Relation of T Cell Profile with Vitamin D Receptor and Vitamin D-Binding Protein Gene Polymorphisms in Atopy

Atopic diseases, including atopic dermatitis (AD) and allergic asthma (AA), are characterized by complex immune responses involving various T cells subsets and their cytokine profiles. It is assumed that single nucleotide polymorphisms (SNPs) in the Vitamin D receptor (<i>VDR</i>) gene and the Vitamin D-binding protein (<i>GC</i>) gene are related to the action of Vitamin D and, consequently, play a role in regulating the immune response. However, there is not enough data to unequivocally support the hypothesis about the relationship between T cells profile and <i>VDR</i> or <i>GC</i> SNPs. Two hundred sixty-six subjects (aged > 18 years) were involved in the study: 100 patients with mild or moderate AD, 85 patients with mild or moderate AA, and 81 healthy individuals. Blood cell counts were determined by standard methods. Flow cytometric analysis was used to evaluate CD4⁺ T-helper (Th) cell subtypes: Th2, Th1, Th17, and T regulatory (Treg) cells in peripheral blood. Measurements of cytokines, total immunoglobulin E (IgE), and Vitamin D levels in serum were evaluated by ELISA. Significantly higher levels of Th1, Th2, and Th17 cells, along with lower levels of Tregs, were found in patients with atopic diseases compared to healthy individuals. Additionally, higher serum levels of interleukin (IL) 5, IL-17A, and transforming growth factor-β1 (TGF-β1), as well as lower levels of IL-10, were observed in patients with atopic diseases than in control. The study established associations between <i>VDR</i> SNPs and immune profiles: the AA genotype of rs731236 was associated with increased Th2 and Th17 cells and a higher Th1/Th2 ratio; the GG genotype of rs731236 was linked to decreased serum IL-10 and TGF-β1 levels; and the TT genotype of rs11168293 was associated with increased IL-10 levels. Additionally, the GG genotype of <i>GC</i> gene SNP rs4588 was associated with reduced Th2 and Th17 lymphocytes, while the TT genotype of rs4588 was linked to decreased IL-10 levels. Furthermore, the CC genotype of rs7041 was associated with higher levels of Th2, Th17, IL-10, and IL-35, as well as reduced levels of TGF-β1, while the GG genotype of rs3733359 was associated with reduced IL-10 levels. In conclusion, our study demonstrates that the Vitamin D receptor gene single nucleotide polymorphisms rs731236 and rs11168293, along with polymorphisms in the Vitamin D-binding protein gene (rs4588, rs7041, rs3733359), are significantly associated with variations in T cell profiles in atopy. These variations may play a crucial role in promoting inflammation and provide insight into the genetic factors contributing to the pathogenesis of atopy.