Association of the STAT4 gene with increased susceptibility for some immune-mediated diseases

Genomic Regions Associated with Resistance to Gastrointestinal Nematode Parasites in Sheep-A Review

Gastrointestinal nematodes (GINs) can be a major constraint and global challenge to the sheep industry. These nematodes infect the small intestine and abomasum of grazing sheep, causing symptoms such as weight loss, diarrhea, hypoproteinemia, and anemia, which can lead to death. The use of anthelmintics to treat infected animals has led to GIN resistance, and excessive use of these drugs has resulted in residue traced in food and the environment. Resistance to GINs can be measured using multiple traits, including fecal egg count (FEC), Faffa Malan Chart scores, hematocrit, packed cell volume, eosinophilia, immunoglobulin (Ig), and dagginess scores. Genetic variation among animals exists, and understanding these differences can help identify genomic regions associated with resistance to GINs in sheep. Genes playing important roles in the immune system were identified in several studies in this review, such as the CFI and MUC15 genes. Results from several studies showed overlapping quantitative trait loci (QTLs) associated with multiple traits measuring resistance to GINs, mainly FEC. The discovery of genomic regions, positional candidate genes, and QTLs associated with resistance to GINs can help increase and accelerate genetic gains in sheep breeding programs and reveal the genetic basis and biological mechanisms underlying this trait.

Assessing the association of rs7574865 STAT4 gene variant and type 1 diabetes mellitus among Egyptian patients

Background

Variants in the signal transducer and activator of transcription 4 (STAT4) gene have an important role in the incident of multiple autoimmune diseases including type 1 diabetes mellitus (T1D). It is a genetically related auto-immune disorder that resulted from T cell-mediated destruction of pancreatic cells that are in control for the production of insulin in the blood. The current study aimed to clarify the role of STAT4 (rs7574865) variant allelic and genotypic variations in the susceptibility to type 1 diabetes among Egyptians by using the real-time PCR.

Results

A total of 100 patients and 100 controls were genotyped for rs7574865, and the biochemical and anthropometric parameters were measured to show that type 1 diabetic patients had significantly higher levels of HbA1c and triglycerides compared to non-diabetic individuals (P < 0.05). And genetically, the T allele and GT genotype have a significant correlation with diabetes type 1.

Conclusion

It was confirmed by this study that the rs7574865 T allele and GT genotype have a significant correlation with diabetes type 1 incidence among Egyptian patients.

STAT4 sequence variant and elevated gene expression are associated with type 1 diabetes in Polish children

Introduction

Type 1 diabetes (T1D) is caused by the autoimmune destruction of pancreatic β cells, resulting from coincident genetic predisposition and some environmental triggers. Signal transducer and activator of transcription 4 (STAT4) gene encodes a transcription factor, which promotes Th1 cell differentiation, interferon γ production, and development of Th17 cells. Polymorphisms of STAT4 are associated with several autoimmune conditions, while studies in T1D provided inconsistent results. This analysis was designed to investigate the association of STAT4 rs7574865 with T1D in Polish children and to assess STAT4 expression in newly diagnosed subjects.

Material and methods

Rs7574865 was genotyped in 656 T1D children and 782 healthy individuals. STAT4 mRNA expression was analyzed in peripheral blood mononuclear cells (PBMCs) from 29 children with T1D and 27 age-matched controls. β-cell and thyroid-specific serum autoantibodies were assessed with radioimmunoassays.

Results

The distribution of rs7574865 genotypes and alleles demonstrated significant difference (p = 0.002, p < 0.001, respectively) between patients vs. controls. Carriers of the minor T allele presented earlier T1D onset (p = 0.017). No differences were found in γ-cell autoantibody in genotype-stratified patients (p > 0.050), while anti-thyroid antibodies were more frequent in carriers of the minor allele(p = 0.039 for anti-thyroperoxidase, p = 0.007 for anti-thyroglobulin antibodies, respectively). STAT4 was overexpressed in PBMCs from T1D patients (p = 0.008), especially subjects with two/three circulating β-cell antibodies (p < 0.001).

Conclusions

The study confirms an association of STAT4 rs7574865 with T1D in Polish patients, and provides an evidence for its relationship with an earlier disease onset and concomitant thyroid autoimmunity. STAT4 expression appears elevated in T1D, especially with more severe reaction against β-cell antigens.

Measuring consistency among gene set analysis methods: A systematic study

Gene set analysis is a quantitative approach for generating biological insight from gene expression datasets. The abundance of gene set analysis methods speaks to their popularity, but raises the question of the extent to which results are affected by the choice of method. Our systematic analysis of 13 popular methods using 6 different datasets, from both DNA microarray and RNA-Seq origin, shows that this choice matters a great deal. We observed that the overall number of gene sets reported by each method differed by up to 2 orders of magnitude, and there was a bias toward reporting large gene sets with some methods. Furthermore, there was substantial disagreement between the 20 most statistically significant gene sets reported by the methods. This was also observed when expanding to the 100 most statistically significant reported gene sets. For different datasets of the same phenotype/condition, the top 20 and top 100 most significant results also showed little to no agreement even when using the same method. GAGE, PAGE, and ORA were the only methods able to achieve relatively high reproducibility when comparing the 20 and 100 most statistically significant gene sets. Biological validation on a juvenile idiopathic arthritis (JIA) dataset showed wide variation in terms of the relevance of the top 20 and top 100 most significant gene sets to known biology of the disease, where GAGE predicted the most relevant gene sets, followed by GSEA, ORA, and PAGE.

Influence of STAT4 gene polymorphisms in the pathogenesis of endometriosis

The STAT4 gene is vital to signaling pathways in the immune response. Immunological alterations are involved in the pathogenesis of endometriosis, and STAT4 polymorphisms may be linked to disease development. This study's aim is to evaluate the possible association between four STAT4 polymorphisms (rs7601754/G > A, rs11889341/C > T, rs7574865/T > G, and rs7582694/C > G) and the pathogenesis of endometriosis in Brazilian women. This case-control study's sample comprised 238 women with endometriosis and 201 healthy, fertile women without endometriosis (which was surgically confirmed). Genotyping was performed using the TaqMan system with a real-time polymerase chain reaction; the genotype, allele, and haplotype frequencies were then compared between groups. A single-polymorphism analysis revealed that the TT genotype of the rs7574865/T > G polymorphism was significantly more frequent in women with minimal or mild endometriosis than in the controls (10% vs. 5%, p = 0.047). The CGAC, GTAT, and GTAC haplotypes were significantly more frequent in the women with endometriosis-related infertility (5.8%, 4.1%, and 2.9%, respectively) than in the controls (2.4%, 1.1%, and 0.8%, respectively; p = 0.020, p = 0.011, and p = 0.032, respectively), but the GGGC and CTAT haplotypes were significantly more prevalent in the control group (34.7% and 13.9%, respectively) than among the infertile group (26.2% and 9.1%, respectively). In addition, the CGAC haplotype was more frequently found in those with minimal or mild endometriosis (6.8%) than in the controls (2.4%, p = 0.009), and the GTAT haplotype was more commonly found in those with moderate or severe disease (3.6%) than in the controls (1.1%, p = 0.028). These findings suggest that STAT4 polymorphisms can influence the pathogenesis of endometriosis.

