Evidence for a genetic interaction in allergy-related responsiveness to vitamin D deficiency

Vitamin D supplementation and immune-related markers: an update from nutrigenetic and nutrigenomic studies

Vitamin D is both a nutrient and a neurologic hormone that plays a critical role in modulating immune responses. While low levels of vitamin D are associated with increased susceptibility to infections and immune-related disorders, vitamin D supplementation has demonstrated immunomodulatory effects that can be protective against various diseases and infections. Vitamin D receptor is expressed in immune cells that have the ability to synthesise the active vitamin D metabolite. Thus, vitamin D acts in an autocrine manner in a local immunologic milieu in fighting against infections. Nutrigenetics and nutrigenomics are the new disciplines of nutritional science that explore the interaction between nutrients and genes using distinct approaches to decipher the mechanisms by which nutrients can influence disease development. Though molecular and observational studies have proved the immunomodulatory effects of vitamin D, only very few studies have documented the molecular insights of vitamin D supplementation. Until recently, researchers have investigated only a few selected genes involved in the vitamin D metabolic pathway that may influence the response to vitamin D supplementation and possibly disease risk. This review summarises the impact of vitamin D supplementation on immune markers from nutrigenetics and nutrigenomics perspective based on evidence collected through a structured search using PubMed, EMBASE, Science Direct and Web of Science. The research gaps and shortcomings from the existing data and future research direction of vitamin D supplementation on various immune-related disorders are discussed.

GeNuIne (gene-nutrient interactions) Collaboration: towards implementing multi-ethnic population-based nutrigenetic studies of vitamin B12 and D deficiencies and metabolic diseases

Gene-nutrient interactions (GeNuIne) collaboration, a large-scale collaborative project, has been initiated to investigate the impact of gene-nutrient interactions on cardiometabolic diseases using population-based studies from ethnically diverse populations. In this project, the relationship between deficiencies of vitamins B12 and D, and metabolic diseases was explored using a nutrigenetic approach. A genetic risk score (GRS) analysis was used to examine the combined effect of several genetic variations that have been shown to be associated with metabolic diseases and vitamin B12 and D deficiencies, respectively. In Sri Lankan, Indonesian and Brazilian populations, those carrying a high B12-GRS had an increased risk of metabolic diseases under the influence of dietary protein, fibre and carbohydrate intakes, respectively; however, in Asian Indians, genetically instrumented metabolic disease risk showed a significant association with low vitamin B12 status. With regards to nutrigenetic studies on vitamin D status, although high metabolic-GRS showed an interaction with dietary carbohydrate intake on vitamin D status, the study in Indonesian women demonstrated a vitamin D GRS-carbohydrate interaction on body fat percentage. In summary, these nutrigenetic studies from multiple ethnic groups have provided evidence for the influence of the dietary factors on the relationship between vitamin B12/D deficiency and metabolic outcomes. Furthermore, these studies highlight the existence of genetic heterogeneity in gene-diet interactions across ethnically diverse populations, which further implicates the significance of personalised dietary approaches for the prevention of these micronutrient deficiencies and metabolic diseases.

Non-association between low vitamin d levels and aeroallergen-positivity evaluated using multiple allergen simultaneous test in Korean adults

Background

Studies on the association between vitamin D levels and allergen sensitization have reported conflicting results. We aimed to evaluate the association between low vitamin D levels and sensitization to 59 aeroallergens in Korean adults.

Methods

We retrospectively reviewed serum 25-hydroxyvitamin D (25[OH]D) measurements of participants (n = 57,467) in a healthcare center between May 2003 and June 2020. Serum 25(OH)D levels were categorized as follows: severe deficiency (< 10 ng/mL), deficiency (10 to < 20 ng/mL), insufficiency (20 to < 30 ng/mL), and sufficiency (≥ 30 ng/mL). Among all subjects, 1277 simultaneously underwent the multiple allergen simultaneous test. Multiple linear and logistic regression analyses were used to estimate coefficients and odds ratios (ORs) with 95% confidence interval (CI) for the association between serum vitamin D deficiency and aeroallergen sensitization after adjustment for potential confounders. Subgroup analyses were conducted for the types of aeroallergen (house dust mites, pollens, animal dander, foods, cockroach, and fungus).

