Protein tyrosine phosphatase PTPN22 in human autoimmunity

Protein tyrosine phosphatase non-receptor type 22 C1858T gene polymorphism in children with down syndrome and autoimmune thyroid diseases

Autoimmune Thyroid Disease (AIT) is a frequent comorbidity in Down Syndrome (DS). Protein Tyrosine Phosphatase Non- Receptor Type 22 C1858T (PTPN-22 C1858T) gene polymorphisms have a role in the progression of AIT. The study on PTPN- 22 C1858T gene polymorphism as the risk factor of AIT in DS children is still limited. This study aims to evaluate PTPN-22 C1858T polymorphism in Indonesian DS children. A cross-sectional study involving 31 DS children with hypothyroidism (19 boys/12 girls) was conducted for ten months from February to November 2020 at Dr. Soetomo General Hospital Surabaya. The PTPN-22 C1858T gene polymorphism was analyzed using Polymerase Chain Reaction-Restriction-Fragment-Length Polymorphism (PCR-RFLP). Anti-Thyroid Peroxidase (Anti- TPO) and Anti-Thyroglobulin (Anti-TG), FT4, T3, and TSH levels were analyzed using Enzyme-Linked-Immunosorbent-Assay (ELISA). The mean age of the subjects was 19.45±17.3 months. The CT variant of PTPN-22 C1858T was observed in all subjects. The mean level of T3, FT4, and TSH were 1.59±0.45 ng/mL, 0.81±0.57 ng/mL, 0.22±0.21 μU/mL, respectively. Around 83.9% of patients suffered from central hypothyroidism, 12.9% from primary hypothyroidism, and 3.2% from subclinical hypothyroidism. The positive anti-TG and anti-TPO were observed in 96.8% and 58.1%, respectively. CT variant was observed in Indonesian DS children who suffered from hypothyroidism.

Current Debates on Etiopathogenesis and Treatment Strategies for Vitiligo

Vitiligo is an acquired, chronic, and progressive depigmentation or hypopigmentation characterized by the destruction of melanocytes and the occurrence of white patches or macules in the skin, mucosal surface of eyes, and ears. Melanocytes are the melanin pigment-producing cells of the skin which are destroyed in pathological conditions called vitiligo. Approximately 0.5 - 2.0% of the population is suffering from vitiligo, and a higher prevalence rate of up to 8.8% has been reported in India. It is caused by various pathogenic factors like genetic predisposition, hyperimmune activation, increased oxidative stress, and alteration in neuropeptides level. Genetic research has revealed a multi- genetic inheritance that exhibits an overlap with other autoimmune disorders. However, melanocytes specific genes are also affected (such as DDR1, XBP1, NLRP1, PTPN22, COMT, FOXP3, ACE, APE, GSTP1, TLR, SOD, and CTLA-4). A number of therapeutic options are employed for the treatment of vitiligo. The topical corticosteroids and immunomodulators are currently in practice for the management of vitiligo. Phototherapies alone and in combinations with other approaches are used in those patients who do not respond to the topical treatment. The main focus of this review is on the etiopathological factors, pharmacological management (phototherapy, topical, systemic, and surgical therapy), and herbal drugs used to treat vitiligo.

Risk of autoimmune diseases in patients with RASopathies: systematic study of humoral and cellular immunity

BACKGROUND

Abnormalities of the immune system are rarely reported in patients affected by RASopathies. Aim of the current study was to investigate the prevalence of immune system dysfunction in a cohort of patients affected by RASopathies.

STUDY DESIGN

A group of 69 patients was enrolled: 60 at the Federico II University, Naples, 7 at University Magna Graecia of Catanzaro, 2 at "Scuola Medica Salernitana", Salerno. An age- and sex-matched control group was also enrolled. Autoimmune disorders were investigated according to international consensus criteria. Immune framework was also evaluated by immunoglobulin levels, CD3, CD4, CD8, CD19, CD56 lymphocyte subpopulations, autoantibodies levels and panel of inflammatory molecules, in both patients and controls.

RESULTS

Frequent upper respiratory tract infections were recorded in 2 patients; pneumonia, psoriasis and alopecia in single patients. Low IgA levels were detected in 8/44 patients (18.18%), low CD8 T cells in 13/35 patients (37.14%). Anti-tg and anti-TPO antibodies were detected in 3/24 patients (12.5%), anti r-TSH in 2 cases (8.33%), all in euthyroidism. Serum IgA and CD8 levels were significantly lower in patients than in controls (p 0.00685; p 0.000656 respectively). All tested patients showed increased inflammatory molecules compared to controls. These findings may anticipate the detection of overt autoimmune disease.

CONCLUSIONS

Patients affected by RASopathies are at risk to develop autoimmune disorders. Routine screening for autoimmunity is recommended in patients with RASopathy.

Modulation of PTPN2/22 Function by Spermidine in CRISPR-Cas9-Edited T-Cells Associated with Crohn's Disease and Rheumatoid Arthritis

Crohn's Disease (CD) and Rheumatoid Arthritis (RA) share some single nucleotide polymorphisms (SNPs) in protein tyrosine phosphatase non-receptor types 2 and 22 (PTPN2/22). Recently, we reported that clinical samples from CD and RA patients associated with PTPN2:rs478582 or PTPN22:rs2476601 genotypes were linked to overactive immune response and exacerbation of inflammation. Here, we investigated in vitro the effects of these SNPs in Jurkat T-cells using CRISPR-Cas9. All cells were evaluated for PTPN22/22 loss of function and effects on cell response. We measured gene expression via RT-qPCR and cytokines by ELISA. We also measured cell proliferation using a BrdU labeling proliferation ELISA, and T-cell activation using CD-25 fluorescent immunostaining. In PTPN2 SNP-edited cells, PTPN2 expression decreased by 3.2-fold, and proliferation increased by 10.2-fold compared to control. Likewise, expression of PTPN22 decreased by 2.4-fold and proliferation increased by 8.4-fold in PTPN22 SNP-edited cells. IFN-γ and TNF-α secretions increased in both edited cell lines. CD25 expression (cell activation) was 80.32% in PTPN2 SNP-edited cells and 85.82% in PTPN22 SNP-edited cells compared to 70.48% in unedited Jurkat T-cells. Treatment of PTPN2 and PTPN22-edited cells with a maximum 20 μM spermidine restored PTPN2/22 expression and cell response including cell proliferation, activation, and cytokines secretion. Most importantly, the effect of spermidine on edited cells restored normal expression and secretion of IFN-γ and TNF-α. The data clearly demonstrated that edited SNPs in PTPN2 or PTPN22 were associated with reduced gene expression, which resulted in an increase in cell proliferation and activation and overactive immune response. The data validated our earlier observations in CD and RA clinical samples. Surprisingly, spermidine restored PTPN2/22 expression in edited Jurkat T-cells and the consequent beneficial effect on cell response and inflammation. The study supports the use of polyamines dietary supplements for management of CD and in RA patients.

Novel immunological and genetic factors associated with vitiligo: A review

Vitiligo is a skin disorder characterized by depigmentation of the skin due to a lack of melanin. This condition affects men and woman of all ages and its incidence is not restricted by ethnicity or region. Vitiligo is a multifactorial disease, in which melanocytes, which serve important functions in skin pigmentation and immune processes, are impaired. There is sufficient evidence that immunological and genetic factors are primarily responsible for the destruction and dysfunction of melanocytes. Therefore, genetic DNA sequence variants that participate in skin homeostasis, pigmentation and immune response regulation, as well as altered expression patterns, may contribute to the risk of developing vitiligo. The current review presented an overview of the mechanism of pigmentation and of currently known factors involved in depigmentation, as well as the classification, epidemiology, associated comorbidities, risk factors, immunopathogenesis and several genetic and molecular changes associated with vitiligo.

