Why is PTPN22 a good candidate susceptibility gene for autoimmune disease?

A multi-ancestry genome-wide association study in type 1 diabetes

Type 1 diabetes (T1D) is an autoimmune disease caused by destruction of the pancreatic β-cells. Genome-wide association (GWAS) and fine mapping studies have been conducted mainly in European ancestry (EUR) populations. We performed a multi-ancestry GWAS to identify SNPs and HLA alleles associated with T1D risk and age at onset. EUR families (N = 3223), and unrelated individuals of African (AFR, N = 891) and admixed (Hispanic/Latino) ancestry (AMR, N = 308) were genotyped using the Illumina HumanCoreExome BeadArray, with imputation to the TOPMed reference panel. The Multi-Ethnic HLA reference panel was utilized to impute HLA alleles and amino acid residues. Logistic mixed models (T1D risk) and frailty models (age at onset) were used for analysis. In GWAS meta-analysis, seven loci were associated with T1D risk at genome-wide significance: PTPN22, HLA-DQA1, IL2RA, RNLS, INS, IKZF4-RPS26-ERBB3, and SH2B3, with four associated with T1D age at onset (PTPN22, HLA-DQB1, INS, and ERBB3). AFR and AMR meta-analysis revealed NRP1 as associated with T1D risk and age at onset, although NRP1 variants were not associated in EUR ancestry. In contrast, the PTPN22 variant was significantly associated with risk only in EUR ancestry. HLA alleles and haplotypes most significantly associated with T1D risk in AFR and AMR ancestry differed from that seen in EUR ancestry; in addition, the HLA-DRB1*08:02-DQA1*04:01-DQB1*04:02 haplotype was 'protective' in AMR while HLA-DRB1*08:01-DQA1*04:01-DQB1*04:02 haplotype was 'risk' in EUR ancestry, differing only at HLA-DRB1*08. These results suggest that much larger sample sizes in non-EUR populations are required to capture novel loci associated with T1D risk.

Autoimmunity-associated allele of tyrosine phosphatase gene PTPN22 enhances anti-viral immunity

The 1858C>T allele of the tyrosine phosphatase PTPN22 is present in 5-10% of the North American population and is strongly associated with numerous autoimmune diseases. Although research has been done to define how this allele potentiates autoimmunity, the influence PTPN22 and its pro-autoimmune allele has in anti-viral immunity remains poorly defined. Here, we use single cell RNA-sequencing and functional studies to interrogate the impact of this pro-autoimmune allele on anti-viral immunity during Lymphocytic Choriomeningitis Virus clone 13 (LCMV-cl13) infection. Mice homozygous for this allele (PEP-619WW) clear the LCMV-cl13 virus whereas wildtype (PEP-WT) mice cannot. This is associated with enhanced anti-viral CD4 T cell responses and a more immunostimulatory CD8α- cDC phenotype. Adoptive transfer studies demonstrated that PEP-619WW enhanced anti-viral CD4 T cell function through virus-specific CD4 T cell intrinsic and extrinsic mechanisms. Taken together, our data show that the pro-autoimmune allele of Ptpn22 drives a beneficial anti-viral immune response thereby preventing what is normally a chronic virus infection.

Bidirectional association between hypothyroidism and myasthenia gravis: a Mendelian randomized study

OBJECTIVES

Although observational studies have suggested a link between hypothyroidism and myasthenia gravis (MG), a causal relationship has not been established. We aimed to investigate the causal association using a two-sample Mendelian randomization (MR) study.

METHODS

Using summary statistics from genome-wide association studies involving 494,577 and 38,243 individuals, single-nucleotide polymorphisms exhibiting no linkage disequilibrium (r2 ≤ 0.001) and displaying significant differences (p ≤ 5 × 10-8) were selected for hypothyroidism and MG. To assess the potential causality relationship between hypothyroidism and MG, MR analysis was conducted using inverse variance weighted (IVW), weighted median method, and MR-Egger. The MR-Egger regression, heterogeneity test, pleiotropy test, and leave-one-out sensitivity test were employed to examine sensitivity analyses. In addition, validation datasets were used to validate the relevant results.

