Interferon-? +874A/T and interleukin-4 intron3 VNTR gene polymorphisms in Chinese patients with idiopathic thrombocytopenic purpura

IL-4Rα (rs1801275) A>G polymorphism in Egyptian immune thrombocytopenia (ITP) patients: a single center experience

INTRODUCTION

Chronic immune thrombocytopenia (cITP) is characterized by dysregulation of the immune response. Until recently, the role of Th2-related cytokine gene polymorphisms was unclear. Interleukin 4 (IL-4) exerts its functions by binding to three types of IL-4 receptor (IL-4R) complexes. We aimed to explore the potential association between the gene polymorphism of IL-4Rα and cITP.

METHODS

We investigated the clinical impact of the IL-4Rα (rs1801275) A>G single nucleotide polymorphism (SNP) using the polymerase chain reaction (PCR) followed by the restriction fragment length polymorphism (RFLP) method in 82 cITP patients and 60 healthy controls (HCs).

RESULTS

The IL-4Rα (rs1801275) A>G polymorphism analysis showed the mutant GG genotype was significantly higher in control females (p = 0.033). The wild AA genotype had a higher bleeding score (p = 0.02) in the adulthood onset group. Furthermore, the wild AA genotype in the cITP childhood onset group was significantly associated with the disease severity, as well as the response to treatment (p = 0.040).

CONCLUSION

The mutant G allele is protective against the susceptibility to cITP in the Egyptian females. The IL-4Rα (rs1801275) A>G polymorphism may affect the clinical severity of cITP and treatment response in the Egyptian population.

Role of interleukin 4 (IL4) and interleukin 6 (IL6) in the pathogenesis and prognosis of childhood primary immune thrombocytopenia

Immune thrombocytopenia (ITP) is an autoimmune disease characterized by the breakdown of immune tolerance. Impairment of the cellular immunity is primarily evaluated by the levels of the cytokines which can help in predicting the course of ITP. We aimed to assess the levels of IL4 and IL6 in children with ITP and evaluate their role in the pathogenesis and prognosis of this disease. A prospective cohort study was carried on 60 children (15 patients with newly diagnosed ITP, 15 patients with persistent ITP, 15 patients with chronic ITP and 15 healthy children as a control group). Serum IL-4 and serum IL-6 were measured using Human IL-4 and IL-6 ELISA kit in patients and controls. Patients with newly diagnosed and persistent ITP had significantly higher levels of IL4 and IL6 compared to patients with chronic ITP and healthy controls (p < 0.001). The mean serum level of IL4 was 762.0, 741.0, 364.6 and 436.8 pg/ml, and the mean serum level of IL6 was 178.5, 164.4, 57.9 and 88.4 pg/ml for patients with newly diagnosed, persistent, chronic ITP and healthy controls respectively. Serum IL-4 was significantly higher in patients who achieved remission than those who did not improve on first line therapy.

CONCLUSION

Serum IL-4 and IL-6 may have a role in the pathogenesis of primary ITP. IL-4 seems to be a good predictor to treatment response.

WHAT IS KNOWN

• There is a delicate balance of specific cytokine levels in immune thrombocytopenia, which has an important role in the immune system and is known to be deregulated in autoimmune diseases. changes in IL-4 and IL-6 might be involved in the pathogenesis of newly diagnosed ITP in both paediatric and adult patients. • We conducted this research study to measure the serum level of IL-4 and IL-6, in newly diagnosed, persistent and chronic ITP patients and study their relation to disease pathogenesis as well as patient's outcome.

WHAT IS NEW

• We found that IL4 seems to be a good predictor to treatment response and it was a very interesting observation in our study, and to the best of our knowledge, there is no published data about this finding.

CD4+ T cell phenotypes in the pathogenesis of immune thrombocytopenia

Immune thrombocytopenia (ITP) is an autoimmune disorder characterized by low platelet counts due to enhanced platelet clearance and compromised production. Traditionally, ITP was regarded a B cell mediated disorder as anti-platelet antibodies are detected in most patients. The very nature of self-antigens, evident processes of isotype switching and the affinity maturation of anti-platelet antibodies indicate that B cells in order to mount anti-platelet immune response require assistance of auto-reactive CD4⁺ T cells. For a long time, ITP pathogenesis has been exclusively reviewed through the prism of the disturbed balance between Th1 and Th2 subsets of CD4⁺ T cells, however, more recently new subsets of these cells have been described including Th17, Th9, Th22, T follicular helper and regulatory T cells. In this paper, we review the current understanding of the role and immunological mechanisms by which CD4⁺ T cells contribute to the pathogenesis of ITP.