The role of PTPN22 in the pathogenesis of autoimmune diseases: A comprehensive review

The incidence of autoimmune diseases is increasing worldwide, thus stimulating studies on their etiopathogenesis, derived from a complex interaction between genetic and environmental factors. Genetic association studies have shown the PTPN22 gene as a shared genetic risk factor with implications in multiple autoimmune disorders. By encoding a protein tyrosine phosphatase expressed by the majority of cells belonging to the innate and adaptive immune systems, the PTPN22 gene may have a fundamental role in the development of immune dysfunction. PTPN22 polymorphisms are associated with rheumatoid arthritis, type 1 diabetes, systemic lupus erythematosus, and many other autoimmune conditions. In this review, we discuss the progress in our understanding of how PTPN22 impacts autoimmunity in both humans and animal models. In addition, we highlight the pathogenic significance of the PTPN22 gene, with particular emphasis on its role in T and B cells, and its function in innate immune cells, such as monocytes, dendritic and natural killer cells. We focus particularly on the complexity of PTPN22 interplay with biological processes of the immune system. Findings highlight the importance of studying the function of disease-associated PTPN22 variants in different cell types and open new avenues of investigation with the potential to drive further insights into mechanisms of PTPN22. These new insights will reveal important clues to the molecular mechanisms of prevalent autoimmune diseases and propose new potential therapeutic targets.

PTPN22 gene functional polymorphism (rs2476601) in older adults with frailty syndrome

The frailty syndrome is a common clinical marker of vulnerability in older adults conducive to an overall decline in inflammatory stress responsiveness; yet little is known about the genetic risk factors for frailty in elderly. Our aim was to investigate the association between the rs2476601 polymorphism in PTPN22 gene and susceptibility to frailty in Mexican older adults. Data included 630 subjects 70 and older from The Coyoacán cohort, classified as frail, pre-frail, and non-frail following Fried's criteria. Sociodemographic and clinical characteristics were compared between groups at baseline and after a multivariate analysis. The rs2476601 polymorphism was genotyped by TaqMan genotyping assay using real-time PCR and genotype frequencies were determined for each frailty phenotype in all participants and subsets by age range. Genetic association was examined using stratified and interaction analyses adjusting for age, sex and variables selected in the multivariate analysis. Disability for day-life activities, depression and cognitive impairment were associated with the risk of pre-frailty and frailty at baseline and after adjustment. Carrying the T allele increased significantly the risk of frailty in patients 76 and older (OR 5.64, 95% CI 4.112-7.165) and decreased the risk of pre-frailty under no clinical signs of depression (OR 0.53; 95% CI 0.17-1.71). The PTPN22 polymorphism, rs2476601, could be a genetic risk factor for frailty as subject to quality of life. This is the first study analyzing such relationship in Mexican older adults. Confirming these findings requires additional association studies on wider age ranges in populations of older adults with frailty syndrome.

PTPN22 gene polymorphism and susceptibility to rheumatoid arthritis (RA): Updated systematic review and meta-analysis

BACKGROUND

Several genome-wide association studies have revealed a genetic background with respect to susceptibility to rheumatoid arthritis (RA). Although several individual case-control studies have evaluated the role of protein tyrosine phosphatase non-receptor 22 (PTPN22) gene rs2476601 single nucleotide polymorphism (SNP) in conferring a risk for RA, the results have been conflicting. Hence, this meta-analysis was aimed to provide a solution for this issue.

METHODS

To search for studies assessing the association between the PTPN22 gene rs2476601 SNP and the risk of RA, a systematic search was conducted in the main databases, including PubMed, Scopus and Web of Science, prior to December 2019. The odds ratio (OR) and corresponding 95% confidence interval (CI) was calculated to assess the possibility of association risk.

RESULTS

The literature search identified 52 case-control studies. The pooled analysis detected significant positive association of rs2476601 in all genetic models, including dominant model (OR = 1.69, 95% CI = 1.55-1.84, P < 0.001), recessive model (OR = 2.50, 95% CI = 2.06-3.05, P < 0.001), allelic model (OR = 1.80, 95% CI = 1.60-2.2, P < 0.001), TT versus CC model (OR = 2.79, 95% CI = 2.28-3.41, P < 0.001) and CT versus CC model (OR = 1.59, 95% CI = 1.50-1.67, P < 0.001). Analyses based on population stratification indicated that rs2476601 SNP strongly increased the risk of RA in Caucasians and Africans under all genotype models.

CONCLUSIONS

This meta-analysis reports that the PTPN22 gene rs2476601 SNP increases RA risk, especially in Caucasians and Africans.

The Impact of Cigarette Smoking on Risk of Rheumatoid Arthritis: A Narrative Review

Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation and subsequent proliferation of synovial tissues, which eventually leads to cartilage and bone destruction without effective treatments. Anti-citrullinated cyclic peptide/protein antibody (ACPA) and rheumatoid factor (RF) are two main characteristic autoantibodies found in RA patients and are associated with unfavorable disease outcomes. Although etiologies and causes of the disease have not been fully clarified yet, it is likely that interactive contributions of genetic and environmental factors play a main role in RA pathology. Previous works have demonstrated several genetic and environmental factors as risks of RA development and/or autoantibody productions. Among these, cigarette smoking and HLA-DRB1 are the well-established environmental and genetic risks, respectively. In this narrative review, we provide a recent update on genetic contributions to RA and the environmental risks of RA with a special focus on cigarette smoking and its impacts on RA pathology. We also describe gene–environmental interaction in RA pathogenesis with an emphasis on cigarette smoking and HLA-DRB1.

Association of Functional Polymorphism in Protein Tyrosine Phosphatase Nonreceptor 22 (PTPN22) Gene with Vitiligo

The protein tyrosine phosphatase nonreceptor 22 (PTPN22) is associated with susceptibility to autoimmune diseases. The functional polymorphism in PTPN22 at 1857 is a strong risk factor for vitiligo susceptibility in Europeans; however, controversy exits in other populations. Present study was aimed to determine whether the PTPN22 C1857T polymorphism confers susceptibility to vitiligo in Saudi Arabians. Genomic DNA was extracted and amplified using tetra primer amplification-refractory mutation system polymerase chain reaction (ARMS-PCR) method. The frequencies of allele T and genotype CT of PTPN22 C1858T polymorphism were significantly higher, whereas those of allele C and genotype CC were lower in patients as compared with controls (P < 0.0001). The genotype TT was absent in both the patients and controls. It is concluded that PTPN22 C1858T polymorphism is strongly associated with vitiligo susceptibility. However, additional studies are warranted using large number of samples from different ethnicities and geographical areas.

PTPN22 1858 C/T polymorphism is associated with alteration of cytokine profiles as a potential pathogenic mechanism in rheumatoid arthritis

INTRODUCTION

Rheumatoid arthritis (RA) is one of the most common prevalent autoimmune diseases. The 1858 C/T (rs2476601) single nucleotide polymorphism (SNP) within the PTPN22 gene has been associated with susceptibility to inflammatory based diseases in several populations. It is implicated that altered cytokine production has a potential pathogenic role in the development of RA. The aim of this work was to analyze the association of 1858 C/T PTPN22 polymorphism in RA patients with cytokine profiles.

MATERIALS AND METHODS

This study was performed on 120 RA patients who were referred to the Rheumatology Research Centre, Shariati Hospital (Tehran, Iran), and 120 healthy controls. Genomic DNA was extracted and genotyped for 1858 C/T PTPN22 gene SNP using the PCR-RFLP technique. Serum levels of IL-2, IL-4, IL-6, IL-10, TNF-α and IFN-γ as well as Anti-CCP and RF was measured by ELISA method.