The genetic pathogenesis, diagnosis and therapeutic insight of rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic autoimmune disease that causes chronic inflammation of the joints. RA is a heterogeneous disorder caused by an abnormal autoimmune response triggered by the complex interactions of genetic and environmental factors that contribute to RA etiology. However, its underlying pathogenic mechanisms are yet to be fully understood. In this review, I provide an overview of the pathogenesis, diagnosis and therapeutic insight in the clinical management of RA in light of the recent updates to classification criteria and recent discoveries of genetic loci associated with susceptibility for RA.

Polymorphisms in the STAT4 gene and tuberculosis susceptibility in a Chinese Han population

The signal transducer and activator of transcription 4 (STAT4) gene encodes a transcription factor that transmits signals induced by several cytokines which play critical roles in the development of autoimmune and chronic inflammatory diseases. We performed an association study between STAT4 single nucleotide polymorphisms (SNPs) and tuberculosis (TB). 624 TB cases and 598 healthy controls were studied to compare allele/genotype frequencies of 4 SNPs in STAT4. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression. Genotyping was performed with the Sequenom MassARRAY SNP genotyping platform. Out of 4 SNPs tested in the study, rs4853542 allele A showed a 25% decreased risk of TB compared with allele G (P = 0.013, OR = 0.75, 95%CI: 0.60-0.94). However, it did not show significant differences under any genetic model after Bonferroni correction. No association was found for the other 3 SNPs with TB. In subgroup analyses, the protective effects of rs485342 allele A were stronger among younger subjects <25 years (P = 0.002, OR = 0.49, 95%CI: 0.31-0.76). Allele A of the rs4853542 polymorphism in STAT4 is not associated with TB susceptibility, but we demonstrated that rs4853542A allele decreased risk of TB in younger adults after Bonferroni correction.

Targeting STATs in neuroinflammation: The road less traveled!

JAK/STAT transduction pathway is a highly conserved pathway implicated in regulating cellular proliferation, differentiation, survival and apoptosis. Dysregulation of this pathway is involved in the onset of autoimmune, haematological, oncological, metabolic and neurological diseases. Over the last few years, the research of anti-neuroinflammatory agents has gained considerable attention. The ability to diminish the STAT-induced transcription of inflammatory genes is documented for both natural compounds (such as polyphenols) and chemical drugs. Among polyphenols, quercetin and curcumin directly inhibit STAT, while Berberis vulgaris L. and Sophora alopecuroides L extracts act indirectly. Also, the Food and Drug Administration has approved several JAK/STAT inhibitors (direct or indirect) for treating inflammatory diseases, indicating STAT can be considered as a therapeutic target for neuroinflammatory pathologies. Considering the encouraging data obtained so far, clinical trials are warranted to demonstrate the effectiveness and potential use in the clinical practice of STAT inhibitors to treat inflammation-associated neurodegenerative pathologies.

Association Between STAT4 rs7574865 Polymorphism and Rheumatoid Arthritis: Debate Unresolved

Background:

STAT4 rs7574865 polymorphism has been evidently associated with susceptibility to Rheumatoid Arthritis (RA) in European and Eastern Asian populations, whereas studies in other countries reported otherwise.

Objective:

We investigated the distribution of STAT4 rs7574865 polymorphism in a group of Syrian RA patients.

Methods:

Eighty-one RA patients and forty healthy controls were enrolled and STAT4 rs7574865 was genotyped by direct sequencing. RA patients were stratified according to Anti-Citrullinated Protein Antibodies (ACPA) status for analysis.

Results:

Minor T allele frequencies were 30.4%, 16.7%, and 23.8% in ACPA-positive RA patients, ACPA-negative RA patients, and healthy controls, respectively. No significant differences in STAT4 rs7574865 allele/genotype frequencies were found between ACPA-positive RA patients, ACPA-negative RA patients, and healthy controls (P>0.05).

Conclusion:

STAT4 rs7574865 TT genotype showed a potential impact on ACPA positivity in Syrian RA patients. However, STAT4 rs7574865 effect on RA onset and severity is minor compared to other genetic factors such as HLA-DRB1 shared epitope alleles.

Genetics and rheumatoid arthritis susceptibility in Iran

Rheumatoid arthritis (RA) is an autoimmune disorder with a number of risk factors, including both genetic and environmental. A number of RA risk associated genomic loci has been identified. In this review, we summarize the association of genetic factors with RA reported in population studies in Iran. No significant association was found between the majority of genetic factors identified in other populations and risk for RA in the Iranian subjects. This conflicting result could be due to the ethnic differences and diversity that are present in Iran. We conclude that there is a need to investigate larger groups of Iranian subjects, encompassing different regions of Iran, to either prove or refute these initial findings.

Polymorphisms of the STAT4 gene in the pathogenesis of tuberculosis

The signal transducer and activator of transcription 4 (STAT4) gene encodes a transcription factor that transmits signals induced by several cytokines which play critical roles in the development of autoimmune and chronic inflammatory diseases. In the present study, we have investigated the association between STAT4 polymorphisms and a predisposition to Mycobacterium tuberculosis (MTB) infection and pulmonary tuberculosis (PTB). In the present study, a total of 209 cases of PTB, 201 subjects with latent TB infection (LTBI), and 204 healthy controls (HC) were included. Logistic regression analyses were used to calculate P-values, odds ratios (ORs), and 95% confidence intervals (CIs) for assessing the association between single nucleotide polymorphisms (SNPs) and disease risk. We used Bonferroni correction to adjust the P-values. Genotyping was conducted using the improved multiplex ligase detection reaction (iMLDR) method. For the rs7574865 polymorphism, the GT genotype is less frequent in the LTBI group compared with HC (P=0.028, OR = 0.62; 95%CI: 0.40-0.95). In addition, the prevalence of the rs897200 CC genotype was lower in the PTB cases compared with LTBI individuals (P=0.039, OR = 0.54; 95%CI: 0.30-0.97). However, no SNPs within STAT4 were associated with PTB or LTBI after Bonferroni correction. Our study demonstrated that STAT4 variants were not related to LTBI and PTB.

Looking at genetic structure and selection signatures of the Mexican chicken population using single nucleotide polymorphism markers

Genetic variation enables both adaptive evolutionary changes and artificial selection. Genetic makeup of populations is the result of a long-term process of selection and adaptation to specific environments and ecosystems. The aim of this study was to characterize the genetic variability of México's chicken population to reveal any underlying population structure. A total of 213 chickens were sampled in different rural production units located in 25 states of México. Genotypes were obtained using the Affymetrix Axiom® 600 K Chicken Genotyping Array. The Identity by Descent (IBD) and the principal components analysis (PCA) were performed by SVS software on pruned single nucleotide polymorphisms (SNPs).ADMIXTURE analyses identified 3 ancestors and the proportion of the genetic contribution of each of them has been determined in each individual. The results of the Neighbor-Joining (NJ) analysis resulted consistent with those obtained by the PCA. All methods utilized in this study did not allow a classification of Mexican chicken in distinct clusters or groups. A total of 3,059 run of homozygosity (ROH) were identified and, being mainly short in length (<4 Mb), these regions are indicative of a low inbreeding level in the population. Finally, findings from the ROH analysis indicated the presence of natural selective pressure in the population of Mexican chicken.The study indicates that the Mexican chicken clearly appear to be a unique creole chicken population that was not subjected to a specific artificial selection. Results provide a genetic knowledge that can be used as a basis for the genetic management of a unique and very large creole population, especially in the view of using it in production of hybrids to increase the productivity and economic revenue of family farming agriculture, which is widely present in México.

