Polymorphisms of Interleukin 7 Receptor are Associated With Mite-Sensitive Allergic Asthma in Children in Taiwan

Memory and naïve gamma delta regulatory T-cell gene expression in the first 24-weeks of peanut oral immunotherapy

BACKGROUND

Peanut oral immunotherapy (POIT) has provided desensitization to peanut allergic individuals. Limited immunological evaluation exists during the first 24-weeks of POIT.

OBJECTIVE

Regulatory T-cells (Tregs) are antigen induced immunosuppressive T-cells important in establishing tolerance. Delineation of early immunologic changes contributing to the development of peanut desensitization would help clarify the mechanism of action in POIT. We performed single-cell RNA sequencing (scRNAseq) on Tregs in pediatric subjects undergoing POIT during the first 24-weeks of therapy to evaluate early immunological changes induced by POIT.

METHODS

PBMC samples from peanut allergic subjects between 5 and 12 years of age enrolled in a Phase 1/2a POIT study were collected and analyzed at 0, 6, and 24-weeks after POIT initiation and samples were compared to healthy non-peanut allergic controls. Tregs were enriched from PBMCs and scRNAseq analysis performed. Cell Ranger 3.1.0 (10× Genomics) was utilized to identify cell clusters and differentially expressed genes, and results were analyzed with Seurat suite version 3.0.0.

RESULTS

Gene analysis revealed 10 major clusters corresponding to different cell types observed to change during POIT when compared to the healthy, non-peanut-allergic state. scRNAseq analysis of Tregs revealed strong CD3G expression correlating with gdTregs. scRNAseq analysis of gdTregs revealed dynamic changes occurring within the first 6-weeks of treatment and cell frequencies of naïve and memory gdTregs at 24-weeks of treatment reducing to levels similar to healthy controls. Analysis of transcriptomic cell identity analysis using SingleR showed gene expression in gdTregs similar to healthy control after 24-weeks of POIT treatment. scRNAseq analysis revealed alterations in gene expression for memory and naïve gdTregs during this timeframe. Specifically, expression of OX40R (TNFRSF4), GITR (TNFRSF18), TGFB1, CTLA4, ISG20, CD69 were upregulated in memory gdTregs compared to naive gdTregs by 24-weeks of POIT, while IL7R and SELL were downregulated in memory gdTregs compared to naïve gdTregs.

CONCLUSIONS

There are specific expression profiles of peripheral naïve and mature gdTreg cells in peanut allergic patients undergoing POIT in the first 24-weeks of treatment implicating pathways involved in maintenance of immune homeostasis. gdTreg cells may contribute to the tolerogenic effect of POIT within the first 24-weeks of POIT treatment. These findings suggest that gdTregs cells may be an early marker of desensitization in subjects undergoing POIT.

IL-7/IL-7R gene variants impact circulating IL-7/IL-7R homeostasis and ART-associated immune recovery status

A relationship between polymorphisms in genes encoding interleukin 7 (IL-7) and its cellular receptor (IL-7R) and antiretroviral therapy (ART)-associated immune recovery in HIV subjects has been previously reported. However, details of this relationship remain unclear, and the association of these polymorphisms with circulating IL-7/IL-7R levels is scarce. Here, we explored whether IL-7/IL-7R axis was associated with quantitative CD4+ T-cell recovery in HIV-infected subjects. IL-7/IL-7R polymorphisms were assessed by genotyping, and multiple inheritance models were used to estimate both, their association with low pre-ART CD4+ T-cell counts and incomplete immune recovery status after 48 weeks of suppressive ART. Integrated data from genetic variants association and soluble plasma IL-7/IL-7R quantification suggest that IL-7/IL-7R genotype expression could alter the homeostatic balance between soluble and membrane-bound receptors. The haplotype analyses indicates that allele combinations impacts pre-ART circulating CD4+ T-cell counts, immune recovery status and the absolute increment of CD4+ T-cell counts. The knowledge about how IL-7/IL-7R axis is related to quantitative CD4+ T-cell recovery and immune recovery status after initiating ART could be useful regarding T-cell reservoirs investigations in HIV subjects.

Expression and Regulation of Thymic Stromal Lymphopoietin and Thymic Stromal Lymphopoietin Receptor Heterocomplex in the Innate-Adaptive Immunity of Pediatric Asthma