RESULTS

Results showed that 1858 C/T PTPN22 SNP significantly (P =  0.007, OR = 2.321, 95% CI = 1.063-5.067) associated with RA. The 1858 T allele frequency was also significantly increased in RA patients in comparison to the controls (P =  0.008, OR = 3.583, 95% CI = 1.3-9.878). Our data demonstrated a significant reduction of IL-4 and IL-10 in PTPN22 1858C/T compared to 1858C/C RA patients. In addition, upregulation of IL-6, IFN-γ, and TNF-α was observed in PTPN22 1858C/T vs. 1858C/C RA patients.

DISCUSSION

Our findings implicate altered cytokine profiles as a possible pathogenic mechanism by which the 1858 T allele may contribute to the progress of RA.

Protein tyrosine phosphatase non-receptor type 22 (PTPN22) gene polymorphisms in liver transplant donors and impact on acute cellular liver transplant rejection

The PTPN22 gene encodes the lymphoid protein tyrosine phosphatase involved in regulation the immune response. The single nucleotide polymorphisms (SNPs) rs1217388, rs1310182, rs2476601, and rs2488457 are located within the PTPN22 gene. We investigated whether these SNPs in liver transplant donors are associated with acute cellular rejection in the recipients. The SNPs were analyzed in donors (n = 104) of recipients who did not develop an acute cellular rejection and in donors (n = 53) of corresponding recipients developing an acute cellular rejection. No significant differences in genotype and allele frequencies of these SNPs were detected in either of the group. Our data suggest that these SNPs in liver transplant donors have no impact on the susceptibility of acute cellular liver transplant rejection.

Thyroid Dysfunction and Diabetes Mellitus: Two Closely Associated Disorders

Thyroid dysfunction and diabetes mellitus are closely linked. Several studies have documented the increased prevalence of thyroid disorders in patients with diabetes mellitus and vice versa. This review critically discusses the different underlying mechanisms linking type 1 and 2 diabetes and thyroid dysfunction to demonstrate that the association of these two common disorders is unlikely a simple coincidence. We assess the current state of knowledge on the central and peripheral control of thyroid hormone on food intake and glucose and lipid metabolism in target tissues (such as liver, white and brown adipose tissue, pancreatic β cells, and skeletal muscle) to explain the mechanism linking overt and subclinical hypothyroidism to type 2 diabetes and metabolic syndrome. We also elucidate the common susceptibility genes and the pathogenetic mechanisms contributing to the autoimmune mechanism involved in the onset of type 1 diabetes mellitus and autoimmune thyroid disorders. An untreated thyroid dysfunction can impair the metabolic control of diabetic patients, and this association can have important repercussions on the outcome of both of these disorders. Therefore, we offer recommendations for the diagnosis, management, and screening of thyroid disorders in patients with diabetes mellitus, including the treatment of diabetic patients planning a pregnancy. We also discuss the major causes of failure to achieve an optimal management of thyroid dysfunction in diabetic patients and provide recommendations for assessing and treating these disorders during therapy with antidiabetic drugs. An algorithm for a correct approach of these disorders when linked is also provided.

The Contribution of PTPN22 to Rheumatic Disease

One of the unresolved questions in modern medicine is why certain individuals develop a disorder such as rheumatoid arthritis (RA) or lupus, while others do not. Contemporary science indicates that genetics is partly responsible for disease development, while environmental and stochastic factors also play a role. Among the many genes that increase the risk of autoimmune conditions, the risk allele encoding the W620 variant of protein tyrosine phosphatase N22 (PTPN22) is shared between multiple rheumatic diseases, suggesting that it plays a fundamental role in the development of immune dysfunction. Herein, we discuss how the presence of the PTPN22 risk allele may shape the signs and symptoms of these diseases. Besides the emerging clarity regarding how PTPN22 tunes T and B cell antigen receptor signaling, we discuss recent discoveries of important functions of PTPN22 in myeloid cell lineages. Taken together, these new insights reveal important clues to the molecular mechanisms of prevalent diseases like RA and lupus and may open new avenues for the development of personalized therapies that spare the normal function of the immune system.

T Helper 1 Cellular Immunity Toward Recoverin Is Enhanced in Patients With Active Autoimmune Retinopathy

Autoimmune retinopathy (AIR) causes rapidly progressive vision loss that is treatable but often is confused with other forms of retinal degeneration including retinitis pigmentosa (RP). Measurement of anti-retinal antibodies (ARA) by Western blot is a commonly used laboratory assay that supports the diagnosis yet does not reflect current disease activity. To search for better diagnostic indicators, this study was designed to compare immune biomarkers and responses toward the retinal protein, recoverin, between newly diagnosed AIR patients, slow progressing RP patients and healthy controls. All individuals had measurable anti-recoverin IgG and IgM antibodies by ELISA regardless of disease status or Western blot results. Many AIR patients had elevated anti-recoverin IgG1 levels and a strong cellular response toward recoverin dominated by IFNγ. RP patients and controls responded to recoverin with a lower IFNγ response that was balanced by IL-10 production. Both AIR and RP patients displayed lower levels of total peripheral blood mononuclear cells that were due to reductions of CD4⁺ T_H cells. A comparison of messenger RNA (mRNA) for immune-related genes in whole blood of AIR patients versus RP patients or controls indicated lower expression of ATG5 and PTPN22 and higher expression of several genes involved in T_H cell signaling/transcription and adhesion. These data indicate that an immune response toward recoverin is normal in humans, but that in AIR patients the balance shifts dramatically toward higher IFNγ production and cellular activation.

Association of protein tyrosine phosphatase non-receptor type 22 gene functional variant C1858T, HLA-DQ/DR genotypes and autoantibodies with susceptibility to type-1 diabetes mellitus in Kuwaiti Arabs

The incidence of type-1 Diabetes Mellitus (T1DM) has increased steadily in Kuwait during recent years and it is now considered amongst the high-incidence countries. An interaction between susceptibility genes, immune system mediators and environmental factors predispose susceptible individuals to T1DM. We have determined the prevalence of protein tyrosine phosphatase non-receptor type 22 (PTPN22) gene functional variant (C1858T; R620W, rs2476601), HLA-DQ and DR alleles and three autoantibodies in Kuwaiti children with T1DM to evaluate their impact on genetic predisposition of the disease. This study included 253 Kuwaiti children with T1DM and 214 ethnically matched controls. The genotypes of PTPN22 gene functional variant C1858T (R620W; rs2476601) were detected by PCR-RFLP method and confirmed by DNA sequencing. HLA-DQ and DR alleles were determined by sequence-specific PCR. Three autoantibodies were detected in the T1DM patients using radio-immunoassays. A significant association was detected between the variant genotype of the PTPN22 gene (C1858T, rs2476601) and T1DM in Kuwaiti Arabs. HLA-DQ2 and DQ8 alleles showed a strong association with T1DM. In T1DM patients which carried the variant TT-genotype of the PTPN22 gene, 93% had at least one DQ2 allele and 60% carried either a DQ2 or a DQ8 allele. Amongst the DR alleles, the DR3-DRB5, DR3-3, DR3-4 and DR4-4 showed a strong association with T1DM. Majority of T1DM patients who carried homozygous variant (TT) genotype of the PTPN22 gene had either DR3-DRB5 or DRB3-DRB4 genotypes. In T1DM patients who co-inherited the high risk HLA DQ, DR alleles with the variant genotype of PTPN22 gene, the majority were positive for three autoantibodies. Our data demonstrate that the variant T-allele of the PTPN22 gene along with HLA-DQ2 and DQ8 alleles constitute significant determinants of genetic predisposition of T1DM in Kuwaiti children.