[The influence of STAT4 rs7574865 (G/T) polymorphism on the risk of clinical and immunological phenotypes of systemic sclerosis in a Russian patient population: Results of a pilot study]

AIM

To examine the association of signal transducer and activator transcription 4 (STAT4) rs7574865 G/T polymorphism with a predisposition to systemic sclerosis (SSC) and associated clinical and autoimmune phenotypes in a Russian population.

SUBJECTS AND METHODS

A total of 102 patients with SSC and 103 healthy individuals as controls were examined. STAT4 rs7574865 polymorphism was investigated by real-time polymerase chain reaction.

RESULTS

The carriers of the T allele showed a statistically significant association with SSC, a diffuse form (DF), the presence of interstitial lung disease (ILD), cardiac injury (CI), and seropositivity for anti-topoisomerase I antibodies (ATA).

CONCLUSION

The findings results confirm the important role of STAT4 gene in the predisposition to SSC and its phenotypes, such as DF, ILD, CI, and ATA in the Russian population.

Association of STAT4 rs7574865 and PTPN22 rs2476601 polymorphisms with rheumatoid arthritis and non-systemically reacting antibodies in Egyptian patients

The aim of this study was to investigate association of protein tyrosine phosphatase non-receptor type 22 (PTPN22) rs2476601 and signal transducer and activator of transcription 4 (STAT4) rs7574865 polymorphisms with rheumatoid arthritis (RA) susceptibility and to assess potential association with the status of rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP) antibodies, serum neopterin, and disease activity. RF, anti-CCP antibodies, and neopterin were assayed in serum of 100 unrelated RA patients and 114 controls. STAT4 rs7574865 G/T and PTPN22 rs2476601 C/T polymorphisms were genotyped by the TaqMan allelic discrimination method. The frequency of STAT4 variant allele was significantly higher in RA patients than in controls (p = 0.01), while the variant allele of PTPN22 was identified in only two RA patients, in a heterozygous form and in none of control subjects. The frequency of STAT4 variant allele carrier genotypes (GT+TT) was significantly higher among RA patients than in controls (43.7 vs. 10.5%, p = 0.02) and associated with RA under additive and dominant models. The frequency of RF and anti-CCP positivity was significantly higher among RA patients carrying T allele genotypes compared to patients carrying wild genotype (P = 0.02 and 0.04, respectively). No significant associations between STAT4 variant and serum neopterin or disease activity parameters were identified. Our study confirmed the association of STAT4 rs7574865 polymorphism with RA and was the first to indicate an association with RF and anti-CCP antibodies positivity. We also found PTPN22 rs2476601 has no role in susceptibility to RA in Egyptian patients.

GenePANDA-a novel network-based gene prioritizing tool for complex diseases

Here we describe GenePANDA, a novel network-based tool for prioritizing candidate disease genes. GenePANDA assesses whether a gene is likely a candidate disease gene based on its relative distance to known disease genes in a functional association network. A unique feature of GenePANDA is the introduction of adjusted network distance derived by normalizing the raw network distance between two genes with their respective mean raw network distance to all other genes in the network. The use of adjusted network distance significantly improves GenePANDA’s performance on prioritizing complex disease genes. GenePANDA achieves superior performance over five previously published algorithms for prioritizing disease genes. Finally, GenePANDA can assist in prioritizing functionally important SNPs identified by GWAS.

Extrahepatic Autoimmune Diseases in Patients with Autoimmune Liver Diseases: A Phenomenon Neglected by Gastroenterologists

Autoimmune liver diseases (AILDs) often coexist with other extrahepatic autoimmune diseases (EHAIDs). The spectrum of EHAIDs in patients with AILDs is similar, whereas the incidence is different. Notably, autoimmune thyroid disease and Sjogren's syndrome are the most common EHAIDs. Associated extrahepatic diseases may predate the appearance of AILDs or coincide with their onset. More frequently, they may appear during the course and even occur years after the diagnosis of AILDs. Importantly, associated EHAIDs may influence the natural course and prognosis of AILDs. To date, a definite pathophysiological pathway which contributes to the coexistence of AILDs and EHAIDs is still lacking. The current view of autoimmunity clustering involves a common susceptibility genetic background which applies to related pathologies. Herein, we review the current published researches regarding EHAIDs in patients with AILDs, particularly in relation to their clinical impact and pathophysiology. In managing patients with AILDs, gastroenterologists should be aware of the possibly associated EHAIDs to ensure a prompt diagnosis and better outcome.

Type I Interferon Is a Catastrophic Feature of the Diabetic Islet Microenvironment

A detailed understanding of the molecular pathways and cellular interactions that result in islet beta cell (β cell) destruction is essential for the development and implementation of effective therapies for prevention or reversal of type 1 diabetes (T1D). However, events that define the pathogenesis of human T1D have remained elusive. This gap in our knowledge results from the complex interaction between genetics, the immune system, and environmental factors that precipitate T1D in humans. A link between genetics, the immune system, and environmental factors are type 1 interferons (T1-IFNs). These cytokines are well known for inducing antiviral factors that limit infection by regulating innate and adaptive immune responses. Further, several T1D genetic risk loci are within genes that link innate and adaptive immune cell responses to T1-IFN. An additional clue that links T1-IFN to T1D is that these cytokines are a known constituent of the autoinflammatory milieu within the pancreas of patients with T1D. The presence of IFNα/β is correlated with characteristic MHC class I (MHC-I) hyperexpression found in the islets of patients with T1D, suggesting that T1-IFNs modulate the cross-talk between autoreactive cytotoxic CD8⁺ T lymphocytes and insulin-producing pancreatic β cells. Here, we review the evidence supporting the diabetogenic potential of T1-IFN in the islet microenvironment.

Effect of donor STAT4 polymorphism rs7574865 on clinical outcomes of pediatric acute leukemia patients after hematopoietic stem cell transplant

STAT4 polymorphism, rs7574865 is linked to various autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis. Its T minor allele is associated with higher STAT4 mRNA and protein expression, indicating a stronger skewed immune response than the norm. Although widely studied in autoimmune disease patients and the general population, its effect on immunocompromised subjects is still unknown. Especially in situations, i.e. post-hematopoietic stem cell transplantation (post-HSCT), where control of the immune response is crucial. Hence, this study investigates if the presence of the T minor allele in donors would affect immunological response and clinical outcomes post-HSCT. Samples from 161 pediatric patients who underwent allogeneic HSCT for acute leukemia and showed complete chimerism by donor cells were obtained. Six clinical outcomes were investigated; hepatic veno-occlusive disease, acute graft-vs-host disease, chronic graft-vs-host disease, cytomegalovirus (CMV) infection, relapse and overall survival. The TT genotype was found to be significant in the occurrence of CMV infection (P=0.049), showing higher incidence of CMV infection compared to the others. Multivariate analysis confirmed that association of the TT genotype is independent from other variables in CMV infection occurrence (P=0.010). This is the first study on STAT4 polymorphism rs7574865 in allogeneic HSCT as well as immunocompromised patients. As the TT genotype is associated with autoimmune diseases, our results seem at a paradox with current evidence hinting at a different role of STAT4 in normal circumstances versus immunocompromised patients. Further investigation is needed to elicit the reason behind this and discover novel applications for better post-transplant outcomes.

