Atopy and asthma: genetic variants of IL-4 and IL-13 signalling

Control of Asthma and Allergy by Regulatory T Cells

BACKGROUND

Epithelial barriers, such as the lungs and skin, face the challenge of providing the tissues' physiological function and maintaining tolerance to the commensal microbiome and innocuous environmental factors while defending the host against infectious microbes. Asthma and allergic diseases can result from maladaptive immune responses, resulting in exaggerated and persistent type 2 immunity and tissue inflammation.

SUMMARY

Among the diverse populations of tissue immune cells, CD4+ regulatory T cells (Treg cells) are central to controlling immune responses and inflammation and restoring tissue homeostasis. Humans and mice that are deficient in Treg cells experience extensive inflammation in their mucosal organs and skin. During past decades, major progress has been made toward understanding the immunobiology of Treg cells and the molecular and cellular mechanisms that control their differentiation and function. It is now clear that Treg cells are not a single cell type and that they demonstrate diversity and plasticity depending on their differentiation stages and tissue environment. They could also take on a proinflammatory phenotype in certain conditions.

KEY MESSAGES

Treg cells perform distinct functions, including the induction of immune tolerance, suppression of inflammation, and promotion of tissue repair. Subsets of Treg cells in mucosal tissues are regulated by their differentiation stage and tissue inflammatory milieu. Treg cell dysfunction likely plays roles in persistent immune responses and tissue inflammation in asthma and allergic diseases.

Phytochemicals as treatment for allergic asthma: Therapeutic effects and mechanisms of action

BACKGROUND

Allergic asthma is an inflammatory disease caused by the immune system's reaction to allergens, inflammation and narrowing of the airways, and the production of more than normal mucus. One of the main reasons is an increased production of inflammatory cytokines in the lungs that leads to the appearance of symptoms of asthma, including inflammation and shortness of breath. On the other hand, it has been proven that phytochemicals with their antioxidant and anti-inflammatory properties can be useful in improving allergic asthma.

PURPOSE

Common chemical treatments for allergic asthma include corticosteroids, which have many side effects and temporarily relieve symptoms but are not a cure. Therefore, taking the help of natural compounds to improve the quality of life of asthmatic patients can be a valuable issue that has been evaluated in the present review.

STUDY DESIGN AND METHODS

In this study, three databases (Scopus, PubMed, and Cochrane) with the keywords: allergic asthma, phytochemical, plant, and herb were evaluated. The primary result was 5307 articles. Non-English, repetitive, and review articles were deleted from the study.

RESULTS AND DISCUSSION

Finally, after carefully reading the articles, 102 were included in the study (2006-2022). The results of this review state that phytochemicals suppress the inflammatory pathways via inhibition of inflammatory cytokines production/secretion, genes, and proteins involved in the inflammation process, reducing oxidative stress indicators and symptoms of allergic asthma, such as cough and mucus production in the lungs.

CONCLUSION

With their antioxidant effects, this study concluded that phytochemicals suppress cytokines and other inflammatory indicators and thus can be considered an adjunctive treatment for improving allergic asthma.

Interleukin-4 (C590T) Gene Polymorphism in Association with Asthma Severity

Background

A significant link between T allele of the IL-4 (C590T) gene and developing asthma in some populations was reported. However, no study discussed the link between IL-4 (C590T) gene polymorphism and asthma severity groups (mild and severe). This study investigated the link between IL-4 gene variation and asthma severity.

Methods

The study included 215 asthmatic patients, of which 102 had mild asthma, and 126 participants were healthy controls. A previously published polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used to identify various IL-4 (C590T) gene polymorphism genotypes.

Results

The T allele frequency was higher in mild asthma (p=0.002) but not in severe asthma (p=0.12) compared to controls. In mild asthma, the CT genotype and (CT+TT versus CC) increased the likelihood of asthma threefold (p<0.001, 0.001). However, no significant association with severe asthma was found in either genetic model. Stratification analysis showed that the C allele and CC genotype increased the risk of severe asthma (p=0.01). The recessive genetic model indicated a decrease in the risk of severe asthma (OR=0.5, p=0.01) in the non-adjusted regression analysis. Adjusting for age, sex, and other risk factors revealed that the IL-4 gene polymorphism did not influence the risk of severe asthma (OR=0.92, p=0.80); however, being an elderly female with a history of childhood-onset disease and associated nasal polyp (NP) increased the likelihood of severe asthma, OR=1.08, 2.01, 2.36, 8.42; p<0.001, 0.05, 0.05, <0.001, respectively.

Conclusion

The T allele and CT genotype in the co-dominant genetic model and the (CT+TT) genotype in the recessive model were found to have a higher likelihood of developing mild asthma but not severe asthma; severe asthma was found to be higher in elderly females with a history of childhood-onset disease and associated nasal polyps.

Sex differences in susceptibility to substance use disorder: Role for X chromosome inactivation and escape?

There is a sex-based disparity associated with substance use disorders (SUDs) as demonstrated by clinical and preclinical studies. Females are known to escalate from initial drug use to compulsive drug-taking behavior (telescoping) more rapidly, and experience greater negative withdrawal effects than males. Although these biological differences have largely been attributed to sex hormones, there is evidence for non-hormonal factors, such as the influence of the sex chromosome, which underlie sex disparities in addiction behavior. However, genetic and epigenetic mechanisms underlying sex chromosome influences on substance abuse behavior are not completely understood. In this review, we discuss the role that escape from X-chromosome inactivation (XCI) in females plays in sex-associated differences in addiction behavior. Females have two X chromosomes (XX), and during XCI, one X chromosome is randomly chosen to be transcriptionally silenced. However, some X-linked genes escape XCI and display biallelic gene expression. We generated a mouse model using an X-linked gene specific bicistronic dual reporter mouse as a tool to visualize allelic usage and measure XCI escape in a cell specific manner. Our results revealed a previously undiscovered X-linked gene XCI escaper (CXCR3), which is variable and cell type dependent. This illustrates the highly complex and context dependent nature of XCI escape which is largely understudied in the context of SUD. Novel approaches such as single cell RNA sequencing will provide a global molecular landscape and impact of XCI escape in addiction and facilitate our understanding of the contribution of XCI escape to sex disparities in SUD.

Association of interleukin-4, interleukin-13 gene polymorphisms, HLA-DQ and DR genotypes with genetic susceptibility of type-1 Diabetes Mellitus in Kuwaiti children

Background

Type-1 diabetes mellitus (T1DM) is a complex multifactorial disease with an autoimmune etiology and is thought to result from an interaction between genetic and non-genetic factors. Cytokines play a crucial role in the pathogenesis of autoimmune diseases due to their effector and regulatory functions in immune responses. Interleukin-4 (IL4) and Interleukin-13 (IL13) are anti-inflammatory cytokines and are considered as important mediators in pathology of the autoimmune diseases.

Methods

We have determined the genotype frequency of IL4 gene promoter polymorphism (-590C/T, rs2243250), IL13 gene polymorphism p.(Arg130Glu, rs20541) and human leukocyte antigen, HLA-DQ and DR genotypes in Kuwaiti children with T1DM to investigate their role in genetic susceptibility. This study included 261 Kuwaiti children with T1DM and 214 healthy controls. The genotypes for IL4 (-590C/T) and IL13 p.(Arg130Glu) gene polymorphisms were detected by PCR-RFLP methods. HLA-DQ and DR genotypes were determined by sequence-specific PCR methods.

Results

The CC genotype of IL4 gene polymorphism (-590C/T) was significantly related to the risk for T1DM in Kuwaiti patients (OR 1.64). The homozygous AA (QQ) and heterozygous AG (RQ) genotypes of IL13 gene polymorphism p.(Arg130Glu), also manifested a statistically significant association with T1DM (OR 2.92 and 4.79). In 55% T1DM patients, the HLA genotype was either DQ2/DQ2 or in combination with a DQ8 allele. Collectively, 91% Kuwaiti T1DM patients had either DQ2 or DQ8 alleles in different combinations highlighting them as the high risk-genotypes in comparison to the controls. In the case of HLA-DR, the genotypes DR3/DRB5, DR3/DR4, DR3/DR7 and DR4/DR4 showed highest frequency amongst the Kuwaiti T1DM patients and thus can be considered as high-risk genotypes when compared to the controls. A high degree of co-inheritance (>80%) was detected between IL4 and IL13 gene polymorphism genotypes (CC and QQ) and the high-risk HLA-DQ and DR genotypes amongst the Kuwaiti T1DM patients.

