Vitamin D and Its Receptor Gene Polymorphisms in Lithuanian, Latvian and Taiwanese Patients With Atopic Dermatitis and Asthma

Study Overview
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Brief Summary
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The role of vitamin D is well known in calcium and phosphate homeostasis; however, in addition to traditional functions, vitamin D has an important role in pathogenesis of different allergic diseases, such as asthma, atopic dermatitis (AD), and food allergy. There are evidences that lower cord blood vitamin D status is observed in infants with eczema. More-over, vitamin D level is decreased in subjects with asthma. One of the most important functions of vitamin D is to modulate the immune system response, both innate and adaptive, by suppressing Th2-type response and increasing natural killer cells. Vitamin D induces a higher level of IL-10, which is known as anti-inflammatory cytokine. Other studies have shown that vitamin D contributes to the conversion of CD4+ T cells to T regulatory cells. Recent studies showed that higher serum 25-hydroxyvitamin D level was associated with a reduced risk of asthma exacerbation and hospitalization. Vitamin D can enhance dexamethasone-induced MAP kinase phosphatase-1 (MKP-1) expression in peripheral blood mononuclear cells. Experimental data suggest that vitamin D can potentially increase the therapeutic response to glucocorticoid and can be used as an add-on treatment in steroid-resistant asthmatics. Vitamin D stimulates the production and regulation of skin antimicrobial peptides, such as cathelicidins, which have both direct antimicrobial activity and induced host cellular response by triggering cytokine release. Recent evidence suggests that low blood vitamin D level is a risk factor for food allergy. Vitamin D acts by binding to the vitamin D receptors (VDRs), which are located in a variety of tissues. VDRs have been identified on nearly all cells of the immune system including T cells, B cells, neutrophils, macrophages, and dendritic cells (DCs). Vitamin D deficiency predisposes to gastrointestinal infections by changing gut micro-biota, which may promote the development of food allergy. However the detail mechanism how vitamin D affects or protects the development of allergic diseases is still unknown. Vitamin D level is determined by sun exposure. Due to the fact that Lithuania, Latvia and Taiwan are located in different latitudes of north hemisphere with markedly different sun exposure, in this Joint collaboration study between Taiwan, Lithuanian and Latvia, we are going to study, (1). Serum vitamin D level in children and adults with AD and/or asthma in Lithuania, Latvia and Taiwan. (2). VDRs genetic polymorphisms of AD and/or asthma in children and adults in Lithuania, Latvia and Taiwan. (3). Finally, we would like to explore the gut microbiome of patients with AD and/or asthma in Lithuanian, Latvian and Taiwanese children and adults; and to estimate possible relationship between gut microbiome and vitamin D level and VDRs genetic polymorphisms. We believe that this study will be the first which compares the populations with different geographical and ecological factors having the same allergic diseases. We hope that these results will provide the answer about the role of vitamin D in the prevention, or in the future, in treatment of allergic diseases.

Official Title
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Comparative Study of Vitamin D and Its Receptor Gene Polymorphisms in Lithuanian, Latvian, and Taiwanese Children and Adults With Atopic Dermatitis and Asthma

Conditions
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Atopic Dermatitis, Asthma

Intervention / Treatment
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* Diagnostic Test: Peripheral vein punction
* Diagnostic Test: Stool collection


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with mild to moderate asthma Patients with mild to moderate atopic dermatitis Healthy individuals Exclusion Criteria: Acute or chronic infections Oncological diseases Acute systemic autoimmune diseases Use of systemic immunosuppressants (wait 1 month) Use of vitamin D supplementation Use of systemic antihistamines (wait 1 week)

Ages Eligible for Study
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Maximum Age: 60 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Atopic dermatitis<br> | Diagnostic Test: Peripheral vein punction<br>* Vitamin D level, vitamin D receptor genetic polymorphisms, allergen specific IgE and total IgE will be measured in peripheral blood<br>Diagnostic Test: Stool collection<br>* Gut microbiome will be investigated in stool samples.<br>|
| Asthma<br> | Diagnostic Test: Peripheral vein punction<br>* Vitamin D level, vitamin D receptor genetic polymorphisms, allergen specific IgE and total IgE will be measured in peripheral blood<br>Diagnostic Test: Stool collection<br>* Gut microbiome will be investigated in stool samples.<br>|
| Healthy individuals<br> | Diagnostic Test: Peripheral vein punction<br>* Vitamin D level, vitamin D receptor genetic polymorphisms, allergen specific IgE and total IgE will be measured in peripheral blood<br>Diagnostic Test: Stool collection<br>* Gut microbiome will be investigated in stool samples.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Vitamin D level in serum in patients with atopic dermatitis, asthma and healthy individuals from Lithuania, Latvia and Taiwan | Comparison of serum vitamin D level (25(OH)D) by ELISA between studied groups | 2nd year of study | 
| Vitamin D receptors (VDRs) genetic polymorphisms in patients with atopic dermatitis, asthma and healthy individuals from Lithuania, Latvia and Taiwan | Comparison of VDRs genetic polymorphisms using genetic evaluation between studied groups | 2nd year of study | 
| Composition of gut microbiome in patients with atopic dermatitis, asthma and healthy individuals from Lithuania, Latvia and Taiwan | Investigation and comparison of gut microbiome using genetic evaluation between studied groups | 3rd year of study |