Protein tyrosine phosphatase gene C1858T allele confers risk for rheumatoid arthritis in Hungarian subjects

Targeting Pathways and Integrated Approaches to Treat Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic symmetrical systemic disorder that not only affects joints but also other organs such as heart, lungs, kidney, and liver. Approximately there is 0.5%-1% of the total population affected by RA. RA pathogenesis still remains unclear due to which its appropriate treatment is a challenge. Further, multitudes of factors have been reported to affect its progression i.e. genetic factor, environmental factor, immune factor, and oxidative factor. Therapeutic approaches available for the treatment of RA include NSAIDs, DMARDs, enzymatic, hormonal, and gene therapies. But most of them provide the symptomatic relief without treating the core of the disease. This makes it obligatory to explore and reach the molecular targets for cure and long-term relief from RA. Herein, we attempt to provide extensive overlay of the new targets for RA treatment such as signaling pathways, proteins, and receptors affecting the progression of the disease and its severity. Precise modification in these targets such as suppressing the notch signaling pathway, SIRT 3 protein, Sphingosine-1-phosphate receptor and stimulating the neuronal signals particularly efferent vagus nerve and SIRT 1 protein may offer long term relief and potentially diminish the chronicity. To target or alter the novel molecules and signaling pathway a specific delivery system is required such as liposome, nanoparticles and micelles and many more. Present review paper discusses in detail about novel targets and delivery systems for treating RA.

Rituximab used for simultaneous treatment of PR3-ANCA positive vasculitis associated with rheumatoid arthritis: A case report

We treated PR3-ANCA positive vasculitis in a patient diagnosed with rheumatoid arthritis using rituximab. Monoclonal antibody therapy can be used to simultaneous treat more than one collagen disease in such patients. This suggests that shared pathogenic pathways exist between different collagen diseases.

Role of Infections in the Pathogenesis of Rheumatoid Arthritis: Focus on Mycobacteria

Rheumatoid arthritis (RA) is a systemic inflammatory autoimmune disease characterized by chronic erosive polyarthritis. A complex interaction between a favorable genetic background, and the presence of a specific immune response against a broad-spectrum of environmental factors seems to play a role in determining susceptibility to RA. Among different pathogens, mycobacteria (including Mycobacterium avium subspecies paratuberculosis, MAP), and Epstein–Barr virus (EBV), have extensively been proposed to promote specific cellular and humoral response in susceptible individuals, by activating pathways linked to RA development. In this review, we discuss the available experimental and clinical evidence on the interplay between mycobacterial and EBV infections, and the development of the immune dysregulation in RA.

Genetic implications in the pathogenesis of rheumatoid arthritis; an updated review

Three important factors, including genetics, environment factors and autoimmunity play a role in the pathogenesis of rheumatoid arthritis (RA). The heritability of RA has been accounted to be 50-60%, while the HLA involvement in heritability of the disease has been accounted to be 10-40%. It has been documented that shared epitope (SE) alleles, such as HLA-DRB1*01 and DRB1*04, some HLA alleles like HLA-DRB1*13 and DRB1*15 are connected to RA susceptibility. An advanced classification of SE categorizes SE alleles into four main groups namely, S1, S2, S3D, and S3P. The S2 and S3P groups have been linked to susceptibility of seropositive RA. Various genome-wide association studies (GWAS) have discovered many susceptibility loci implicated in pathogenesis of RA. Some of the important single nucleotide polymorphisms (SNPs) linked to RA are TRAF1, STAT4, CTLA4, IRF5, CCR6, PTPN22, IL23R, and PADI4. HLA and non-HLA genes may discriminate anti-cyclic citrullinated peptide (anti-CCP) antibody-positive and anti-CCP-negative RA groups. Furthermore, risk of the disease has also been linked to environmental agents, mainly cigarette smoking. Pharmacogenomics has also confirmed SNPs or genetic patterns that might be linked to drugs responses. Different aspects of genetic involvement in the pathogenesis, etiology, and RA complications are reviewed in this article.

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.

Association of ANCA associated vasculitis and rheumatoid arthritis: a lesser recognized overlap syndrome

BACKGROUND

ANCA associated vasculitis (AAV) is an autoimmune disease with significant morbidity and mortality, in which diagnostic delay is associated with worse outcomes. AAV is rarely found in association with other immune mediated diseases. Early recognition of such overlaps enables more timely diagnosis and may impact on disease outcome. We reviewed cases of AAV in which there was an overlap with rheumatoid arthritis (RA).

METHODS

We performed a retrospective analysis of our vasculitis database for patients who had a diagnosis of AAV and RA, and a literature search to find other reported cases of this overlap syndrome.