Asthma is a chronic inflammatory disease affecting the airway, and it is characterized by a wheezing breathing sound, variable airflow obstruction and the presence of inflammatory cells in the submucosa of the bronchi. Viral infection, pollutants and sensitivity to aeroallergens damage the epithelium from childhood, which causes asthma. The pathogenesis of asthma includes pathways of innate stimulation by environmental microbes and irritant pathogens. Damaged epithelial cells produce thymic stromal lymphopoietin (TSLP) and stimulate myeloid dendritic cell maturation through the thymic stromal lymphopoietin receptor (TSLPR) heterocomplex. TSLP-activated myeloid dendritic cells promote naive CD4⁺ T cells to differentiate into T helper type 2 (Th2) phenotype CD4⁺ T cells. Re-exposure to allergens or environmental stimuli causes an adaptive immune response. TSLP-activated dendritic cells expressing the OX40 ligand (OX40L; CD252) trigger naive CD4⁺ T cells to differentiate into inflammatory Th2 effector cells secreting the cytokines interleukin-4, 5, 9, and 13 (IL-4, IL-5, IL-9 and IL-13), and the dendritic cells (DCs) promote the proliferation of allergen-specific Th2 memory cells. Allergen presentation by Th2 cells through its interaction with their receptors in the presence of major histocompatibility complex (MHC) class II on B cells and through costimulation involving CD40 and CD40L interactions results in immunoglobulin class switching from IgM to IgE. DCs and other blood cell subsets express the TSLPR heterocomplex. The regulatory mechanism of the TSLPR heterocomplex on these different cell subsets remains unclear. The TSLPR heterocomplex is composed of the IL-7Rα chain and TSLPR chain. Moreover, two isoforms of TSLP, short isoform TSLP (sfTSLP) and long isoform TSLP (lfTSLP), have roles in atopic and allergic development. Identifying and clarifying the regulation of TSLPR and IL-7Rα in pediatric asthma are still difficult, because the type of blood cell and the expression for each blood cell in different stages of atopic diseases are poorly understood. We believe that further integrated assessments of the regulation mechanism of the TSLP–TSLPR heterocomplex axis in vitro and in vivo can provide a faster and earlier diagnosis of pediatric asthma and promote the development of more effective preventive strategies at the onset of allergies.

Upregulated thymic stromal lymphopoietin receptor expression in children with asthma

BACKGROUND

Thymic stromal lymphopoietin (TSLP) plays an important role in pathogenesis in patients with asthma. However, the role of thymic stromal lymphopoietin receptor (TSLPR) and correlation with IL-7Rα and clinical severity in asthmatic or nonasthmatic children remain unclear. We investigated TSLPR and IL-7Rα mRΝΑ levels in asthma and nonasthma and assessed TSLPR expression in children who were sensitive to mites.

MATERIALS AND METHODS

We enrolled asthmatic and nonasthmatic children. To minimize the influence of allergy, we also divided participants into following 4 groups: nonallergic and nonasthmatic group (NN) (healthy children), allergic but nonasthmatic group (AN), nonallergic but asthmatic group (NA) and allergic asthmatic group (AA). We drew blood samples to check total IgE, allergen-specific IgE and TSLP and measured the expression of the TSLPR and IL-7Rα genes using reverse-transcription polymerase chain reaction (RT-PCR) and real-time PCR. Asthma symptom score was also recorded.

RESULTS

Thymic stromal lymphopoietin and TSLPR levels were found to be significantly higher in asthmatic than in nonasthmatic children. The levels of TSLP were found to be significantly different between AA and NN groups (P < 0·05). TSLPR expression in NA and AA groups was found to be significantly higher than in NN group (P < 0·05). TSLPR did not differ significantly between NA and AA groups. The TSLPR expression correlated strongly with IL-7Rα and weakly with mite-specific IgE. Clinical asthmatic severity of children was found to exert no influence on TSLPR level.

CONCLUSION

Thymic stromal lymphopoietin receptor might be a significant disease biomarker for asthma. The levels of TSLPR were found to be higher in asthmatic patients than in healthy children, but were found to be not different between allergic and nonallergic asthmatic patients.

Association of interleukin 7 receptor (rs1494555 and rs6897932) gene polymorphisms with asthma in a north Indian population

Background:

Interleukin 7R (IL-7R), a cytokine receptor gene, plays an important role in the development of innate and adaptive inflammatory response in asthma etiology.

Objective:

IL-7R is a heterodimeric protein composed of α chain and γ chain. The α chain of IL-7R has a range of single nucleotide polymorphisms, which give rise to nonsynonymous amino-acid substitutions that might result in an increased production of inflammatory cytokines and cause asthma.

Methods:

A case-control study was conducted with a total of 964 subjects, including 483 healthy controls and 481 patients with asthma. DNA samples were extracted from blood, and genotyping was done by using sequence-specific-primer–polymerase chain reaction.

Results:

Statistical analysis revealed that IL-7R + 1237A/G (rs1494555) gene polymorphism shows a highly protective association toward asthma (odds ratio [OR] 0.56, p < 0.001) in AG genotype as well as in mutant GG genotype (OR 0.64, p = 0.029). However, IL-7R + 2087T/C (rs6897932) polymorphism showed an increased risk toward asthma in TC genotype (OR 1.70, p = 0.002) as well as in the CC genotype (OR 1.68, p = 0.002). Furthermore, the GT and AC haplotypes in the IL-7R polymorphisms were also found to be significantly associated with asthma (p < 0.001 and p = 0.037, respectively).

Conclusions:

The study conducted in a north Indian population indicated that the protective association was observed for the +1237A/G position, and a significant risk was observed for the +2087T/C position in asthma.

The burden of allergic asthma in children: a landscape comparison based on data from Lithuanian, Latvian, and Taiwanese populations

Asthma is one of the most common chronic respiratory diseases with an increasing prevalence and financial burden worldwide. This disease affects individuals in all countries and all ethnic groups; however, prevalence rates of asthma have been reported to vary significantly between different regions. To understand the origin of asthma and to manage it effectively, it is necessary to analyze the genetic and environmental factors that cause these geographic differences. Therefore, we aimed to review published data from the investigations of asthma patients in Eastern Europe, represented by Latvia and Lithuania, and of patients from Eastern Asia represented by Taiwan. We hope that some of the common factors can be identified and different variants can be compared among these three countries for development of a new strategy to prevent childhood asthma.