Results

Vitamin D deficiency, defined as serum 25(OH)D level < 20 ng/mL, was noted in 56.4% of participants. There were significant differences in serum 25(OH)D levels according to sex, age, season, and bone mineral density (all P < 0.001). In multiple linear regression analyses, serum 25(OH)D levels were significantly lower in young subjects (adjusted coefficient [95% CI], 0.188 [0.101, 0.275]) and during winter (− 4.114 [− 6.528, − 1.699]). However, no significant association was observed between serum 25(OH)D levels and allergen sensitization (adjusted coefficients [95% CI], − 0.211 [− 1.989, 1.567], P = 0.816). In multivariate logistic regression analyses, male sex, young age, and winter season were significant risk factors for vitamin D deficiency. However, allergen sensitization showed no significant association with 25(OD)D levels after adjusting for confounders (adjusted OR [95% CI], 1.037 [0.642, 1.674] in insufficiency; 0.910 [0.573, 1.445] in deficiency; 0.869 [0.298, 2.539] in severe deficiency groups, P for trend = 0.334). There were consistent findings across subgroups regarding type of aeroallergen sensitized.

Conclusion

Vitamin D deficiency was prevalent but was not significantly associated with aeroallergen sensitization in Korean adults. To the best of our knowledge, this is the first large-scale study to evaluate the association between vitamin D deficiency and sensitization to 59 different aeroallergens.

Genetic polymorphisms in vitamin D pathway influence 25(OH)D levels and are associated with atopy and asthma

Background

Vitamin D deficiency or insufficiency, has been associated with atopy and lack of asthma control. Our objective was to investigate associations between variants in genes of vitamin D pathway with serum levels of 25-hydroxyvitamin D (25(OH)D), atopy, asthma and asthma severity in teenagers from Northeast Brazil.

Methods

This is a cross sectional study nested in a cohort population of asthma. 25(OH)D was quantified from 968 of 11–17 years old individuals by ELISA. Asthma diagnosis was obtained by using the ISAAC Phase III questionnaire. Specific IgE was determined by ImmunoCAP; genotyping was performed using the 2.5 HumanOmni Biochip from Illumina. Statistical analyses were performed in PLINK 1.07 and SPSS 22.1.

Results

After quality control, 104 Single Nucleotides Variants (SNVs) in vitamin D pathway genes, typed in 792 individuals, were included in the analysis. The allele A of rs10875694 on VDR was positively associated with atopy (OR = 1.35; 95% CI 1.01–1.81). The allele C of rs9279 on VDR, was negatively associated with asthma risk (OR = 0.66; 95% CI 0.45–0.97), vitamin D insufficiency (OR = 0.78; 95% CI 0.70–0.96) and higher VDR expression. Two variants in VDR were associated with asthma severity, the allele A of rs2189480 (OR = 0.34; 95% CI 0.13–0.89) and the allele G of rs4328262 (OR = 3.18; 95% CI 1.09–9.28). The combination of variants in CYP2R1 and CYP24A1 (GAC, to rs10500804, rs12794714 and rs3886163, respectively) was negatively associated with vitamin D production (β = − 1.24; 95% CI − 2.42 to − 0.06).

Conclusions

Genetic variants in the vitamin D pathway affect vitamin D serum levels and, thus, atopy and asthma.

Vitamin D over the first decade and susceptibility to childhood allergy and asthma

BACKGROUND

Vitamin D (25(OH)D) deficiency has been implicated as a possible risk factor for asthma development, but studies at selected time points measuring 25(OH)D levels during childhood have yielded conflicting findings. Prospective studies tracking 25(OH)D levels during the initiation phase of asthma in early childhood have not been reported.

