Association of HLA-DRB1 Gene Polymorphism with Risk of Asthma: A Meta-Analysis

Toward Consensus Epitopes B and T of Tropomyosin Involved in Cross-Reactivity across Diverse Allergens: An In Silico Study

Tropomyosin (TM) is a pan-allergen with cross-reactivity to arthropods, insects, and nematodes in tropical regions. While IgE epitopes of TM contribute to sensitization, T-cell (MHC-II) epitopes polarize the Th2 immune response. This study aimed to identify linear B and T consensus epitopes among house dust mites, cockroaches, Ascaris lumbricoides, shrimp, and mosquitoes, exploring the molecular basis of cross-reactivity in allergic diseases. Amino acid sequences of Der p 10, Der f 10, Blo t 10, Lit v 1, Pen a 1, Pen m 1, rAsc l 3, Per a 7, Bla g 7, and Aed a 10 were collected from Allergen Nomenclature and UniProt. B epitopes were predicted using AlgPred 2.0 and BepiPred 3.0. T epitopes were predicted with NetMHCIIpan 4.1 against 10 HLA-II alleles. Consensus epitopes were obtained through analysis and Epitope Cluster Analysis in the Immune Epitope Database. We found 7 B-cell epitopes and 28 linear T-cell epitopes binding to MHC II. A unique peptide (residues 160-174) exhibited overlap between linear B-cell and T-cell epitopes, highly conserved across tropomyosin sequences. These findings shed light on IgE cross-reactivity among the tested species. The described immuno-informatics pipeline and epitopes can inform in vitro research and guide synthetic multi-epitope proteins' design for potential allergology immunotherapies. Further in silico studies are warranted to confirm epitope accuracy and guide future experimental protocols.

Impact of HLA polymorphisms on the susceptibility to SARS-CoV-2 infection and related mortality in patients with renal replacement therapy

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection could present in a clinical spectrum of varying severity. Human leukocyte antigen (HLA) is a crucial component of the viral antigen presentation pathway and immune response to the virus. Therefore, we aimed to assess the impact of HLA allele polymorphisms on the susceptibility to SARS-CoV-2 infection and related mortality in Turkish kidney transplant recipients and wait listed patients, along with clinical characteristics of the patients. We analysed data from 401 patients with clinical characteristics according to presence (n = 114, COVID+) or absence of SARS-CoV-2 infection (n = 287, COVID-) who had previously been HLA typed to support transplantation. The incidence of coronavirus disease-19 (COVID-19) was 28 %, and the mortality rate was 19 % in our wait listed/ transplanted patients. Multivariate logistic regression analysis showed that a significant HLA association between HLA- B*49 (OR = 2.57, 95 % CI, 1.13-5.82; p = 0.02) and HLA- DRB1*14 (OR = 2.48, 95 % CI, 1.18-5.20; p = 0.01) with SARS-CoV-2 infection. Besides, in COVID + patients, HLA-C*03 was correlated to mortality (OR = 8.31, 95 % CI, 1.26-54.82; P = 0.03). The new finding from our analysis suggests that HLA polymorphisms could be associated with the occurrence of SARS-CoV-2 infection and COVID-19 mortality in Turkish patients with renal replacement therapy. This study may provide new information for the clinician to identify and manage sub-populations at risk in the setting of the current COVID-19 pandemic.

Gene polymorphisms in asthma: a narrative review

Background and Objective

Asthma is a heterogeneous disease caused by interactions between genetic and environmental factors. Genome-wide association studies (GWAS) have revealed that genetic variation plays a crucial role in the occurrence and development of asthma. The objective is to systematically review the existing literature on the association between gene polymorphisms and asthma to better understand the relationship between genetic factors and the occurrence and development of asthma.

Methods

We used keywords "asthma" and "gene polymorphism" with their combinations to search for relevant literature published from 2000 to 2021 in the PubMed database and the foreign medical literature retrieval service (FMRS). All articles included in the review are English. Then, we summarized the information pertaining to the genetic factors related to asthma susceptibility.

Key Content and Findings

This study summarized the information on 10 gene variants related to the risk of asthma published over the past 20 years, which will assist in further understanding the role of genetic variants in the risk of asthma.

Conclusion

Dozens of candidate genes have been identified that were associated with asthma risk. Asthmatics existed specific gene variation performed different response to therapy. Personalized therapy based on genotypic profiling would be an important direction in the future. However, it remains a great challenge for us to explore the relationship between gene polymorphisms and pathophysiological mechanism of asthma.