PTPN22 Silencing in Human Acute T-Cell Leukemia Cell Line (Jurkat Cell) and its Effect on the Expression of miR-181a and miR-181b

Purpose: T-cell acute lymphoblastic leukemia (T-ALL) is one of the most common malignancies associated with T-lymphocytes, accounting for 10 to 15 percent of ALL cases in children and 25 percent in adults. Innovative therapeutic approaches that overcome ineffective treatments on tumor cells may be a potential source of improvement in therapeutic approaches. Suppression of gene expression at transfusion level is one of the important strategies in gene therapy. The expression of PTPN22 and miR-181 genes in all types of hematologic malignancies increases and is likely to contribute to the survival and death of cells by affecting a variety of signaling pathways. The purpose of this study was to determine the role of PTPN22 inhibition by siRNA, and alteration in miR-181a and miR-181b in Jurkat cell line.

Methods: Jurkat cells were transfected with 80 pmol of siRNA to inhibit PTPN22. After that, expression of PTPN22 mRNA and transcript levels of miR-181a and miR-181b were measured with Real-time PCR after 48hrs.

Results: Experiments demonstrated that siRNA transfection resulted in significant downregulation of PTPN22 mRNA after 48 hrs in 80 pmol dose of siRNA. Moreover, transcript levels of both miR-181a and miR-181b was decreased after transfection.

Conclusion: PTPN22, miR-181a and miR-181b might be involved in progression of Jurkat cells and targeting these molecules by RNAi might confer promising tool in treatment of T-ALL.

Association of PTPN22 gene polymorphism with non-segmental vitiligo in South Indian Tamils

INTRODUCTION

Non-segmental vitiligo (NSV) is a depigmentation skin disease with loss of melanocytes in the skin.

AIM

To evaluate whether the protein tyrosine phosphatase non-receptor type (PTPN22) single nucleotide polymorphism at +1858C/T had any association with non-segmental vitiligo in South Indian Tamils.

MATERIAL AND METHODS

Genomic DNA was extracted using the phenol-chloroform method, and PTPN22 +1858C/T polymorphism was assayed by Taqman 5'allele discrimination assay. Protein levels were quantified by ELISA.

RESULTS

We found that the allelic frequency of variants of PTPN22 (rs2476601) were significantly different between controls and cases showing a vitiligo risk in the South Indian Tamil population. PTPN22 levels were higher in the heterozygous CT genotype in NSV, when compared with that of the major variant CC genotype of rs2476601.

CONCLUSIONS

This study suggests that the heterozygous CT genotype, of the PTPN22 SNP rs2476601, has a strong risk association with non-segmental vitiligo in South Indian Tamils.

Genetics of type 1 diabetes

Type 1 diabetes (T1D) results from immune-mediated loss of pancreatic beta cells leading to insulin deficiency. It is the most common form of diabetes in children, and its incidence is on the rise. This article reviews the current knowledge on the genetics of T1D. In particular, we discuss the influence of HLA and non-HLA genes on T1D risk and disease progression through the preclinical stages of the disease, and the development of genetic scores that can be applied to disease prediction. Racial/ethnic differences, challenges and future directions in the genetics of T1D are also discussed.

Target identification reveals protein arginine methyltransferase 1 is a potential target of phenyl vinyl sulfone and its derivatives

Phenyl vinyl sulfone (PVS) and phenyl vinyl sulfonate (PVSN) inactivate protein tyrosine phosphatases (PTPs) by mimicking the phosphotyrosine structure and providing a Michael addition acceptor for the active-site cysteine residue of PTPs, thus forming covalent adducts between PVS (or PVSN) and PTPs. We developed a specific antiserum against PVS. This antiserum can be used in general antibody-based assays such as immunoblotting, immunofluorescence staining, and immunoprecipitation. Target identification through immunoprecipitation and mass spectrometry analysis reveals potential targets of PVS, mostly proteins with reactive cysteine residues or low-pK_a cysteine residues that are prone to reversible redox modifications. Target identification of PVSN has been conducted because the anti-PVS antiserum can also recognize PVSN. Among the targets, protein arginine methyltransferase 1 (PRMT1), inosine-5'-monophosphate dehydrogenase 1, vimentin, and glutathione reductase (GR) were further confirmed by immunoprecipitation followed by immunoblotting. In addition, PVSN and Bay11-7082 inhibited GR activity, and PVS, PVSN, and Bay 11-7082 inhibited PRMT1 activity in in vitro assays. In addition, treatment of PVSN, Bay11-7082, or Bay 11-7085 in cultured HeLa cells can cause the quick decline in the levels of protein asymmetric dimethylarginine. These results indicate that the similar moiety among PVS, PVSN, Bay 11-7082, and Bay 11-7085 can be the key structure of lead compounds of PRMT1. Therefore, we expect to use this approach in the identification of potential targets of other covalent drugs.

Covalent inhibition of protein tyrosine phosphatases

Protein tyrosine phosphatases (PTPs) are a large family of 107 signaling enzymes that catalyze the hydrolytic removal of phosphate groups from tyrosine residues in a target protein. The phosphorylation status of tyrosine residues on proteins serve as a ubiquitous mechanism for cellular signal transduction. Aberrant function of PTPs can lead to many human diseases, such as diabetes, obesity, cancer, and autoimmune diseases. As the number of disease relevant PTPs increases, there is urgency in developing highly potent inhibitors that are selective towards specific PTPs. Most current efforts have been devoted to the development of active site-directed and reversible inhibitors for PTPs. This review summarizes recent progress made in the field of covalent inhibitors to target PTPs. Here, we discuss the in vivo and in vitro inactivation of various PTPs by small molecule-containing electrophiles, such as Michael acceptors, α-halo ketones, epoxides, and isothiocyanates, etc. as well as oxidizing agents. We also suggest potential strategies to transform these electrophiles into isozyme selective covalent PTP inhibitors.

Role of PTPN2/22 polymorphisms in pathophysiology of Crohn's disease

AIM

To establish the relationship of protein tyrosine phosphatase non-receptor type 2 and 22 (PTPN2/22) polymorphisms and mycobacterial infections in Crohn's disease (CD).

METHODS

All 133 subjects' blood samples were genotyped for nine single nucleotide polymorphisms (SNPs) in PTPN2/22 using TaqMan™ genotyping, while the effect of the SNPs on PTPN2/22 and IFN-γ gene expression was determined using RT-PCR. Detection of Mycobacterium avium subspecies paratuberculosis (MAP) IS900 gene was done by nPCR after DNA extraction from the isolated leukocytes of each subjects' blood samples. T-cells isolated from the patient samples were tested for response to phytohematoagglutonin (PHA) mitogen or mycobacterial antigens by BrdU proliferation assays for T-cell activity.

RESULTS

Out of the nine SNPs examined, subjects with either heterozygous (TC)/minor (CC) alleles in PTPN2:rs478582 occurred in 83% of CD subjects compared to 61% healthy controls (P-values < 0.05; OR = 3.03). Subjects with either heterozygous (GA)/minor (AA) alleles in PTPN22:rs2476601 occurred in 16% of CD compared to 6% healthy controls (OR = 2.7). Gene expression in PTPN2/22 in CD subjects was significantly decreased by 2 folds compared to healthy controls (P-values < 0.05). IFN-γ expression levels were found to be significantly increased by approxiately 2 folds in subjects when either heterozygous or minor alleles in PTPN2:rs478582 and/or PTPN22:rs2476601 were found (P-values < 0.05). MAP DNA was detected in 61% of CD compared to only 8% of healthy controls (P-values < 0.05, OR = 17.52), where subjects with either heterozygous or minor alleles in PTPN2:rs478582 and/or PTPN22:rs2476601 had more MAPbacteremia presence than subjects without SNPs did. The average T-cell proliferation in CD treated with PHA or mycobacteria antigens was, respectively, 1.3 folds and 1.5 folds higher than healthy controls without any significant SNP.