OBJECTIVE

We sought to elucidate relationships between 25(OH)D levels from birth to age 10 years and susceptibility to allergic sensitization, respiratory tract infections, and asthma.

METHODS

Asthma-, allergy-, and respiratory tract infection-associated phenotypes (including pathogen identification) were characterized in a high-risk birth cohort. Plasma 25(OH)D concentrations were quantified at birth and at clinical follow-ups at the ages of 0.5, 1, 2, 3, 4, 5, and 10 years, and relationships with clinical outcomes were examined.

RESULTS

Cross-sectional analyses demonstrated inverse associations between 25(OH)D concentrations and the risk for concurrent sensitization at age 0.5, 2, and 3 years, and mixed-effects regression demonstrated inverse longitudinal associations of 25(OH)D levels with both sensitization and eczema. Multivariate regression modeling suggested that the number of 25(OH)D-deficient follow-ups was positively associated with risk for asthma/wheeze, eczema, and sensitization at 10 years; adjustment for sensitization (particularly by 2 years) in the asthma/wheeze models reduced 25(OH)D associations with these latter outcomes. 25(OH)D levels were also inversely associated with early nasopharyngeal colonization with Streptococcus species and age of first febrile lower respiratory illness, both of which are known asthma risk factors.

CONCLUSION

25(OH)D deficiency in early childhood is associated with increased risk for persistent asthma, potentially through modulating susceptibility to early allergic sensitization, upper respiratory tract colonization with bacterial pathogens, or both. These relationships are only evident if 25(OH)D status is monitored prospectively and longitudinally.

Epidemiology of food allergy and food-induced anaphylaxis: is there really a Western world epidemic?

PURPOSE OF REVIEW

Food-induced anaphylaxis continues to be an important cause of hospital admissions, particularly in children. This review outlines recent advances in understanding the epidemiology of IgE-mediated food allergy and potential mechanisms for its rise in prevalence.

RECENT FINDINGS

The rise in food allergy prevalence in Western countries has happened more quickly than changes to the genome can occur; thus, environmental changes are likely to be important. Recent studies, however, suggest that genetic risk determines responses to environmental risk factors. Environmental peanut exposure has been associated with increased peanut allergy risk in individuals with filaggrin null mutations, consistently with sensitization occurring through a damaged skin barrier. Reduced microbial and vitamin D exposure is also leading candidates for risk factors for food allergy in the context of genetic susceptibility. In addition, HLA-DR and HLA-DQ gene region variants appear to play a role in peanut allergy, although no studies have yet assessed their susceptibility to environmental cues. Finally, findings from observational cohorts and the first large-scale intervention trials for food allergy prevention support early oral allergen exposure to reduce the prevalence of specific food allergies, which is informing changes in public health guidelines at the population level. Further research will be required to assess the impact of these guideline changes on the population prevalence of food allergy.

SUMMARY

New studies are providing important insights into the prevalence, causes, and mechanisms of food allergy. Recent findings are informing changes to population health guidelines in developed countries, which have the potential to halt or reverse the increase in food allergy prevalence. By contrast, food allergy in the developing world remains understudied.

Polymorphisms affecting vitamin D-binding protein modify the relationship between serum vitamin D (25[OH]D3) and food allergy

BACKGROUND

There is evolving evidence that vitamin D insufficiency may contribute to food allergy, but findings vary between populations. Lower vitamin D-binding protein (DBP) levels increase the biological availability of serum vitamin D. Genetic polymorphisms explain almost 80% of the variation in binding protein levels.

OBJECTIVE

We sought to investigate whether polymorphisms that lower the DBP could compensate for adverse effects of low serum vitamin D on food allergy risk.

METHODS

From a population-based cohort study (n = 5276) we investigated the association between serum 25-hydroxyvitamin D3 (25[OH]D3) levels and food allergy at age 1 year (338 challenge-proven food-allergic and 269 control participants) and age 2 years (55 participants with persistent and 50 participants with resolved food allergy). 25(OH)D3 levels were measured using liquid chromatography-tandem mass spectrometry and adjusted for season of blood draw. Analyses were stratified by genotype at rs7041 as a proxy marker of DBP levels (low, the GT/TT genotype; high, the GG genotype).