Conclusions

We have identified the association of IL4 and IL13 gene polymorphisms with susceptibility to T1DM in Kuwaiti children and the co-inheritance of these polymorphisms with high-risk HLA genotypes. The findings may contribute to early identification of childhood diabetes.

Non-additive QTL mapping of lactation traits in 124,000 cattle reveals novel recessive loci

BACKGROUND

Deleterious recessive conditions have been primarily studied in the context of Mendelian diseases. Recently, several deleterious recessive mutations with large effects were discovered via non-additive genome-wide association studies (GWAS) of quantitative growth and developmental traits in cattle, which showed that quantitative traits can be used as proxies of genetic disorders when such traits are indicative of whole-animal health status. We reasoned that lactation traits in cattle might also reflect genetic disorders, given the increased energy demands of lactation and the substantial stresses imposed on the animal. In this study, we screened more than 124,000 cows for recessive effects based on lactation traits.

RESULTS

We discovered five novel quantitative trait loci (QTL) that are associated with large recessive impacts on three milk yield traits, with these loci presenting missense variants in the DOCK8, IL4R, KIAA0556, and SLC25A4 genes or premature stop variants in the ITGAL, LRCH4, and RBM34 genes, as candidate causal mutations. For two milk composition traits, we identified several previously reported additive QTL that display small dominance effects. By contrasting results from milk yield and milk composition phenotypes, we note differing genetic architectures. Compared to milk composition phenotypes, milk yield phenotypes had lower heritabilities and were associated with fewer additive QTL but had a higher non-additive genetic variance and were associated with a higher proportion of loci exhibiting dominance.

CONCLUSIONS

We identified large-effect recessive QTL which are segregating at surprisingly high frequencies in cattle. We speculate that the differences in genetic architecture between milk yield and milk composition phenotypes derive from underlying dissimilarities in the cellular and molecular representation of these traits, with yield phenotypes acting as a better proxy of underlying biological disorders through presentation of a larger number of major recessive impacts.

Genetics and Epigenetics in Allergic Rhinitis

The pathogenesis of allergic rhinitis is associated with genetic, environmental, and epigenetic factors. Genotyping of single nucleotide polymorphisms (SNPs) is an advanced technique in the field of molecular genetics that is closely correlated with genome-wide association studies (GWASs) in large population groups with allergic diseases. Many recent studies have paid attention to the role of epigenetics, including alteration of DNA methylation, histone acetylation, and miRNA levels in the pathogenesis of allergic rhinitis. In this review article, genetics and epigenetics of allergic rhinitis, including information regarding functions and significance of previously known and newly-discovered genes, are summarized. Directions for future genetic and epigenetic studies of allergic rhinitis are also proposed.

Anti-Allergic Rhinitis Effects of Medicinal Plants and Their Bioactive Metabolites via Suppression of the Immune System: A Mechanistic Review

Allergic rhinitis (AR) is a common inflammatory condition of the nasal mucosa and it is an immunoglobulin E-mediated disease. The incidence and prevalence of AR globally have been escalating over recent years. Antihistamines, intranasal corticosteroids, decongestants, intranasal anticholinergics, intranasal cromolyn, leukotriene receptor antagonists and immunotherapy have been used in the treatment of AR. However, there is a need to search for more effective and safer remedies as many of the current treatments have reported side effects. Medicinal plants have been used traditionally to relief symptoms of AR but their efficacy and safety have not been scientifically proven. In this review, up-to-date reports of studies on the anti-allergic rhinitis of several medicinal plants and their bioactive metabolites through suppression of the immune system are compiled and critically analyzed. The plant samples were reported to suppress the productions of immunoglobulin E, cytokines and eosinophils and inhibit histamine release. The suppression of cytokines production was found to be the main mechanistic effect of the plants to give symptomatic relief. The prospect of these medicinal plants as sources of lead molecules for development of therapeutic agents to treat AR is highlighted. Several bioactive metabolites of the plants including shikonin, okicamelliaside, warifteine, methylwarifteine, luteolin-7-O-rutinoside, tussilagone, petasin, and mangiferin have been identified as potential candidates for development into anti-allergic rhinitis agents. The data collection was mainly from English language articles published in journals, or studies from EBSCOHOST, Medline and Ovid, Scopus, Springer, and Google Scholar databases from the year 1985-2020. The terms or keywords used to find relevant studies were allergic rhinitis OR pollinosis OR hay fever, AND medicinal plant OR single plant OR single herb OR phytotherapy. This comprehensive review serves as a useful resource for medicinal plants with anti-allergic rhinitis potential, understanding the underlying mechanisms of action and for future exploration to find natural product candidates in the development of novel anti-allergic rhinitis agents.

IL-13 and FOXO3 genes polymorphisms regulate IgE levels in asthmatic patients

Immunoglobulin E (IgE) serves a crucial role in the pathogenesis of several allergic disorders, and elevated levels of total serum IgE have been associated with asthma. IgE is responsible for the release of several asthma-associated inflammatory mediators from mast cells, such as histamine and prostaglandins. The aim of the present study was to assess the association of interleukin (IL)-13 single nucleotide polymorphism (SNP) rs20541 and forkhead box O3a (FOXO3a) SNP rs13217795 with IgE levels in asthmatic patients and a healthy control group. Genetic polymorphism analysis of SNPs was performed using PCR/restriction fragment length polymorphism. Total serum IgE levels were measured using an ELISA kit. Genotypes were grouped into three models: Co-dominant, dominant and recessive. Major and minor alleles for IL-13 SNP rs20541 and FOXO3a SNP rs13217795 were C and T, whereas for IL-13, they were G and A, respectively. There was a significant association between the IL-13 rs20541 SNP and the total IgE serum levels, in which pure minor alleles were associated with a significant reduction (~5x lower) in IgE serum levels compared with the major alleles in asthmatic subjects and to a lesser extent in the control subjects. Additionally, the FOXO3a rs13217795 SNP was associated with a significant increase in total IgE levels (~5x higher) in the asthmatic patients compared with the control subjects. In conclusion, the present study confirmed that there was a significant association between the IL-13 SNP rs20541 and asthma, and an association between the FOXO3a SNP rs13217795 with asthma pathogenicity in Jordanian subjects.

Association of cytokine gene polymorphisms with susceptibility to cutaneous leishmaniasis in a Turkish population

AIMS

The objective of this study was to determine the association of TNF-α -308 G/A, IFN-γ +874 T/A, IL-12B + 1188 A/C, IL-10 -1082 G/A and IL-4 -590 C/T polymorphisms with susceptibility to CL.

METHODS AND RESULTS

A total of 55 CL patients and 110 controls from Sanlıurfa province of Turkey were included to this study. Polymorphisms were genotyped by 'polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP)' and 'amplification refractory mutation system-PCR (ARMS-PCR)' methods. A statistically significant difference was noted in the allele (P < .001, P = .002) and genotype (P < .001, P = .001,) frequencies of TNF-α -308 G/A and IL-4 -590 C/T, respectively. TNF-α 308 GG versus GA genotype (OR = 19.556 [95% CI 8.310-46.019] P < .001), GG versus GA + AA genotype (OR = 20.444 [95% CI 8.707-48.004] P < .001) and G versus A allele (OR = 6.968 [95% CI 3.903-12.440] P < .001) revealed significant association with CL. IL-4 -590 CC versus TT + CT genotype (OR = 2.049 [95% CI 1.025-4.096], P = .041) and C versus T allele (OR = 2.441 [95% CI 1.355-4.396], P = .002) revealed significant association with CL.

CONCLUSION

Our study indicates that TNF-α 308 G/A and IL-4-590 C/T polymorphisms are significantly associated with susceptibility to CL. Individuals carrying A allele at TNF-α promoter -308 position and T allele at IL-4 promoter -590 position are at a higher risk for CL.

Biologics for Allergic Dermatologic Diseases

PURPOSE OF REVIEW

Atopic dermatitis (AD), chronic spontaneous urticaria (CSU), and allergic contact dermatitis (ACD) represent three important allergic dermatoses with many unmet therapeutic needs. The development of biologic agents has opened the door to both new treatment options and improved understanding of the underlying pathophysiology, both shared and unique for these entities. With several FDA-approved medications available and many more in development, the biologic revolution has begun for allergic dermatoses.