Dual Effect of Low-Molecular-Weight Bioregulators of Bacterial Origin in Experimental Model of Asthma

Asthma is one of the most common noncommunicable diseases, affecting over 200 million people. A large number of drugs control asthma attacks, but there is no effective therapy. Identification of reasons for asthma and preventing this disease is a relevant task. The influence of bacterial components is necessary for the normal development of the immune system and the formation of an adequate immune response to antigens. In the absence of microorganisms or their insufficient exposure, the prerequisites are formed for excessive reactivity to harmless antigens. In the present study, we analyzed cellular and humoral factors in a standard mouse model of OVA-induced asthma modified by 5-fold intraperitoneal injection of bacterial cell wall fragments of glucosaminylmuramyl dipeptide (GMDP) 5 μg/animal or 1 μg lipopolysaccharide (LPS) per animal for 5 days before sensitization by ovalbumin (OVA). Preliminary administration of LPS or GMDP to animals significantly reduced goblet cells as well as the number of neutrophils, lymphocytes, and eosinophils in bronchoalveolar lavage, wherein GMDP corrected neutrophilia to a 2-fold degree, and LPS reduced the severity of eosinophilia by 1.9 times. With OVA administration of GMDP or LPS at the sensitization stage, an increase in the total number of bronchoalveolar lavage cells due to neutrophils, macrophages, lymphocytes, and eosinophils in relation to the group with asthma without GMDP or LPS was observed. The administration of GMDP or LPS to normal mice without asthma for 5 days had no statistically significant effect on the change in the number and population composition of cells in bronchoalveolar lavage in comparison with the control group receiving PBS. As a result of a study in a mouse model of asthma, a dual effect of LPS and GMDP was established: the introduction of LPS or GMDP before sensitization reduces neutrophilia and eosinophilia, while the introduction of LPS or GMDP together with an allergen significantly increases neutrophilia and eosinophilia. The study of the immunoglobulin status shows that in normal-asthma mice, GMDP and LPS slightly increase IgA in bronchoalveolar lavage; at the same time, in the asthma model, injections of GMDP or LPS before sensitization contribute to a significant decrease in IgA (2.6 times and 2.1 times, respectively) in BALF and IgE (2.2 times and 2.0 times, respectively) in blood serum. In an experimental model of asthma, the effect of GMDP and LPS was multidirectional: when they are repeatedly administered before sensitization, the bacterial components significantly reduce the severity of the allergic process, while in the case of a joint injection with an allergen, they increase the influx of macrophages, lymphocytes, and neutrophils into the lungs, which can aggravate the course of pathological process. Thus, the insufficient effect of antigens of a bacterial nature, in particular, with prolonged use of antibiotics can be compensated for by substances based on low-molecular-weight bioregulators of bacterial origin to establish the missing signals for innate immunity receptors, whose constant activation at a certain level is necessary to maintain homeostasis.

Vitamin D Sufficiency Has a Limited Effect on Placental Structure and Pathology: Placental Phenotypes in the VDAART Trial

Vitamin D insufficiency during pregnancy is widespread. The effects of active vitamin D on the human placenta in vivo are unknown. We test the hypotheses that 25(OH)D sufficiency (arbitrarily defined as 25(OH)D ≥32 ng/mL) modulates placental structure and function in vivo in a population of women whose offspring are at risk for childhood asthma, and that placental pathology is more common in offspring that evolve asthma at age 3. Pregnant volunteers in the St. Louis, MO, cohort of the Vitamin D Antenatal Asthma Reduction Trial (VDAART, NIH grant #HL091528) participated in a nested case-control study and consented for the study of placentas after delivery. Maternal concentrations of 25(OH)D were measured at trial entry and in the third trimester. The histopathology of the placentas from women with sufficient 25(OH)D, versus insufficient, showed no clinically significant differences, but morphometry revealed villi of women with sufficient third-trimester 25(OH)D had a higher villous surface density. Notably, analyses of transcripts, extracted from formalin-fixed paraffin-embedded specimens, revealed higher expression of INTS9, vWF, MACC1, and ARMS2, and diminished expression of the CNTN5 genes in the insufficient group. A larger proportion of placentas showed chronic chorioamnionitis in offspring with versus without asthma at age 3. These findings suggest that maternal 25(OH)D insufficiency has a limited effect on human placental villous histopathology and morphometry, but attenuates a small number of placental gene expression profiles in this selected population. The association of placental chronic chorioamnionitis and offspring asthma is worthy of further study.

Autoimmune polyglandular syndrome type 2 and autoimmune hepatitis with thymoma-associated myasthenia gravis: case report

BACKGROUND

Autoimmune polyglandular syndrome type 2 (APS-2) is a rare and complex clinical entity, and little is known about its etiology and progression.