CONCLUSION

The data suggests that SNPs in PTPN2/22 affect the negative regulation of the immune response in CD patients, thus leading to an increase in inflammation/apoptosis and susceptibility of mycobacteria.

Coincidence of PTPN22 c.1858CC and FCRL3 -169CC genotypes as a biomarker of preserved residual β-cell function in children with type 1 diabetes

BACKGROUND

Genotype-phenotype studies in type 1 diabetes (T1DM) patients are needed for further development of therapy strategies.

OBJECTIVE

Our aims were to investigate the distribution of selected PTPN22 and FCRL3 gene polymorphisms and their associations with clinical course of disease in children with newly diagnosed T1DM from the Pomeranian region of Poland.

SUBJECTS/METHODS

The prospective, longitudinal study of 147 children with newly diagnosed T1DM-autoimmune subtype was conducted. The PTPN22 c.1858T>C (rs2476601) and FCRL3 -169C>T (rs7528684) polymorphisms were analyzed using polymerase chain reaction-restriction fragment length polymorphism method (PCR-RFLP) and DNA sequencing. The frequencies of genotypes were compared between the study and population-matched control group (327 random anonymous samples from the Pomeranian region). Selected patients underwent a 24-monthly follow up [periodic re-evaluation of fasting C-peptide concentration (FCP) and hemoglobin A1c (HbA1c ) level].

RESULTS

A significantly lower coincidence of the PTPN22 c.1858CC and FCRL3 -169CC genotypes was found in the study group compared with controls (P = 0.04). The PTPN22 c.1858CC and FCRL3 -169CC genotype combination, restricted to female patients only, was associated with well-preserved residual β-cell function throughout the entire follow up (prolonged FCP level increase up to the sixth month of disease, with further very stable dynamics-FCP median level ≥0.67 ng/mL without significant decrease up to the 24th month). HbA1c levels in this subgroup also remained the lowest during the observation period.

CONCLUSIONS/INTERPRETATION

Ascertained phenomenon could be explained by an interacting mechanism of the two polymorphisms through estrogen-regulated nuclear factor kappa B signaling in regulatory T (T_reg ) lymphocytes. This hypothesis, if confirmed, may lead to further development of T_reg administration-based therapies.

Intracellular B Lymphocyte Signalling and the Regulation of Humoral Immunity and Autoimmunity

B lymphocytes are critical for effective immunity; they produce antibodies and cytokines, present antigens to T lymphocytes and regulate immune responses. However, because of the inherent randomness in the process of generating their vast repertoire of antigen-specific receptors, B cells can also cause diseases through recognizing and reacting to self. Therefore, B lymphocyte selection and responses require tight regulation at multiple levels and at all stages of their development and activation to avoid diseases. Indeed, newly generated B lymphocytes undergo rigorous tolerance mechanisms in the bone marrow and, subsequently, in the periphery after their migration. Furthermore, activation of mature B cells is regulated through controlled expression of co-stimulatory receptors and intracellular signalling thresholds. All these regulatory events determine whether and how B lymphocytes respond to antigens, by undergoing apoptosis or proliferation. However, defects that alter regulated co-stimulatory receptor expression or intracellular signalling thresholds can lead to diseases. For example, autoimmune diseases can result from altered regulation of B cell responses leading to the emergence of high-affinity autoreactive B cells, autoantibody production and tissue damage. The exact cause(s) of defective B cell responses in autoimmune diseases remains unknown. However, there is evidence that defects or mutations in genes that encode individual intracellular signalling proteins lead to autoimmune diseases, thus confirming that defects in intracellular pathways mediate autoimmune diseases. This review provides a synopsis of current knowledge of signalling proteins and pathways that regulate B lymphocyte responses and how defects in these could promote autoimmune diseases. Most of the evidence comes from studies of mouse models of disease and from genetically engineered mice. Some, however, also come from studying B lymphocytes from patients and from genome-wide association studies. Defining proteins and signalling pathways that underpin atypical B cell response in diseases will help in understanding disease mechanisms and provide new therapeutic avenues for precision therapy.

Association of the protein tyrosine phosphatase non-receptor 22 polymorphism (PTPN22) with endometriosis: a meta-analysis

Objective

To evaluate PTPN22 C1858T polymorphism and the risk of endometriosis.

Methods

A meta-analysis of 10 published case-control studies (from four articles), with a total sample of 971 cases and 1,181 controls, was performed. We estimated risk (odds ratio and 95% confidence intervals) of endometriosis associations with the C1858T polymorphism.

Results

A significant increased risk in all genetic models of the variant T allele with endometriosis (odds ratio: 3.14-5.55; p<0.00001-0.002) was found. The analysis without the study whose controls deviated from the Hardy-Weinberg equilibrium exacerbated these effects in the homozygous and recessive models (odds ratio: 7.19-9.45; p<0.00001-0.0002). In the Italian subgroup, a significant risk association was found in the homozygous and recessive models (odds ratio: 8.72-11.12; p=0.002).

Conclusion

The associations observed between PTPN22 (C1858T) and the risk of endometriosis suggest this polymorphism might be a useful susceptibility marker for this disease.

PTPN22 and islet-specific autoimmunity: What have the mouse models taught us?

An allelic variant of the protein tyrosin phosphatase non-receptor 22 (PTPN22) gene, PTPN22 R620W, constitutes the strongest non-HLA genetic risk factor for the development of type 1 diabetes (T1D). A number of studies using mouse models have addressed how PTPN22 predisposes to T1D. PTPN22 downmodulation, overexpression or expression of the variant gene in genetically manipulated mice has generated controversial results. These discrepancies probably derive from the fact that PTPN22 has differential effects on innate and adaptive immune responses. Moreover, the effects of PTPN22 are dependent on other genetic variables. Here we discuss these findings and try to explain the discrepancies. Exploring the mechanism by which PTPN22 contributes to islet-specific autoimmunity could help us understand its role in T1D pathogenesis and exploit it as a potential therapeutic target to prevent the disease.

Effects of Type 1 Diabetes Risk Alleles on Immune Cell Gene Expression

Genetic studies have identified 61 variants associated with the risk of developing Type 1 Diabetes (T1D). The functions of most of the non-HLA (Human Leukocyte Antigen) genetic variants remain unknown. We found that only 16 of these risk variants could potentially be linked to a protein-coding change. Therefore, we investigated whether these variants affected susceptibility by regulating changes in gene expression. To do so, we examined whole transcriptome profiles of 600 samples from the Type 1 Diabetes Genetics Consortium (T1DGC). These comprised four different immune cell types (Epstein-Barr virus (EBV)-transformed B cells, either basal or after stimulation; and cluster of differentiation (CD)4+ and CD8+ T cells). Many of the T1D-associated risk variants regulated expression of either neighboring (cis-) or distant (trans-) genes. In brief, 24 of the non-HLA T1D variants affected the expression of 31 nearby genes (cis) while 25 affected 38 distant genes (trans). The effects were highly significant (False Discovery Rate p < 0.001). In addition, we searched in public databases for expression effects of T1D single nucleotide polymorphisms (SNPs) in other immune cell types such as CD14+ monocytes, lipopolysaccharide (LPS) stimulated monocytes, and CD19+ B cells. In this paper, we review the (expression quantitative trait loci (eQTLs) associated with each of the 60 T1D variants and provide a summary of the genes impacted by T1D risk alleles in various immune cells. We then review the methodological steps involved in analyzing the function of genome wide association studies (GWAS)-identified variants, with emphasis on those affecting gene expression. We also discuss recent advancements in the methodologies and their advantages. We conclude by suggesting future study designs that will aid in the study of T1D risk variants.