RESULTS

We found six subjects who had a diagnosis of RA and developed AAV at a median of 10.5 years (range 4-43 years) after the diagnosis of RA. They had been treated with a mean of 2 disease modifying drugs (0-4) and all had evidence of renal involvement with median creatinine of 227 μmol/l (range 128-700 μmol/l). Only one had a diagnosis of granulomatosis with polyangiitis, while the rest had a clinical diagnosis of microscopic polyangiitis. Half of the patients had positive rheumatoid factor (RhF) at the time of vasculitis diagnosis, three had MPO-ANCA, one PR3-ANCA, and two had ANCA-negative pauci-immune vasculitis. Additionally, we found 29 other cases reported of this overlap, which also most frequently presented with vasculitic renal manifestations, and were frequently RhF positive at the time of AAV diagnosis.

CONCLUSIONS

AAV occurs in subjects with RA rarely, and often with significant delay from the first rheumatological manifestations. Renal involvement is common.

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.

Genetics of rheumatoid arthritis - a comprehensive review

The "Bermuda triangle" of genetics, environment and autoimmunity is involved in the pathogenesis of rheumatoid arthritis (RA). Various aspects of genetic contribution to the etiology, pathogenesis and outcome of RA are discussed in this review. The heritability of RA has been estimated to be about 60 %, while the contribution of HLA to heritability has been estimated to be 11-37 %. Apart from known shared epitope (SE) alleles, such as HLA-DRB1*01 and DRB1*04, other HLA alleles, such as HLA-DRB1*13 and DRB1*15 have been linked to RA susceptibility. A novel SE classification divides SE alleles into S1, S2, S3P and S3D groups, where primarily S2 and S3P groups have been associated with predisposition to seropositive RA. The most relevant non-HLA gene single nucleotide polymorphisms (SNPs) associated with RA include PTPN22, IL23R, TRAF1, CTLA4, IRF5, STAT4, CCR6, PADI4. Large genome-wide association studies (GWAS) have identified more than 30 loci involved in RA pathogenesis. HLA and some non-HLA genes may differentiate between anti-citrullinated protein antibody (ACPA) seropositive and seronegative RA. Genetic susceptibility has also been associated with environmental factors, primarily smoking. Some GWAS studies carried out in rodent models of arthritis have confirmed the role of human genes. For example, in the collagen-induced (CIA) and proteoglycan-induced arthritis (PgIA) models, two important loci - Pgia26/Cia5 and Pgia2/Cia2/Cia3, corresponding the human PTPN22/CD2 and TRAF1/C5 loci, respectively - have been identified. Finally, pharmacogenomics identified SNPs or multiple genetic signatures that may be associated with responses to traditional disease-modifying drugs and biologics.

The PTPN22 C1858T polymorphism and rheumatoid arthritis: a meta-analysis

The aim of this study was to determine whether the protein tyrosine phosphatase nonreceptor 22 (PTPN22) C1858T polymorphism confers susceptibility to rheumatoid arthritis (RA) in populations with different ethnicities. MEDLINE database and manual search were utilized to identify articles in which the PTPN22 polymorphism was determined in RA patients and controls. A meta-analysis was conducted on the associations between the PTPN22 C1858T polymorphism and RA using (1) allelic contrast and (2) dominant model. A total of 30 separate comparisons involving 17,961 RA patients and 18,611 controls were considered in this meta-analysis. Meta-analysis showed an association between the T allele and RA in all subjects (OR = 1.490, 95% CI = 1.332-1.668, P < 1.0 × 10(-9)). After stratification by ethnicity, analysis indicated that the T allele was significantly associated with RA in Europeans and in Non-Europeans (OR = 1.423, 95% CI = 1.260-1.605, P = 1.0 × 10(-8); OR = 1.902, 95% CI = 1.488-2.430, P = 2.8 × 10(-8)). Meta-analysis of the CT + TT genotype showed the same result patterns as that shown by the PTPN22 C1858T polymorphism T allele. Furthermore, a direct comparison between rheumatoid factor (RF)-positive and RF-negative subjects revealed a significant association with the T allele in RA patients with RF, but not in subjects without RF (OR = 1.561, 95% CI = 1.373-1.775, P < 1.0 × 10(-9)). This meta-analysis confirms that the PTPN22 C1858T polymorphism is associated with RA susceptibility in different ethnic groups, especially in Europeans, and the PTPN22 C1858T polymorphism T allele is significantly more prevalent in RF-positive patents than in RF-negative patients.

Association of ANCA-associated vasculitis-rheumatoid arthritis overlap syndrome in four patients: rituximab may be the right choice?

OBJECTIVES

There have been few reports on the association of rheumatoid arthritis (RA) with anti-neutrophil cytoplasmic antigen (ANCA)-associated systemic vasculitides.

