Involvement of IL-4, IL-13 and Their Receptors in Pancreatic Cancer

Interleukin (IL)-4 and IL-13 are known as pleiotropic Th2 cytokines with a wide range of biological properties and functions especially in immune responses. In addition, increasing activities have also been determined in oncogenesis and tumor progression of several malignancies. It is now generally accepted that IL-4 and IL-13 can exert effects on epithelial tumor cells through corresponding receptors. Type II IL-4 receptor (IL-4Rα/IL-13Rα1), predominantly expressed in non-hematopoietic cells, is identified to be the main target for both IL-4 and IL-13 in tumors. Moreover, IL-13 can also signal by binding to the IL-13Rα2 receptor. Structural similarity due to the use of the same receptor complex generated in response to IL-4/IL-13 results in overlapping but also distinct signaling pathways and functions. The aim of this review was to summarize knowledge about IL-4 and IL-13 and their receptors in pancreatic cancer in order understand the implication of IL-4 and IL-13 and their receptors for pancreatic tumorigenesis and progression and for developing possible new diagnostic and therapeutic targets.

IL4RA gene expression in relation to I50V, Q551R and C-3223T polymorphisms

BACKGROUND

Interleukin 4 (IL-4) and its receptor play important roles in the pathologies of asthma and atopy. The alpha subunit of the IL-4 receptor (IL-4RA) is included in 2 types of receptors which have different modulatory effects on immune responses. This distinct pattern reflects involvement in the immunopathology of both asthma and atopy. A number of studies have proven the association between IL4RA gene polymorphisms and asthma and atopy, but it is still an open question whether these variants are functional.

OBJECTIVES

To analyze the data from IL4RA gene expression in PBMC in relation to specific polymorphisms - the most frequently studied I50V and Q551R and the less known C-3223T.

MATERIAL AND METHODS

The analysis was performed for 36 subjects, both atopic and non-atopic. Real-time polymerase chain reaction (PCR) was used with specific primers for the quantification and genotyping. Delta Ct (ΔCT) and delta-delta Ct (ΔΔCT) values were used for the relative quantification of IL4RA expression in PBMC.

RESULTS

We observed no significant differences in the IL4RA expression profile between the 3 genotypes. A trend toward higher relative expression was observed for homozygous minor I50V and C-3223T genotypes.

CONCLUSIONS

We did not find a statistically significant relationship between the genetic polymorphisms and the relative expression of IL4RA. The effect of genetic polymorphism on IL4RA mRNA expression could interfere with other factors, such as environmental stimuli, and should be evaluated in future studies.

Genetic variants in IL4RA, IL6, and IL12B genes and susceptibility to hepatitis B and C virus infections among Iraqi patients

Hepatitis B and C viruses (HBV and HCV) are common causative pathogens of viral hepatitis. Progression of both infections is determined by virus- and host-related factors. Cytokines are important host genetic factors that may have a predisposing role in HBV and HCV infections. This case-control study evaluated the genetic association of IL4RA+1902 (rs1801275), IL6-174 (rs1800795), IL6-597 (rs1800797), and IL12B-1188 (rs3212227) variants with chronic HBV and HCV infections among Iraqi patients. A total of 220 viral hepatitis patients were enrolled in the study (113 HBV and 107 HCV), together with 141 healthy subjects. Sequence-specific primer polymerase chain reaction assay was the genotyping method. Results revealed that under a dominant genetic model, IL6-174 variant was significantly associated with HBV infection, whereas no association with the HCV risk was reported. However, the risk for both infections was markedly associated with IL6-597 variant under recessive, dominant, and codominant genetic models. Estimation of IL6-174 -IL6-597 haplotypes depicted that G-A haplotype was significantly associated with an increased risk to develop HBV infection, whereas a significantly decreased risk was associated with G-G and C-G haplotypes. For HCV, G-G and C-A haplotypes were significantly associated with risk of HCV infection. IL4RA+1902 and IL12B-1188 variants showed no association with HBV or HCV risk. Analysis of variance revealed no significant association between genotypes of the four determined single-nucleotide polymorphisms and HBV or HCV viral load. In conclusion, the study supports the concept that IL6-597 variant is associated with susceptibility to HBV and HCV infections among Iraqis. The risk of HBV infection is further associated with IL6-174 variant.

The establishment of humanized IL-4/IL-4RA mouse model by gene editing and efficacy evaluation

Asthma is a common respiratory immune disease in children and adults, and interleukin-4 (IL-4) is one of the key factors for the onset of asthma. Therefore, targeting human IL-4 and IL-4 receptor alpha (IL-4RA) has become one of the strategies for targeted therapy of cytokines. Herein, we established an animal model of asthmatic airway inflammation using double humanized IL-4/IL-4RA (hIL-4/hIL-4RA) mice, where human IL-4 and IL-4RA replaced their murine counterparts, respectively. We successfully identified the phenotype by Southern blotting, ELISA, and flow cytometry. The hIL-4/hIL-4RA mice induced by ovalbumin (OVA) exhibited several important features of asthma, such as inflammatory cell infiltration, IgE release, goblet cell hyperplasia, and Th2 cytokine secretion. Furthermore, treatment of these humanized mice with anti-human IL-4RA antibodies significantly inhibited level of these pathological indicators. Thus, hIL-4/hIL-4RA mice provide a validated preclinical mouse model to interrogate new therapeutic agents targeting this specific cytokine pathway in asthma.

Anti-inflammatory effects of interleukin-4 on intervertebral disc cells

BACKGROUND CONTEXT

Inflammation has been associated with a number of pathological conditions including intervertebral disc (IVD) degeneration, increased risks of low back pain and other spinal diseases. Downregulating disc inflammation may be a strategy to reduce degeneration and more importantly back pain. Interleukin (IL)-4 was first discovered as a T-cell secreted factor that enhanced the proliferation of anti-IgM stimulated B cells and is now known as a cytokine that can stimulate cell proliferation and differentiation, tissue regeneration and neurological functions. IL-4 has been shown to be effective in inhibiting inflammatory pathways in chondrocytes. Immunohistochemical studies have shown that disc tissues are immunopositive for IL-4 receptor α (IL-4Rα) and IL-4. Yet, the roles of IL-4 and IL-4R in disc biology remain unknown.

PURPOSE

The purpose of this study is to understand the roles of IL-4 and IL-4Rα in IVDs and to determine if IL-4 can function to inhibit inflammation in IVD cells.

STUDY DESIGN/SETTING

In vitro experiment.

METHODS

Deidentified patient IVD tissues were collected after surgery under the Orthopedic Information, Tissue and Implant Repository (ORA L00011021). IVD cells were isolated and cultured in monolayer. IL-4R protein expression was analyzed using immunocytochemistry. To test if the IL-4R was responsive to its ligand, signal transducer and activator of transcription 6 (STAT6) phosphorylation was analyzed on cell lysates of IVD cells treated with recombinant human IL-4 for 30 minutes using enzyme linked immunosorbent assay kit. Gene expression analysis of IL-4 up- and downregulated genes were analyzed using real-time RT-PCR. Anti-inflammatory effects of IL-4 were determined by cotreating disc cells with lipopolysaccharide (LPS) and IL-4 and measuring gene expression and protein release of inflammatory markers, IL-6 and IL-8. The significance of differences among means of data on gene expression and protein analyses were analyzed by one-way analysis of variance or student t test. Differences were considered significant when the p value was below 0.05.

RESULTS

Immunocytochemistry staining for IL-4Rα in primary IVD cells (n=8) showed the majority of immunopositive staining was intracellular. After IVD cells (n=3-7) were treated with different concentrations of recombinant human IL-4 (0.1-100 ng/mL) for 30 minutes, phospho-STAT6 levels significantly increased by two- to four-fold at all concentrations tested compared with untreated cells. Gene expression of IL-4Rα and IL-6 increased significantly in cells undergoing IL-4 treatment for 24 hours compared with control treated IVD cells (n=5-10). LPS stimulated inflammatory gene expression of interferon (IFN)β, IL-12, IL-6, and IL-8 were downregulated significantly in the presence of IL-4 (n=7). Lastly, protein release of IL-6 and IL-8 were reduced significantly in cells treated with IL-4 and LPS compared with those treated with LPS alone (n=7).

CONCLUSIONS

This study was the first to explore the function of IL-4 and IL-4R in IVD cells. Immunocytochemistry studies confirmed that the majority of cells isolated from patient IVDs expressed IL-4Rα at the protein level. Also, IVD cells can respond to IL-4 by up-regulating IL-4Rα and IL-6 genes and inhibiting inflammatory genes and proteins induced by LPS. Further studies to test the anti-inflammatory effects of IL-4 in the IVD would be needed in animal models.

CLINICAL RELEVANCE

Biological therapies which include intradiscal delivery of cells, anti-inflammatories or growth factors are being investigated to treat disc degeneration and back pain in animal models and in the clinic. Based on our findings that IL-4 has anti-inflammatory effects on IVD cells, the results of this study suggest including recombinant IL-4 delivery into the intervertebral disc may be a beneficial therapeutic strategy to treat patients with back pain by reducing disc inflammation.