Involvement of Interferon-γ + 874A/T Polymorphism in the Pathogenesis of and Therapeutic Response to Immune Thrombocytopenia

BACKGROUND

Immune thrombocytopenia (ITP) is an autoimmune disease characterized by symptoms of thrombocytopenia and bleeding due to production of autoantibodies against platelets. Recently, the occurrence of polymorphisms has been identified as one of the main causes of disease onset.

METHODS

To conduct this study, we recruited 140 patients and control individuals with no history of platelet loss. After collection of specimens, the prevalence of interferon-γ polymorphism was evaluated using the allele-specific oligonucleotide-polymerase chain reaction (ASO-PCR) technique and confirmed by sequencing techniques.

RESULTS

The results showed that the frequency of the AA genotype was higher in the control group, compared with patients with ITP; however, in the acute and chronic groups, the frequency of the AT genotype was higher than that of the AA genotype. We also discovered that there was no significant correlation between platelet counts before and after treatment, nor in its related parameters with interferon (IFN)-γ polymorphism.

CONCLUSION

rs2430561 does not seem to have any role in ITP pathogenesis and treatment response.

Association between gene polymorphisms and clinical features in idiopathic thrombocytopenic purpura patients

: Immune thrombocytopenic purpura (ITP) is an autoimmune disease in which increased platelet destruction and thrombocytopenia are diagnostic features. In fact, the exact pathogenesis of this disease is still unknown, but genetic changes can be a potential factor in the development of ITP. In this study, the relationship between polymorphisms with platelet destruction has been studied, which leads to decreased platelet count. Relevant literature was identified by a PubMed search (2000-2016) of English language papers using the terms 'ITP', 'polymorphism,' and 'immune system'. The majority of genetic changes (polymorphisms) occur in immune system genes, including interferon (IFN)-γ gene. These changes lead to the dysfunction of immune system and production of pathogenic antibodies against platelet surface glycoproteins such as glycoprotein IIb/IIIa, which eventually result in the destruction of platelets and increasing disease severity. In addition, IFN-γ as well as factors and cytokines involved in megakaryopoiesis, including stem cell factor and interleukin-3 (IL-3), leads to the differentiation of megakaryocytes and platelet release. Considering the fact that IFN-γ is a factor of inflammation and thrombocytopenia, coexistence of this cytokine with thrombopoietin, stem cell factor, and IL-3 results in megakaryocytes differentiation and platelet production, which can be effective to reduce disease severity and increase the platelet counts.

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.

The IL4-VNTR P1 Allele, IL4-VNTR P2P2 Genotype, and IL4-VNTR_IL6-174CG P2P1-GG Genotype Are Associated with an Increased Risk of Brucellosis

In this study, associations between IL-4, IL-6, and macrophage migration inhibitory factor (MIF) polymorphisms and susceptibility to brucellosis were investigated. Consecutive adult patients with no known treatment against brucellosis and who did not have any other autoimmune and/or chronic disorders, were included in this study (n = 120, Group I). Age and sex-matched controls who had no other autoimmune and/or chronic disorders were also included (n = 120, healthy volunteers, Group II). The IL4_P2P2 genotype, IL4_P1 allele, and IL4_variable number of tandem repeats (VNTR)_IL6-174CG compound genotype were found to be more frequent in the patient group than in control subjects. There were significant differences between the patients and controls with respect to the frequencies of the IL4_P2P2 genotype (77.5% versus 87.5%; p = 0.001; OR, 0.36; 95% confidence interval [CI], 0.21-0.62) and the IL4_P1 allele (12.1% versus 6.7%; p = 0.030; OR, 0.92; CI, 1.02-3.64). The IL4-VNTR_IL6-174CG compound genotype was also present at a significantly higher frequency in the patient group than in control subjects (11.7% versus 4.2%; p = 0.027, OR, 3.04; CI, 1.06-8.68). No statistically significant differences in the frequencies of the IL-6-174, MIF-173, IL-4_P1P1, and IL4_P2P1 genotypes were observed between patients and control subjects. The IL4_VNTR P1 allele, P2P2 genotypes, and IL4-VNTR_IL6-174CG P2P1-GG genotypes are common in southern Turkey, and carriers of these polymorphisms are susceptible to brucellosis.