Investigation of the genetic overlap between rheumatoid arthritis and psoriatic arthritis in a Greek population

OBJECTIVES

Several rheumatoid arthritis (RA) susceptibility loci have also been found to be associated with psoriatic arthritis (PsA), demonstrating that there is a degree of genetic overlap between various autoimmune diseases. We sought to investigate whether single nucleotide polymorphisms (SNPs) mapping to previously reported RA and/or PsA susceptibility loci, including PLCL2, CCL21, REL, STAT4, CD226, PTPN22, and TYK2, are associated with risk for the two diseases in a genetically homogeneous Greek population.

METHOD

This study included 392 RA patients, 126 PsA patients, and 521 healthy age- and sex-matched controls from Greece. Genotyping of the SNPs was performed with Taqman primer/probe sets. Bioinformatic analysis was performed using BlastP, PyMOL, and Maestro and Desmond.

RESULTS

A significant association was detected between the GC genotype of rs34536443 (TYK2) in both the PsA and RA cohorts. The C allele of this SNP was associated with PsA only. Evidence for association with PsA was also found for the GG genotype and G allele of the rs10181656 SNP of STAT4. The TC genotype of the rs763361 SNP of CD226 was associated with PsA only.

CONCLUSIONS

Genetic overlap between PsA and RA was detected for the rs34536443 SNP of the TYK2 gene within a Greek population. An association of STAT4 (rs10181656) with PsA was confirmed whereas CD226 (rs763361) was associated with PsA but not with RA, in contrast to previous reports. The different findings of this study compared to previous ones highlights the importance of comparative studies that include various ethnic or racial populations.

STAT4 single nucleotide gene polymorphisms and susceptibility to endometriosis-related infertility

INTRODUCTION

Endometriosis is a multifactorial benign gynecologic disorder, characterized by the ectopic growth of misplaced endometrial cells with complex genetic inheritance and changing of some immune based factors and also shares some autoimmune characteristics. However, it is not clear yet that how and when these immunological factors affect the initiation or progression of the disease. It has been shown that STAT4 is a predisposing gene in the development of some autoimmune diseases.

METHOD

The study group comprised 114 patients with endometriosis and 92 sex-, age-, and ethnicity-matched healthy controls of Iranian ancestry. Four SNPs (rs7574865, rs7601754, rs7582694 and rs11889341) were genotyped using the MGB TaqMan.

RESULTS

A significant association in rs7582694 between C allele (P=0.002, OR=1.986, 95% CI: 1.262-3.126) and endometriosis was found in our study, while the G allele (P=0.002, OR=0.0503, 95% CI: 0.319-0.792) was significantly decreased in the patients population. The GC genotype (P=0.004, OR=2.234, 95% CI: 1.301-4.150) was also significantly overrepresented in the patients with endometriosis, while the frequency of GG genotype was significantly lower in the patient group, compared to the controls (P=0.007, OR=0.457, 95% CI: 0.256-0.813).

CONCLUSIONS

Our results for the first time showed a significant association between rs7582694 alleles and genotypes and susceptibility to endometriosis in a population.

Genetic data: The new challenge of personalized medicine, insights for rheumatoid arthritis patients

Rapid advances in genotyping technology, analytical methods, and the establishment of large cohorts for population genetic studies have resulted in a large new body of information about the genetic basis of human rheumatoid arthritis (RA). Improved understanding of the root pathogenesis of the disease holds the promise of improved diagnostic and prognostic tools based upon this information. In this review, we summarize the nature of new genetic findings in human RA, including susceptibility loci and gene-gene and gene-environment interactions, as well as genetic loci associated with sub-groups of patients and those associated with response to therapy. Possible uses of these data are discussed, such as prediction of disease risk as well as personalized therapy and prediction of therapeutic response and risk of adverse events. While these applications are largely not refined to the point of clinical utility in RA, it seems likely that multi-parameter datasets including genetic, clinical, and biomarker data will be employed in the future care of RA patients.

Association of STAT4 rs7574865 polymorphism with susceptibility to inflammatory bowel disease: A systematic review and meta-analysis

OBJECTIVE

Association of Signal transducers and activators of transcription-4 (STAT4) gene polymorphism with susceptibility to inflammatory bowel disease have been investigated in a number of epidemiological studies, but the results are inclusive. The aim of this meta-analysis was to more precisely estimate the relationship.

METHODS

The databases of Pubmed and CBM updated to October, 2014 were retrieved. Random- or fixed-effect model was used to estimate odd radio (OR) and corresponding 95% confidence interval (95%CI) on the basis of heterogeneity.

RESULTS

Seven articles containing 2196 Crohn's disease (CD) cases, 1588 ulcerative colitis (UC) cases and 4126 controls were identified. We detected a significant association between STAT4 rs7574865 polymorphism and IBD susceptibility in overall population (GG vs. GT+TT, OR=0.855, 95% CI=0.760-0.962, P=0.009), but not in Caucasian and Asian population, respectively. No association was detected between rs7574865 polymorphism and CD susceptibility in overall, Asian and Caucasian population, respectively. Interestingly, a significant association was detected between rs7574865 with UC susceptibility in overall population (G vs. T, OR=0.881, 95% CI=0.798-0.972, P=0.012; GG vs. GT+TT, OR=0.788, 95% CI=0.679-0.914, P=0.002; GG vs. TT, OR=0.683, 95% CI=0.498-0.937, P=0.018) and Caucasians (GG vs. GT+TT, OR=0.833, 95% CI=0.701-0.990, P=0.038; GG+GT vs. TT, OR=0.667, 95% CI=0.456-0.975, P=0.037; GG vs. TT, OR=0.636, 95% CI=0.433-0.934, P=0.021), respectively, and a possible association was found in Asian population (GG vs. GT+TT, OR=0.709, 95% CI=0.503-0.998, P=0.049).

CONCLUSIONS

STAT4 rs7574865 gene is IBD risk factor, and this gene polymorphism is associated with UC susceptibility, especially in Caucasians. To confirm these findings, further studies with more sample size are required for a definitive conclusion.

Association of PTPN22 rs2476601 and STAT4 rs7574865 polymorphisms with rheumatoid arthritis: A meta-analysis update

BACKGROUND

Rheumatoid arthritis (RA) is a common autoimmune disease with a complex genetic background. The genes encoding protein tyrosine phosphatase non-receptor type 22 (PTPN22) and signal transducer and activator of transcription 4 (STAT4) have been reported to be associated with RA in several ethnic populations.