RECENT FINDINGS

This is a narrative review on the current state of pathomechanisms and appropriately targeted biologic agents for these three common allergic skin conditions. The importance of Th2 inflammation and the effect of inflammatory cytokines on the skin barrier may help explain the impressive efficacy of biologic agents, while maintaining relative safety. While some of the biologic agents show efficacy across multiple allergic dermatoses, more often it seems these more targeted pathways show accordingly precise efficacy. However, in each disease, multiple agents hold promise, and may be differentiated by safety and adverse effect profile rather than simply by efficacy. New understanding of the pathogenesis of the allergic dermatoses has ushered in a new era of biologic therapies. Competing mechanisms and molecules will continue to be developed and vetted in trials with hopes of continuously refined precision therapies with optimized safety and efficacy profiles.

Interleukin-4 and Interleukin-13 Gene Polymorphisms in Children With Idiopathic Nephrotic Syndrome

Background: Idiopathic Nephrotic syndrome (INS) is an immune-mediated disease in which a number of cytokines, including IL-4 and IL-13, have been implicated in the pathogenesis. Cytokine gene polymorphisms might affect their levels and activity. Therefore, may affect INS susceptibility and response to treatment. The aim of the study was to determine the association of IL-4 and IL-13 gene polymorphisms and INS susceptibility and their effects on steroid responsiveness in children. Methods: The polymorphisms in IL-4 and IL-13 genes were detected by PCR-RFLP in 155 INS patients and 64 controls. Results: A total of 132 steroid-sensitive (SS) and 23 steroid resistance (SR) INS patients; mean age 7.3 ± 4.0 years, were included. Male: Female ratio was 2:1. No significant statistical differences were detected in the frequency of CC, CT, and TT genotypes of IL-4 gene compared to controls (P = 0.57, 0.61, and 1.00, respectively). There was no significant difference in the T and C-allele frequencies, in SS and SR subgroups. Analysis of IL-13 gene polymorphism also did not show significant statistical differences in the frequency of QQ, RQ, and RR genotypes compared to controls (P = 0.74, 1.00, and 0.68, respectively). No significant difference was found in the Q and R-allele frequency. However, the heterozygous RQ genotype of the IL13 gene was significantly higher in SS INS patients compared to the SR INS cases (P = 0.04). Conclusion: Our findings did not show an association between IL-4 and IL-13 gene polymorphisms and INS susceptibility. However, IL-13 RQ genotype was expressed more in children with INS who are steroid sensitive.

Anti-Atopic Effect of Acorn Shell Extract on Atopic Dermatitis-Like Lesions in Mice and Its Active Phytochemicals

To investigate the potential effects of acorn shells on atopic dermatitis (AD), we utilized oxazolone (OX)- or 2,4-dinitrochlorobenzene (DNCB)-induced AD-like lesion mouse models. Our research demonstrates that Acorn shell extract (ASE) improved the progression of AD-like lesions, including swelling, which were induced by oxazolone on Balb/c mouse ears. Additionally, ASE significantly decreased the ear thickness (OX: 0.42 ± 0.01 mm, OX-ASE: 0.32 ± 0.02 mm) and epidermal thickness (OX: 75.3 ± 32.6 µm, OX-ASE: 46.1 ± 13.4 µm). The continuous DNCB-induced AD mouse model in SKH-1 hairless mice demonstrated that ASE improved AD-like symptoms, including the recovery of skin barrier dysfunction, Immunoglobulin E hyperproduction (DNCB: 340.1 ± 66.8 ng/mL, DNCB-ASE: 234.8 ± 32.9 ng/mL) and an increase in epidermal thickness (DNCB: 96.4 ± 21.9 µm, DNCB-ASE: 52.4 ± 16.3 µm). In addition, we found that ASE suppressed the levels of AD-involved cytokines, such as Tumor Necrosis Factor α, IL-1β, IL-25 and IL-33 in both animal models. Furthermore, gallic acid and ellagic acid isolated from ASE suppressed β-hexosaminidase release and IL-4 expression in RBL-2H3 cells. The acorn shell and its active phytochemicals have potential as a new remedy for the improvement of atopic dermatitis and other inflammatory diseases.

Preventive effects of a novel herbal mixture on atopic dermatitis-like skin lesions in BALB/C mice

BACKGROUND

A combination of parts of Cornus officinalis, Rosa multiflora, Lespedeza bicolor, Platycladus orientalis, and Castanea crenata is commonly used for alleviating inflammatory skin disorders. Therefore, this study was carried out to evaluate the in vitro and in vivo preventive effects of a novel herbal formula made from the five plants (C2RLP) against atopic dermatitis in BALB/C mice.

METHODS

Mice were allocated into five groups (n = 8) including, control (Normal, petrolatum, and betamethasone treated) and treatment groups (treated with 2.5 and 5% C2RLP ointment). Atopic lesion was induced by applying 1-Chloro-2, 4-dinitrobenzene to the dorsal thoracic area of mice. Macroscopical and histological evaluations were performed to determine the effects of treatment on the progress of the skin lesions. The effects of treatment on the production and release of interleukins, interferon -ϒ, nitrite, prostaglandin E2, thymus and activation-receptor chemokine, and β-hexosaminidase were evaluated and comparisons were made between groups. In addition, the chemical compounds present in C2RLP were identified by Liquid Chromatography-Mass Spectrometry.

RESULTS

Topical application of C2RLP reduced the dermatitis score and suppressed histopathological changes in mice. Treatment significantly reduced (P < 0.05) plasma IL-4 level, the production of nitrite, prostaglandin E2, and thymus and activation-receptor chemokine production. The lipopolysaccharide-induced iNOS-mRNA expression in RAW 264.7 cells was also suppressed by high concentrations of C2RLP. In addition, C2RLP showed an inhibitory effect against DPPH free radical (IC50 = 147.5 μg/ml) and β-hexosaminidase release (IC50 = 179.5 μg/ml). Liquid Chromatography-Mass Spectrometry analysis revealed the presence of various compounds, including loganin, ellagic acid, and kaempferol 3-glucoside.

CONCLUSION

Down-regulation of T- helper 2 cellular responses and suppression of inflammatory mediators contributed to the protective effects of C2RLP from atopic dermatitis in BALB/C mice.

Effects of human rhinovirus on epithelial barrier integrity and function in children with asthma

BACKGROUND

Bronchial epithelial tight junctions (TJ) have been extensively assessed in healthy airway epithelium. However, no studies have yet assessed the effect of human rhinovirus (HRV) infection on the expression and resultant barrier function in epithelial tight junctions (TJ) in childhood asthma.

OBJECTIVES

To investigate the impact of HRV infection on airway epithelial TJ expression and barrier function in airway epithelial cells (AECs) of children with and without asthma. Furthermore, to test the hypothesis that barrier integrity and function is compromised to a greater extent by HRV in AECs from asthmatic children.

METHODS

Primary AECs were obtained from children with and without asthma, differentiated into air-liquid interface (ALI) cultures and infected with rhinovirus. Expression of claudin-1, occludin and zonula occluden-1 (ZO-1) was assessed via qPCR, immunocytochemistry (ICC), in-cell western (ICW) and confocal microscopy. Barrier function was assessed by transepithelial electrical resistance (TER; R_T ) and permeability to fluorescent dextran.

RESULTS

Basal TJ gene expression of claudin-1 and occludin was significantly upregulated in asthmatic children compared to non-asthmatics; however, no difference was seen with ZO-1. Interestingly, claudin-1, occludin and ZO-1 protein expression was significantly reduced in AEC of asthmatic children compared to non-asthmatic controls suggesting possible post-transcriptional inherent differences. HRV infection resulted in a transient dissociation of TJ and airway barrier integrity in non-asthmatic children. Although similar dissociation of TJ was observed in asthmatic children, a significant and sustained reduction in TJ expression concurrent with both a significant decrease in TER and an increase in permeability in asthmatic children was observed.

CONCLUSION

This study demonstrates novel intrinsic differences in TJ gene and protein expression between AEC of children with and without asthma. Furthermore, it correlates directly the relationship between HRV infection and the resultant dissociation of epithelial TJ that causes a continued altered barrier function in children with asthma.

Novel Therapeutic Approaches to Atopic Dermatitis

Atopic dermatitis (AD) is one of the most common inflammatory skin diseases. The number of people affected by AD is relatively high and seems to be rising. Although mild and moderate forms of the disease can be well controlled by the use of emollients, topical corticosteroids, and topical calcineurin inhibitors, treatment of severe is still a huge challenge. The new hope is biologic drugs, magic bullets in allergy, targeted at different points of the complex pathomechanism of inflammation in AD. In this review, novel biologic therapies are discussed, including recombinant monoclonal antibodies directed against various interleukin pathways (such as IL-4, IL-13, TSLP, IL-31, and IL-12/23), on immunoglobulin E, molecules acting as T cells, B cells, etc. Of biological drugs, the most promising seems to be anti-IL-4/IL-13 therapy (dupilumab-the biological agent) and phosphodiesterase-4 inhibitor (crisaborole-a small molecule). A deep understanding of the AD pathomechanism provides a new perspective for tailor-made treatment of severe atopic dermatitis.