IL4Rα Signaling Abrogates Hypoxic Neutrophil Survival and Limits Acute Lung Injury Responses In Vivo

Rationale: Acute respiratory distress syndrome is defined by the presence of systemic hypoxia and consequent on disordered neutrophilic inflammation. Local mechanisms limiting the duration and magnitude of this neutrophilic response remain poorly understood. Objectives: To test the hypothesis that during acute lung inflammation tissue production of proresolution type 2 cytokines (IL-4 and IL-13) dampens the proinflammatory effects of hypoxia through suppression of HIF-1α (hypoxia-inducible factor-1α)-mediated neutrophil adaptation, resulting in resolution of lung injury. Methods: Neutrophil activation of IL4Ra (IL-4 receptor α) signaling pathways was explored ex vivo in human acute respiratory distress syndrome patient samples, in vitro after the culture of human peripheral blood neutrophils with recombinant IL-4 under conditions of hypoxia, and in vivo through the study of IL4Ra-deficient neutrophils in competitive chimera models and wild-type mice treated with IL-4. Measurements and Main Results: IL-4 was elevated in human BAL from patients with acute respiratory distress syndrome, and its receptor was identified on patient blood neutrophils. Treatment of human neutrophils with IL-4 suppressed HIF-1α-dependent hypoxic survival and limited proinflammatory transcriptional responses. Increased neutrophil apoptosis in hypoxia, also observed with IL-13, required active STAT signaling, and was dependent on expression of the oxygen-sensing prolyl hydroxylase PHD2. In vivo, IL-4Ra-deficient neutrophils had a survival advantage within a hypoxic inflamed niche; in contrast, inflamed lung treatment with IL-4 accelerated resolution through increased neutrophil apoptosis. Conclusions: We describe an important interaction whereby IL4Rα-dependent type 2 cytokine signaling can directly inhibit hypoxic neutrophil survival in tissues and promote resolution of neutrophil-mediated acute lung injury.

Serum IgE and Allergy Related Genotypes of IL-4R α and IL-13 Genes: Association with Glioma Susceptibility and Glioblastoma Prognosis

Gliomas are the commonest type of primary brain tumor in adult. Glioblastoma maltiforms (GBM) is the malignant form with poor prognosis. Certain genotypes of inflammatory gene which associated with asthma and allergic conditions (IL-4R α and IL- 13) are inversely associated with glioma risk. We studied the relation between allergic conditions and serum level of IgE and glioma risk. We also examined the role of SNP of inflammatory genes IL-4 R α (rs 1801275) and IL-13 (rs 1800925) in development of glioma and to find out factors which can modify the prognosis of glioblastoma. This study included 98 Egyptian glioma cases and 98 healthy controls. Full history and clinical data were taken; total serum IgE were assayed, genotyping of IL-4 R α (rs 1801275) and IL-13 (rs 1800925) genes was carried out by restriction digestion after genes amplification. In cases group histopathological examination and tumor grading were done. Past history of allergic condition and elevated serum levels of IgE were more frequent in controls than in cases group (P< 0.05). Genotypes AA and AG of IL- 4R α were significantly frequent in cases and A allele were considered risk factor for glioma OR 2.31(1.53- 3.48), P < 0.001. We also found that C allele of IL-13 is risk factor for glioma susceptibility with p value = 0.006. Longer median survival period in glioblastoma were associated with elevated serum IgE level and who were AA genotypes of IL-4 R α. We conclude an inverse relation between glioma risk, and allergy biomarker IgE and allergy related (IL-4R α; rs 1801275) gene polymorphisms. GBM patients with IL-4Rα AA genotype, have longest survival. Chemotherapy and gross total resection improve GBM prognosis.

The cytokine polymorphisms affecting Th1/Th2 increase the susceptibility to, and severity of, chronic ITP

BACKGROUND

T-helper cell type 1 (Th1) polarization in chronic immune thrombocytopenia (cITP) has been reported at the protein and mRNA levels. We evaluated the impact of Th1/Th2 cytokine and cytokine receptor functional polymorphisms on both susceptibility to, and severity of, cITP. We analysed IFN-γ + 874 T/A, IFN-γR -611G/A, IL-4 -590C/T, and IL-4Rα Q576R polymorphisms in 126 cITP patients (male/female: 34/92; median age: 47.7 years) and 202 healthy control donors. Genotyping was determined by PCR and direct sequencing. The Th1/Th2 ratio was detected in peripheral blood mononuclear cells via flow cytometry.

RESULTS

cITP patients had a higher frequency of the IL-4Rα 576 non-QQ genotype compared to healthy subjects (P = 0.04). cITP patients with the IFN-γ +874 non-AA genotype (high expression type) showed more severe thrombocytopenia than those with the AA genotype (P < 0.05). cITP patients had a significantly higher Th1/Th2 ratio than control patients (P < 0.01); this ratio was inversely correlated with platelet counts. Furthermore, patients with both IFN-γ +874 non-AA genotype (high expression type) and IFN-γR -611 non-AA genotype (high-function type) had a significantly higher Th1/Th2 ratio (P < 0.05).

CONCLUSIONS

The cytokine polymorphisms affecting Th1/Th2 increase the susceptibility to, and severity of, chronic ITP.

Duodenal Mucosa of Patients With Type 1 Diabetes Shows Distinctive Inflammatory Profile and Microbiota

CONTEXT

Increasing evidences suggest a correlation between gut and type 1 diabetes (T1D).

OBJECTIVE

The objective of this study is to evaluate the gut inflammatory profile and microbiota in patients with T1D compared with healthy control (CTRL) subjects and patients with celiac disease (CD) as gut inflammatory disease controls.

DESIGN/SETTING/PARTICIPANTS

The inflammatory status and microbiome composition were evaluated in biopsies of the duodenal mucosa of patients with T1D (n = 19), in patients with CD (n = 19), and CTRL subjects (n = 16) recruited at San Raffaele Scientific Institute, in Milan, Italy, between 2009 and 2015.

MAIN OUTCOME MEASURES

Inflammation was evaluated by gene expression study and immunohistochemistry. Microbiome composition was analyzed by 16S ribosomal RNA gene sequencing.

RESULTS

An increased expression of CCL13, CCL19, CCL22, CCR2, COX2, IL4R, CD68, PTX3, TNFα, and VEGFA was observed in patients with T1D compared with CTRL subjects and patients with CD. Immunohistochemical analysis confirmed T1D-specific inflammatory status compared with healthy and CD control tissues, mainly characterized by the increase of the monocyte/macrophage lineage infiltration. The T1D duodenal mucosal microbiome results were different from the other groups, with an increase in Firmicutes and Firmicutes/Bacteroidetes ratio and a reduction in Proteobacteria and Bacteroidetes. The expression of genes specific for T1D inflammation was associated with the abundance of specific bacteria in the duodenum.

CONCLUSIONS

This study shows that duodenal mucosa in T1D presents disease-specific abnormalities in the inflammatory profile and microbiota. Understanding the mechanisms underlying these features is critical to disentangle the complex pathogenesis of T1D and to gain new perspectives for future therapies targeting the intestine.

Association of IL4, IL13, and IL4R polymorphisms with gastrointestinal cancer risk: A meta-analysis

Background

Previous studies have suggested that IL4, IL13, and IL4R are associated with serum IgE levels and allergies, and common variants of these genes may alter cancer risk. To clarify these associations, we conducted a meta-analysis to investigate the associations of IL4, IL13, and IL4R polymorphisms with gastrointestinal cancer risk.

Methods

We used 27 eligible case–control studies describing the associations of six polymorphisms of IL4, IL13, and IL4R with gastrointestinal cancer risk to calculate summary odds ratios (ORs) and 95% confidence intervals (CIs) using five different genetic models. The Q-statistic and I² statistic were calculated to examine heterogeneity.

Results

The IL4 rs2070874 T allele seems to be associated with an increased risk of gastrointestinal cancer (OR 1.11; 95% CI, 1.00–1.24 for T allele vs. C allele). This association was significant in studies conducted outside of Asia (OR 1.28; 95% CI, 1.03–1.58 for T allele vs. C allele) and in studies investigating the association with gastric cancer (OR 1.17; 95% CI, 1.03–1.34 for T allele vs. C allele). However, the IL4R rs1801275 heterozygote seems to be associated with a reduced risk of gastrointestinal cancer (OR 0.79; 95% CI, 0.65–0.96 for AG vs. AA). Other polymorphisms did not show any significant associations with gastrointestinal cancer risk in any of the genetic models and subgroup analyses.

Conclusions

Our results suggest that certain polymorphisms of IL4 and IL4R may affect susceptibility to gastrointestinal cancer. However, further studies are required to confirm these findings.

•

This meta-analysis included 27 eligible case–control studies.

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IL4 rs2070874 T allele may increase the risk of gastrointestinal cancer.

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IL4R rs1801275 variant may reduce the risk of gastrointestinal cancer.

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Polymorphisms in IL4 and IL4R may affect susceptibility to gastrointestinal cancer.

IL-4 mRNA Is Downregulated in the Liver of Pancreatic Cancer Patients Suffering from Cachexia

BACKGROUND

Interleukin-4 (IL-4) together with interleukin-13 (IL-13) play an important role in inflammation and wound repair, and are known to be upregulated in human skeletal muscle after strenuous physical exercise. Additionally, these cytokines may act as autocrine growth factors in pancreatic cancer cells. We hypothesize that IL-4, IL-13, and their corresponding receptors are involved in mechanism of cancer cachexia.