OBJECTIVES

This work aims to assess the association between PTPN22 rs2476601 and STAT4 rs7574865 polymorphisms with RA susceptibility through an updated meta-analysis of available case-control studies.

METHODS

A literature search of all relevant studies published from January 2007 up to December 2014 was conducted using Pubmed and Science Direct databases. The observed studies that were related to an association between PTPN22 rs2476601 and STAT4 rs7574865 polymorphisms with RA susceptibility were identified. Meta-analysis of the pooled and stratified data was done and assessed using varied genetic models.

RESULTS

Thirty-seven case-control studies with a total of 47 comparisons (29 for PTPN22 rs2476601 polymorphism and 18 for STAT4 rs7574865 polymorphism) met our inclusion criteria. The meta-analysis showed an association between PTPN22 T allele, CT+TT and TT genotypes with RA susceptibility. Furthermore, The meta-analysis showed an association between STAT4 T allele, GT+TT and TT genotypes with RA susceptibility. Stratification of RA patients according to ethnic groups showed that PTPN22 T allele, CT+TT genotypes, STAT4 T allele and STAT4 GT+TT were significantly associated with RA in European, Asian, African subjects, while PTPN22 TT genotype was significantly associated with RA in European but not in Asian and African subjects and STAT4 TT genotype was significantly associated with RA in European and Asian but not in African subject. A subgroup analysis according to the presence or absence of rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP) antibodies revealed that the association between PTPN22 rs2476601 and STAT4 rs7574865 polymorphisms with RA susceptibility may not be dependent on RF and anti-CCP antibodies.

CONCLUSIONS

Our meta-analysis demonstrated that PTPN22 rs2476601 and STAT4 rs7574865 polymorphisms confers susceptibility to RA in total subjects and in major ethnic groups. The association may not be dependent on RF and anti-CCP antibodies.

Signal transducer and activator of transcription 4 in liver diseases

STAT4 is a member of the signal transducer and activator of transcription (STAT) family of molecules that localizes to the cytoplasm. STAT4 regulates various genes expression as a transcription factor after it is phosphorylated, dimerizes and translocates to the nucleus. STAT4 activation is detected virtually in the liver of several mouse models of liver injury, as well as the human liver of chronic liver diseases. STAT4 gene polymorphism has been shown to be associated with the antiviral response in chronic hepatitis C and drug-induced liver injury (DILI), primary biliary cirrhosis (PBC), HCV-associated liver fibrosis and in hepatocellular carcinoma (HCC). However, the roles of STAT4 in the pathogeneses of liver diseases are still not understood entirely. This review summarizes the recent advances on the functional roles of STAT4 and its related cytokines in liver diseases, especially in regulating hepatic anti-viral responses, inflammation, proliferation, apoptosis and tumorigenesis. Targeting STAT4 signaling pathway might be a promising strategy in developing therapeutic approaches for treating hepatitis in order to prevent further injury like cirrhosis and liver cancer.

Vitamin C enhances Nanog expression via activation of the JAK/STAT signaling pathway

Vitamin C (Vc), also known as ascorbic acid, is involved in many important metabolic and physiological reactions in the body. Here, we report that Vc enhances the expression of Nanog and inhibits retinoic acid-induced differentiation of embryonic stem cells. We investigated Vc regulation of Nanog through Janus kinase/signal transducer and activator of transcription pathway using cell signaling pathway profiling systems, and further confirmed by specific pathway inhibition. Using overexpression and knockdown strategies, we demonstrated that STAT2 is a new positive regulator of Nanog and is activated by phosphorylation following Vc treatment. In addition, site mutation analysis identified that STAT2 physically occupies the Nanog promoter, which was confirmed by chromatin immunoprecipitation and electrophoretic mobility shift assays. Taken together, our data suggest a role for Vc in Nanog regulation networks and reveal a novel role for STAT2 in regulating Nanog expression.

Rheumatoid arthritis susceptibility genes: An overview

Rheumatoid arthritis (RA) is a chronic, inflammatory autoimmune disease sustained by genetic factors. Various aspects of the genetic contribution to the pathogenetics and outcome of RA are still unknown. Several genes have been indicated so far in the pathogenesis of RA. Apart from human leukocyte antigen, large genome wide association studies have identified many loci involved in RA pathogenesis. These genes include protein tyrosine phosphatase, nonreceptor type 22, Peptidyl Arginine Deiminase type IV, signal transducer and activator of transcription 4, cytotoxic T-lymphocyte-associated protein 4, tumor necrosis factor-receptor associated factor 1/complement component 5, tumor necrosis factor and others. It is important to determine whether a combination of RA risk alleles are able to identify patients who will develop certain clinical outcomes, such myocardium infarction, severe infection or lymphoma, as well as to identify patients who will respond to biological medication therapy.

Association of STAT4 rs7574865 with susceptibility to systemic lupus erythematosus in Iranian population

Systemic lupus erythematosus (SLE) is a multifactorial autoimmune disease with complex genetic inheritance that affecting different organs and systems. STAT4 has been newly identified as a susceptible gene in the development of SLE. According to recent studies, STAT4 has been associated with SLE in various populations. We investigated whether STAT4 single nucleotide polymorphisms (SNPs) were associated with susceptibility and clinical features of SLE in Iranian patients. The study group comprised 280 patients with SLE and 281 sex-, age-, and ethnicity-matched healthy controls of Iranian ancestry. Two SNPs (rs7574865 and rs7601754) were genotyped using the TaqMan MGB Allelic Discrimination method. Our results showed a significant association between rs7574865 T allele (odds ratio (OR) = 1.50, 95 % CI = 1.18-1.92, P = 0.002) and susceptibility to SLE. The rs7574865TT genotype (P = 0.02, OR = 1.94, 95 % CI = 1.74-3.19) and GT genotype (P = 0.008, OR = 1.71, 95 % CI = 1.19-2.45) showed a significant association with the risk of SLE in the Iranian population. We concluded that STAT4 rs7574865 is associated with SLE susceptibility in the Iranian population and this SNP might be a factor in the pathogenesis of SLE. However, further studies are required to investigate the mechanism by which polymorphisms in this gene lead to SLE.

Association of STAT4 gene rs7574865G > T polymorphism with ulcerative colitis risk: evidence from 1532 cases and 3786 controls

INTRODUCTION

Several studies have reported the relationship between the STAT4 rs7574865G > T polymorphism as a susceptibility factor to ulcerative colitis (UC). However, the results have been controversial. Therefore, we conducted this meta-analysis to obtain the most reliable estimate of the association.

MATERIAL AND METHODS

PubMed, Embase and Web of Science databases were searched. Crude odds ratios (OR) with 95% confidence intervals (CI) were extracted and pooled to assess the strength of the association between the STAT4 rs7574865G > T polymorphism and risk of UC. A total of five eligible studies including 1532 cases and 3786 controls based on the search criteria were involved in this meta-analysis.