Ameliorative effect of atractylenolide III in the mast cell proliferation induced by TSLP

Atractylenolide III (ATL-III) is an active compound of Atractylodes lancea, which has been widely used for the treatment of cancer. Cancer is closely connected with inflammation, and many anti-inflammatory agents are also used to treat cancer. We investigated the influence of ATL-III on thymic stromal lymphopoietin (TSLP)-induced inflammatory reactions. Pretreatment with ATL-III suppressed murine double minute 2 levels and promoted p53 levels in TSLP-treated human mast cell, HMC-1 cells. Mast cell proliferation increased by TSLP or IL-3 stimulation was significantly decreased by ATL-III pretreatment. Interleukin (IL)-13 and phosphorylated signal transducer and activator of transcription 3, 5, and 6 levels in TSLP-treated HMC-1 cells were also decreased by ATL-III pretreatment. In addition, ATL-III decreased the TSLP-induced production of proinflammatory cytokines (IL-6, IL-1β, tumor necrosis factor-α, and IL-8). ATL-III decreased the levels of Bcl2 and procaspase-3 and increased caspase-3 activation and cleaved PARP levels. Furthermore, ATL-III decreased TSLP-induced mast cell proliferation and the production of inflammatory cytokine by LAD2 cells. Taken together, these findings suggest that ATL-III plays a useful role as an anti-inflammatory agent and should be viewed as a potential anti-cancer agent.

The Role of Interleukins 4 and/or 13 in the Pathophysiology and Treatment of Atopic Dermatitis

Moderate to severe atopic dermatitis (AD) can be debilitating and often requires use of systemic immunosuppressant therapy to achieve adequate disease control. There are currently no US Food and Drug Administration-approved systemic agents for the long-term treatment of AD. Recent insight has identified the T helper 2 cytokines, interleukins 4 and 13, as playing a major role in the pathogenesis of AD. There are multiple novel biologic agents in development that target interleukins 4 and/or 13 for the treatment of moderate to severe AD. The age of targeted biologics for AD has arrived.

Genotyping of IL-4 -590 (C>T) Gene in Iraqi Asthma Patients

This study is the first investigation in Iraq dealing with genotyping of IL-4 −590 (C>T) gene, especially in Iraqi patients with asthma. We studied forty-eight blood samples collected from patients with asthma and compared with age-matched 25 healthy individuals as controls. The polymorphism results of IL-4 −590 (C>T) gene by using amplification refractory mutation system (ARMS-PCR) showed the presence of C and T alleles and three genotypes (CC, CT, and TT). Interestingly the frequency of C allele and CC genotype was higher in patients with asthma in comparison with the same allele and genotype in control (P 1 × 10⁻⁶). This increase was associated with an increased risk factor of asthma (odds ratio [OR] 9.21; 95% confidence interval [CI] 3.58–23.71). Genotypes analysis by using Hardy-Weinberg distribution showed no significant differences between patients with asthma and healthy subjects. In conclusion, the increasing risk of asthma was associated with C allele and the CC genotype and these are revealed as etiological fraction with risk by having this disease, while the T allele percentage ratio in controls was higher when it is compared with asthma patients suggesting that these alleles have a protective effect (preventive fraction).

IL-4R suppresses airway inflammation in bronchial asthma by inhibiting the IL-4/STAT6 pathway

OBJECTIVE

This study aims to explore the mechanisms of how IL-4R suppresses airway inflammation in bronchial asthma by inhibiting the IL-4/STAT6 pathway.

METHODS

A total of 27 BALB/c male mice were selected and divided into control, asthma and IL-4R groups. Ovalbumin-induced mouse asthma model was established. Maximal pulmonary resistance was recorded. Hematoxylin and eosin (HE) and periodic acid Schiff (PAS) staining were conducted to observe the pathological changes in lung tissue. Optical microscope was used to detect numbers of total cells, mastocytes, eosinophils (EOS), neutrophils, and lymphocytes. Enzyme-linked immunosorbent assay (ELISA) was adopted for the levels of immunoglobulin (IgE), IL-4, IL-5, IL-13 and interferon (IFN)-γ, flow cytometry for the percentages of IL-4⁺ CD4⁺, IFN-γ⁺ CD4⁺ and IFN-γ⁺/IL-4⁺ in total thymus-derived (T) cells, qRT-PCR for the mRNA expressions of IL-4, IL-5, IL-13, STAT6, pSTAT6, suppressor of cytokine signaling (SOCS), inducible nitric oxide synthase (iNOS) and vascular cell adhesion molecule (VCAM)-1, and Western blotting for the protein expressions of STAT6 and pSTAT6.

RESULTS

Compared with the control group, the asthma group had irregular tissue structure and severe inflammation, increases in maximal pulmonary resistance, numbers of total cells, EOS, neutrophils, and lymphocytes, levels of IgE, IL-4, IL-5 and IL-13, percentages of IFN-γ⁺ CD4⁺ and IFN-γ⁺/IL-4⁺ in total T cells, mRNA expressions of IL-4, IL-5, IL-13, STAT6, pSTAT6, SOCS, iNOS and VCAM-1, and protein expressions of STAT6 and pSTAT6, but decreases in IFN-γ level and percentage of IL-4⁺ CD4⁺ in total T cells. Compared with the asthma group, the IL-4R group had relatively regular tissue structure and light inflammation, declined maximal RL, numbers of total cells, EOS, neutrophils, and lymphocytes, contents of IgE, IL-4, IL-5 and IL-13, percentages of IFN-γ⁺ CD4⁺ and IFN-γ⁺/IL-4⁺ in total T cells, mRNA expressions of IL-4, IL-5, IL-13, STAT6, pSTAT6, SOCS, iNOS and VCAM-1, and protein expressions of STAT6 and pSTAT6, but elevated IFN-γ content and percentage of IL-4⁺ CD4⁺ in total T cells.

CONCLUSION

Our results demonstrate that IL-4R can suppress airway inflammation in bronchial asthma by inhibited the IL-4/STAT6 pathway, which may provide a new therapeutic approach for the treatment of bronchial asthma.

Analysis of changes in expression of IL-4/IL-13/STAT6 pathway and correlation with the selected clinical parameters in patients with atopic asthma

INTRODUCTION

Asthma is associated with activation of interleukin-4 (IL-4)/interleukin-13 (IL-13)/signal transducer and activator of transcription factor-6(STAT6) inflammatory response via overexpression of all pathway components: IL-4, IL-13, and STAT6.

OBJECTIVES

To evaluate the association of IL-4, IL-13, and STAT6 expression and immunoexpression with atopic asthma development.

PATIENTS AND METHODS

Fifty patients with atopic asthma and 20 healthy controls were enrolled into the study. Relative gene expression was analyzed by qPCR method. Immunoexpression was assessed by ELISA method.

RESULTS

The expression levels of IL-4, IL-13, and STAT6 were higher in patients compared to the controls, but a statistically significant difference was observed only for IL-13 (P = 0.03). In immunoexpression analysis, a statistically significant difference between patients and controls was found for IgE (P = 0.03). Significant positive correlations in the patient group were found between IL-13 gene expression and total level of serum IgE (rho = 0.230, P = 0.033), STAT6 gene/STAT6 protein and total level of serum IgE (STAT6: rho = 0.077, P = 0.038; STAT6: rho = 0.049, P = 0.042), IL-4, and STAT6 expression (rho = 0.098, P = 0.048). Any significant correlations were found between expression/immunoexpression levels of the studied genes and clinical classification, clinical features, or lung function parameters.

CONCLUSIONS

Our data support the role of Th2 cytokines (IL-4, IL-13) and STAT6 in Th1/Th2 imbalance and highlight the etiological relationship between IL-4/IL-13/STAT6 signaling and atopy and asthma.

Association between HLA Class II Locus and the Susceptibility to Artemisia Pollen–Induced Allergic Rhinitis in Chinese Population

OBJECTIVE

The aim of the study was to determine whether susceptibility or resistance to Artemisia pollen-induced allergic rhinitis was associated with HLA class II DQA1, DQB1 loci. Study design and setting Forty-one subjects with allergic rhinitis and 41 healthy controls from Beijing were genotyped at HLA class II DQA1, DQB1 alleles by polymerase chain reaction amplification with sequence-specific primers-based technique.