RESULTS

Genetic liability to hypothyroidism was positively associated with MG (IVW, OR: 1.36, 95% CI: 1.17-1.58, p = 7.53 × 10-05; weighted median, OR: 1.19, 95% CI: 0.70-2.02, p = 0.522; MR-Egger, OR: 1.19, 95% CI: 0.98-1.45, p = 0.080). Among the three MR methods, the correlation between hypothyroidism and MG genetic prediction was consistent. The independent validation set (IVW, OR: 466.47, 95% CI: 4.70 -46,285.95, p = 0.01) further supported this. Additionally, bidirectional studies showed that using IVW, there was no reverse causality (OR: 1.104, 95%CI: 0.96-1.27, p = 0.170).

DISCUSSION

This MR study showed that hypothyroidism can increase the risk of MG. Further investigation into the underlying mechanisms of this potential causality is warranted to offer novel therapeutic options for MG in the future.

PTPN22 intron polymorphism rs1310182 (c.2054-852T>C) is associated with type 1 diabetes mellitus in patients of Armenian descent

Protein tyrosine phosphatase, nonreceptor type 22 (PTPN22), is an archetypal non-HLA autoimmunity gene. It is one of the most prominent genetic contributors to type 1 diabetes mellitus outside the HLA region, and prevalence of its risk variants is subject to enormous geographic variability. Here, we address the genetic background of patients with type 1 diabetes mellitus of Armenian descent. Armenia has a population that has been genetically isolated for 3000 years. We hypothesized that two PTPN22 polymorphisms, rs2476601 and rs1310182, are associated with type 1 diabetes mellitus in persons of Armenian descent. In this association study, we genotyped the allelic frequencies of two risk-associated PTPN22 variants in 96 patients with type 1 diabetes mellitus and 100 controls of Armenian descent. We subsequently examined the associations of PTPN22 variants with the manifestation of type 1 diabetes mellitus and its clinical characteristics. We found that the rs2476601 minor allele (c.1858T) frequency in the control population was very low (q = 0.015), and the trend toward increased frequency of c.1858CT heterozygotes among patients with type 1 diabetes mellitus was not significant (OR 3.34, 95% CI 0.88-12.75; χ2 test p > 0.05). The control population had a high frequency of the minor allele of rs1310182 (q = 0.375). The frequency of c.2054-852TC heterozygotes was significantly higher among the patients with type 1 diabetes mellitus (OR 2.39, 95% CI 1.35-4.24; χ2 test p < 0.001), as was the frequency of the T allele (OR 4.82, 95% CI 2.38-9.76; χ2 test p < 0.001). The rs2476601 c.1858CT genotype and the T allele correlated negatively with the insulin dose needed three to six months after diagnosis. The rs1310182 c.2054-852CC genotype was positively associated with higher HbA1c at diagnosis and 12 months after diagnosis. We have provided the first information on diabetes-associated polymorphisms in PTPN22 in a genetically isolated Armenian population. We found only a limited contribution of the prototypic gain-of-function PTPN22 polymorphism rs2476601. In contrast, we found an unexpectedly close association of type 1 diabetes mellitus with rs1310182.

Identification of Novel Associations and Localization of Signals in Idiopathic Inflammatory Myopathies Using Genome-Wide Imputation

OBJECTIVE

The idiopathic inflammatory myopathies (IIMs) are heterogeneous diseases thought to be initiated by immune activation in genetically predisposed individuals. We imputed variants from the ImmunoChip array using a large reference panel to fine-map associations and identify novel associations in IIM.