METHODS

Tissue samples from human skeletal muscle, white fat, liver, healthy pancreas, and pancreatic ductal adenocarcinoma were analyzed by quantitative real-time polymerase chain reaction for mRNA expression levels of IL-4, IL-13, IL-4 receptor α, and IL-13 receptor α1.

RESULTS

We demonstrate for the first time that liver IL-4 mRNA is downregulated in vivo in patients with pancreatic cancer and cachexia. Additionally, IL-4 mRNA in the liver inversely correlated with musculus psoas thickness.

CONCLUSION

We speculate that suppression of IL-4 is involved in cancer cachexia, although the exact mechanisms have to be further elucidated.

A practical overview of pediatric atopic dermatitis, part 2: triggers and grading

In part 2 of this 3-part series on atopic dermatitis (AD) in children, triggers for the appearance and flaring of AD are reviewed. The role of AD in the atopic march is explored. Furthermore, the usage of grading systems in the development of therapeutics and in clinical care is discussed. The natural history of AD has changed from improvement to 50% persistence and therefore it is important to council guardians and patients accordingly.

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.

Identification, characterization, and targeting of IL-4 receptor by IL-4-Pseudomonas exotoxin in mouse models of anaplastic thyroid cancer

Thyroid cancer is a rapidly increasing endocrine cancer. Since interleukin-4 receptor (IL-4R) is overexpressed in human solid cancer, we examined expression of IL-4R in 50 cases of anaplastic thyroid cancer (ATC), 37 well-differentiated papillary cancer (WDPC), 35 well-differentiated follicular cancer of thyroid (WDFC), and 37 normal thyroid specimens by immunohistochemistry (IHC) and in-situ hybridization (ISH) techniques. We demonstrated that IL-4Rα was overexpressed in 36/50 (72%) ATC, 20/35 (57%) WDFC, and 11/37 (30%) WDPC tumors. Other two subunits of IL-4R, interleukin-13 receptor α1 (IL-13Rα1) and interleukin-2 receptor gamma (IL-2RγC), were either weakly expressed or absent. As ATC is a highly aggressive cancer with higher incidence of IL-4Rα expression, we characterized IL-4R in 3 ATC cell lines. RT-qPCR and IFA results showed that IL-4Rα is overexpressed while IL-13Rα1 is weakly expressed. Control human umbilical vein endothelial cell line (HUVEC) showed weak expression of IL-4Rα. Binding and competition studies with 125I-IL-4 in ATC cell lines demonstrated that IL-4 specifically bound to IL-4Rα on cell surface. ATC cell lines were highly sensitive to a chimeric fusion cytotoxin consisting of circularly permuted IL-4 and truncated Pseudomonas exotoxin (IL-4-PE), which killed them in a concentration dependent manner. IL-4-PE also blocked colony formation of ATC cell lines in clonogenic assays. IL-4-PE mediated a significant antitumor activity in mouse models of ATC. Intratumoral administration of IL-4-PE caused significant regression of established tumors in a dose dependent manner and increased the overall survival without any visible toxicity. Thus, IL-4Rα in ATC may represent a novel therapeutic target and IL-4-PE may serve as an investigational therapeutic option for ATC.

Inherited Inflammatory Response Genes Are Associated with B-Cell Non-Hodgkin's Lymphoma Risk and Survival

BACKGROUND

Malignant B-cell clones are affected by both acquired genetic alterations and by inherited genetic variations changing the inflammatory tumour microenvironment.

METHODS

We investigated 50 inflammatory response gene polymorphisms in 355 B-cell non-Hodgkin's lymphoma (B-NHL) samples encompassing 216 diffuse large B cell lymphoma (DLBCL) and 139 follicular lymphoma (FL) and 307 controls. The effect of single genes and haplotypes were investigated and gene-expression analysis was applied for selected genes. Since interaction between risk genes can have a large impact on phenotype, two-way gene-gene interaction analysis was included.

RESULTS

We found inherited SNPs in genes critical for inflammatory pathways; TLR9, IL4, TAP2, IL2RA, FCGR2A, TNFA, IL10RB, GALNT12, IL12A and IL1B were significantly associated with disease risk and SELE, IL1RN, TNFA, TAP2, MBL2, IL5, CX3CR1, CHI3L1 and IL12A were, associated with overall survival (OS) in specific diagnostic entities of B-NHL. We discovered noteworthy interactions between DLBCL risk alleles on IL10 and IL4RA and FL risk alleles on IL4RA and IL4. In relation to OS, a highly significant interaction was observed in DLBCL for IL4RA (rs1805010) * IL10 (rs1800890) (HR = 0.11 (0.02-0.50)). Finally, we explored the expression of risk genes from the gene-gene interaction analysis in normal B-cell subtypes showing a different expression of IL4RA, IL10, IL10RB genes supporting a pathogenetic effect of these interactions in the germinal center.

CONCLUSIONS

The present findings support the importance of inflammatory genes in B-cell lymphomas. We found association between polymorphic sites in inflammatory response genes and risk as well as outcome in B-NHL and suggest an effect of gene-gene interactions during the stepwise oncogenesis.

Gene polymorphisms of stress hormone and cytokine receptors associate with immunomodulatory profile and psychological measurement

OBJECTIVE

We sought to identify whether stable single nucleotide polymorphisms (SNPs) of various endocrine and immune molecules could be used as biomarkers associated with specific immune alterations and chronic stress measures in normal humans.

METHODS

A total of 207 volunteer participants answered stress questionnaire and gave peripheral blood cells for identification of SNPs in genes coding for glucocorticoid receptor (GR), beta 2 adrenergic receptor (B2AR), interferon-gamma receptors (IFNGR1, IFNGR2), and interleukin-4 receptor (IL4R). Immunoregulatory profiles were measured by flow cytometry and genotyping assays were performed by allelic discrimination real-time PCR.

RESULTS

Several significant differences were revealed in associations between stress marker and immune indicators based on SNP categories. For instance, Th1 levels of the minor alleles of GR TthIIII (AA) and IFNGR2 Q64R (Arg/Arg) groups were positively associated with chronic stress (PSS) (p = 0.024 and 0.005, respectively) compared with wild type (WT) and negatively associated with PSS in the heterozygous genotypes of GR BclI and IL4R Ile50Val (p = 0.040 and p = 0.052, respectively). Treg levels of the minor alleles of BclI (GG) and IFNGR1 T-56C (CC) groups were positively associated with PSS (p = 0.045 and p = 0.010, respectively) and negatively associated in the minor allele (Val/Val) of IL4R Ile50Va and the heterozygous genotype of IL4R Q576R (p = 0.041 and p = 0.017, respectively) compared to WT.

CONCLUSION

The data support the notion that gene polymorphisms from various components of the psychoneuroendocrine-immune network may be useful as biomarkers to categorize individual stress-associated immune responses.

[IMMUNOGENETICS AND PROGRESSION OF CHRONIC VIRAL HEPATITES]

AIM OF INVESTIGATION

To estimate the role of polymorphic variants of genes IL4 (C-590T), IL4RA (I50V), TNF (G-308A) and SLC1IAI (D543N) in chronic viral hepatitis progression.

MATERIAL AND METHODS

Overall 121 patients with chronic viral hepatitis C and B.

RESULTS

Study results have demonstrated, that of all investigated polymorphic variants of genes IL4 (C-590T), IL4RA (150V), TNF (G-308A) and SLC11A1 (D543N) in patients with chronic liver diseases of various etiology the <<Val/Val>> IL4RA gene variant (II50Val) is associated with HBV-infection chronization. The allele <<A>> gene TNF-α (G-308A) is protective for chronic viral hepatitis and is associated with a low level of production by mononuclear cells of TNF-α and IL-12, high secretion of IL-4 and low degree of collagenopathy in the liver. Genotype <<CT>> of IL4 (C-590T) gene is an adverse marker for progression of chronic viral hepatitis B. There was significant correlation of polymorphic variants TNF (G-308A) and IL4 (C-590T) genes with production of the key interleukins, that determine type of immune response (Th-1, Th-2) and products of collagen metabolism that testifies genetic determination of system immune response and collagen formation processes in the liver at chronic viral hepatitis.

Association of the IL4R single-nucleotide polymorphism I50V with recurrent spontaneous abortion (RSA)

BACKGROUND

Recurrent spontaneous abortion (RSA) is defined as three or more consecutive abortions before the 20th week of gestation. There is increasing evidence to support an immunological mechanism for the occurrence of RSA. The purpose of our study was to examine whether single-nucleotide polymorphisms (SNPs) of the interleukin-4 receptor gene IL4R influence susceptibility to, recurrent spontaneous abortion.

MATERIALS AND METHODS

This is a case-control study. We recruited 200 patients with RSA (case group) using established diagnostic criteria and 200, normal individuals (control group) at the fertility and infertility center in Yazd city and Isfahan city during 2012 to 2013. We screened the I50V variant in IL-4R in patients and controls by PCR-RFLF method, and we performed an association analysis between I50V variant and RSA.the data was analyzed by spss 16 software using Chi-square test.

RESULTS

No differences in the genotype and allele frequencies of the I50V SNPs were identified between patients with RSA and healthy controls.