METHODS

Here we present four cases of RA overlapping with Wegener's granulomatosis (WG), microscopic polyangiitis (MPA) and Churg-Strauss syndrome (CSS). All these cases had both the diagnosis of RA and that of ANCA-associated vasculitis.

RESULTS

After we tried corticosteroids, multiple immunosuppressive drugs, sometimes plasmapheresis, rituximab was introduced to 3 out of 4 cases. Rituximab therapy was found to be effective in these three overlap cases. In the fourth case, rituximab was and will be considered; however, the patient has not given consent.

CONCLUSION

To our knowledge, this is the first report on RA+CSS association. Common pathogenic background, such as genetic predisposition and ANCA may account for the development of RA+vasculitis overlaps. In DMARD-refractory cases, such as the ones presented here, biologics, especially rituximab may be highly effective.

The genetics of pemphigus

Pemphigus vulgaris (PV) is an autoimmune blistering disorder with a complex etiology involving an interplay of genetic as well as environmental factors, most of which remain unknown. Despite the identification of several human leukocyte antigen (HLA) alleles as risk factors for disease, no other non-HLA genes have clearly been implicated in disease susceptibility. Newer candidate gene and whole-genome approaches are needed to illuminate the full palate of genetic risk elements in PV. Based on this information, genetic-based tools can be expected to provide a scientific rationale for future clinical decision-making by physicians and facilitate an era of personalized medicine.

PTPN22 1858C>T polymorphism distribution in Europe and association with rheumatoid arthritis: case-control study and meta-analysis

Objective

The PTPN22 rs2476601 polymorphism is associated with rheumatoid arthritis (RA); nonetheless, the association is weaker or absent in some southern European populations. The aim of the study was to evaluate the association between the PTPN22 rs2476601 polymorphism and RA in Italian subjects and to compare our results with those of other European countries, carrying out a meta-analysis of European data.

Methods

A total of 396 RA cases and 477 controls, all of Italic ancestry, were genotyped for PTPN22 rs2476601 polymorphism. Patients were tested for autoantibodies positivity. The meta-analysis was performed on 23 selected studies.

Results

The PTPN22 T1858 allele was significantly more frequent in RA patients compared to controls (5.7% vs. 3.7%, p = 0.045). No clear relationship arose with the autoantibodies tested. The 1858T allele frequency in Italian RA patients was lower than the one described in northern European populations and similar to the frequency found in Spain, Turkey, Greece, Tunisia. A clear-cut North-South gradient arose from the analysis.

Conclusions

The PTPN22 T1858 allele is associated with RA in the Italian population. A North-South gradient of the allele frequency seems to exist in Europe, with a lower prevalence of the mutation in the Mediterranean area.

PTPN22 1858T is not a risk factor for North American pemphigus vulgaris

Alterations in the protein tyrosine phosphatase N22 (PTPN22) gene affect the threshold for lymphocyte activation. The PTPN22 1858T polymorphism leads to uninhibited T-cell receptor cascade propagation. An elevated PTPN22 1858C/T genotype frequency has been correlated with several autoimmune disorders which have T-cell and humoral components. However, a recent Tunisian report demonstrated no association between PTPN22 1858T and patients with Pemphigus vulgaris (PV), an autoantibody-associated blistering disorder. Because PTPN22 1858T allele frequency is known to vary across ethnic populations, we conducted a case-control study investigating the relationship between PTPN22 1858T and PV in North American patients of either Ashkenazi Jewish or Caucasian (non-Ashkenazi) decent. Participant genotype was determined in 102 PV patients and 102 healthy controls by restriction fragment length polymorphism-polymerase chain reaction genotyping. Relationships were calculated using Fisher's exact tests and chi-squared tests. We report that the PTPN22 1858C/T genotype is not significantly associated with PV in either Caucasians (P = 0.83) or Ashkenazi Jews (P = 0.60). Further stratification of the patient population by gender, age of disease onset, HLA-type, family history of autoimmune disease, history of anti-desmoglein (anti-Dsg) 3 or anti-Dsg1 antibody response, history of lesion morphology, and disease duration did not uncover significant associations between the PTPN22 1858T allele and PV subgroups. Our data indicate that the PTPN22 1858T mutation is not associated with PV in the North American population. We do observe an elevation of PTPN22 1858C/T genotype frequency in male PV patients. Further investigation will be required to determine if this trend reaches significance in larger studies.

