have a small association with allergies. Childhood infections and exposure to certain microbial antigens on the other hand seem to present a strong negative correlation with allergies, and therefore the increase of the allergic burden in the Western world has been frequently related to a decline of childhood infections giving birth to the "Hygiene Hypothesis". We address the issue with emphasis on the associated pathophysiology tightrope walking between the skepticism of the critics, which cast doubt on it, and the pilgrims' belief of having discovered allergy's Holy Grail.

Vitamin D level in children is correlated with severity of atopic dermatitis but only in patients with allergic sensitizations

Vitamin D is believed to affect the progression and severity of atopic dermatitis (AD). Allergic sensitization may cause this effect to vary. Individuals who fulfilled the Hanifin and Rajka criteria for AD underwent epidermal prick tests and blood tests for specific immunoglobulin E(IgE), serum total IgE, 25-hydroxy vitamin D, and peripheral blood eosinophil count and percentage. Disease severity was determined according to the Scoring Atopic Dermatitis (SCORAD) index. Patients were grouped according to allergic sensitization. Seventy-three children with AD (median age 33.0 mos, interquartile range 19.0-61.5 mos) were enrolled in the study; 33 (45.2%) were found to have allergic sensitization. In this group there was a negative correlation between SCORAD score and serum vitamin D level (p = 0.047, correlation coefficient [r] = -0.349), whereas there was no correlation in the group without sensitization (p = 0.30, r = -0.168). Vitamin D was not correlated with total IgE and eosinophil percentage in either AD group (p = 0.77, r = 0.054 and p = 0.73, r = -0.062, respectively). Vitamin D may affect the severity of AD, especially in children with allergic sensitization.

Cathelicidin LL-37: an antimicrobial peptide with a role in inflammatory skin disease

Chronic inflammatory skin diseases such as atopic dermatitis, psoriasis or rosacea are very common. Although their exact pathogenesis is not completely understood all three diseases are characterized by dysregulation of cutaneous innate immunity. Cathelicidin LL-37 is an important effector molecule of innate immunity in the skin and atopic dermatitis, psoriasis or rosacea show defects in cathelicidin expression, function or processing. In atopic dermatitis, cathelicidin induction might be disturbed resulting in defective antimicrobial barrier function. In contrast, psoriasis is characterized by overexpression of cathelicidin. However to date it is unclear whether pro- or anti-inflammatory functions of cathelicidin predominate in lesional skin in psoriasis. In rosacea, cathelicidin processing is disturbed resulting in peptide fragments causing inflammation, erythema and telangiectasias. In this review, the current evidence on the role of cathelicidin LL-37 in the pathogenesis of inflammatory skin diseases will be outlined. As cathelicidin LL-37 might also serve as a future treatment target potential novel treatment strategies for those diseases will be discussed.