RESULTS

We observed that the STAT4 rs7574865G > T polymorphism was significantly correlated with UC risk when all studies were pooled into the meta-analysis (the allele contrast model: OR = 1.13, 95% CI = 1.02-1.25; the heterozygote codominant model: OR = 1.22, 95% CI = 1.04-1.43; the dominant model: OR = 1.25, 95% CI = 1.07-1.45). In the stratified analysis by ethnicity, significant associations were observed in Spanish for the allele contrast model (OR = 1.20; 95% CI = 1.04-1.39), for the homozygote codominant model (OR = 1.57; 95% CI = 1.07-2.31), for the dominant model (OR = 1.20; 95% CI = 1.01-1.43), and for the recessive model (OR = 1.50; 95% CI = 1.03-2.19).

CONCLUSIONS

This meta-analysis suggests that the STAT4 rs7574865G > T polymorphism is a low-penetrant risk factor for UC, especially in Spanish.

Signal transducer and activator of transcription 4 (STAT4) G>T gene polymorphism in Egyptian cases with rheumatoid arthritis

BACKGROUND

The gene encoding signal transducer and activator of transcription 4 (STAT4) has been reported to be associated with rheumatoid arthritis (RA) in several populations. This work aimed at assessing the association of STAT4 G>T gene polymorphism with the susceptibility, activity and functional disability of RA in Egyptian subjects.

SUBJECTS AND METHODS

This study included 112 unrelated RA Egyptian patients who were compared to 122 healthy unrelated individuals taken from the same locality. For all subjects, DNA was genotyped for STAT4 G>T (rs7574865) polymorphism using the PCR-RFLP technique. Antibodies to cyclic citrullinated peptides (anti-CCP) were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Cases showed a significantly higher frequency of the STAT4 T allele carriage (GT+TT genotypes) compared to controls (51.8% vs. 31.1%, OR = 2.37, 95% CI = 1.39-4.05, p = 0.001). Also the frequency of the STAT4 T allele was significantly higher among cases compared to controls (30.4% vs. 16.8%, OR = 2.16, 95% CI = 1.39-3.35, p = 0.001). Cases positive to the STAT4 T allele (GT+TT genotypes) showed no significant difference compared to those with the GG genotype regarding their clinical and immune parameters. Nonetheless, they showed a more functional disability presented in their significantly higher health assessment questionnaire (HAQ) score (p = 0.02).

CONCLUSIONS

This study gives an extra evidence to the association of the STAT4 T allele with the susceptibility and functional disability of RA.

Rs7574865 polymorphism in signal transducers and activators of transcription 4 gene and rheumatoid arthritis: an updated meta-analysis of 28 case-control comparisons

OBJECTIVES

The objective of the present meta-analysis was to investigate whether the combined evidence shows an association between the STAT4 rs7574865 polymorphism and RA.

METHODS

A systematic search of all relevant studies published through April 2013 was conducted using MEDLINE, EMBASE, OVID, and ScienceDirect. The observational studies that were related to an association between the STAT4 rs7574865 polymorphism and RA were identified. The association between the STAT4 rs7574865 polymorphism and RA susceptibility was assessed using genetic models.

RESULTS

Seventeen case-control studies with a total of 28 comparisons (25 300 RA patients and 26 326 controls) met the inclusion criteria. A meta-analysis was conducted for genotype TT versus GT+GG, GT+TT versus GG, TT versus GG and T-allele. The meta-analysis showed an association between RA and the STAT4 rs7574865 TT genotype, GT+TT genotype and T-allele in all subjects. Stratification of RA patients according to ethnic group showed that the TT genotype, GT+TT genotype and T-allele were significantly associated with RA in Europeans, Asians, Africans and Latin Americans. A subgroup analysis according to the absence or presence of rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP) antibodies revealed that the association between the STAT4 rs7574865 polymorphism and RA may be independent of the presence of RF and anti-CCP antibodies.

CONCLUSIONS

This meta-analysis demonstrated that the STAT4 rs7574865 polymorphism confers susceptibility to RA in major ethnic groups. The association may not be dependent on the presence of RF and anti-CCP antibodies.

Insight into gene polymorphisms involved in toll-like receptor/interferon signalling pathways for systemic lupus erythematosus in South East Asia

Polymorphisms in genes involved in toll-like receptor/interferon signalling pathways have been reported previously to be associated with SLE in many populations. This study aimed to investigate the role of seven single nucleotide polymorphisms within TNFAIP3, STAT4, and IRF5, which are involved in upstream and downstream pathways of type I interferon production, in SLE in the South East Asian populations. Genotyping of 360 Malaysian SLE patients and 430 normal healthy individuals revealed that minor alleles of STAT4 rs7574865 and rs10168266 were associated with elevated risk of SLE in the Chinese and Malay patients, respectively (P = 0.028, odds ratio (OR) = 1.42; P = 0.035, OR = 1.80, respectively). Polymorphisms in TNFAIP3 and IRF5 did not show significant associations with SLE in any of the ethnicities. Combined analysis of the Malays, Chinese, and Indians for each SNP indicated that STAT4 rs10168266 was significantly associated with the Malaysian SLE as a whole (P = 0.014; OR = 1.435). The meta-analysis of STAT4 rs10168266, which combined the data of other studies and this study, further confirmed its importance as the risk factor for SLE by having pooled OR of 1.559 and P value of <0.001.

Beyond gene discovery in inflammatory bowel disease: the emerging role of epigenetics

In the past decade, there have been fundamental advances in our understanding of genetic factors that contribute to the inflammatory bowel diseases (IBDs) Crohn's disease and ulcerative colitis. The latest international collaborative studies have brought the number of IBD susceptibility gene loci to 163. However, genetic factors account for only a portion of overall disease variance, indicating a need to better explore gene-environment interactions in the development of IBD. Epigenetic factors can mediate interactions between the environment and the genome; their study could provide new insight into the pathogenesis of IBD. We review recent progress in identification of genetic factors associated with IBD and discuss epigenetic mechanisms that could affect development and progression of IBD.

Meta-analysis reveals an association of STAT4 polymorphisms with systemic autoimmune disorders and anti-dsDNA antibody

Signal transducer and activator of transcription 4 (STAT4) has been recently identified as a susceptibility gene for multiple autoimmune diseases. Here we performed a comprehensive analysis of the association between STAT4 and several different autoimmune disorders to identify potential common inflammatory principles behind this association. Our meta-analysis revealed that the STAT4 rs7574865 polymorphism is associated with four autoimmune diseases with systemic pathology, including systemic lupus erythematosus (OR = 1.52; 95% CI = 1.48 - 1.56, P<1.0 × 10(-16)), rheumatoid arthritis (OR = 1.27; 95% CI = 1.21 - 1.33, P < 1.00 × 10(-16)), systemic sclerosis (OR = 1.38; 95% CI = 1.27 - 1.50, P < 1.44 × 10(-14)), and primary Sjogren's syndrome (OR = 1.32; 95% CI = 1.01 - 1.73, P = 4.40 × 10(-2)), while no association was found with type I diabetes, juvenile idiopathic arthritis, ulcerative colitis and Crohn's disease. Furthermore, the stratified meta-analysis also demonstrate that the STAT4 rs7574865 polymorphism is associated with the presence of autoantibodies with systemic reactivity (anti-ds-DNA antibodies) in SLE patients (OR = 1.37; 95% CI = 1.21 - 1.56, P = 1.12 × 10(-6)). However, no such specific association was seen in RA with regard to the presence of non-systemically reacting antibodies, including rheumatoid factor and anti-cyclic citrullinated peptide antibodies. Taken together, these results suggest that STAT4 polymorphisms are associated with autoimmune diseases which are characterized by a systemic pathology and anti-dsDNA antibody.