RESULTS

The allele frequencies of HLA-DQA1*0201, DQB1*0602 were lower in patients with allergic rhinitis compared with the controls (24.39% versus 46.34%, P = 0.038; 4.88% versus 26.83%, P = 0.007), and the frequency of DQA1*0302 was higher among patients than the controls (58.54% versus 14.63%, P = 0.00004, Pc = 0.0004).

CONCLUSION AND SIGNIFICANCE

HLA-DQA1 and -DQB1 genes may be involved in the development of Artemisia pollen-induced allergic rhinitis. HLA-DQA1*0201, DQB1*0602 alleles may be a protective factor and DQA1*0302 may be a susceptible factor for Artemisia pollen-induced allergic rhinitis.

Association of IL4 and IL4R polymorphisms with multiple sclerosis susceptibility in Caucasian population: A meta-analysis

BACKGROUND

Previous studies have suggested a role for interleukin-4 (IL4) and its receptor (IL4R) gene in susceptibility to multiple sclerosis (MS), but the results remain controversial and under-powered.

OBJECTIVES

To investigate the contradictory results, we performed a meta-analysis to assess the possible association between polymorphisms of the IL4 rs2243250 (C/T), variable number of tandem repeat (VNTR) polymorphism in intron-3 (I3(709)VNTR), IL4R rs1801275 (T/C) and MS in Caucasian populations.

METHODS

A comprehensive search was conducted to identify all case-control or cohort design studies. The fixed or random effect pooled measure was selected based on the homogeneity test among studies that was evaluated with I(2). Publication bias was estimated using the Begg's and Egger's test.

RESULTS

A total of ten studies were included in the meta-analysis. The crude odds ratios (ORs) with 95% confidence intervals (95% CI) were calculated to evaluate the association. Overall, after excluding articles deviating from Hardy-Weinberg equilibrium in controls and sensitive analysis, the meta-analysis showed a significant association between polymorphism of IL4 rs2243250 and MS susceptibility in allele model (OR=1.209, 95% CI=1.022-1.429, P=0.026) and dominant model (OR =1.225, 95% CI=1.013-1.480, P=0.036). However, no significant association was found between polymorphisms of IL4 I3(709)*VNTR, IL4R rs1801275 and MS susceptibility, respectively.

CONCLUSIONS

The meta-analysis indicates that the T allele, CT and TT genotype of polymorphism of IL4 rs2243250 (C/T) may reduce the risk of MS in Caucasian populations, while polymorphisms of IL4 I3(709)*VNTR and IL4R rs1801275 may not associated with risk of MS in Caucasian populations.

Interleukin-4 polymorphism is associated with severity of respiratory syncytial virus infection

AIM

Respiratory syncytial virus (RSV) infection is a major health problem in young children. This study aimed to investigate whether the interleukin (IL)-4 -590C/T and -33 C/T polymorphisms were associated with the susceptibility to RSV infection in Chinese Han children and with the severity of the infection.

METHODS

The IL-4 -590C/T and -33 C/T SNPs were evaluated in 218 inpatients with RSV bronchiolitis and 303 healthy controls. The severity of RSV bronchiolitis was evaluated using a respiratory scoring system.

RESULTS

The frequencies of IL-4 -590 CC, CT and TT in the 218 RSV bronchiolitis patients versus the 303 controls were 1.4% versus 1.7%, 21.1% versus 34% and 77.5% versus 64.4%, respectively. The frequencies of IL-4 -33 CC, CT and TT were 1.4%, 20.6% and 78%, respectively, in RSV bronchiolitis patients and 2.3%, 35.6% and 62%, respectively, in the controls. The frequencies of the IL-4 -590C/T and -33 C/T polymorphisms were significantly different between the two groups. There was a significant difference in the frequency of the T-T haplotype formed by -590C/T and -33C/T between the two groups. The respiratory score of the RSV bronchiolitis cases with -590TT was 3.02 ± 0.44, which was significantly higher than those with -590CT (2.80 ± 0.44). The score for patients with -33TT was 3.03 ± 0.43, which was significantly higher than the score of 2.78 ± 0.46 for patients with -33CT.

CONCLUSIONS

In Chinese Han children, the IL-4 -590C/T and -33 C/T polymorphisms were associated with the susceptibility to RSV and the severity of the infection.

A Herbal Formula, Atofreellage, Ameliorates Atopic Dermatitis-Like Skin Lesions in an NC/Nga Mouse Model

We evaluated the anti-atopic dermatitis (AD) effect of Atofreellage (AF), a herbal formula composed of 10 medicinal plants. AD was induced on the dorsal skin areas of NC/Nga mice (male, seven weeks old) by daily application of 2,4-dinitrochlorobenzene (DNCB) for five weeks. After three weeks of DNCB application, 200 μL of AF (0, 25, 50 or 100 mg/mL) was applied to the skin lesions. Histological findings, blood cell populations, serum levels of immunoglobulin E (IgE), histamine, pro-inflammatory cytokines, and inflammatory signaling in the skin tissue, and T-helper cell type 2 (Th₂)-related cytokines in splenocytes were analyzed. Histopathological findings showed AF treatment notably attenuated the thickness of dorsal skin, and eosinophil infiltration. AF treatment (especially 100 mg/mL) also demonstrably ameliorated the blood cell population abnormalities, as the notable elevation of serum concentrations of IgE, histamine, TNF-α, IL-6 and IL-1β were remarkably normalized by AF treatment. Western blot analysis evidenced the apparent normalization of inflammatory signals (ERK, p38 MAP kinase, JNK, and NF-κB) in the skin tissue. Additionally, AF treatment notably attenuated the activation of Th₂-dominant cytokines (IL-13, IL-4, and IL-5) in Con A-treated splenocytes in an ex vivo assay. In conclusion, this study provides experimental evidence for the clinical relevance of Atofreellage.

Genetic Associations of Interleukin-related Genes with Graves' Ophthalmopathy: a Systematic Review and Meta-analysis

Graves’ ophthalmopathy (GO) is the commonest extra-thyroidal manifestation of Graves’ disease (GD). Associations between interleukin-related (IL) gene polymorphisms and GO have been reported in different populations. We aim to confirm such associations by conducting a meta-analysis. Totally 382 publications were retrieved in MEDLINE and EMBASE up to 25/2/2015. After removing the duplicates and assessing the studies, we retrieved 16 studies that met the selection criteria for meta-analysis, involving 12 polymorphisms in 8 IL-related genes, and 1650 GO cases and 2909 GD controls. The summary odds ratio (OR) and 95% confidence intervals (CI) were estimated. We found one polymorphism in IL1A (rs1800587, c.-889C>T) showing a suggestive association with GO in the meta-analysis (allelic model [T vs. C]: OR = 1.62, 95% CI: 1.00–2.62, P = 0.050, I² = 53.7%; recessive model [TT vs. TC + CC]: OR = 2.39, 95% CI: 1.07–5.37, P = 0.039, I² = 23.6%; heterozygous model [TC vs. CC]: OR = 1.52, 95% CI: 1.04–2.22, P = 0.034, I² = 37.0%). No association with GO was detected for the other 7 genes (IL1B, IL1RA, IL4, IL6, IL12B, IL13 and IL23R). Our results thus indicate that IL1A is likely to be a genetic biomarker for GO. Further studies with larger sample sizes are warranted to confirm the associations of IL1A and other IL-related genes with GO.

The potential anti-proliferative effect of β-sitosterol on human mast cell line-1 cells

Thymic stromal lymphopoietin (TSLP) was reported to induce mast cell proliferation and aggravate allergic reactions through activation of mouse double minute 2 (MDM2). We aimed to ascertain that β-sitosterol (SI), which is one of the several phytosterols found mostly in foods, would regulate TSLP-induced mast cell proliferation. The results showed that SI significantly decreased the proliferation of human mast cell line (HMC-1) cells promoted by TSLP. SI significantly decreased the mRNA expression of Ki-67 in the TSLP-treated HMC-1 cells. SI significantly suppressed the production and mRNA expression of interleukin-13 in the TSLP-treated HMC-1 cells. Furthermore, SI downregulated the expression of MDM2 and phosphorylation of STAT6, whereas it upregulated the expression of p53, activation of caspase-3, and cleavage of poly ADP-ribose polymerase in the TSLP-treated HMC-1 cells. Results of this study suggest that SI may be a potential therapeutic agent for mast cell-mediated allergic diseases.