CONCLUSIONS

The frequency of SNP in IL-4 receptor (I50V) in patients with recurrent spontaneous abortion did not differ significantly compared with the control group. Analysis of IL4R SNP haplotypes or complex alleles suggested no dominant protection in patients with RSA.

Construction and application of elastin like polypeptide containing IL-4 receptor targeting peptide

Various human solid tumors highly express IL-4 receptors which amplify the expression of some of anti-apoptotic proteins, preventing drug-induced cancer cell death. Thus, IL-4 receptor targeted drug delivery can possibly increase the therapeutic efficacy in cancer treatment. Macromolecular carriers with multivalent targeting moieties offered great advantages in cancer therapy as they not only increase the plasma half-life of the drug but also allow delivery of therapeutic drugs to the cancer cells with higher specificity, minimizing the deleterious effects of the drug on normal cells. In this study we designed a library of elastin like polypeptide (ELP) polymers containing tumor targeting AP1 peptide using recursive directional ligation method. AP1 was previously discovered as an atherosclerotic plaque and breast tumor tissue homing peptide using phage display screening method, and it can selectively bind to the interleukin 4 receptor (IL-4R). The fluorescently labeled [AP1-V₁₂]₆, an ELP polymer containing six AP1 enhanced tumor-specific targeting ability and uptake efficiency in H226 and MDA-MB-231 cancer cell lines in vitro. Surface plasmon resonance analysis showed that multivalent presentation of the targeting ligand in the ELP polymer increased the binding affinity towards IL-4 receptor compared to free peptide. The binding of [AP1-V₁₂]₆ to cancer cells was remarkably reduced when IL-4 receptors were blocked by antibody against IL-4 receptor further confirmed its binding. Importantly, the Cy5.5-labeled [AP1-V₁₂]₆ demonstrated excellent homing and longer retention in tumor tissues in MDA-MB-231 xenograft mouse model. Immunohistological studies of tumor tissues further validated the targeting efficiency of [AP1-V₁₂]₆ to tumor tissue. These results indicate that designed [AP1-V₁₂]₆ can serve as a novel carrier for selective delivery of therapeutic drugs to tumors.

Small intestinal nematode infection of mice is associated with increased enterobacterial loads alongside the intestinal tract

Parasitic nematodes are potent modulators of immune reactivity in mice and men. Intestinal nematodes live in close contact with commensal gut bacteria, provoke biased Th2 immune responses upon infection, and subsequently lead to changes in gut physiology. We hypothesized that murine nematode infection is associated with distinct changes of the intestinal bacterial microbiota composition. We here studied intestinal inflammatory and immune responses in mice following infection with the hookworm Heligmosomoidespolygyrusbakeri and applied cultural and molecular techniques to quantitatively assess intestinal microbiota changes in the ileum, cecum and colon. At day 14 post nematode infection, mice harbored significantly higher numbers of γ-Proteobacteria/Enterobacteriaceae and members of the Bacteroides/Prevotella group in their cecum as compared to uninfected controls. Abundance of Gram-positive species such as Lactobacilli, Clostridia as well as the total bacterial load was not affected by worm infection. The altered microbiota composition was independent of the IL-4/-13 – STAT6 signaling axis, as infected IL-4Rα^-/- mice showed a similar increase in enterobacterial loads. In conclusion, infection with an enteric nematode is accompanied by distinct intestinal microbiota changes towards higher abundance of gram-negative commensal species at the small intestinal site of infection (and inflammation), but also in the parasite-free large intestinal tract. Further studies should unravel the impact of nematode-induced microbiota changes in inflammatory bowel disease to allow for a better understanding of how theses parasites interfere with intestinal inflammation and bacterial communities in men.

Assessing the validity of asthma associations for eight candidate genes and age at diagnosis effects

BACKGROUND

Before the advent of genome-wide association studies (GWAS), ADAM33, ADRB2, CD14, MS4A2 (alias FCER1B), IL13, IL4, IL4R, and TNF constituted the most replicated non-HLA candidate genes with asthma and related traits. However, except for the IL13-IL4 region, none of these genes have been found in close proximity of genome-wide significant hits among GWAS for asthma or related traits. Here we aimed to assess the reproducibility of these asthma associations and to test if associations were more evident considering the effect of age at diagnosis.

METHODOLOGY/PRINCIPAL FINDINGS

We systematically evaluated 286 common single nucleotide polymorphisms (SNPs) of these 8 genes in a sample of 1,865 unrelated Spanish individuals (606 asthmatics and 1,259 controls). We found that variants at MS4A2, IL4R and ADAM33 genes demonstrated varying association effects with the age at diagnosis of asthma, with 10 SNPs showing study-wise significance after the multiple comparison adjustment. In addition, in silico replication with GWAS data supported the association of IL4R.

CONCLUSIONS/SIGNIFICANCE

Our results support the important role of MS4A2, IL4R and ADAM33 genes in asthma and/or atopy susceptibility. However, additional studies in larger samples sets are needed to firmly implicate these genes in asthma susceptibility, and also to identify the causal variation underlying the associations found.

Association between interleukin-4 receptor α chain (IL4RA) I50V and Q551R polymorphisms and asthma risk: an update meta-analysis

BACKGROUND

The associations between the interleukin-4 receptor α chain (IL4RA) I50V and Q551R polymorphisms and asthma risk remained controversial.

METHODS

We searched the Pubmed, Embase, Chinese National Knowledge Infrastructure (CNKI) and Wanfang databases for studies published before February 2013. The strengths of the associations were calculated using odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

A total of 50 studies were included in this meta-analysis. There was a significant association between the IL4RA I50V polymorphism and asthma risk in a dominant genetic model (OR = 1.13, 95% CI 1.04-1.23, P = 0.005). The IL4RA Q551R polymorphism was associated with a significantly elevated asthma risk in a recessive genetic model (OR = 1.46, 95% CI 1.22-1.75, P<0.0001). Subgroup analyses found that the IL4RA I50V polymorphism was significantly associated with asthma risk in Asians (OR = 1.72, 95% CI 1.31-2.25, P<0.0001), pediatric asthma risk (OR = 1.50, 95% CI 1.13-1.99, P = 0.005), and atopic asthma risk (OR = 1.88, 95% CI 1.27-2.79, P = 0.002).

CONCLUSIONS

The results of this meta-analysis suggested that the IL4RA I50V and Q551R polymorphisms may be risk factors for developing asthma.

Reduced interleukin-4 receptor α expression on CD8+ T cells correlates with higher quality anti-viral immunity

With the hope of understanding how interleukin (IL)-4 and IL-13 modulated quality of anti-viral CD8⁺ T cells, we evaluated the expression of receptors for these cytokines following a range of viral infections (e.g. pox viruses and influenza virus). Results clearly indicated that unlike other IL-4/IL-13 receptor subunits, IL-4 receptor α (IL-4Rα) was significantly down-regulated on anti-viral CD8⁺ T cells in a cognate antigen dependent manner. The infection of gene knockout mice and wild-type (WT) mice with vaccinia virus (VV) or VV expressing IL-4 confirmed that IL-4, IL-13 and signal transducer and activator of transcription 6 (STAT6) were required to increase IL-4Rα expression on CD8⁺ T cells, but not interferon (IFN)-γ. STAT6 dependent elevation of IL-4Rα expression on CD8⁺ T cells was a feature of poor quality anti-viral CD8⁺ T cell immunity as measured by the production of IFN-γ and tumor necrosis factor α (TNF-α) in response to VV antigen stimulation in vitro. We propose that down-regulation of IL-4Rα, but not the other IL-4/IL-13 receptor subunits, is a mechanism by which CD8⁺ T cells reduce responsiveness to IL-4 and IL-13. This can improve the quality of anti-viral CD8⁺ T cell immunity. Our findings have important implications in understanding anti-viral CD8⁺ T cell immunity and designing effective vaccines against chronic viral infections.

Mental quality of life is related to a cytokine genetic pathway

BACKGROUND

Quality of life (QoL) in patients with chronic disease is impaired and cannot be solely explained by disease severity. We explored whether genetic variability and activity contributes to QoL in patients with Marfan syndrome (MFS), a genetic connective tissue disorder.

METHODOLOGY/PRINCIPAL FINDINGS

In 121 MFS patients, patient characteristics (i.e. demographics and MFS-related symptoms) were assessed. Patients completed the SF-36 to measure QoL. In addition, transcriptome wide gene expression and 484 Single Nucleotide Polymorphysms (SNPs) in cytokine genes were available. QoL was first analyzed and associated with patient characteristics. Patients' physical QoL was impaired and weakly related with age and scoliosis, whereas mental quality of life (MCS) was normal. To explain a largely lacking correlation between disease severity and QoL, we related genome wide gene expression to QoL. Patients with lower MCS scores had high expression levels of CXCL9 and CXCL11 cytokine-related genes (p=0.001; p=0.002); similarly, patients with low vitality scores had high expression levels of CXCL9, CXCL11 and IFNA6 cytokine-related genes (p=0.02; p=0.02; p=0.04), independent of patient characteristics. Subsequently, we associated cytokine related SNPs to mental QoL (MCS and vitality). SNP-cluster in the IL4R gene showed a weak association with MCS and vitality (strongest association p=0.0017). Although overall mental QoL was normal, >10% of patients had low scores for MCS and vitality. Post-hoc analysis of systemic inflammatory mediators showed that patients with lowest MCS and vitality scores had high levels of CCL11 cytokine (p=0.03; p=0.04).