Inactivation of the transcription factor STAT-4 prevents inflammation-driven fibrosis in animal models of systemic sclerosis

OBJECTIVE

The transcription factor STAT-4 has recently been identified as a genetic susceptibility factor in systemic sclerosis (SSc) and other autoimmune diseases. The aim of this study was to investigate the contribution of STAT-4 in the development of a fibrotic phenotype in 2 different mouse models of experimental dermal fibrosis.

METHODS

STAT-4-deficient (stat4(-/-) ) mice and their wild-type littermates (stat4(+/+) ) were injected with bleomycin or NaCl. Infiltrating leukocytes, T cells, B cells, and monocytes were quantified in the lesional skin of stat4(-/-) and stat4(+/+) mice. Inflammatory and profibrotic cytokines were measured in sera and lesional skin samples from stat4(-/-) and stat4(+/+) mice. The outcome of mice lacking STAT-4 was also investigated in the tight skin 1 (TSK-1) mouse model.

RESULTS

Stat4(-/-) mice were protected against bleomycin-induced dermal fibrosis, with a reduction in dermal thickening (mean ± SEM 65 ± 3% decrease; P = 0.03), hydroxyproline content (68 ± 5% decrease; P = 0.02), and myofibroblast counts (71 ± 6% decrease; P = 0.005). Moreover, the number of infiltrating leukocytes, especially T cells, was significantly decreased in the lesional skin of stat4(-/-) mice (mean ± SEM 63 ± 5% reduction in T cell count; P = 0.02). Stat4(-/-) mice also displayed decreased levels of inflammatory cytokines such as tumor necrosis factor α, interleukin-6 (IL-6), IL-2, and interferon-γ in lesional skin. Consistent with a primary role of STAT-4 in inflammation, STAT-4 deficiency did not ameliorate fibrosis in TSK-1 mice.

CONCLUSION

The results of this study demonstrate that the transcription factor STAT-4 exerts potent profibrotic effects by controlling T cell activation and proliferation and cytokine release. These findings confirm the results of genetics studies on the role of STAT-4 in the development of SSc.

Polymorphisms of STAT4 and the risk of inflammatory bowel disease: A case-control study in Chinese Han population

Signal transducer and activator of transcription 4 (STAT4) is a transcription factor involved in the signaling pathways of several cytokines, playing an essential role in the development of inflammation in various immune-mediated diseases. Genetic association studies have shown that the STAT4 gene was significantly associated with inflammatory bowel disease (IBD) in Spanish and Caucasian populations. However, these associations in other ethnic populations remain unknown. In the present study, we evaluated the role of the STAT4 rs7574865 and rs7582694 polymorphisms on IBD in 562 unrelated Chinese Han subjects by assessing distributions of genotypes and allele frequencies. Results showed that neither rs7574865 [Crohn's disease (CD): P=0.66, odds ratio (OR) = 0.95, 95% confidence interval (CI) 0.74-1.21; ulcerative colitis (UC): P=0.43, OR=0.85, 95% CI 0.56-1.28; IBD: P=0.52, OR=0.93, 95% CI 0.73-1.17] nor rs7582694 (CD: P=0.40, OR=1.12, 95% CI 0.86-1.44; UC: P=0.50, OR=0.86, 95% CI 0.56-1.33; IBD: P=0.62, OR=1.06, 95% CI 0.83-1.36) was significantly associated with IBD, although the genotype frequency of rs7574865 varied in patients and the controls. In conclusion, our data did not support that STAT4 variants contribute to IBD susceptibility in the Chinese Han population.

Association between polymorphism in STAT4 gene and risk of rheumatoid arthritis: a meta-analysis

BACKGROUND

Rheumatoid arthritis (RA) is a common chronic inflammatory autoimmune disease, affecting 1% of the population worldwide. Single nucleotide polymorphisms (SNPs) of signal transducer and activator of transcription 4 (STAT4) gene are suspected to have some relationship with the risk of RA. This meta-analysis aimed to evaluate the relationship between the polymorphism rs7574865 in STAT4 gene with RA and also examine whether the associations that have been reported in these studies differ between ethnic groups.

METHODS

We retrieved the relevant articles from PubMed, EMBASE and the China National Knowledge Infrastructure (CNKI) databases. The odds ratios (ORs) and their 95% confidence intervals (95% CIs) associated with the minor T allele of STAT4 rs7574865 SNP were extracted from the published studies and included in the analysis. Meta-analyses were performed on the total data set and separately for the major ethnic groups and RF and anti-CCP status. All analyses were performed using the Stata software.

RESULTS

Twenty-three articles were included in the present analysis. Meta-analysis showed an association between the STAT4 polymorphism and RA in all subjects (OR=1.299, 95%CI=1.230-1.371, P<0.001). Stratified analyses indicated that the STAT4 rs7574865 T allele was significantly associated with RA in both Caucasians and Asians, in both positive and negative RF patients versus controls, also significantly in the presence of anti-CCP, both positive and negative. As for genotypes of rs7574865 polymorphism, all the results were significant, no matter in total subjects or stratified analyses by ethnic groups or by RF and anti-CCP status.

CONCLUSION

Genetic polymorphism rs7574865 in STAT4 gene might be associated with RA susceptibility in total subjects, major ethnic groups and different status of anti-CCP or RF.

Associations between interleukin-23 receptor polymorphisms and susceptibility to rheumatoid arthritis: a meta-analysis

The aim of this study was to determine whether interleukin-23 receptor (IL-23R) polymorphisms confer susceptibility to rheumatoid arthritis (RA). A meta-analysis was conducted on the associations between the IL-23R rs1343151, rs10489629, rs7517847, rs11209026, rs1004819, and rs2201841 polymorphisms and RA using (1) allele contrast, (2) the recessive model, (3) the dominant model, and (4) the additive model. A total of 13 studies from eight articles involving 10,016 RA patients and 11,967 controls were considered in the meta-analysis. Meta-analysis identified a significant association between RA and the A allele of the rs1343151 polymorphism in the overall population (OR = 1.110, 95 % CI = 1.056-1.168, p = 4.7 × 10(-6)). Stratification by ethnicity identified a significant association between this polymorphism and RA in Europeans (OR = 1.105, 95 % CI = 1.049-1.163, p = 1.4 × 10(-5)). An association was also found between RA and the A allele carrier of the rs1343151 polymorphism in Europeans (OR = 1.135, 95 % CI = 1.058-1.217, p = 4.0 × 10(-5)). Meta-analysis revealed a significant association between RA and the A allele of the rs10489629 polymorphism in the overall population (OR = 1.079, 95 % CI = 1.029-1.131, p = 0.002) and in Europeans (OR = 1.092, 95 % CI = 1.038-1.149, p = 0.001). Meta-analyses of recessive, dominant, and additive models showed the same pattern as the meta-analysis of the A allele of the rs10489629 polymorphism, that is, a significant association with RA in Europeans. However, no association was found between the IL-23R rs7517847, rs11209026, rs1004819, and rs2201841 polymorphisms and RA susceptibility. This meta-analysis shows that the IL-23R rs1343151 and rs10489629 polymorphisms are associated with the development of RA in Europeans. These findings suggest that the IL-23R genes confer susceptibility to RA in the European population, but further study of this association is required in other ethnic groups.