HDAC10 promotes angiogenesis in endothelial cells through the PTPN22/ERK axis

Angiogenesis is crucially involved in many physiological and pathological processes including tumor growth, but the molecular mechanisms regulating angiogenesis are incompletely understood. In this study, we investigated the functions and mechanism of histone deacetylase 10 (HDAC10), a member of the HDAC II family, in regulation of angiogenesis. HDAC10 overexpression in human umbilical vein endothelial cells (HUVECs) promoted tube formation, whereas depletion of HDAC10 from HUVECs inhibited tube formation in vitro and in vivo. Mechanistically, HDAC10 overexpression increased extracellular-regulated kinase 1/2 (ERK1/2) activation, whereas depletion of HDAC10 inhibited ERK1/2 activation. Finally, HDAC10 promoted ERK1/2 phosphorylation by deacetylating the promoter of protein tyrosine phosphatase, non-receptor type 22 (PTPN22) and inhibiting the expression of PTPN22, which is a negative regulator of ERK phosphorylation. Collectively, our results identify HDAC10 as a key regulator of angiogenesis and reveal that HDAC10 functions in this process by binding and deacetylating the PTPN22 promoter and subsequently inhibiting PTPN22 expression, which in turn increases ERK1/2 phosphorylation. Our studies suggest that HDAC10 is a potential target for therapeutic intervention to inhibit angiogenesis and tumor growth.

Beta-cell Specific Autoantibodies: Are they Just an Indicator of Type 1 Diabetes?

BACKGROUND

Autoantibodies (AAbs) against islet autoantigens (AAgs) are used for type 1 diabetes (T1D) diagnosis and prediction. Islet-specific AAbs usually appear early in life and may fluctuate in terms of number and titer sometimes for over 20 years before T1D develops. Whereas their predictive power is high for pediatric subjects with high genetic risk who rapidly progress to multiple AAb positivity, they are less reliable for children with low genetic risk, single AAb positivity and slow disease progression.

OBJECTIVE

It is unknown how AAbs develop and whether they are involved in T1D pathogenesis. So far an increase in AAb number seems to only indicate AAg spreading and progression towards clinical T1D. The goal of this review is to shed light on the possible involvement of AAbs in T1D development.

METHOD

We thoroughly review the current literature and discuss possible mechanisms of AAb development and the roles they may play in disease pathogenesis.

RESULTS

Genetic and environmental factors instigate changes at the molecular and cellular levels that promote AAb development. Although direct involvement of AAbs in T1D is less clear, autoreactive B cells are clearly involved in various immune and autoimmune responses via antigen presentation, immunoregulation and cytokine production.

CONCLUSION

Our analysis suggests that understanding the mechanisms that lead to islet-specific AAb development and the diabetogenic processes that autoreactive B cells promote may uncover additional biomarkers and therapeutic targets.

Relapse prediction in Graves´ disease: Towards mathematical modeling of clinical, immune and genetic markers

PROBLEM

Graves' disease (GD) is an important and prevalent thyroid autoimmune disorder. Standard therapy for GD consists of antithyroid drugs (ATD) with treatment periods of around 12 months but relapse is frequent. Since predictors for relapse are difficult to identify the individual decision making for optimal treatment is often arbitrary.

METHODS

After reviewing the literature on this topic we summarize important factors involved in GD and with respect to their potential for relapse prediction from markers before and after treatment. This information was used to design a mathematical model integrating thyroid hormone parameters, thyroid size, antibody titers and a complex algorithm encompassing genetic predisposition, environmental exposures and current immune activity in order to arrive at a prognostic index for relapse risk after treatment.

CONCLUSION

In the search for a tool to analyze and predict relapse in GD mathematical modeling is a promising approach. In analogy to mathematical modeling approaches in other diseases such as viral infections, we developed a differential equation model on the basis of published clinical trials in patients with GD. Although our model needs further evaluation to be applicable in a clinical context, it provides a perspective for an important contribution to a final statistical prediction model.

Lack of the Association of the PTPN22 C1858T Gene Polymorphism With Susceptibility to Familial Mediterranean Fever

Objectives

This study aims to investigate whether the protein tyrosine phosphatase non-receptor type 22 (PTPN22) C1858T gene polymorphism plays a role in the pathogenesis of familial Mediterranean fever (FMF) through T-lymphocyte activation.

Patients and methods

We conducted a case-control study with 180 FMF patients (68 males, 112 females; mean age 38.2±1.6 years; range 16 to 81 years) and 184 healthy controls (86 males, 98 females; mean age 32.9±9.2 years; range 18 to 58 years). The PTPN22 C1858T polymorphism (rs2476601) was genotyped by polymerase chain reaction restriction fragment length polymorphism. In patients with FMF, clinical features, disease severity score, the frequencies of amyloidosis, positive family history, and Mediterranean fever gene mutations were determined.

Results

The frequencies of heterozygous genotype (CT) were 4.5% in FMF patients and 2.8% in healthy controls, respectively. The frequencies of polymorphic homozygous genotypes (TT) were 0.5% in both FMF patients and healthy controls. There were no statistically significant differences in the frequencies of CT and TT genotypes between FMF patients and healthy controls (odds ratio: 1.65, 95% confidence interval: 0.53-5.14, p>0.05 for CT genotype). The frequencies of clinical features, sex, amyloidosis, positive family history, Mediterranean fever gene mutations, and disease severity score were not significantly different between the patients.

Conclusion

The distribution of PTPN22 C1858T polymorphism did not reveal any association with FMF in a Turkish population.

Association between a gain-of-function variant of PTPN22 and rejection in liver transplantation

BACKGROUND

The protein tyrosine phosphatase nonreceptor 22 gene (PTPN22) encodes a strong T-cell regulator called lymphoid protein tyrosine phosphatase. Previously, PTPN22 was described as a susceptibility gene for autoimmunity because it contains single nucleotide polymorphisms (SNPs) associated with several autoimmune diseases. One SNP (rs2476601; 1858G>A) has emerged as a particularly potent risk factor for autoimmunity. We address the question whether PTPN22 polymorphisms are also associated with acute rejection after liver transplantation.

METHODS

We investigated the influence of six PTPN22 SNPs on the susceptibility to acute liver allograft rejection. Consequently, we carried out a retrospective study genotyping 345 German liver recipients at six SNP loci, which include rs2488457 (-1123G>C), rs33996649 (788C>T), rs2476601 (1858G>A), rs1310182 (-852A>G), rs1217388 (-2200G>A), rs3789604 (64434T>G). Our study enrolled 165 recipients who did not develop rejection, 123 who showed one rejection episode, and 57 patients who suffered from multiple acute rejections after transplantation.

RESULTS

The 1858A allele containing genotypes (GA+AA) and the 1858A allele had a significantly higher frequency in the group of patients with multiple rejection episodes (35.1% and 18.4%) compared to rejection-free patients (15.8% and 7.9%; P=0.022 and 0.023). In contrast, we could not detect any association between rejection and the other tested SNPs. Additionally, we identified one haplotype contributing to risk of multiple rejections, however, exhibiting no stronger impact than the 1858A allele alone.

CONCLUSION

We conclude that the 1858G>A SNP may confer susceptibility to multiple acute liver transplant rejections in the German population.