CONCLUSIONS/SIGNIFICANCE

Variation in the cytokine genetic pathway and its activation is related to mental QoL. These findings might allow us to identify and, ultimately, treat patients susceptible to poor QoL.

Polymorphisms in the IL-13 and IL-4R genes are associated with the development of renal cell carcinoma

BACKGROUND

Cytokines are the important modulators that bind to their relevant receptors in response to some stimuli to mediate the homeostasis. It has been suggested that the imbalance of immune system of the host might affect the generation of diseases, including cancers.

PATIENTS AND METHODS

We investigated the association between six functional polymorphisms of IL-4, IL-13, and IL-4R genes and susceptibility to renal cell cancer in a hospital-based study, including 620 renal cell carcinoma (RCC) patients and 623 controls. Logistic regression model was used to assess the genetic effects on the development of RCC.

RESULTS

Overall, individuals with IL-4R Ile50Val CT/TT genotypes had a 0.34-fold significantly decreased RCC risk (CT/TT versus CC), and the T variant allele was associated with a decreased risk of RCC in a dose-response manner (Ptrend=0.009). In addition, we also observed that IL-13 C-1055T and Arg130Gln polymorphisms could decrease the risk of RCC [TT versus

CC/CT

odds ratio=0.36, 95% confidence interval (CI)=0.16-0.78; AA versus GG/GA: 0.66, 0.44-0.97, respectively]. Furthermore, a multiplicative interaction association between the combined IL-4R Ile50Val and IL-13 C-1055T genotypes was observed to decrease the risk of RCC (P=0.036).

CONCLUSION

IL-13 and IL-4R may play an important role in the etiology of RCC.

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.

A predictive model of the association between gene polymorphism and the risk of noise-induced hearing loss caused by gunfire noise

BACKGROUND

Noise-induced hearing loss (NIHL) is one of the common diseases in otology. In general, we assume that most people who are exposed to loud noise constantly, e.g., soldiers, will suffer from hearing loss. Hearing loss is related to the gene polymorphisms, with the Wolfram syndrome type 1 gene (T2500C), interleukin-4 receptor α chain (Q576R) and chloride channel-Kb (T481S) polymorphisms being most related to NIHL.

METHODS

We analyzed the association between the polymorphisms and the risk of NIHL in 119 subjects who were exposed to the same loud gunfire. In the current study, 39 persons with hearing loss and 80 with normal hearing were recruited from military officers and soldiers that were exposed to gunfire.

RESULTS

The results showed that the genetic variation of Wolfram syndrome type 1 gene was a more crucial factor than other genes in causing hearing loss. There was a significant difference (p=0.027) in WFS1 (T2500C) polymorphism between NIHL subjects and controls.

CONCLUSION

In this study, we found that although loud noise could usually result in hearing damage, the clinical characteristics of hearing loss were irrelevant to gunfire noise. The gene polymorphisms provide predictors for us to evaluate the risk of NIHL prior to gunshot training.

The role of CD23 in IgE dependent signaling: implications from pharmacogenetics

The association of immunoglobulin E (IgE) with allergic diseases and asthma is well established. IgE binds to two receptors on various immune and inflammatory cells. The lower-affinity IgE Fc receptor, CD23, has multiple functions in enhancing the regulation of IgE production itself, and that of various pro-inflammatory activities and mediators. The data in this report are derived from an analysis of variation in the CD23 gene that leads to a coding exchange and to a single nucleotide polymorphism (SNP) associated with the substitution of an arginine residue for a tryptophan residue in the protein structure of CD23. This genetic variation is associated with three findings identified in this report. First, the tryptophan exchange is associated with greater expression of RNA for the interleukin (IL)-4 receptor alpha chain and greater expression of RNA for egr-1 transcription factor, both of which are proinflammatory gene products that influence allergy-related immune functions. Second, the exchange is associated with cell surface expression of IL-4R. Third, an analysis of potential arginine-to-tryptophan exchanges in the entire human genome has identified a number of interesting exchanges in immunologic genes of interest for their role in allergic responses. A discussion of these three findings is presented.

[Meta-analysis on interleukin-4 receptor α chain Q576R gene polymorphisms and bronchial asthma susceptibility]

OBJECTIVE

to study the association between interleukin-4 receptor α chain (IL-4RA) Q576R polymorphisms and bronchial asthma susceptibility by Meta-analysis.

METHODS

four medical databases, including Pubmed, Embase, CNKI and Wanfang, were searched for the case-control studies about the IL-4RA polymorphisms and bronchial asthma susceptibility. Odds ratios (OR) of IL-4RA Q576R genotype distributions in asthma patients against healthy controls were analyzed in both RR vs QR + QQ model and QR + RR vs QQ model. Analyses were performed for asthma in general and for subgroups based on the atopy status of the asthma population. The sensitivity analysis and the publication bias tests were conducted.

RESULTS

fifteen case-control studies, with 2675 asthma cases, 1202 atopic asthma cases and 331 nonatopic asthma cases respectively, were identified and all control group genotype frequencies were consistent with Hardy-Weinberg equilibrium. In genotype RR vs QR + QQ model no heterogeneity among the studies was found, while in genotype QR + RR vs QQ model, heterogeneity among these studies was found. These studies were analyzed by fixed-effect model (RR vs QR + QQ model) or random-effect model (QR + RR vs QQ model). The pooled odds ratio of IL-RA Q576R genotype RR vs QR + QQ was 2.02 (95%CI: 1.53 - 2.66), and the pooled odds ratio in this model in the atopic asthma subgroup was 2.26 (95%CI: 1.47 - 3.49), while the pooled odds ratio (QR + RR vs QQ model) was 1.02 (95%CI: 1.06 - 1.53).

CONCLUSION

a meta-analysis of results from case-control studies strongly supports the conclusion that IL-4RA Q576R polymorphisms impart a modest yet significant risk for asthma.

[Syntropic genes of allergic diseases]

Common (syntropic) genes of allergic diseases (ADs) HLA-DQB1, HLA-DRB1, IL4, IL4RA, MS4A2, HLA-DQA1, LTC4S, IL13, IL10, and TGFBL have been identified on the basis of information from the HuGENet internet database. The functional sphere of competence of these genes is associated mainly with the initiation and regulation of an immune response and inflammation. Importance of these processes in the development of ADs is underlined. The results of cluster analysis of allergic diseases obtained using the data on common genes predisposing to their development are presented. Genetic clusterization ofADs confirms their accepted clinical classification.

Differential requirements for interleukin (IL)-4 and IL-13 in protein contact dermatitis induced by Anisakis

BACKGROUND

Exposure to antigens of the fish parasite Anisakis is associated with the development of protein contact dermatitis in seafood-processing workers. Understanding the basic mechanisms controlling allergic sensitization through the skin is critical for designing therapies that will prevent the progression of allergic disease.

OBJECTIVE

To investigate the roles of interleukin (IL)-4, IL-13 and the IL-4Ralpha in both local skin pathology and systemic sensitization following epicutaneous exposure to Anisakis proteins.

METHODS

BALB/c wild-type (WT) mice and mice deficient in IL-4, IL-13 or IL-4 and IL-13, as well as mice with cell-specific impairment of IL-4Ralpha expression, were sensitized to Anisakis antigen by repeated epicutaneous application of Anisakis extract. Following this sensitization, skin pathology was recorded and systemic responses were investigated. Intravenous challenge with Anisakis extract was performed to test for the development of biologically relevant systemic sensitization.

RESULTS

In WT mice, epicutaneous sensitization with Anisakis larval antigens induced localized inflammation, epidermal hyperplasia, production of T(H)2 cytokines, antigen-specific IgE and IgG1. Intravenous challenge of sensitized mice resulted in anaphylactic shock. Interestingly, IL-13 deficient mice failed to develop epidermal hyperplasia and inflammation, whilst anaphylaxis was reduced only in strains deficient either in IL-4 only, or deficient in IL-4 and IL-13 concurrently, as well as in mice deficient in IL-4Ralpha or with impaired IL-4Ralpha expression on CD4(+) T cells.

CONCLUSIONS

Interleukin-13 plays a central role in protein contact dermatitis associated with repeated epicutaneous exposure to Anisakis extract, whereas IL-4 drives systemic sensitization and resultant anaphylactic shock.

Polymorphisms in IL4 and iLARA confer susceptibility to asthma

BACKGROUND

Asthma is a complex disease that is caused by genetic and environmental factors. The production of interleukin (IL)-4, which can influence mast cell responsiveness to immunoglobulin (Ig) E--mediated signaling, could be modified by genetic variants in the IL-4 promoter.

OBJECTIVE

To investigate the association between the IL-4 and IL-4RA promoter polymorphisms and asthma in a sample of Iranian patients.

METHODS

We used polymerase chain reaction with sequence-specific primers to investigate the allele and genotype frequencies of 2 polymorphic genes coding for IL-4 and IL-4RA in 59 Iranian patients with asthma and 139 healthy controls.