Association of genetic polymorphisms in interferon-γ, interleukin-6 and transforming growth factor-β1 gene with oral lichen planus susceptibility

BACKGROUND

Oral lichen planus (OLP) is a premalignant mucocutaneous disease in which genetic factors and immune responses play a major role. Cytokines play an important role in the pathogenesis and disease progression of OLP. The aim of this study was to investigate the impact of gene polymorphisms of T helper cell subtype Th1 and Th2 cytokines, interferon-gamma (IFN-γ), interleukin-6 (IL-6) and transforming growth factor (TGF)-β1 on OLP susceptibility in a Saudi cohort.

METHODS

Forty two unrelated patients with OLP and 195 healthy controls were genotyped for IFN-γ (874A/T), IL-6 (174G/C) and TGF-β1 (509C/T) polymorphisms.

RESULTS

The frequency of genotype AT of IFN-γ (874A/T) was significantly higher while genotype AA was lower in OLP patients as compared to controls (P < 0.05). The frequency of T containing genotypes (AT + TT) was also higher in OLP patients as compared to that in controls (P = 0.003). The frequencies of allele T was higher while that of allele A lower in patients than the controls however the difference was not statistically significant (P = 0.07). There was no significant difference in the frequencies of alleles and genotypes of IL-6 (174G/C) and TGF-β1 (509C/T) polymorphisms between patient and control groups. These results indicated that genotype AT of IFN-γ (874A/T) polymorphism is associated with OLP risk and genotype AA is protective to OLP. On the other hand the polymorphisms IL-6 (174G/C) and TGF-β1 (509C/T) may not be associated with OLP risk in our population.

CONCLUSION

It is concluded that IFN-γ (874A/T) polymorphism is associated with the susceptibility of OLP, however further studies with large sample size involving different ethnic populations should be conducted to strengthen our results.

Expression of IL4 (VNTR intron 3) and IL10 (-627) genes polymorphisms in childhood immune thrombocytopenic purpura

OBJECTIVE

Immune thrombocytopenic purpura (ITP) is an acquired autoimmune disorder caused by the production of antiplatelet antibodies. These autoantibodies opsonize platelets for splenic clearance, resulting in low levels of circulating platelets. Interleukin 4 (IL4) and interleukin 10 (IL10) are important immunoregulatory cytokines mainly produced by macrophages, monocytes, T cells, B cells, and mast cells. Our study was aimed at detecting the frequency of IL4 (VNTR intron 3) and IL 10 (-627) gene polymorphisms in Egyptian ITP children as genetic markers for ITP risk and clarifying their possible role in the pathogenesis of ITP as well as their correlation with the clinical presentation and laboratory data.

METHODS

IL4 (VNTR intron 3) and IL10 (-627) gene polymorphisms were studied in 70 ITP patients and 50 age- and sex-matched healthy controls using polymerase chain reaction-restriction fragment length polymorphism assay (PCR-RFLP).

RESULTS

IL4 RP2 and IL10 A alleles were detected more frequently among ITP patients compared to controls. A statistically significant difference was observed in IL10 and IL4 gene polymorphism distribution between acute and chronic ITP patients, with higher A allele and RP2 allele among chronic ITP patients versus acute ITP patients. Combined polymorphisms of IL4 and IL10 genes were associated with greater risk of ITP.

CONCLUSION

IL4 and IL10 gene polymorphisms may contribute to susceptibility for ITP in children.

Association between interferon-γ +874 T/A polymorphism and susceptibility to autoimmune diseases: a meta-analysis

OBJECTIVE

The aim of this study was to explore whether the interferon (IFN)-γ +874 T/A polymorphism plays a role in modifying the risk of autoimmune diseases.

METHODS

A meta-analysis was conducted on the association between the IFN-γ +874 T/A polymorphism and autoimmune diseases.