RESULTS

Low serum 25(OH)D3 level (≤50 nM/L) at age 1 years was associated with food allergy, particularly among infants with the GG genotype (odds ratio [OR], 6.0; 95% CI, 0.9-38.9) but not in those with GT/TT genotypes (OR, 0.7; 95% CI, 0.2-2.0; P interaction = .014). Maternal antenatal vitamin D supplementation was associated with less food allergy, particularly in infants with the GT/TT genotype (OR, 0.10; 95% CI, 0.03-0.41). Persistent vitamin D insufficiency increased the likelihood of persistent food allergy (OR, 12.6; 95% CI, 1.5-106.6), particularly in those with the GG genotype.

CONCLUSIONS

Polymorphisms associated with lower DBP level attenuated the association between low serum 25(OH)D3 level and food allergy, consistent with greater vitamin D bioavailability in those with a lower DBP level. This increases the biological plausibility of a role for vitamin D in the development of food allergy.

Association of serum 25-hydroxyvitamin D with serum IgE levels in Korean adults

OBJECTIVE

Studies about the association between vitamin D and allergic disease and the immune-modulatory function of vitamin D have increased in the recent years. However, not enough studies have been conducted for concrete conclusion about the association vitamin D and allergy. We investigate the association between serum immunoglobulin E (IgE) and serum 25-hydroxyvitamin D (25(OH)D) levels in Korean adults.

METHODS

We used data of 1969 subjects from the 2010 Korean National Health and Nutrition Examination Survey. Total IgE, Dermatophagoides farinae (Df)-specific IgE, and serum 25(OH)D levels were analyzed. Other variables included sex, age, body mass index, smoking history, and economic status. Adjusted regression analysis was used to examine the independent association of 25(OH)D with serum IgE levels.

RESULTS

When we divided all subjects into four groups according to the serum 25(OH)D level: Q1 (lowest), Q2, Q3, and Q4 (highest), the median TIgE level increased with higher quartiles in the Kruskal-Wallis test (p<0.001). Also, the prevalence of Df sensitization was highest in Q4. Serum vitamin D was positively associated with logarithmic transformed total IgE with base of 10 (LogTIgE) (coefficient (B), 0.011; 95% confidence interval, 0.001-0.021). Furthermore, a positive association between 25(OH)D and LogTIgE was found only in men with Df sensitization, but not in men without Df sensitization and women with/without Df sensitization. However, the mean serum 25(OH)D level was significantly lower in participants who were clinically diagnosed with asthma or atopic dermatitis than participants without a history of asthma or atopic dermatitis, respectively.

CONCLUSION

Serum 25(OH)D levels were positively associated with total IgE levels. Furthermore, the association between serum 25(OH)D and total IgE levels could vary depending on sex or allergic sensitization. But, the mean serum 25(OH)D level was lower in participants with asthma or atopic dermatitis history than participants without history of asthma or atopic dermatitis. Prospective further studies will be required to verify this discrepancy.

Cord blood vitamin D and neurocognitive development are nonlinearly related in toddlers

BACKGROUND

Little is known about the relation between vitamin D status in early life and neurodevelopment outcomes.

OBJECTIVE

This study was designed to examine the association of cord blood 25-hydroxyvitamin D [25(OH)D] at birth with neurocognitive development in toddlers.

METHODS

As part of the China-Anhui Birth Cohort Study, 363 mother-infant pairs with complete data were selected. Concentrations of 25(OH)D in cord blood were measured by radioimmunoassay. Mental development index (MDI) and psychomotor development index (PDI) in toddlers were assessed at age 16-18 mo by using the Bayley Scales of Infant Development. The data on maternal sociodemographic characteristics and other confounding factors were also prospectively collected.