RESULTS

The most frequent genotypes in the patient group were IL-4TC (-590), IL-4TC (-33), IL-4 GT (-1098), and IL-4RA GA (+1902). In contrast, the frequencies of IL-4 CC (-590), IL-4 CC (-33), IL-4TT (-1098), and IL-4RAAA (+1902) were significantly lower in the patient group than in the control group. The most frequent haplotypes in our patients were IL-4 TCT and GTC at positions -1098,-590,-33. The mean total serum IgE level in patients with the TTT/GCC genotype was 258.8 IU/mL, which was significantly higher than the 95.4 IU/mL observed for other genotypes.

CONCLUSION

We showed a strong association between the polymorphisms of the IL-4 gene promoter at positions -590, -33 and -1098 and bronchial asthma. We also demonstrated an association between their haplotypes and serum total IgE.

Study of gene-gene interactions for endophenotypic quantitative traits in Chinese asthmatic children

BACKGROUND

Asthma is a complex disease resulting from interactions between multiple genes and environmental factors. Study of gene-gene interactions could provide insight into the pathophysiology of asthma.

METHODS

We investigated the interactions among 18 single-nucleotide polymorphisms in eight candidate genes for plasma total immunoglobulin E (IgE) concentration and peripheral blood (PB) eosinophil count in 298 Chinese asthmatic children and 175 controls. Generalized multifactor dimensionality reduction and generalized linear model were used to analyze gene-gene interactions for the quantitative traits.

RESULTS

A significant interaction was found between R130Q in IL13 and I50V in IL4RA for plasma total IgE concentration, with a cross-validation (CV) consistency of nine of 10 and a prediction error of 41.1% (P = 0.013). Plasma total IgE concentration was significantly higher in the high-risk than the low-risk groups (P < 0.0001). For PB eosinophil count, significant interaction was found between C-431T in TARC and RsaI_in2 in FCERIB, with a CV consistency of nine of 10 and a prediction error of 40.2% (P = 0.009). PB eosinophil count was significantly higher in the high-risk group than the low-risk groups (P < 0.0001). Generalized linear model also revealed significant gene-gene interaction for the above two endophenotypes with P = 0.013 for plasma total IgE concentration and P = 0.029 for PB eosinophil count respectively.

CONCLUSIONS

Our data suggest significant interactions between IL13 and IL4RA for plasma total IgE concentration, and this is the first report to show significant interaction between TARC and FCERIB for PB eosinophil count in Chinese asthmatic children.

[Genetics factors determining predisposition to chronic course of virus hepatitis and fibrosis in liver]

Polymorphic variants of several genes IL4 C(-590)T, IL4RA Ile50Val, TNF G(-308)A were studied for their association with extent of the disease chronization which is marked by hepatic fibrosis stage. Gradual decrease in A allele frequency of polymorphic marker G(-308)A in TNF gene, from patients with weak fibrosis to patients with cirrhosis. Group of patients with weak fibrosis was characterized by higher frequency of A allele (24.5%) comparing with patients with moderate and pronounced fibrosis (13.4%) and cirrhosis (8.7%). Differences in heterozygous genotype frequencies of IL4 C(-590)T were found between patients with cirrhosis (68.2%) and groups of patients with moderate and marked fibrosis (39.1%).

CD4+ T cell-specific deletion of IL-4 receptor alpha prevents ovalbumin-induced anaphylaxis by an IFN-gamma-dependent mechanism

IL-4Ralpha-mediated STAT6 activation serves an essential role in various animal models of allergy and asthma at both the sensitization and effector phases. IL-4 and IL-13 signaling via the IL-4Ralpha chain exacerbates murine anaphylaxis, but the cell-specific requirements for IL-4Ralpha expression are unclear. The purpose of this study was to elucidate the mechanisms of systemic anaphylaxis to OVA in gene-targeted mice with a deletion of the IL-4Ralpha chain in the macrophage/neutrophil or CD4+ T lymphocyte population. Results demonstrated that anaphylaxis in this model was entirely dependent upon the FcgammaRII/III and was associated with mast cell degranulation. Expression of the IL-4Ralpha on CD4+ T cells, but not macrophages or neutrophils, was critical for severe anaphylaxis, characterized by diarrhea, hypothermia, and death. Ab depletion experiments demonstrated that IFN-gamma protected against mortality and severe intestinal pathology despite the presence of Ag and specific Ab. This protection was associated with reduced levels of mast cell protease, a marker of mast cell degranulation, suggesting that IFN-gamma may inhibit mast cell degranulation in vivo. These data suggest that it may be possible to limit the severity of anaphylaxis using rational therapies designed to increase numbers of IFN-gamma-producing cells by targeting IL-4Ralpha signaling in CD4+ T lymphocytes.

Confirmation of an Association Between the TNF(−308) Promoter Polymorphism and Stroke Risk in Children With Sickle Cell Anemia

Background and Purpose— The etiology of stroke in children with sickle cell anemia (SCA) is complex and poorly understood. Growing evidence suggests that genetic factors beyond the sickle cell mutation influence stroke risk in SCA. We previously reported risk associations with polymorphisms in several proinflammatory genes in SCA children with ischemic stroke. The aim of this replication study was to confirm our previous findings of associations between the TNF(−308) G/A, IL4R 503 S/P, and ADRB2 27 Q/E polymorphisms and large vessel stroke risk.

Methods— Using previously collected MRA data, we assessed an independent population of SCA children from the multicenter Stroke Prevention Trial in Sickle Cell Anemia (STOP) for the presence or absence of large vessel stenosis. Samples were genotyped for 104 polymorphisms among 65 candidate vascular disease genes. Genotypic associations with risk of large vessel stroke were screened using univariable analysis and compared with results from our original study. Joint analysis of the 2 study populations combined was performed using multivariable logistic regression.

Results— A total of 96 children (49 MRA-positive, 47 MRA-negative) were included in this study. Of the SNP associations previously identified in the original study, the TNF(−308) G/A association with large vessel stroke remained significant and the IL4R 503 S/P variant approached significance in the joint analysis of the combined study populations. Consistent with our original findings, the TNF(−308) GG genotype was associated with a >3-fold increased risk of large vessel disease (OR=3.27; 95% CI=1.6, 6.9; P =0.006). Unadjusted analyses also revealed a previously unidentified association between the LTC4S(−444) A/C variant and large vessel stroke risk.

Conclusions— Similar findings in 2 independent study populations strongly suggest that the TNF(−308) G/A promoter polymorphism is a clinically important risk factor for large vessel stroke in children with SCA. The previously observed association with the IL4R 503 S/P variant and the novel association with the LTC4S(−444) A/C variant suggest that these loci may also contribute to large vessel stroke risk in children with SCA.

Deletion of IL-4Ralpha on CD4 T cells renders BALB/c mice resistant to Leishmania major infection

Effector responses induced by polarized CD4⁺ T helper 2 (Th2) cells drive nonhealing responses in BALB/c mice infected with Leishmania major. Th2 cytokines IL-4 and IL-13 are known susceptibility factors for L. major infection in BALB/c mice and induce their biological functions through a common receptor, the IL-4 receptor α chain (IL-4Rα). IL-4Rα–deficient BALB/c mice, however, remain susceptible to L. major infection, indicating that IL-4/IL-13 may induce protective responses. Therefore, the roles of polarized Th2 CD4⁺ T cells and IL-4/IL-13 responsiveness of non-CD4⁺ T cells in inducing nonhealer or healer responses have yet to be elucidated. CD4⁺ T cell–specific IL-4Rα (Lck^creIL-4Rα^−/lox) deficient BALB/c mice were generated and characterized to elucidate the importance of IL-4Rα signaling during cutaneous leishmaniasis in the absence of IL-4–responsive CD4⁺ T cells. Efficient deletion was confirmed by loss of IL-4Rα expression on CD4⁺ T cells and impaired IL-4–induced CD4⁺ T cell proliferation and Th2 differentiation. CD8⁺, γδ⁺, and NK–T cells expressed residual IL-4Rα, and representative non–T cell populations maintained IL-4/IL-13 responsiveness. In contrast to IL-4Rα^−/lox BALB/c mice, which developed ulcerating lesions following infection with L. major, Lck^creIL-4Rα^−/lox mice were resistant and showed protection to rechallenge, similar to healer C57BL/6 mice. Resistance to L. major in Lck^creIL-4Rα^−/lox mice correlated with reduced numbers of IL-10–secreting cells and early IL-12p35 mRNA induction, leading to increased delayed type hypersensitivity responses, interferon-γ production, and elevated ratios of inducible nitric oxide synthase mRNA/parasite, similar to C57BL/6 mice. These data demonstrate that abrogation of IL-4 signaling in CD4⁺ T cells is required to transform nonhealer BALB/c mice to a healer phenotype. Furthermore, a beneficial role for IL-4Rα signaling in L. major infection is revealed in which IL-4/IL-13–responsive non-CD4⁺ T cells induce protective responses.