CASE PRESENTATION

A 52-year-old woman with autoimmune hepatitis (AIH) and bronchial asthma was diagnosed with APS-2; autoimmune Addison's disease (AD), and Hashimoto's thyroiditis (HT), and she underwent prednisolone (PSL) treatment. Five months later, she presented ptosis and was diagnosed with thymoma-associated myasthenia gravis (MG). Thymectomy and PSL treatment with immuno-suppressants appeared to ameliorate MG, AD, AIH, HT, and bronchial asthma. HLA typing analysis revealed that the patient had susceptible HLA alleles to MG, AIH, and HT in a Japanese population.

CONCLUSIONS

This case suggests common endocrinological and autoimmune aspects of APS-2 and AIH with thymoma-associated MG, which are considered to be extremely rare complications.

Coordinated DNA Methylation and Gene Expression Data for Identification of the Critical Genes Associated with Childhood Atopic Asthma

Asthma is a chronic inflammatory disorder of airways that involves in many cells and factors. This study aimed to screen critical genes and miRNAs involved in childhood atopic asthma. DNA methylation and gene expression data (access numbers GSE65163 and GSE65204) were downloaded from Gene Expression Omnibus (GEO) database, which included 72 atopic asthmatic subject samples and 69 healthy samples. The differentially expressed genes (DEGs) with DNA methylation changes were identified, followed by Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Gene coexpression network and miRNA-target gene regulatory networks were then constructed. Besides, we screened critical drug molecules that have high correlation with atopic asthma in children. A total of 146 critical DEGs with DNA methylation changes were screened from atopic asthmatic samples compared with healthy control samples. GO and KEGG pathway enrichment analysis showed that the critical genes were mainly related to 20 GO terms and 13 KEGG pathways. In the coexpression network, tumor necrosis factor (TNF) and major histocompatibility complex, class II, DP alpha 1 (HLA-DPA1) were identified that were significantly related to immune response process. Analysis of miRNA-target gene network showed that hsa-miR-148b had the highest number of target genes(degree = 21). Besides, we found that Alsterpaullone had a correlation value closest to -1 (correlation = -0.884, p = 0.0031), which indicated that the agent might be considered as a potential agent that antagonized to asthma. The dysregulation of TNF, HLA-DPA1, and miR-148b might be related to the immune response of childhood atopic asthma.

Effect of HLA on development of asthma

Background

Asthma is a disease characterized by a chronic inflammation of the airways caused by the interaction of genetic susceptibility with environmental factors. Inflammation and remodeling are critical components of asthma. It is shown that many genes are involved in the pathogenesis of asthma.

Aim of study

To identify/compare the association between HLA-DRB1 alleles and development of asthma in a sample of Iraqi Arab Muslims.

Patients and methods

A case-control study (forty patients and forty healthy control) was carried out in Medical city Teaching Hospital, Baghdad-Iraq. The study participants were patients with asthma consulted the hospital from September - 2013 to January - 2015. HLA –DRB1genotyping was done using a panel of sequence-specific oligonucleotide probes (SSOP) using HLA-DRB1amplification and hybridization kits (SSO HLA type DRB1 plus and Mastermix for HLA type DRB1 Amp plus kits -Innogenetics-Belgium) using automated method by AutoLipa – 48Innogenetics-Belgum.

Results

There was an increased frequency of HLADRB1*03:01:01 in control group compared with patients group (P = 0.009, Odds ratio = 0.1228, 95% CI: 0.0254–0.5930). Other allele like HLA-DRB1* 070101was significantly increased in asthmatic patients in compares with control group (P = 0.005, Odds ratio = 6.641, 95% CI: 1.7319–25.4657).

Conclusions

HLA alleles have an effect on development asthma in patients with HLA-DRB1*070101 while HLADRB1* 030101 may have a protective effect in Iraqi Arab Muslims individuals against development of asthma.

•

Asthma is a disease characterized by a chronic inflammation of the airways caused by the interaction of genetic susceptibility with environmental factors.

•

To identify/compare the association between HLA-DRB1 alleles and development of asthma in a sample of Iraqi Arab Muslims.

•

A case-control study ( forty patients and forty healthy control) was carried out in Medical city Teaching Hospital, Baghdad-Iraq.

•

There was an increased frequency of HLADRB1*03:01:01 in control group compared with patients group (P = 0.009, Odds ratio = 0.1228, 95% CI: 0.0254–0.5930). Other allele like HLA-DRB1* 070101 was significantly increased in asthmatic patients in compares with control group (P = 0.005, Odds ratio = 6.641, 95% CI: 1.7319–25.4657).