Relationship between the IL-4 gene promoter -590C/T (rs2243250) polymorphism and susceptibility to autoimmune diseases: a meta-analysis

OBJECTIVE

Studies investigating the association between interleukin (IL)-4 gene promoter -590C/T (rs2243250) polymorphism and autoimmune diseases report conflicting results. To derive a more precise estimation of the relationship, a meta-analysis was performed.

METHODS

A systematic literature search was conducted to identify relevant studies. Pooled odds ratio (OR) with 95% confidence interval (CI) was used to estimate the strength of association.

RESULTS

A total of 6001 cases and 6788 controls from 24 studies were analysed. Significant association of the C allele of IL-4 rs2243250 polymorphism with rheumatoid arthritis (RA) was detected (odds ratio (OR) = 0.696, 95% confidence interval (CI) = 0.601-0.807). Stratification by ethnicity indicated an association between the IL-4 rs2243250 polymorphism and RA in Caucasians. Furthermore, the overall ORs of the associations between the C allele and multiple scleorosis (MS) were 1.340 (95% CI = 1.102-1.630). However, we failed to reveal any association between IL-4 rs2243250 polymorphism and systemic lupus erythematosus (SLE), type 1 diabetes (T1D) or Graves' disease (GD).

CONCLUSIONS

The present study suggests that the IL-4 rs2243250 polymorphism might be associated with genetic susceptibility to autoimmune diseases, including RA and MS.

Interleukin-4 receptor α-chain polymorphisms and susceptibility to allergic rhinitis: a meta-analysis

Several polymorphisms in interleukin-4 receptor α-chain (IL-4RA) have been implicated in susceptibility to allergic rhinitis (AR), but the results are inconclusive. This meta-analysis was aimed to clarify the impact of IL-4RA polymorphisms on AR risk. Pubmed, EMBASE and Cochrane Library were searched until 2 October 2013 for eligible studies on IL-4RA polymorphism. Data were extracted, and pooled odd ratios (ORs) as well as 95 % confidence intervals (95 % CIs) were calculated. Ten studies with 1,552 AR patients and 1,473 controls were included. The results indicated that IL4RA Gln551Arg polymorphism was associated with AR susceptibility in Asian (AG vs. AA OR = 1.63, 95 % CI 1.17-2.28, I (2) = 57 %; GG vs. AA, OR = 1.69, 95 % CI 1.00-2.86, I (2) = 7 %; AG + GG vs. AA, OR = 1.68, 95 % CI 1.18-2.39, I (2) = 64 %; GG vs. AG + AA, OR = 1.47, 95 % CI 0.87-2.49, I (2) = 0 %; G vs. A, OR = 1.54, 95 % CI 1.14-2.10, I (2) = 64 %) but not in Caucasian. IL4RA Ile50 Val as well as Ser478Pro polymorphisms were not associated with AR susceptibility both in Asian and in Caucasian. Gene-gene and gene-environment interactions should be investigated in the future.

Association of IL-13 gene polymorphisms with airway hyperresponsiveness in a Japanese adult asthmatic population

BACKGROUND

A single nucleotide polymorphism (SNP; rs20541) in the IL-13 gene has been recognized as a risk factor for asthma. This SNP causes Arg to Gln (Q) substitution at position 110 in the mature IL-13 protein. We have recently showed that FEV1 in asthmatics with the Q110 variant of IL-13 declined faster, and progressive airway remodeling was observed in these subjects (Wynn, 2003 [1]). However, the effects of the IL-13 variant on airway hyperresponsiveness (AHR) remain to be elucidated. We analyzed the relationship between SNP rs20541 in IL-13 and AHR in asthmatics.

METHODS

We recruited 182 asthmatics who visited the asthma outpatient clinic at Iwate Medical University Hospital from 2006 to 2011. Subjects were genotyped for rs20541. Asthma severity, atopic status, age of asthma onset, serum IgE concentration, AHR, and pulmonary function were studied in these subjects. AHR was measured using the continuous methacholine inhalation method (Astograph; Chest; Tokyo, Japan).

RESULTS

Genotyping of rs20541 revealed 26 A/A, 77 A/G, and 79 G/G patient genotypes. The D min (U) of the 3 genotypes was 1.17±0.300 in A/A, 1.99±0.35 in A/G, and 2.85±0.39 in G/G. The D min in the 3 genotypes was significantly different. Spirometric data revealed that % FEV1 and % FEF75 were significantly different among the 3 groups of IL-13 genotypes, whereas no significant differences were observed in therapeutic steps, atopic status, house dust mite sensitization, or serum IgE concentration.

CONCLUSION

The SNP rs20541 in IL-13 was associated with AHR in Japanese adult asthmatics.

Associations of interleukin-4 receptor gene polymorphisms (Q551R, I50V) with rheumatoid arthritis: evidence from a meta-analysis

BACKGROUND AND AIMS

Published data on the associations between interleukin-4 receptor (IL-4R) gene polymorphisms (Q551R, I50V) and rheumatoid arthritis (RA) risk are controversial. To quantitatively evaluate the relationships, a meta-analysis was performed.

METHODS

Studies were identified from the databases of PubMed, MEDLINE, Chinese Biomedical Literature Database, and Chinese National Knowledge Infrastructure, with the last report up to June 2012. The effect summary odds ratio (OR) and 95% confidence interval (CI) were obtained.

RESULTS

A total of six separate comparisons involving 2173 patients and 1892 controls were included to assess the association of IL-4R gene Q551R polymorphism and RA susceptibility. Overall, no significantly elevated RA risk was found in the meta-analysis. The pooled OR for the minor R allele was 0.942 (95% CI: 0.848-1.047, p=0.268) in patients with RA. After stratification by ethnicity, there was still no significant association detected in the European population (OR=0.979, 95% CI: 0.875-1.094). As for I50V polymorphism, there were four comparisons involving 1653 patients and 1584 controls in this meta-analysis. The pooled OR for the V allele was 1.104 (95% CI: 1.001-1.217) in RA, the V allele of the IL-4R gene I50V variant might be a risk factor for RA. However, the relationship between the V allele of IL-4R gene I50V polymorphism and rheumatoid factor positive in patients with RA was not identified through a minor meta-analysis, including four independent relevant comparisons.

CONCLUSIONS

This meta-analysis indicates that the I50V polymorphism of IL-4R gene may confer susceptibility to RA; up to now, there is still not enough evidence to reveal the association of the IL-4R gene Q551R polymorphism with RA risk.

Retroviral infections in sheep and goats: small ruminant lentiviruses and host interaction

Small ruminant lentiviruses (SRLV) are members of the Retrovirus family comprising the closely related Visna/Maedi Virus (VMV) and the Caprine Arthritis-Encephalitis Virus (CAEV), which infect sheep and goats. Both infect cells of the monocyte/macrophage lineage and cause lifelong infections. Infection by VMV and CAEV can lead to Visna/Maedi (VM) and Caprine Arthritis-Encephalitis (CAE) respectively, slow progressive inflammatory diseases primarily affecting the lungs, nervous system, joints and mammary glands. VM and CAE are distributed worldwide and develop over a period of months or years, always leading to the death of the host, with the consequent economic and welfare implications. Currently, the control of VM and CAE relies on the control of transmission and culling of infected animals. However, there is evidence that host genetics play an important role in determining Susceptibility/Resistance to SRLV infection and disease progression, but little work has been performed in small ruminants. More research is necessary to understand the host-SRLV interaction.

STAT6 and lung inflammation

Lung inflammation has many etiologies, including diseases of Th2-type immunity, such as asthma and anti-parasitic responses. Inflammatory diseases of the lung involve complex interactions among structural cells (airway epithelium, smooth muscle, and fibroblasts) and immune cells (B and T cells, macrophages, dendritic cells, and innate lymphoid cells). Signal transducer and activator of transcription 6 (STAT6) has been demonstrated to regulate many pathologic features of lung inflammatory responses in animal models including airway eosinophilia, epithelial mucus production, smooth muscle changes, Th2 cell differentiation, and IgE production from B cells. Cytokines IL-4 and IL-13 that are upstream of STAT6 are found elevated in human asthma and clinical trials are underway to therapeutically target the IL-4/IL-13/STAT6 pathway. Additionally, recent work suggests that STAT6 may also regulate lung anti-viral responses and contribute to pulmonary fibrosis. This review will focus on the role of STAT6 in lung diseases and mechanisms by which STAT6 controls immune and structural lung cell function.