RESULTS

Eighteen studies with a total of 2952 patients and 3832 controls were included in the meta-analysis. The meta-analysis revealed no association between autoimmune diseases and the IFN-γ +874 T allele in all study subjects (odds ratio (OR)=1.023, 95% confidence interval (CI) = 0.894-1.171, p = 0.738), but stratification by ethnicity indicated an association between the IFN-γ +874 T allele and autoimmune diseases in Latin American subjects (OR = 0.780, 95% CI = 0.629-0.953, p = 0.015). Meta-analysis also revealed an association between autoimmune diseases and the IFN-γ +874 T/A polymorphism in Caucasian and Middle Eastern subjects under a dominant inheritance model (OR = 0.686, 95% CI = 0.489-0.964, p = 0.003; OR = 1.414, 95% CI = 1.102-1.813, p = 0.006). Meta-analysis by autoimmune disease type indicated an association between ITP and the IFN-γ +874 T allele (OR = 1.753, 95% CI = 1.228-2.503, p = 0.002), but not for vasculitis, vitiligo, and auto-immune thyroid disease. Meta-analysis also showed a significant association between the IFN-γ +874 T/A polymorphism and systemic lupus erythematosus (SLE) under the dominant model (OR = 1.668, 95% CI = 1.114-2.497, p = 0.013).

CONCLUSIONS

This meta-analysis indicates that the IFN-γ +874 T/A polymorphism may play a significant role in modifying the risk of autoimmune diseases in Caucasian, Latin American, and Middle Eastern subjects, and in particular shows that the IFN-γ +874 T/A polymorphism is associated with increased genetic susceptibility to idiopathic thrombocytopenic purpura and SLE.

Clinical and laboratory predictors of chronic immune thrombocytopenia in children: a systematic review and meta-analysis

Childhood immune thrombocytopenia (ITP) is a rare autoimmune bleeding disorder. Most children recover within 6 to 12 months, but individual course is difficult to predict. We performed a systematic review and meta-analysis to identify predictors of chronic ITP. We found 1399 articles; after critical appraisal, 54 studies were included. The following predictors of chronic ITP in children, assessed in at least 3 studies, have been identified: female gender (odds ratio [OR] 1.17, 95% confidence interval [CI] 1.04-1.31), older age at presentation (age ≥11 years; OR 2.47, 95% CI 1.94-3.15), no preceding infection or vaccination (OR 3.08, 95 CI 2.19-4.32), insidious onset (OR 11.27, 95% CI 6.27-20.27), higher platelet counts at presentation (≥20 × 10(9)/L: OR 2.15, 95% CI 1.63-2.83), presence of antinuclear antibodies (OR 2.87, 95% 1.57-5.24), and treatment with a combination of methylprednisolone and intravenous immunoglobulin (OR 2.67, 95% CI 1.44-4.96). Children with mucosal bleeding at diagnosis or treatment with intravenous immunoglobulin alone developed chronic ITP less often (OR 0.39, 95% CI 0.28-0.54 and OR 0.71, 95% CI 0.52-0.97, respectively). The protective effect of intravenous immunoglobulin is remarkable and needs confirmation in prospective randomized trials as well as future laboratory studies to elucidate the mechanism of this effect.

Relationship between γ-interferon gene polymorphisms and susceptibility to brucellosis infection

Interferon-gamma (IFN-γ) is a pro-inflammatory cytokine that plays a pivotal role in the defense mechanism against Brucella infection. It was hypothesized that the IFN-γ in (+874 A/T in intron 1) TT and +5644 T/A, TT genotypes, which are reportedly associated with high IFN production, are associated with susceptibility to brucellosis in Iranian subjects. Genotyping of these IFN-γ variants by an allele-specific polymerase chain reaction method was performed in 281 subjects, comprising 153 patients with active brucellosis and 128 healthy controls. It was found that the +874 minor allele (A) and homozygote genotype (AA) were significantly more frequently present in brucellosis patients than in controls (OR = 2.588; 95% CI, 1.313-5.104; P = 0.006 for the AA genotype; OR = 1.575; 95% CI, 1.124-2.216; P = 0.010 for the A allele). However, the allelic and genotypic distribution of the IFN-γ polymorphism at position UTR5644 A>T did not differ significantly between patients and controls (P > 0.05). The distribution of haplotypes in this study suggests that the T/A haplotype (+874/UTR5644), which was present more frequently in controls than in patients, may protect subjects against Brucella infection. It is suggested that IFN-γ +874 AA genotype and A allele are risk factors for developing brucellosis infection in Iranian subjects.

Interleukin-4 genetic variants correlate with its transcript and protein levels in patients with vitiligo

BACKGROUND

Vitiligo is an acquired pigmentary disorder resulting from loss of melanocytes. Interleukin (IL)-4 has been shown to stimulate B-cell proliferation, to regulate immunoglobulin class switching (IgG1 and IgE) and to promote T-cell development. Polymorphisms in the IL4 gene are known to increase its expression, thereby implicating its role in vitiligo susceptibility.