Genome wide identification of new genes and pathways in patients with both autoimmune thyroiditis and type 1 diabetes

Autoimmune thyroid diseases (AITD) and Type 1 diabetes (T1D) frequently occur in the same individual pointing to a strong shared genetic susceptibility. Indeed, the co-occurrence of T1D and AITD in the same individual is classified as a variant of the autoimmune polyglandular syndrome type 3 (designated APS3v). Our aim was to identify new genes and mechanisms causing the co-occurrence of T1D + AITD (APS3v) in the same individual using a genome-wide approach. For our discovery set we analyzed 346 Caucasian APS3v patients and 727 gender and ethnicity matched healthy controls. Genotyping was performed using the Illumina Human660W-Quad.v1. The replication set included 185 APS3v patients and 340 controls. Association analyses were performed using the PLINK program, and pathway analyses were performed using the MAGENTA software. We identified multiple signals within the HLA region and conditioning studies suggested that a few of them contributed independently to the strong association of the HLA locus with APS3v. Outside the HLA region, variants in GPR103, a gene not suggested by previous studies of APS3v, T1D, or AITD, showed genome-wide significance (p < 5 × 10(-8)). In addition, a locus on 1p13 containing the PTPN22 gene showed genome-wide significant associations. Pathway analysis demonstrated that cell cycle, B-cell development, CD40, and CTLA-4 signaling were the major pathways contributing to the pathogenesis of APS3v. These findings suggest that complex mechanisms involving T-cell and B-cell pathways are involved in the strong genetic association between AITD and T1D.

Signaling mechanisms regulating B-lymphocyte activation and tolerance

It is becoming more and more accepted that, in addition to producing autoantibodies, B lymphocytes have other important functions that influence the development of autoimmunity. For example, autoreactive B cells are able to produce inflammatory cytokines and activate pathogenic T cells. B lymphocytes can react to extracellular signals with a range of responses from anergy to autoreactivity. The final outcome is determined by the relative contribution of signaling events mediated by activating and inhibitory pathways. Besides the B cell antigen receptor (BCR), several costimulatory receptors expressed on B cells can also induce B cell proliferation and survival, or regulate antibody production. These include CD19, CD40, the B cell activating factor receptor, and Toll-like receptors. Hyperactivity of these receptors clearly contributes to breaking B-cell tolerance in several autoimmune diseases. Inhibitors of these activating signals (including protein tyrosine phosphatases, deubiquitinating enzymes and several adaptor proteins) are crucial to control B-cell activation and maintain B-cell tolerance. In this review, we summarize the inhibitory signaling mechanisms that counteract B-cell activation triggered by the BCR and the coreceptors.

PTPN22 R620W polymorphism and ANCA disease risk in white populations: a metaanalysis

OBJECTIVE

No clear consensus has been reached on the PTPN22 R620W polymorphism and anti-neutrophil cytoplasmic antibody (ANCA) disease, especially when stratified by ANCA specificity and disease phenotypes.

METHODS

A metaanalysis was conducted on the PTPN22 R620W polymorphism across 4 studies in 1399 white patients with ANCA disease and 9934 normal control subjects.

RESULTS

Overall, metaanalysis showed a statistically significant association between the A allele and ANCA disease in all subjects (OR 1.44, 95% CI 1.26-1.64, p < 0.00001), and stratification by disease category indicated the A allele was associated with granulomatosis with polyangiitis (Wegener's; GPA; OR 1.72, 95% CI 1.35-2.20, p < 0.0001) and microscopic polyangiitis (MPA; OR 1.53, 95% CI 1.08-2.15, p = 0.02) as compared to controls. However, when stratified by ANCA specificity, the association of the A allele was statistically evident among those with proteinase 3 (PR3) ANCA disease (OR 1.74, 95% CI 1.25-2.430, p = 0.001), with the same trend but not statistically associated with myeloperoxidase ANCA disease (OR 1.94, 95% CI 0.64-5.85, p = 0.24). The marked associations were also demonstrated between this allele with lung (OR 1.69, 95% CI 1.21-2.36, p = 0.002), ENT (OR 2.03, 95% CI 1.45-2.84, p < 0.0001), skin (OR 2.55, 95% CI 1.69-3.84, p < 0.0001), and peripheral neuropathy involvement (OR 2.12, 95% CI 1.39-3.22, p = 0.0005).

CONCLUSION

The PTPN22 620W allele confers susceptibility to the occurrence and development of ANCA disease in whites, with specific evidence among subsets with GPA, MPA, and PR3 ANCA.

Interleukin-2 and subunit alpha of its soluble receptor in autoimmune Addison's disease--an association study and expression analysis

Autoimmune Addison's disease (AAD) results from T cell-mediated destruction of the adrenal cortex, commonly accompanied by autoantibodies to 21-hydroxylase (21OH). In order to gain insight into the obscure aetiology of this disease, we investigated the roles of the IL2 and IL2RA genes, encoding interleukin-2 and subunit alpha of its receptor (IL2Ra), respectively. The association of AAD with IL2 and IL2RA polymorphisms (rs6822844, rs2069762, rs3136534, rs11594656, rs3118470 and rs2104286) was tested in 223 patients and 672 healthy controls. Functional studies consisted of gene expression analysis in cultured PBMCs exposed to 21OH and evaluation of serum interleukin by ELISA assays. The frequency of the minor C allele of rs3136534 was significantly decreased in AAD subjects compared to controls (OR 0.71; 95%CI 0.561-0.887; p = 0.003). Only AAD cells responded to 21OH with an elevated IL2 and IL2RA mRNA synthesis (p = 0.004 and p = 0.009 versus controls, respectively), paralleled by increased supernatant levels of both cytokines (p = 0.031 and p = 0.001 versus controls). IL2 mRNA level in 21OH-stimulated AAD PBMCs correlated negatively with age (p = 0.036) and positively with serum antibodies to 21OH (p = 0.006). Carriers of the rs2104286 AA genotype demonstrated higher IL2RA mRNA (p = 0.022) and soluble IL2Ra secretion (p = 0.029) upon 21OH stimulation. Serum interleukin-2 in AAD subjects was significantly higher compared to controls (4.61 ± 4.3 versus 1.71 ± 3.2 pg/mL, p < 0.001), whereas sIL2Ra levels remained similar in both groups (p = 0.885). In conclusion, the study reveals an association between AAD and IL2 locus. It confirms specific 21OH-directed reactivity of the peripheral AAD lymphocytes, which display increased synthesis of interleukin-2 and sIL2Ra.

Association Between PTPN22 Polymorphisms and IgE Responses to Staphylococcal Superantigens in Chronic Urticaria

Protein tyrosine phosphatase-22 (PTPN22) gene encodes lymphoid-specific tyrosine phosphatase (Lyp), an inhibitor of T cell activation. A polymorphism of the PTPN22 gene has been found to be associated with chronic urticaria (CU). We investigated the associations between PTPN22 gene polymorphisms and CU characteristics, including serum specific IgE antibodies response to toxic shock syndrome toxin-1 (TSST-1) and staphylococcal enterotoxin A (SEA). CU patients (n=409) and normal healthy controls (n=388) were enrolled in the present study. Serum specific IgE to TSST-1 and SEA were measured by ImmunoCAP®. Five PTPN22 single nucleotide polymorphisms, -1123G>C, 1858C>T, 13145A>G, 14943C>T, and 20628A>G, were genotyped. There were no significant differences in genotype or haplotype frequencies of these polymorphisms between the 2 groups. CU patients carrying the GG genotype at 20628A>G (P=0.035) or haplotype 3 [GGG] (P=0.047) had a significantly higher prevalence of serum specific IgE to TSST-1 compared to non-carriers. Similarly, CT/TT genotype at 14943C>T had a significantly higher prevalence of serum specific IgE to SEA (P=0.045). The findings suggest that the PTPN22 gene polymorphisms at 20628A>G and 14943C>T may enhance serum specific IgE responses to TSST-1 and SEA, which may contribute to CU pathogenesis.