Genetic associations in acquired immune-mediated bone marrow failure syndromes: insights in aplastic anemia and chronic idiopathic neutropenia

Increasing interest on the field of autoimmune diseases has unveiled a plethora of genetic factors that predispose to these diseases. However, in immune-mediated bone marrow failure syndromes, such as acquired aplastic anemia and chronic idiopathic neutropenia, in which the pathophysiology results from a myelosuppressive bone marrow microenvironment mainly due to the presence of activated T lymphocytes, leading to the accelerated apoptotic death of the hematopoietic stem and progenitor cells, such genetic associations have been very limited. Various alleles and haplotypes of human leucocyte antigen (HLA) molecules have been implicated in the predisposition of developing the above diseases, as well as polymorphisms of inhibitory cytokines such as interferon-γ, tumor necrosis factor-α, and transforming growth factor-β1 along with polymorphisms on molecules of the immune system including the T-bet transcription factor and signal transducers and activators of transcription. In some cases, specific polymorphisms have been implicated in the outcome of treatment on those patients.

Variants within STAT genes reveal association with anticitrullinated protein antibody-negative rheumatoid arthritis in 2 European populations

OBJECTIVE

STAT3 and 4 are, among other factors, critical for the interleukin 12 (IL-12)-mediated Th1 response, for transfer of IL-23 signals, and for survival and expansion of Th17 cells. We investigated the association of STAT3 and STAT4 polymorphisms with serologically distinct subgroups of rheumatoid arthritis (RA).

METHODS

A total of 41 single-nucleotide polymorphisms (SNP) within STAT3 and STAT1-STAT4 loci were investigated in a Swedish cohort of 2043 RA cases and 1115 controls. Nine of the associated SNP were tested in a Spanish cohort of 1223 RA cases and 1090 controls.

RESULTS

Fourteen SNP in the STAT3 and STAT1-STAT4 loci were associated with anticitrullinated protein antibody (ACPA)-negative RA in the Swedish cohort. Three of the SNP in STAT4 and 2 SNP in STAT3 remained associated with ACPA-negative RA after considering the Spanish results. In addition, rs7574865 and rs10181656, in STAT4, were associated with ACPA-positive RA in the Swedish study. One of these SNP, rs7574865, showed a similar pattern of the association in serologically distinct subgroups of RA in a metaanalysis of all 7 published studies.

CONCLUSION

Our findings suggest that variants in STAT genes may contribute differentially to susceptibility to RA in seropositive and in seronegative patients.

Genetics of rheumatoid arthritis: an impressionist perspective

Rheumatoid arthritis (RA) is the most common rheumatic disease. The genetic basis of RA is supported through the identification of more than 30 susceptibility genetic variants. Each of these genes individually makes only a slight contribution to the risk of disease. Moreover, there is significant disparity in the genetic variants associated with different RA subgroups and patient ethnicities, which emphasizes the intricate nature of the disease's pathogenesis, and the complexities involved in large-scale genetic studies. This review evaluates critically the recent literature on the genetic contribution to RA and assesses the methodology used to identify these risk alleles.

Association of STAT4 rs7574865 polymorphism with autoimmune diseases: a meta-analysis

The association between the signal transducer and activator of transcription 4 (STAT4) gene rs7574865 single nucleotide polymorphism and different autoimmune diseases remains controversial and ambiguous. We conducted this study to investigate whether combined evidence shows the association between STAT4 rs7574865 polymorphism and autoimmune diseases. Comprehensive Medline search and review of the references were used to get the relevant reports published before September 2011. Meta-analysis was conducted for genotype T/T (recessive effect), T/T + G/T (dominant effect) and T allele in random effects models. 40 studies with 90 comparisons including 32 systemic lupus erythematosus (SLE), 19 rheumatoid arthritis (RA), 3 type 1 diabetes (T1D), 11 Systemeric Sclerosis (SSc), 4 inflammatory bowed diseases (IBD), 3 Primary Sjogren's syndrome (pSS), 4 juvenile idiopathic arthritis (JIA), 2 Primary antiphospholipid syndrome (APS), 1 Autoimmune thyroid diseases, 1 multiple sclerosis, 1 Psoriasis, 1 Wegener's granulomatosis, 1 Type 2 diabetes, and 1 giant cell arteritis disease were available for this meta-analysis. The overall odds ratios for rs7574865 T-allele significantly increased in SLE, RA, T1D, SSc, JIA, and APS (OR = 1.56, 1.25, 1.13, 1.34, 1.25, and 2.15, respectively, P < 0.00001) and in IBD-UC and pSS (OR = 1.11 and 1.33, respectively, P < 0.05). This meta-analysis demonstrates that the STAT4 rs7574865 T allele confers susceptibility to SLE, RA, T1D, SSc, JIA, APS, IBD-UC, and pSS patients, supporting the hypothesis of association between STAT4 gene polymorphism and subgroup of autoimmune diseases.

The impact of genomics on pediatric research and medicine

In this review, we discuss some of the most recent developments in genomics research and their relevance to the field of pediatrics. In particular, we examine 3 major approaches that are being used to identify genetic correlates of disease: genome-wide association studies, copy number variation studies, and next-generation sequencing. In the past few years, these approaches have yielded major insights into the causes and pathophysiology of a wide range of diseases but are also constrained by certain limitations. This review provides an overview of the genomic landscape in complex pediatric disorders and sets the stage for translating new discoveries into clinical practice, the future of genomic medicine.

The genetics of lupus: a functional perspective

Systemic lupus erythematosus (SLE) is an autoimmune disease with a strong genetic component and is characterized by chronic inflammation and the production of anti-nuclear auto-antibodies. In the era of genome-wide association studies (GWASs), elucidating the genetic factors present in SLE has been a very successful endeavor; 28 confirmed disease susceptibility loci have been mapped. In this review, we summarize the current understanding of the genetics of lupus and focus on the strongest associated risk loci found to date (P <1.0 × 10−8). Although these loci account for less than 10% of the genetic heritability and therefore do not account for the bulk of the disease heritability, they do implicate important pathways, which contribute to SLE pathogenesis. Consequently, the main focus of the review is to outline the genetic variants in the known associated loci and then to explore the potential functional consequences of the associated variants. We also highlight the genetic overlap of these loci with other autoimmune diseases, which indicates common pathogenic mechanisms. The importance of developing functional assays will be discussed and each of them will be instrumental in furthering our understanding of these associated variants and loci. Finally, we indicate that performing a larger SLE GWAS and applying a more targeted set of methods, such as the ImmunoChip and next generation sequencing methodology, are important for identifying additional loci and enhancing our understanding of the pathogenesis of SLE.