OBJECTIVES

To explore intron 3 VNTR (IVS3) and -590 C/T (rs2243250) promoter polymorphisms in the IL4 gene and to correlate them with the IL4 transcript, serum IL-4 and IgE levels to achieve genotype-phenotype correlation in patients with vitiligo from Gujarat. A replication study was done in a North Indian population.

METHODS

The case-control study was performed to investigate these polymorphisms in 505 patients and 744 controls in Gujarat, and 596 patients and 397 controls in North India by polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism analysis. IL4 transcript levels were monitored by real-time PCR. Serum IL-4 and IgE levels were measured by enzyme-linked immunosorbent assay and electrochemiluminescence immunoassay, respectively.

RESULTS

The genotype frequencies differed significantly between patients with generalized vitiligo and controls for both the polymorphisms in both populations. Allele frequencies significantly differed between patients with generalized vitiligo and controls for both the polymorphisms in the population from Gujarat. Interestingly, genotype and allele frequencies for -590 C/T single nucleotide polymorphism were significantly different between patients with localized vitiligo and controls in both the populations. The study revealed significantly increased IL4 mRNA, serum IL-4 and IgE levels in patients from Gujarat. Age of onset analysis of disease in patients suggested that the TTR2R2, TTR1R2 and CTR2R2 haplotypes had a profound effect in the early onset of the disease.

CONCLUSIONS

Our results suggest that these polymorphisms of the IL4 gene may be genetic risk factors for susceptibility towards vitiligo and the upregulation of the IL4 transcript, protein and IgE levels in individuals with susceptible haplotypes reveal the crucial role of IL-4 in the pathogenesis of vitiligo.

The T allele of the interferon-gamma +874A/T polymorphism is associated with bipolar disorder

BACKGROUND

Previous studies have shown that patients with bipolar disorder (BD) tend to have altered immune system function. Several studies have reported that changes in interferon-gamma (IFN-γ) may play an important role in the development of BD.

AIMS

To investigate the relationship between IFN-γ and BD, 156 patients with BD and 175 control subjects were genotyped for the IFN-γ +874A/T single nucleotide polymorphism.

RESULTS

We detected significant differences in the genotype distributions and allele frequencies of the IFN-γ +874A/T single nucleotide polymorphism (rs2430561) between patients with BD and normal controls. The T allele was found to be significantly more common among patients with BD than in controls. Additionally, significant differences in scores on the Young Mania Rating Scale (YMRS) were found between the three genotypes of this polymorphism.

CONCLUSIONS

Our results suggest that the IFN-γ +874A/T polymorphism may have important effects related to susceptibility to BD and that the T allele may be associated with an increased risk of developing BD.

Single nucleotide polymorphism in DNMT3B promoter and the risk for idiopathic thrombocytopenic purpura in Chinese population

OBJECTIVE

Epigenetic changes in gene expression, including DNA methylation and histone modifications, might contribute to autoimmunity. DNA methylation is mediated by a family of DNA methyltransferases. Polymorphisms of the DNA methyltransferase 3B (DNMT3B) gene may influence DNMT3B activity on DNA methylation, thereby modulating the susceptibility to some diseases. The purpose of this study was to investigate the association between the single nucleotide polymorphism (SNP) in promoter of the DNMT3B gene and the risk for development of idiopathic thrombocytopenic purpura (ITP).

METHODS

In this hospital-based case-control study, the DNMT3B SNP was genotyped in 201 patients with ITP and 136 healthy controls by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

The C/C genotype was not detected in both the patients with ITP and the controls. In the controls, the frequencies of T/T and C/T genotypes and T and C alleles were 97.8%, 2.2%, 98.9%, and 1.1%, respectively. There was no significant difference in genotype and allele distribution between the patients with ITP and the controls (P = 0.745 and 0.747, respectively). No significant difference was observed in genotype and allele distribution between the two groups when stratified by the age. The similar results were shown among the four groups of patients with ITP: acute childhood, chronic childhood, acute adult, and chronic adult.

CONCLUSION

This polymorphism was distributed similarly between the patients with ITP and the controls. It demonstrated that it may not be used as a stratification marker to predict the susceptibility to ITP, at least in the population of North China.