Association between the interleukin-4, interleukin-13 polymorphisms and asthma: a meta-analysis

A numbers studies had been reported that the polymorphisms in the Interleukin 4 (IL-4) and Interleukin 13 (IL-13) genes were associated with susceptibility to asthma. However, the results were inconsistent and inconclusive. We carried out a meta-analysis of case-control genetic association studies to assess whether the combined data showed this association by using a genetic model-free approach. Thirty studies (total 12,781 asthma and 11,500 controls) for the IL-4 C-33T and C-589T, IL-13 C-1112T and G+2044A with asthma were included in the meta-analysis. The results indicated that there were an association between the IL-4 C-33T (P = 0.006) and C-589T (P = 0.04), IL-13 C-1112T (P = 0.002) and G+2044A (P = 0.04) and susceptibility to asthma. And the definition of asthma subgroup meta-analysis demonstrates that the IL-4 C-33T is not associated with nonatopic or atopic, and IL-4 C-589T and IL-13 C-1112T polymorphisms are not associated with atopic. In the ethnicity subgroup meta-analysis, the IL-4 -589T (P = 0.003) and the IL-13 -1112T (P < 0.00001) alleles are associated with asthma among Caucasian, but not on the IL-13 +2044A allele. In conclusion, IL-4 C-33T and C-589T, IL-13 C-1112T and G+2044A could be proposed as asthma susceptible SNPs. Further investigation in larger studies and meta-analysis is required.

The release of IL-31 and IL-13 after nasal allergen challenge and their relation to nasal symptoms

Background

IL-31, a recently discovered member of the gp130/IL-6 cytokine family, is mainly expressed by human mast cells and T helper type 2 cells. IL-31 is a key trigger of atopic dermatitis. Recent studies also suggest a role of IL-31 in the pathogenesis of other allergic diseases including allergic rhinitis. In the present study we studied the release of IL-31 and IL-13 in allergen-challenged allergic rhinitis patients.

Methods

Seven seasonal allergic volunteers underwent unilateral nasal provocation with allergen (and a control challenge) with the disc method out of the allergy season. Nasal symptom scores (rhinorrhea, itching, sneezing, obstruction) and bilateral nasal secretions were quantified before and after allergen provocation. IL-13 and IL-31 in nasal secretions and serum were measured by electrochemiluminescent immunoassay or ELISA, respectively.

Results

Nasal allergen challenge induced the typical clinical symptoms and physiological changes. IL-31 and IL-13 in nasal secretions increased in four and five, respectively, volunteers at 5 h after allergen but not after control challenge. We observed correlation trends between nasal IL-31 concentrations and IL-13 concentrations (r = 0.9, p = 0.002), and IL-31 contents and symptom scores (r = 0.9, p = 0.013) 5 h after allergen provocation. No IL-31 could be detected contralaterally or systemically in the sera.

Conclusions

The observed local upregulation of IL-31 mainly during the late phase reaction after nasal allergen challenge suggests a role of IL-31 in allergic rhinitis. In which way IL-31 modulates the inflammatory reaction and type 2 responses in allergic rhinitis remains to be investigated.

Association of interleukin 4 (-590 T/C) and interleukin 4 receptor (Q551R A/G) gene polymorphisms with acne vulgaris

BACKGROUND AND OBJECTIVES

Acne vulgaris is a common skin disorder. The complete etiology of this disease remains to be identified; however, it seems that aberrant expression of cytokine genes might be a contributing factor. This study aimed to investigate the association of genetic polymorphisms related to interleukin 4 (IL-4) promotor and receptor (IL-4R) genes as inflammatory modulators with acne vulgaris.

DESIGN AND SETTING

A case-control study 95 acne patients recruited from outpatient dermatology clinics affiliated with Qassim University, Qassim, Saudi Arabia.

PATIENTS AND METHODS

Acne patient data were compared with 87 normal healthy unrelated controls from the same locality. The genomic DNA was extracted and processed using the real-time polymerase chain reaction amplification for characterization of polymorphisms related to IL-4 (-590 T/C) and IL-4R (Q551R A/G) genes.

RESULTS

Acne patients compared to controls showed no significant difference in the frequencies of IL-4 (-590 T/C) polymorphic genotypes (P=.8), yet had a highly significant difference in IL-4R (Q551R A/G) genotypes (P<.001). The frequencies of the mutant genotype IL-4R GG as well as the allele IL-4R G were significantly higher in cases of acne than in controls. Furthermore, acne cases showed higher frequencies of combined genotypes IL4R_GG with IL-4_CC, CT, or TT. However, no significant difference was noted on comparing subgroups related to disease severity or response to treatment (P>.05).

CONCLUSIONS

This study provides evidence for a significant association of IL-4R (Q551R A/G) genetic polymorphisms with the susceptibility rather than the severity of acne vulgaris.

The differences in the involvements of loci of promoter region and Ile50Val in interleukin-4 receptor α chain gene between atopic dermatitis and Japanese cedar pollinosis

BACKGROUND

Atopic dermatitis (AD) and Japanese cedar pollinosis (JCP) are common chronically allergic diseases associated with the activation of T-helper 2 cells. Recent studies have shown that polymorphisms in the genes for IL-4 receptor α chain (IL4RA) may contribute to susceptibility of AD and JCP, although the differences in the involvements of loci of IL4RA gene between AD and JCP are unclear. In this study, we investigated the role of polymorphisms in IL-4RA gene in conferring susceptibility to the development of AD and/or JCP using a family analysis and an association analysis in a Japanese population.

METHODS

Five polymorphisms in the IL-4RA gene, C-3223T, T-1914C, T-890C, Ile50Val and Glu375Ala, have been genotyped using PCR-based methods in 75 trios families, including 15 AD families, 30 JCP families, and 30 families with combination of AD and JCP in the family analysis. Forty-five AD, 60 JCP and 125 control children constituted the association study.

RESULTS

The transmission disequilibrium test showed that the allele of Ile50 was significantly transmitted to children with JCP alone (p < 0.05). Haplotype analysis showed that the -3223T/Ile50 haplotype was preferentially transmitted to both AD (p < 0.01) and JCP children (p < 0.01), while that the C-3223/Ile50 haplotype was preferentially transmitted to only JCP children (p < 0.01). The association study showed that -3223T and haplotype of -3223T/Ile50 were associated with AD children, but not with JCP. Ile50 was associated with both AD and JCP.

CONCLUSIONS

Our data suggest that -3223T and the -3223T/Ile50 haplotype were risk factors for AD. Ile50 allele seems to be involved in both JCP and AD. Interactions of the IL-4RA loci may play a role both conferring susceptibility and modulating severity of AD.

Influence of inhaled beclomethasone and montelukast on airway remodeling in mice

This study examined the effect of montelukast and beclomethasone on airway remodeling in murine model of asthma. Mice were sensitized by i.p. injection of ovalbumin (OVA) on days 0 and 14, and then challenged by nebulization of 1% OVA 3 days/week for 6 or 10 weeks. Results of 6-week OVA-challenged group showed moderate inflammation, but the 10-week OVA-challenged group exhibited mild inflammation. The OVA challenge (6 and 10 weeks) exhibited marked airway fibrosis, illustrated by significant increase in goblet cell hyperplasia and epithelial thickness, increased lung content of collagen and transforming growth factor-β(1), together with a decrease in nitric oxide production; also, there was an increase in bronchoalveolar lavage fluid level of interleukin-13. Administration of montelukast or beclomethasone before each OVA challenge was capable of restoring most of the measured parameters to near normal levels. Inhalation of beclomethasone has a similar role in airway remodeling as montelukast, but its effects in regulating inflammatory changes is less pronounced than montelukast.

Association of STAT6 and ADAM33 single nucleotide polymorphisms with asthma bronchiale and IgE level and its possible epigenetic background

BACKGROUND

ADAM33 and STAT6 belong to the candidate genes that have been commonly associated with asthma, bronchial hyperresponsiveness or IgE levels. Our objective was to assess the association of 11 SNPs of the ADAM33 and 6 of the STAT6 and their haplotypes with IgE levels and asthma. We also evaluated the possible role of parental origin of haplotypes on IgE levels.

METHODS

We enrolled 109 children with asthma and 45 healthy controls. Genotyping was performed by TaqMan probes and confirmed by sequencing. Haplotype construction was based on the knowledge of parental genotypes and also inferred by using the EM algorithm and Bayes' theorem.

RESULTS

None of the SNPs were associated with elevated IgE level or asthma. We found that the most frequent STAT6 haplotype ATTCAA (built from rs324012, rs324011, rs841718, rs3024974, rs3024974, rs4559 SNPs, respectively) was associated with elevated total IgE levels (P=0.01) and this haplotype was predominantly transmitted paternally (P<0.001). We compared our results with those of studies performed on German and Australian Caucasian populations and found that rs324011, rs3024974 and rs4559 SNPs in STAT6 should have a major effect on IgE levels. Therefore, we suggest the TCA haplotype alone (built from rs324011, rs3024974 and rs4559 SNPs, respectively) in STAT6 is associated with total IgE elevation.