Leishmaniasis is a disease induced by a protozoan parasite and transmitted by the sandfly. Several forms of infection are identified, and the different diseases have wide-ranging symptoms from localized cutaneous sores to visceral disease affecting many internal organs. Animal models of human cutaneous leishmaniasis have been established in which disease is induced by infecting mice subcutaneously with Leishmania major. Different strains of inbred mice have been found to be susceptible or resistant to L. major infection. “Healer” C57BL/6 mice control infection with transient lesion development. The protective response to infection in this strain is dominated by type 1 cytokines inducing parasite killing by nitric oxide. Conversely, “nonhealer” BALB/c mice are unable to control infection and develop nonhealing lesions associated with a dominant type 2 immune response driven by cytokines IL-4 and IL-13. However, mice deficient in IL-4/IL-13 signaling are not protected against development of cutaneous leishmaniasis. Here we describe a BALB/c mouse where the ability to polarize to a dominant type 2 response is removed by cell-specific deletion of the receptor for IL-4/IL-13 on CD4⁺ T cells. These mice are resistant to L. major infection similar to C57BL/6 mice, which highlights the role of T helper 2 cells in driving susceptibility and the protective role of IL-4/IL-13 signaling in non-CD4⁺ T cells in BALB/c mice.

Association between Q551R IL4R genetic variants and atopic asthma risk demonstrated by meta-analysis

BACKGROUND

IL4R, the gene encoding the alpha chain of the IL-4 and IL-13 receptors, has received extensive attention as a candidate gene for asthma risk. However, the results from studies testing for associations of the I50V and Q551R IL4R genetic variants are conflicting.

OBJECTIVE

We sought to determine the average risk of asthma associated with the I50V and Q551R IL4R variants based on the results of case-control studies reported in the literature.

METHODS

Meta-analyses were performed with data from case-control association studies that met specified inclusion criteria (9 and 8 studies for I50V and Q551R, respectively). Random-effects models were used to calculate combined odds ratios (ORs) and significance of associations. Analyses were performed for asthma in general and for subgroups based on the atopy status of the asthma population.

RESULTS

The R551 IL4R variant was significantly associated with increased risk of asthma, most notably atopic asthma (combined OR, 1.6; P = .004). Exclusion of the outlier study reporting an OR of less than 1 greatly increased the significance of association (OR, 1.8; P = 3 x 10(-9)). I50V variants were not significantly associated with asthma.

CONCLUSIONS

A meta-analysis of results from case-control studies strongly supports the conclusion that the R551 IL4R variant imparts a modest yet significant risk for atopic asthma.

CLINICAL IMPLICATIONS

Knowledge that the R551 IL4R variant is associated with increased asthma risk should provide a basis for understanding the heterogeneity of asthma pathogenesis and for pharmacogenetic approaches to treat individuals carrying this variant.

Polymorphisms of interleukin (IL)-4 receptor alpha and signal transducer and activator of transcription-6 (Stat6) are associated with increased IL-4Ralpha-Stat6 signalling in lymphocytes and elevated serum IgE in patients with Graves' disease

Activated interleukin (IL)-4Ralpha stimulates production of IgE through signal transducer and activator of transcription-6 (Stat6) activation in lymphocytes. Genetic studies have shown an association between polymorphisms in the genes encoding IL-4Ralpha and Stat6 and elevated serum IgE in patients with atopic disease. Some authors, including us, have reported an association of Graves' disease and elevated serum IgE. To analyse the relationship between IL-4Ralpha and Stat6 polymorphisms and elevated serum IgE in patients with Graves' disease, 169 patients with Graves' disease were studied. We investigated whether these polymorphisms affect IL-4Ralpha-Stat6 signalling in cultured human lymphocytes. A high frequency of both the Ile50 polymorphism in IL-4Ralpha and 13GT repeat variants of the Stat6 gene was observed in patients with Graves' disease and elevated serum IgE (Ile50 allele; P < 0.05, 13GT allele; P < 0.01 versus controls) but not in subjects with normal IgE. Cultured human lymphocytes with the Ile50 IL-4Ralpha polymorphism and the 13GT repeat variant of Stat6 showed increased IL-4 (and/or IL-13)-induced Stat6 activation (2.7-fold; P < 0.05 and 2.2-fold; P < 0.05, respectively). These findings suggest that polymorphisms in the IL-4Ralpha and Stat6 genes play an important role in elevation of serum IgE through increased Stat6 action in patients with Graves' disease.

Interaction between variants in the interleukin-4 receptor alpha and interleukin-9 receptor genes in childhood wheezing: evidence from a birth cohort study

BACKGROUND

Several polymorphisms in the IL-4 receptor alpha (IL4RA) gene have been associated with asthma and atopy, but with variable success in different populations. Immunologic studies suggest that IL4RA may interact with other cytokines and receptors, and gene-gene interactions have also been observed with respect to asthma. Such interactions have been proposed to explain partly the difficulties in replicating association studies.

METHODS

Using the prospective birth cohort BAMSE, we examined eight single nucleotide polymorphisms (SNPs) and corresponding haplotypes in the IL4RA gene in relation to wheezing and sensitization up to age 4. We also evaluated potential interaction effects (departure from a multiplicative interaction model) between the IL4RA SNPs and four SNPs in the IL-9 receptor (IL9R) gene previously associated with childhood wheezing.

RESULTS

We found no main effect of the IL4RA SNPs alone and only weak associations to wheezing and sensitization when haplotypes were considered. Gene-gene interactions between several IL4RA and IL9R SNPs with regard to wheezing were observed (P=0.009), especially between IL4RA Q576R (rs1801275) and IL9R rs731476 (P=0.005). An interaction was also seen between IL4RA and IL9R haplotypes.

CONCLUSION

Variants in the IL4RA gene alone may not exert any major influence on susceptibility to asthma-related diseases in childhood, but in combination with other genes, such as IL9R, IL4RA may be an important gene for disease susceptibility.

Polymorphisms in the IL-4, IL-4 receptor alpha chain, TNF-alpha, and lymphotoxin-alpha genes and risk of asthma in Hong Kong Chinese adults

BACKGROUND

Susceptibility to the development of asthma and other atopic diseases is known to be associated with genetic components. However, association studies with interleukin-4 (IL-4), IL-4 receptor alpha subunit (IL-4R alpha), tumor necrosis factor-alpha (TNF-alpha) and lymphotoxin-alpha (LT-alpha) genes were inconclusive, as both positive and negative results were obtained in several populations studied. We aimed to investigate the association of the polymorphisms for IL-4 (C-589T), IL-4R alpha (Gln576Arg), TNF-alpha (G-308A) and LT-alpha (A252G) genes as candidates and asthma in adult Hong Kong Chinese population.

METHODS

The association study was conducted in an age- and smoking status-matched case-control design in asthma patients (n = 292) and healthy controls (n = 292) using polymerase chain reaction and restriction fragment length polymorphism.

RESULTS

No significant differences were found in allele and genotype frequencies of all four genes between patients and controls. After stratification by atopic status, the heterozygous AG genotype of LT-alpha (A252G) was found to increase risk of asthma in atopic population [odds ratio (OR) = 2.00, 95% CI 1.09-3.67, p = 0.024]. When stratified by smoking status, we found increased risk of asthma with subjects carrying the heterozygous AG and homozygous GG genotypes of LT-alpha in ever-smokers (OR = 2.73, 95% CI 1.11-6.69, p = 0.028 for heterozygotes; OR = 3.34, 95% CI 1.16-9.62, p = 0.026 for homozygotes).

CONCLUSION

Our results suggest that the variability of LT-alpha genotypes may have potential implications for individual susceptibility to asthma in atopic or in ever-smoking Chinese adults in Hong Kong.

Overexpression of interleukin-13 induces minimal-change-like nephropathy in rats

IL-13 has been implicated in the pathogenesis of minimal-change nephrotic syndrome. This study aimed to investigate the role of IL-13 on the development of proteinuria and expression of podocyte-related genes that are associated with nephrotic syndrome. IL-13 was overexpressed in Wistar rats through transfection of a mammalian expression vector cloned with the rat IL-13 gene, into the quadriceps by in vivo electroporation. Serum IL-13, albumin, cholesterol, and creatinine and urine albumin were measured serially. Kidneys were harvested after day 70 for histology and electron microscopy. Glomerular gene expression of nephrin, podocin, dystroglycan, B7-1, and IL-13 receptor subunits were examined using real-time PCR with hybridization probes and expressed as an index against beta-actin. Protein expression of these molecules was determined by immunofluorescence staining. The IL-13-transfected rats (n = 41) showed significant albuminuria, hypoalbuminemia, and hypercholesterolemia when compared with control rats (n = 17). No significant histologic changes were seen in glomeruli of IL-13-transfected rats. However, electron microscopy showed up to 80% of podocyte foot process fusion. Glomerular gene expression was significantly upregulated for B7-1, IL-4Ralpha, and IL-13Ralpha2 but downregulated for nephrin, podocin, and dystroglycan. Immunofluorescence staining intensity was reduced for nephrin, podocin, and dystroglycan but increased for B7-1 and IL-4Ralpha in IL-13-transfected rats compared with controls. In conclusion, these results suggest that IL-13 overexpression in the rat could lead to podocyte injury with downregulation of nephrin, podocin, and dystroglycan and a concurrent upregulation of B7-1 in the glomeruli, inducing a minimal change-like nephropathy that is characterized by increased proteinuria, hypoalbuminemia, hypercholesterolemia, and fusion of podocyte foot processes.

