STAT6 polymorphisms are associated with neonatal regulatory T cells and cytokines and atopic diseases at 3 years.

BACKGROUND: The transcription factor STAT6 is crucial for activation of the interleukin (IL)-4/IL-13 pathway and has been linked to regulatory T cells (Tregs). Associations of STAT6 polymorphisms with IgE levels were described; however, their impact on neonatal immune responses and early disease development is unknown. METHODS: STAT6 polymorphisms were genotyped in cord blood mononuclear cells by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Gene expression was assessed by real-time polymerase chain reaction (PCR) and cytokines by Multiplex. At age 3 years, atopic diseases were assessed by questionnaires. RESULTS: STAT6 rs324011 but not rs1059513 polymorphism was associated with significant or borderline significant decreased mRNA expression of Treg-associated genes (FOXP3, GITR, LAG3). Heterozygotes and minor allele homozygotes of rs324011 had low levels of tumor necrosis factor alpha (TNF-α) and increased interferon gamma (IFN-γ) (P ≤ 0.04), while heterozygotes and minor allele homozygotes of rs1059513 had increased TNF-α and Granulocyte-macrophage colony-stimulating factor (GM-CSF) (P ≤ 0.05). In minor allele homozygotes of rs324011, expression of Treg-associated genes was strongly inverse correlated with IFN-γ (unstimulated, r = -0.7, P = 0.111; LpA stimulation, r = -0.8, P = 0.011), but not in heterozygotes or major allele homozygotes. Heterozygotes and minor allele homozygotes of rs324011 presented a lower risk of atopic dermatitis and obstructive bronchitis until age 3 years. CONCLUSIONS: Two STAT6 polymorphisms were associated with altered immune responses already at birth. STAT6 rs324011 was associated with lower neonatal Treg and increased Th1 response. Those neonates had a lower risk of atopic dermatitis and obstructive bronchitis until 3 years. Our data suggest a role for STAT6 polymorphisms in early immune regulation and implications on early atopic disease development.

TLR2 polymorphisms influence neonatal regulatory T cells depending on maternal atopy.

BACKGROUND: Toll-like receptor (TLR) polymorphisms have been associated with atopic diseases in children and adults. Development of atopic diseases may be modified by TLR-mediated signals that modulate T-regulatory cells (Tregs) early in life when maternal influences are still present and relevant. The aim of this study was to assess whether genetic TLR variants influence Tregs in neonates. METHODS: Twelve single nucleotide polymorphisms located in TLR1, TLR2, TLR4, TLR6, and TLR10 were genotyped in 200 cord blood samples (72 samples from atopic, 128 from nonatopic mothers). Cord blood mononuclear cells were cultured without or with stimulation [lipid A (LpA), peptidoglycan (Ppg), phytohemagglutinin, house dust mite]. mRNA expression of Treg marker genes [forkhead box protein P3 (FOXP3), glucocorticoid-induced tumor necrosis factor receptor (GITR), lymphocyte activation gene 3 (LAG3)], TLR2, Th1/Th2 cytokines, and tumor necrosis factor alpha (TNF-α) was measured. RESULTS: In children with the AA genotype of the TLR2 promoter variant rs4696480, gene expression of FOXP3 and Treg marker genes GITR and LAG3 as well as Th2 cytokines and TNF-α secretion was significantly increased in the presence of maternal atopy and Tregs decreased without maternal atopy. In carriers of the GG genotype for TLR2 rs1898830, gene expression of Treg marker genes was significantly decreased with and increased without maternal atopy. FOXP3 expression was also modified by TLR1 rs4833095 (P ≤ 0.03) and trendwise by TLR10 rs4129009 after LpA and Ppg stimulation. CONCLUSIONS: Genetic variations of TLR2, TLR1, and TLR10 affect Treg marker gene expression in cord blood. Gene-immunological interactions of the TLR pathway influence Tregs early in life, modulated by maternal atopy. This may be relevant for immune maturation in the development of atopic diseases in childhood.