No association of PTPN22 gene polymorphism with rheumatoid arthritis in Turkey

Although the association of rheumatoid arthritis (RA) with HLA-DRB1 (shared epitope) is well demonstrated in many ethnic populations, the role of other RA-associated risk loci is not clarified. In this study, the functional single nucleotide polymorphism (SNP) of PTPN22 gene was investigated in Turkey. 167 patients with RA and 177 healthy controls are genotyped by polymerase chain reaction (PCR)-RFLP for the SNP (rs2476601, A/G) of PTPN22 gene. Polymorphic region was amplified by PCR and digested with Xcm I enzyme. Heterozygous genotype (AG) was present in 5.1% (9/177) of the controls and in 6.6% (11/167) of RA group (p = 0.55, OR 1.3, 95% CI 0.53–3.26). There was also no association between any clinical feature, RF positivity and presence of this SNP. In conclusion, the distribution of PTPN22 polymorphism did not reveal any association with RA in Turkey.

Genetics of rheumatoid arthritis: GWAS and beyond

The study of complex genetics in autoimmune diseases has progressed at a tremendous pace over the last 4 years, as a direct result of the enormous gains made by genome wide association studies (GWAS). Novel genetic findings are continuously being reported alongside the rapid development of genetic technologies, sophisticated statistical analysis, and larger sample collections. It is now becoming clear that multiple genes contribute to disease risk in many complex genetic disorders including rheumatoid arthritis (RA) and that there are common genetic risk factors that underlie a spectrum of autoimmune diseases. This review details the current genetic landscape of RA, and describes what GWAS has taught us in terms of missing heritability, subsets of disease, existence of genetic heterogeneity, and shared autoimmune risk loci. Finally, this review addresses the initial challenges faced in translating the wealth of genetic findings into determining the biological mechanisms that contribute to the relationship between genotype and phenotype. Unraveling the mechanism of how genes directly influence the cause of RA will lead to a better understanding of the disease and will ultimately have a direct clinical impact, informing the development of new therapies that can be utilized in the treatment of RA.

A candidate gene study of CLEC16A does not provide evidence of association with risk for anti-CCP-positive rheumatoid arthritis

CLEC16A, a putative immunoreceptor, was recently established as a susceptibility locus for type I diabetes and multiple sclerosis. Subsequently, associations between CLEC16A and rheumatoid arthritis (RA), Addison's disease and Crohn's disease have been reported. A large comprehensive and independent investigation of CLEC16A variation in RA was pursued. This study tested 251 CLEC16A single-nucleotide polymorphisms in 2542 RA cases (85% anti-cyclic citrullinated peptide (anti-CCP) positive) and 2210 controls (N=4752). All individuals were of European ancestry, as determined by ancestry informative genetic markers. No evidence for significant association between CLEC16A variation and RA was observed. This is the first study to fully characterize common genetic variation in CLEC16A including assessment of haplotypes and gender-specific effects. The previously reported association between RA and rs6498169 was not replicated. Results show that CLEC16A does not have a prominent function in susceptibility to anti-CCP-positive RA.

Update on the genetic risk factors for rheumatoid arthritis

Rheumatoid arthritis (RA) is a complex disease, meaning that multiple genetic variants, environmental factors and random events interact to trigger pathological pathways. Although many of these etiological factors have not yet been identified, recent groundbreaking advances have expanded our knowledge about the genetic factors that contribute to RA. Here, we review the most recent findings on the genetic risk factors for RA. First, we give an overview of the genetics of RA and briefly describe the susceptibility loci discovered prior to the availability of genome-wide association studies (GWAS). Second, we focus on the newly discovered RA loci that have arisen from GWAS in populations of European ancestry. Through these studies, the number of established RA susceptibility loci has now grown to 13. Third, we discuss several important issues emerging from GWAS, such as ethnic heterogeneity and shared autoimmunity risk loci. Finally, we discuss what still needs to be accomplished before a more complete picture of the genetic risk to RA can be attained.

Pharmacogenetics of rheumatoid arthritis: Potential targets from susceptibility genes and present therapies

Rheumatoid arthritis (RA) is a chronic heterogeneous autoimmune disorder of unknown etiology resulting in inflammation in the synovium, cartilage, and bone. Genetic factors play an important role in susceptibility to RA as the heritability of RA is between 50% and 60%, with the human leukocyte antigen (HLA) locus accounting for at least 30% of overall genetic risk. Outside the major histocompatibility complex (MHC) region, six additional risk loci have been identified and validated including PTPN22, STAT4, PADI4, CTLA4, TNFAIP3-OLIG3, and TRAF1/C5. Genetic factors are also important in RA pharmacotherapy due to the gene-dependent activity of enzymes involved in the pharmacokinetics and/or pharmacodynamics of RA medications. Indeed, there is great variability in drug efficacy as well as adverse events associated with any anti-rheumatic therapy and genetics is thought to contribute significantly to this inter-individual variability in response. This review will summarize the genetic factors that have been implicated in the pathogenesis of RA, and how these determinants may factor into the potential pharmacogenetics of this disease. We will also review the therapeutic agents that are currently being utilized or presently being evaluated in the treatment of RA, along with potential pharmacogenetic markers that have been proposed for such medications.