RESULTS

Toddlers in the lowest quintile of cord blood 25(OH)D exhibited a deficit of 7.60 (95% CI: -12.4, -2.82; P = 0.002) and 8.04 (95% CI: -12.9, -3.11; P = 0.001) points in the MDI and PDI scores, respectively, compared with the reference category. Unexpectedly, toddlers in the highest quintile of cord blood 25(OH)D also had a significant deficit of 12.3 (95% CI: -17.9, -6.67; P < 0.001) points in PDI scores compared with the reference category.

CONCLUSIONS

This prospective study suggested that there was an inverted-U-shaped relation between neonatal vitamin D status and neurocognitive development in toddlers. Additional studies on the optimal 25(OH)D concentrations in early life are needed.

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.

A role of FCER1A and FCER2 polymorphisms in IgE regulation

BACKGROUND

Both FCER2 and FCER1A encode subunits of IgE receptors. Variants in FCER1A were previously identified as major determinants of IgE levels in genome-wide association studies.

METHODS

Here we investigated in detail whether FCER2 polymorphisms affect IgE levels alone and/or by interaction with FCER1A polymorphisms. To cover the genetic information of FCER2, 21 single-nucleotide polymorphisms (SNPs) were genotyped by Illumina HumanHap300 BeadChip (5 SNPs) and the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS; 14 SNPs) in at least 1303 Caucasian children (651 asthmatics) (ISAAC II/ MAGICS population); genotypes of two SNPs were imputed.

RESULTS

SNP rs3760687 showed the most consistent effect on total serum IgE levels (b [SE] = -0.38 [0.16]; P = 0.016), while FCER2 polymorphisms in general were predominantly associated with mildly-to-moderately increased IgE levels (50th and 66th percentiles). Gene-by-gene interaction analysis suggests that FCER2 polymorphism rs3760687 influences IgE levels mainly in individuals not homozygous for the risk allele of FCER1A polymorphism rs2427837, which belongs to the major IgE-determining tagging bin in the population.

CONCLUSION

FCER2 polymorphism rs3760687 affects moderately elevated total serum IgE levels, especially in the absence of homozygosity for the risk allele of FCER1A SNP rs2427837.

Low vitamin D levels are associated with atopic dermatitis, but not allergic rhinitis, asthma, or IgE sensitization, in the adult Korean population

BACKGROUND

The effect of vitamin D on allergic conditions is unclear. In particular, large-scale, population-based studies examining this relationship in adult Asian populations are lacking.

OBJECTIVE

To evaluate the association between serum vitamin D levels and allergic conditions in the general adult Korean population.

METHODS

A cross-sectional study was performed by using data collected from 15,212 individuals 19 years or older who participated in the Korean National Health and Nutrition Examination Survey from 2008 to 2010. The confounder-adjusted mean serum 25-hydroxyvitamin D (25[OH]D) levels of participants with and without allergic conditions (including atopic dermatitis, asthma, allergic rhinitis, and increased total and allergen-specific serum IgE) were compared by using multiple linear regression analyses. Multiple logistic regression analyses with confounder adjustment estimated the odds ratios (ORs) for developing each condition according to adequate, inadequate, or deficient serum 25(OH)D levels.

RESULTS

After adjusting for potential confounders, mean serum 25(OH)D levels were significantly lower in participants diagnosed with atopic dermatitis than in those without this diagnosis (mean ± SE, 18.58 ± 0.29 ng/mL vs 19.20 ± 0.15 ng/mL; P = .02). Compared with participants with adequate vitamin D levels (≥20 ng/mL), confounder-adjusted ORs of atopic dermatitis were significantly higher in those with inadequate (12-19.99 ng/mL) or deficient (<12 ng/mL) levels (OR [95% CI], 1.50 [1.10-2.06] and 1.48 [1.04-2.12], respectively; P = .02). This relationship was not observed in participants with the other allergic conditions.

CONCLUSION

Vitamin D-insufficient adult individuals within the general Korean population have an increased likelihood of atopic dermatitis, but not asthma, allergic rhinitis, or IgE sensitization.