CONCLUSIONS

The influence of paternal origin of the STAT6 haplotype on IgE levels is surprising but the exact role of possible paternal imprinting in STAT6 regulation should be investigated and confirmed in future studies.

Stat6 activity-related Th2 cytokine profile and tumor growth advantage of human colorectal cancer cells in vitro and in vivo

Signal transducer and activator of transcription 6 (Stat6) is critical in Th2 polarization of immune cells and active Stat6 activity has been suggested in anti-tumor immunity in animal models. The present study aims at investigating the impact of natural Stat6 activity on tumor microenvironment in human colorectal cancer cells in vitro and in vivo. Using colorectal cancer cell lines HT-29 and Caco-2 whose IL-4/Stat6 activities were known and nude mice as a model, we examined correlative relationships between Stat6 activities and gene expression profiles together with cellular behaviors in vitro and in vivo. HT-29 cells carrying active Stat6 signaling displayed spontaneous expression profiles favoring Th2 cytokines, cell cycle promotion, anti-apoptosis and pro-metastasis with increased mRNA levels of IL-4, IL-13, GATA-3, CDK4, CD44v6 and S100A4 using RT-PCR. In contrast, Caco-2 cells carrying defective Stat6 signaling exhibited spontaneous expression profiles favoring Th1 and Th17 cytokines, cell cycle inhibition, pro-apoptosis and anti-metastasis with elevated mRNA expression of IFNγ, TNFα, IL-12A, IL-17, IL-23, T-bet, CDKN1A, CDKNIB, CDKN2A and NM23-H1. Xenograft tumors of Stat6-active HT-29 cells showed a growth advantage over those of Stat6-defective Caco-2 cells. Furthermore, mice bearing HT-29 tumors expressed increased levels of Th2 cytokines IL-4 and IL-5 in the blood and pro-growth and/or pro-metastasis proteins CDK4 and CD44v6 in the tumor. To the contrary, mice bearing Caco-2 tumors expressed heightened levels of Th1 cytokines IFNγ and TNF in the blood and pro-apoptosis and anti-metastatic proteins p53 and p27(kip1) in the tumor. Colorectal cancer cells carrying active Stat6 signaling may create a microenvironment favoring Th2 cytokines and promoting expression of genes related to pro-growth, pro-metastasis and anti-apoptosis, which leads to a tumor growth advantage in vivo. These findings may imply why Stat6 pathway is constitutively activated in a number of human malignancies.

Association study on IL4, IL13 and IL4RA polymorphisms in mite-sensitized persistent allergic rhinitis in a Chinese population

Background

The IL4, IL13, and IL4 receptor α chain (IL4RA) genes are candidate genes for atopic diseases. We hypothesized that the polymorphisms in these genes are associated with persistent allergic rhinitis (PER).

Objective

To investigate the association of the potential functional polymorphisms in IL4, IL13, and IL4RA with PER induced by house dust mites in a Chinese population.

Methods

Using the TaqMan method, we genotyped six single nucleotide polymorphisms (SNPs) including C-590T in IL4, C-1055T and Arg130Gln in IL13, and Ile50Val, Ser478Pro and Gln551Arg in IL4RA, in a case-control study of 265 patients with PER and 275 healthy controls.

Results

We found that the CT/CC genotypes in IL4 C-590T were associated with a significantly decreased risk of mite-sensitized PER [adjusted odds ratio (OR)  = 0.64, 95% confidence interval (CI) 0.45–0.92], compared to the TT genotype. Furthermore, PER patients with CT/CC genotypes had significantly lower serum levels of total IgE than those with TT genotype (P = 0.001). However, there was no significant association of the IL13 and IL4RA polymorphisms with mite-sensitized PER (P>0.05).

Conclusions

Our results suggest that the C-590T polymorphism in IL4 may contribute to the susceptibility to mite-sensitized PER in a Chinese population.

Association of polymorphisms in genes encoding IL-4, IL-13 and their receptors with atopic dermatitis in a Korean population

Th2-dominated immune responses are believed to contribute to the pathogenesis of atopic dermatitis (AD). IL-4 and IL-13 are typical pleiotropic Th2 cytokines that play a central role in IgE-dependent inflammatory reactions. Single-nucleotide polymorphisms (SNPs) in IL-4 and IL-13 have been reported in patients with allergic disease from numerous countries. Gene-gene interactions among genes have been identified in patients with asthma, although negative results have been reported. To investigate the associations of SNPs in these genes and the interactions between these genes in AD, we genotyped 23 SNPs of the IL-4, IL-13, IL-4R, IL-13Rα1 and IL-13Rα2 genes for 1089 case-control samples (631 AD patients and 458 controls) and analysed the SNPs and haplotypes in these genes. We also searched for gene-gene interactions among these five genes. Our data identified an association between rs3091307 and rs20541 in the IL-13 gene and between rs2265753 and rs2254672 in the IL-13Rα1 gene and the AD phenotype. In particular, three of the four SNPs were especially predictive of the allergic type of AD (ADe), and the haplotype TCGG in the IL-13Rα1 gene showed significant association with AD, especially ADe. Furthermore, the combination of rs3091307 GG/ rs2265753 GG (IL-13/IL-13Rα1) conveyed a significantly higher risk for developing ADe. However, we did not identify any SNPs in the IL-4, IL-4R and IL-13Rα2 genes that were associated with AD. As IL-13Rα1 is most likely expressed in Th17 cells rather than in Th2 cells, these data suggest diversity in the classification of Th cells that needs to be verified in future studies.

Characterization of STAT6 target genes in human B cells and lung epithelial cells

Using ChIP Seq, we identified 556 and 467 putative STAT6 target sites in the Burkitt's lymphoma cell line Ramos and in the normal lung epithelial cell line BEAS2B, respectively. We also examined the positions and expression of transcriptional start sites (TSSs) in these cells using our TSS Seq method. We observed that 44 and 132 genes in Ramos and BEAS2B, respectively, had STAT6 binding sites in proximal regions of their previously reported TSSs that were up-regulated at the transcriptional level. In addition, 406 and 109 of the STAT6 target sites in Ramos and BEAS2B, respectively, were located in proximal regions of previously uncharacterized TSSs. The target genes identified in Ramos and BEAS2B cells in this study and in Th2 cells in previous studies rarely overlapped and differed in their identity. Interestingly, ChIP Seq analyses of histone modifications and RNA polymerase II revealed that chromatin formed an active structure in regions surrounding the STAT6 binding sites; this event also frequently occurred in different cell types, although neither STAT6 binding nor TSS induction was observed. The rough landscape of STAT6-responsive sites was found to be shaped by chromatin structure, but distinct cellular responses were mainly mediated by distinct sets of transcription factors.

Associations of IL-4, IL-4R, and IL-13 gene polymorphisms in coal workers' pneumoconiosis in China: a case-control study

BACKGROUND

The IL-4, IL-4 receptor (IL4R), and IL-13 genes are crucial immune factors and may influence the course of various diseases. In the present study, we investigated the association between the potential functional polymorphisms in IL-4, IL-4R, and IL-13 and coal workers' pneumoconiosis (CWP) risk in a Chinese population.

METHODS

Six polymorphisms (C-590T in IL-4, Ile50Val, Ser478Pro, and Gln551Arg in IL-4R, C-1055T and Arg130Gln in IL-13) were genotyped and analyzed in a case-control study of 556 CWP and 541 control subjects.

RESULTS

Our results revealed that the IL-4 CT/CC genotypes were associated with a significantly decreased risk of CWP (odds ratio (OR) = 0.74, 95% confidence interval (CI) = 0.58-0.95), compared with the TT genotype, particularly among subgroups of age <65 years (OR = 0.68, 95%CI = 0.46-0.99) and dust exposure years ≥26 years (OR = 0.69, 95%CI = 0.50-0.94). Moreover, the polymorphism was significantly associated with risk of CWP patients with stage I. In addition, a combined effect was observed in a dose-dependent manner with increasing numbers of risk variant alleles (P(trend) = 0.023), and individuals with 11-12 risk alleles had a 47% higher risk of CWP than those with 0-8 risk alleles (OR = 1.47, 95% CI = 1.05-2.05).

CONCLUSIONS

Our results suggest that the IL-4 C-590T polymorphism is involved in the etiology of CWP and susceptibility to this disease. Larger studies are warranted to validate our findings.