•

HLA alleles have an effect on development asthma in patients with HLA-DRB1*070101 while HLADRB1* 030101 may have a protective effect.

Lipopolysaccharide Exposure Alleviates Asthma in Mice by Regulating Th1/Th2 and Treg/Th17 Balance

Background

It is generally believed that endotoxin exposure exacerbates risk of developing asthmatic symptoms. However, recent studies have indicated that prior bacterial exposure may prevent future symptoms of asthma. Here, we evaluated the influence of pre-exposure to different concentrations of lipopolysaccharide (LPS) to subsequent ovalbumin (OVA) allergen sensitization and challenge.

Material/Methods

Four-week-old Balb/c mice were treated intranasally with varying concentrations of LPS (1 ug, 10 ug, and 100 ug) or sterile PBS for 10 days, then 2 weeks later they were exposed to OVA. Both the molecular and functional airway responses to OVA administration were assessed following prior exposure to different doses of LPS or controls. Additionally, the Th1/Th2 and Treg/Th17 balance was measured.

Results

Airway responsiveness and immune cell recruitment in the bronchoalveolar lavage (BALF) were decreased in animals exposed to a low dose of LPS (1 ug) treatment compared with the asthma group. Moderate-dose (10 ug) and high-dose (100 ug) LPS administration showed no differences from controls. Further, low-dose LPS (1 ug) exposure was associated with increased Th1 cytokines, T-bet, Treg cytokine (IL-10, TGF-β), and Foxp3 expression, but decreased Th2 cytokines (IL-4,5,13), GATA3, Th17, and ROR-γt expression compared with the asthma group. Finally, higher numbers of CD4+CD25+Foxp3+Treg cells, and CD4+INF-γ+T cells, and lower CD4+IL-4+T cells and CD4+IL-17+T cells were observed in the low-dose LPS-treated groups compared to controls.

Conclusions

Our findings suggest that prior exposure to low doses of LPS may protect from OVA-induced airway hyperresponsiveness (AHR) and histopathologic changes through regulation of the Th1/Th2 and Treg/Th17 balance.

Genetic Mechanisms of Asthma and the Implications for Drug Repositioning

Asthma is a chronic disease that is caused by airway inflammation. The main features of asthma are airway hyperresponsiveness (AHR) and reversible airway obstruction. The disease is mainly managed using drug therapy. The current asthma drug treatments are divided into two categories, namely, anti-inflammatory drugs and bronchodilators. However, disease control in asthma patients is not very efficient because the pathogenesis of asthma is complicated, inducing factors that are varied, such as the differences between individual patients. In this paper, we delineate the genetic mechanisms of asthma, and present asthma-susceptible genes and genetic pharmacology in an attempt to find a diagnosis, early prevention, and treatment methods for asthma. Finally, we reposition some clinical drugs for asthma therapy, based on asthma genetics.

Association Between Secretoglobin Family 3A Member 2 (SCGB3A2) Gene Polymorphisms and Asthma in a Korean Population

Background

Secretoglobin family 3A member 2 (SCGB3A2) plays an important role in secreting lung surfactant protein, which is a downstream target of thyroid transcription factor.

Material/Methods

We investigated whether single-nucleotide polymorphisms (SNPs) of SCGB3A2 gene contribute to susceptibility to asthma. To explore this possible association, 2 promoter SNPs (rs6882292, 659 G/A and rs1368408, −112 G/A) and missense SNP (rs151333009, stop codon) were tested in SCGB3A2 gene in 101 asthma patients and 377 healthy control subjects. SNPStats was used to obtain odds ratio (OR), 95% confidence intervals (CI), and P value adjusted for age and sex as covariables. Logistic regression method in each model (dominant, recessive, and log-additive) was applied to analyze genetic data.

Results

rs151333009 SNP showed a monomorphic genotype. Two promoter SNPs (rs6882292, −659 G/A and rs1368408, −112 G/A) showed significant association with asthma (rs6882292, OR=2.66, 95% CI=1.42–5.01, p=0.0033 in dominant model, OR=2.45, 95% CI=1.33–4.54, p=0.0055 in log-additive model; rs1368408, OR=1.59, 95% CI=1.02–2.49, p=0.041 in dominant model, OR=3.02, 95% CI=1.15–7.90, p=0.03 in recessive model, OR=1.63, 95% CI=1.63, 95% CI=1.12–2.37, p=0.012 in log-additive model).

Conclusions

These results suggest that the promoter SNPs (rs6882292 and rs1368408) of SCGB3A2 gene may contribute to susceptibility to asthma in a Korean population.