Protein tyrosine phosphatase PTPN22 +1858C/T polymorphism is associated with active vitiligo

Vitiligo is characterized by a skin depigmentation disorder resulting from an autoimmune response targeting melanocytes. Within the genetic factors involved in the development of the vitiligo immune response, various genes in the major histocompatibility complex (MHC) and non-MHC loci have been considered to be risk factors. The PTPN22 gene encodes for a lymphoid protein tyrosine phosphatase, a regulator of the activation and development of T-cells. The +1858C/T polymorphism has been associated to autoimmune disease susceptibility in different populations and could be implicated in the onset of vitiligo. To assess the possible association between the presence of PTPN22 +1858C/T and vitiligo, 187 patients with vitiligo and 223 control subjects were analyzed in the study. Genomic DNA was isolated using the salting-out method and samples were subjected to polymerase chain reaction-restriction fragment length polymorphism in order to detect the PTPN22 +1858C/T polymorphism. Causal associations were determined by χ² test and their respective odds ratio (OR) was assessed in a 2×2 contingency table. The results showed an association between active vitiligo and the allele T load [P=0.0418; OR, 2.5706; 95% confidence interval (CI), 1.0040-6.5816], and active vitiligo-CT genotype (P=0.0389, OR, 2.6548; 95% CI, 1.0191-6.9156). In conclusion, the present data indicates a possible association between the PTPN22 +1858C/T genotype and a significant susceptibility of developing an active form of vitiligo.

Protein Tyrosine Phosphatase Non-receptor 22 Gene C1858T Polymorphism in Patients with Coexistent Type 2 Diabetes and Hashimoto's Thyroiditis

BACKGROUND

A protein tyrosine phosphatase non-receptor type 22 (PTPN22) C1858T gene polymorphism has been reported to be associated with both Type 2 diabetes mellitus (T2DM) and Hashimoto's thyroiditis (HT) separately. However, no study has been conducted to explore the C1858T polymorphism in T2DM and HT coexistent cases up to now.

AIMS

The study aimed to determine whether a relationship exists or not between the PTPN22 C1858T polymorphism and this coexistent patient group.

STUDY DESIGN

Case-control study.

METHODS

Peripheral blood samples from 135 T2DM patients, 102 patients with coexistent T2DM+HT, 71 HT patients and 135 healthy controls were collected into ethylenediaminetetraacetic acid (EDTA) anticoagulant tubes and genomic DNA was extracted. The PTPN22 C1858T polymorphism was analyzed using polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP) methods.

RESULTS

Statistically significant differences were not observed between the patient and control groups. This study demonstrated a statistically significant association between both the CT genotype and the T allele in the female patient group with coexistent T2DM+HT (CT genotype: p=0.04; T allele: p=0.045) with a statistically significant association between the CT genotype and the mean values of body mass index (BMI) and free T3 levels (FT3) (BMI: p=0.044 and FT3: p=0.021) that was detected in the patient group with coexistent T2DM+HT. The minor genotype TT was observed in none of the groups in this study. The CT genotype frequency was [number (frequency): 5 (3.8%), 7 (6.86%), 5 (7.04%), 3 (2.22%), while the T allele frequency was 5 (1.86%), 7 (3.44%), 5 (3.53%) and 3 (1.12%)] in the T2DM, T2DM+HT, HT and control groups, respectively.

CONCLUSION

Our data suggest that the PTPN22 1858T allele and the CT genotype are associated with increased risk in female patients for coexistent T2DM+HT. The CT genotype was associated with high mean BMI and free T3 values in the patient group with coexistent T2DM+HT. These results demonstrate that T allele carriers were more often in the T2DM+HT group than in the T2DM group. Therefore, the combination of T2DM and HT with female gender may have higher T allele carriage in comparison to the T2DM only and male groups.

T cell receptor-associated protein tyrosine kinases: the dynamics of tolerance regulation by phosphorylation and its role in systemic lupus erythematosus

There are different abnormalities that lead to the autoreactive phenotype in T cells from systemic lupus erythematosus (SLE) patients. Proximal signaling, involving the T-cell receptor (TCR) and its associated protein tyrosine kinases (PTKs), is significantly affected in SLE. This ultimately leads to aberrant responses, which include enhanced tyrosine phosphorylation and calcium release, as well as decreased IL-2 secretion. Lck, ZAP70 and Syk, which are PTKs with a major role in proximal signaling, all present abnormal functioning that contributes to an altered T cell response in these patients. A number of other molecules, especially regulatory proteins, are also involved. This review will focus on the PTKs that participate in proximal signaling, with specific emphasis on their relevance in maintaining peripheral tolerance, their abnormalities in SLE and how these contribute to an altered T cell response.

The association of PTPN22 R620W polymorphism is stronger with late-onset AChR-myasthenia gravis in Turkey

A functional single nucleotide polymorphism (SNP) of the PTPN22 gene encoding a protein tyrosine phosphatase has been associated with autoimmune disorders including myasthenia gravis (MG). As the PTPN22 R620W polymorphism has a wide variation of allele frequencies among different populations, this polymorphism was investigated in MG in Turkey. An emphasis is put on MG subgroups according to autoantibody (Abs) production and presence of thymoma. DNA samples from 416 patients with clinically diagnosed generalized MG (231 with Abs to acetylcholine receptor, AChR-MG), 53 with Abs to muscle-specific kinase (MuSK-MG), 55 patients with no detectable Abs (SN-MG), 77 patients with thymoma (TAMG) and 293 healthy controls (HC) were genotyped for the SNP (PTPN22 R620W, C1858T, rs2476601). The PTPN22 T allele was increased in AChR-MG patients (odds ratio [OR]: 2.5, 95%CI: 1.2–5.1). The association was stronger in late disease-onset AChR (LOMG, OR: 3.1, 95%CI: 1.2–8.2). MuSK-MG, SN-MG and TAMG groups did not carry the variant allele more frequently than the HC. In contrast to findings in other autoimmune diseases, the distribution of the PTPN22 polymorphism in this population provides a susceptibility marker for AChR-MG. The strongest association is detected in patients with LOMG.

Mechanisms of autoimmune thyroid diseases: from genetics to epigenetics

Recent advances in our understanding of genetic-epigenetic interactions have unraveled new mechanisms underlying the etiology of complex autoimmune diseases. Autoimmune thyroid diseases (AITDs) are highly prevalent, affecting 1% to 5% of the population. The major AITDs include Graves disease (GD) and Hashimoto's thyroiditis (HT); although these diseases contrast clinically, their pathogenesis involves shared immunogenetic mechanisms. Genetic data point to the involvement of both shared and unique genes. Among the shared susceptibility genes, HLA-DRβ1-Arg74 (human leukocyte antigen DR containing an arginine at position β74) confers the strongest risk. Recent genome-wide analyses have revealed new putative candidate genes. Epigenetic modulation is emerging as a major mechanism by which environmental factors interact with AITD susceptibility genes. Dissecting the genetic-epigenetic interactions underlying the pathogenesis of AITD is essential to uncover new therapeutic targets.

Genetics of the type I interferon pathway in systemic lupus erythematosus

Genetic studies of systemic lupus erythematosus (SLE) have been successful, identifying numerous risk factors for human disease. While the list is not yet complete, it is clear that important immune system pathways are represented, one of which being type I interferon (IFN). Circulating type I IFN levels are high in SLE patients and this IFN pathway activation is heritable in families with SLE. We summarize our current understanding of the genetics of the type I IFN pathway in SLE, with an emphasis on studies that demonstrate an impact of the SLE-risk alleles upon type I IFN pathway activation in SLE patients. These studies illustrate that variations in type I IFN pathway genes represent a common genetic feature of SLE. By understanding the genetic regulation of type I IFN, we may be able to intervene in a more personalized fashion, based upon the molecular dysregulation present in a given individual.