Mechanisms and potential therapeutic targets in allergic inflammation: recent insights

Deeper insight into pathogenetic pathways and into the biological effects of immunomodulatory agents will help to optimize or adopt therapeutic strategies for atopic disorders. In this article, we highlight selected findings of potential therapeutic relevance that emerged from recent mechanistic studies with focus on molecular and cellular aspects of allergic inflammation. Furthermore, the often complex mechanisms of action of pleiotropic immunomodulatory agents, such as glucocorticoids, vitamin D, or intravenous immunoglobulin (IVIG), are discussed, as their dissection might reveal targets for novel therapeutics or lead to a more rational use of these compounds. Besides reporting novel evidence, this article points to areas of current debate or uncertainty and aims at stimulating scientific discussion and experimental work.

1,25(OH)₂D₃ and specific IgE levels in children with recurrent tonsillitis, and allergic rhinitis

OBJECTIVES

We investigated 1,25-dihydroxyvitamin D3 [1,25(OH)₂D₃] and specific immunoglobulin E (IgE) levels in children with recurrent tonsillitis (RT) plus allergic rhinitis (AR).

METHODS

Thirty children with RT+AR were included in the study group, and 30 healthy children comprised the control group. AR-related symptoms were determined using a symptom scale. 1,25(OH)₂D₃ and specific IgE measurements were made in both groups.

RESULTS

The 1,25(OH)₂D₃ value was significantly lower in the RT+AR group than in the control group. Specific IgE (mixed) panels were in normal limits in both groups; whereas specific IgE (mixed) grass pollen panel value of RT+AT group was significantly higher than that of the control group. Higher nasal itching, nasal obstruction, and concha edema scores were related to significantly higher specific IgE values for the (mixed) grass pollen panel, whereas higher sneeze scores were related to higher specific IgE values for the (mixed) pediatric panel.

CONCLUSIONS

Children with grass pollen allergy may not be exposed to sufficient sunlight. With reduced 1,25(OH)₂D₃, T helper cells may increase, and allergic response also increases. As allergic events increased, these children did not go outside and thus lacked sun exposure. This vicious cycle must be broken, and children with RT+AR should have sunlight exposure to increase 1,25(OH)₂D₃ levels.

The relationship between vitamin D status and adrenal insufficiency in critically ill children

CONTEXT

Recent studies in critically ill populations have suggested both adrenal insufficiency (AI) and vitamin D deficiency to be associated with worse clinical outcome. There are multiple mechanisms through which these pleiotropic hormones might synergistically influence critical illness.

OBJECTIVE

The aim of the study was to investigate potential relationships between vitamin D status, adrenal status, and cardiovascular dysfunction in critically ill children.

DESIGN

We conducted a secondary analysis of data from a prospective cohort study.

SETTING AND PATIENTS

The study was conducted on 319 children admitted to 6 Canadian tertiary-care pediatric intensive care units.

MAIN OUTCOME MEASURES

Vitamin D status was determined through total 25-hydroxyvitamin D (25OHD) levels. AI was defined as a cortisol increment under 9 μg/dL after low-dose cosyntropin. Clinically significant cardiovascular dysfunction was defined as catecholamine requirement during pediatric intensive care unit admission.

RESULTS

Using 3 different thresholds to define vitamin D deficiency, no association was found between vitamin D status and AI. Furthermore, linear regression failed to identify a relationship between 25OHD and baseline or post-cosyntropin cortisol. However, the association between AI and cardiovascular dysfunction was influenced by vitamin D status; compared to children with 25OHD above 30 nmol/L, AI in the vitamin D-deficient group was associated with significantly higher odds of catecholamine use (odds ratio, 5.29 vs 1.63; P = .046).

CONCLUSIONS

We did not find evidence of a direct association between vitamin D status and critical illness-related AI. However, our results do suggest that vitamin D deficiency exacerbates the effect of AI on cardiovascular stability in critically ill children.