Ethnicity-specific gene-gene interaction between IL-13 and IL-4Ralpha among African Americans with asthma

RATIONALE

Genes in the interleukin (IL)-4/IL-13/IL-4Ralpha pathway have been shown to be associated with asthma and related phenotypes in some populations, but not in others. Furthermore, interaction between these genes has been shown to affect asthma in white and Chinese populations.

OBJECTIVES

To determine whether there are IL-4/IL-13 and IL-4Ralpha gene-gene interactions that are associated with asthma in African Americans.

METHODS

Eighteen single-nucleotide polymorphisms (SNPs) in IL-4, IL-13, and IL-4Ralpha genes were genotyped in 264 African Americans with asthma and 176 healthy control subjects. We tested the SNPs for genetic associations and gene-gene interactions with asthma, baseline lung function, bronchodilator drug response, and total serum IgE levels.

MEASUREMENTS AND MAIN RESULTS

We identified 94 SNPs in IL-4, IL-13, and IL-4Ralpha genes by directly sequencing these genes in 24 African-American subjects with asthma. Seventeen SNPs were analyzed for association with asthma and related phenotypes. We found no evidence of association in the IL-4 gene. One SNP in the IL-13 gene (A-646G, rs2069743) and two SNPs in the IL-4Ralpha gene (A+4679G, rs1805010, and C+22656T, rs1805015) showed association with lung function (both baseline and post-bronchodilator). Although the association between individual SNPs and asthma-related phenotypes differed from previous studies performed in white and Chinese populations, significant gene-gene interaction was found between the IL-13 (A-646G) and IL-4Ralpha (A+4679G) SNPs for baseline lung function among African-American subjects with asthma.

CONCLUSIONS

Gene-gene interaction between the IL-13 and IL-4Ralpha genes may play an important role in asthma among African Americans.

Diisocyanate asthma and gene-environment interactions with IL4RA, CD-14, and IL-13 genes

BACKGROUND

Diisocyanate asthma (DA) affects 2% to 10% of exposed workers, yet the pathogenetic mechanisms underlying this disorder remain ill defined.

OBJECTIVE

To determine if specific single nucleotide polymorphisms (SNPs) of interleukin 4 receptor alpha (IL4RA), IL-13, and CD14 promoter genes are associated with DA.

METHODS

Sixty-two workers with DA confirmed by specific inhalation challenge (SIC) and 75 diisocyanate-exposed, SIC-negative workers were analyzed for SNPs associated with IL4RA, IL-13, and CD14 promoter genes.

RESULTS

No associations were found with individual SNPs and DA. When stratified according to specific diisocyanate exposure, a significant association was found between IL4RA (I50V) II and DA among individuals exposed to hexamethylene diisocyanate (HDI) (odds ratio [OR], 3.29; 95% confidence interval [CI], 1.33-8.14; P = .01) only. Similarly, the IL4RA (I50V) II and IL-13 (R110Q) RR combination was significantly associated with DA in HDI-exposed workers (OR, 4.13; 95% CI, 1.35-12.68; P = .01), as was the IL4RA (I50V) II and CD14 (C159T) CT genotype combination (OR, 5.2; 95% CI, 1.82-14.88; P = .002) and the triple genotype combination IL4RA (I50V) II, IL-13 (R110Q) RR, and CD14 (C159T) CT (OR, 6.4; 95% CI, 1.57-26.12; P = .01).

CONCLUSIONS

Gene-environmental interactions may contribute to the pathogenesis of DA, and gene-gene interactions may modulate this relationship.

Polymorphisms in the IL4 and IL4RA genes in Colombian patients with rheumatoid arthritis

OBJECTIVE

Rheumatoid arthritis (RA) is considered a Th1-driven disease. Interleukin 4 (IL-4) binds to its receptor, promoting Th2 differentiation and limiting Th1 responses, but its role in the pathogenesis of RA is conflicting. We analyzed 2 polymorphisms of the IL4 gene and 4 polymorphisms of the IL4RA gene in patients with RA and in a control population, as well as rheumatoid factor (RF) seropositivity, titers of RF, and history of replacement joint surgery among patients with RA.

METHODS

The study population consisted of 102 patients with RA and 102 matched healthy controls. Genotyping of IL4 -590, IL4RA +148, +1124, +1218, and +1902 was determined by restriction fragment length polymorphism-polymerase chain reaction (PCR) and sequence-specific primer-PCR. IL4 variable number tandem repeat polymorphism was determined by direct amplification.

RESULTS

The IL4 -590TT genotype was significantly more frequent in patients with RA than in controls (p = 0.018, OR 3.34, 95% CI 1.08-11.04). The IL4RA +148A allele was significantly associated with the presence of RF (p = 0.0019, OR 2.55, 95% CI 1.55-4.86) and a history of articular joint replacement (p = 0.024, OR 2.08, 95% CI 1.04-4.18). The IL4RA +1902G allele was more frequently seen in patients with RA and high RF titers (p = 0.00067, OR 4, 95% CI 1.64-9.93).

CONCLUSION

Highly complex pathways lead to the development of RA and may not be similar in all patients. Our findings of higher frequency of IL4 and IL4RA genotypes and alleles with RA, presence of RF, RF titers, and history of articular joint replacement support the polygenic expression of RA and the likely role of IL-4 in influencing its initiation and development.

Skeletal muscle IL-4, IL-4Ralpha, IL-13 and IL-13Ralpha1 expression and response to strength training

Interleukin-4 (IL-4) and interleukin-13 (IL-13) are Th2 cytokines involved in various immune responses and only a few reports examine skeletal muscle and the possible role of Th2 cytokines in myoblast fusion and myotube maturation. We hypothesized that IL-4, IL-13 and their receptors are involved in skeletal muscle adaptations to strength training. We investigated the effects of 6 weeks of strength training with different muscle load on IL-4, IL-13, IL-4Ralpha and IL-13Ralpha1 expression in skeletal muscle: training with maximal contractions (Max group, n = 12) and training with lower load combined with ballistic and stretch-shortening contractions (Combi group, n = 12). Muscle samples were taken from triceps brachii before and after the 6 weeks of training. mRNA levels of IL-4, IL-13, IL-4Ralpha and IL-13Ralpha1 expression were determined by real-time PCR and IL-4 protein expression by ELISA. We demonstrate for the first time that IL-4, IL-13, IL-4Ralpha and IL-13Ralpha1 are expressed in skeletal muscle in vivo and are up-regulated after strength training. Higher training load in Max leads to higher cytokine responses, which was significant for IL-4Ralpha though IL-4 protein expression did not change significantly. Although the exact mechanisms have yet to be established, and these results may be preliminary, we speculate that IL-4, IL-13, IL-4Ralpha and IL-13Ralpha1 are involved in muscle hypertrophy, MHC-transformation and anti-inflammatory damage control that occur during strength training.

IL4R alpha mutations are associated with asthma exacerbations and mast cell/IgE expression

BACKGROUND

Severe asthma has been associated with severe exacerbations, lower lung function and greater tissue inflammation. Previous studies have suggested that mutations in interleukin-4 receptor alpha (IL4Ralpha) are associated with lower lung function, higher IgE, and a gain in receptor function. However, an effect on exacerbations and tissue inflammation has not been shown.

HYPOTHESIS

Allelic substitutions in IL4Ralpha are associated with asthma exacerbations, lower lung function, and tissue inflammation, in particular to mast cells and IgE.

METHODS

Two well-characterized cohorts of subjects with severe asthma were analyzed for five single nucleotide polymorphisms (SNPs) in IL4Ralpha. These polymorphisms were compared with the history of severe asthma exacerbations and lung function. In the primary (National Jewish) cohort, these polymorphisms were also compared with endobronchial tissue inflammatory cells and local IgE.

RESULTS

In both cohorts, the presence of the minor alleles at E375A and Q551R, which were more common in African Americans, was associated with a history of severe exacerbations and lower lung function. In the National Jewish cohort, the C allele at E375A was associated with higher tissue mast cells and higher levels of IgE bound to mast cells. The significance for most of these associations remained when whites (the larger racial subgroup) were analyzed separately.

CONCLUSIONS

SNPs in IL4Ralpha, which are more common in African Americans, are associated with severe asthma exacerbations, lower lung function, and increased mast cell-related tissue inflammation. Further studies of the impact of these mutations in African Americans and on receptor function are indicated.

Polymorphisms in the IL-13 and IL-4 receptor alpha genes and allergic rhinitis

The IL-4 receptor (IL-4R) and IL-13 genes are candidate genes in atopic diseases. The IL-4Ralpha chain and IL-13 promoter polymorphisms are gain-of-function mutations associated with atopy. We tested whether polymorphisms in the IL-4Ralpha chain and the coding region of the IL-13 gene are associated with allergic rhinitis in a Korean population. Polymerase chain reaction-based assays for IL-4Ralpha Gln551Arg and IL-13 exon 4 G2044A were used for genotyping. There were no differences in the frequencies of the genotypes and alleles of IL-4Ralpha between the controls and patients. The frequency of the IL-13 exon 4 2044A allele was statistically different between the controls and patients. Our results suggest that the IL-13 exon 4 G2044A polymorphism confers susceptibility to the development of allergic rhinitis in Koreans, whereas the IL-4Ralpha Gln551Arg polymorphism is not related to allergic rhinitis.