METHODS

We analyzed 2,565 Caucasian IIM patient samples collected through the Myositis Genetics Consortium (MYOGEN) and 10,260 ethnically matched control samples. We imputed 1,648,116 variants from the ImmunoChip array using the Haplotype Reference Consortium panel and conducted association analysis on IIM and clinical and serologic subgroups.

RESULTS

The HLA locus was consistently the most significantly associated region. Four non-HLA regions reached genome-wide significance, SDK2 and LINC00924 (both novel) and STAT4 in the whole IIM cohort, with evidence of independent variants in STAT4, and NAB1 in the polymyositis (PM) subgroup. We also found suggestive evidence of association with loci previously associated with other autoimmune rheumatic diseases (TEC and LTBR). We identified more significant associations than those previously reported in IIM for STAT4 and DGKQ in the total cohort, for NAB1 and FAM167A-BLK loci in PM, and for CCR5 in inclusion body myositis. We found enrichment of variants among DNase I hypersensitivity sites and histone marks associated with active transcription within blood cells.

CONCLUSION

We found novel and strong associations in IIM and PM and localized signals to single genes and immune cell types.

Molecular Mechanisms in Autoimmune Thyroid Disease

The most common cause of acquired thyroid dysfunction is autoimmune thyroid disease, which is an organ-specific autoimmune disease with two presentation phenotypes: hyperthyroidism (Graves-Basedow disease) and hypothyroidism (Hashimoto’s thyroiditis). Hashimoto’s thyroiditis is distinguished by the presence of autoantibodies against thyroid peroxidase and thyroglobulin. Meanwhile, autoantibodies against the TSH receptor have been found in Graves-Basedow disease. Numerous susceptibility genes, as well as epigenetic and environmental factors, contribute to the pathogenesis of both diseases. This review summarizes the most common genetic, epigenetic, and environmental mechanisms involved in autoimmune thyroid disease.

Analysis of PTPN22 -1123 G>C, +788 G>A and +1858 C>T Polymorphisms in Patients with Primary Sjögren's Syndrome

BACKGROUND

Primary Sjögren's syndrome (pSS) is an autoimmune exocrinopathy characterized by lymphocytic infiltration, glandular dysfunction and systemic manifestations. Lyp protein is a negative regulator of the T cell receptor encoded by the tyrosine phosphatase nonreceptor-type 22 (PTPN22) gene. Multiple single-nucleotide polymorphisms (SNPs) in the PTPN22 gene have been associated with susceptibility to autoimmune diseases. This study aimed to investigate the association of PTPN22 SNPs rs2488457 (-1123 G>C), rs33996649 (+788 G>A), rs2476601 (+1858 C>T) with pSS susceptibility in Mexican mestizo subjects.

METHODS

One hundred fifty pSS patients and 180 healthy controls (HCs) were included. Genotypes of PTPN22 SNPs were identified by PCR-RFLP. PTPN22 expression was evaluated through RT-PCR analysis. Serum anti-SSA/Ro and anti-SSB/La levels were measured using an ELISA kit.

RESULTS

Allele and genotype frequencies for all SNPs studied were similar in both groups (p > 0.05). pSS patients showed 17-fold higher expression of PTNP22 than HCs, and mRNA levels correlated with SSDAI score (r² = 0.499, p = 0.008) and levels of anti-SSA/Ro and anti-SSB/La autoantibodies (r² = 0.200, p = 0.03 and r² = 0.175, p = 0.04, respectively). Positive anti-SSA/Ro pSS patients expressed higher PTPN22 mRNA levels (p = 0.008), with high focus scores by histopathology (p = 0.02). Moreover, PTPN22 expression had high diagnostic accuracy in pSS patients, with an AUC = 0.985.

CONCLUSIONS

Our findings demonstrate that the PTPN22 SNPs rs2488457 (-1123 G>C), rs33996649 (+788 G>A) and rs2476601 (+1858 C>T) are not associated with the disease susceptibility in the western Mexican population. Additionally, PTPN22 expression may be helpful as a diagnostic biomarker in pSS.

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.

HLA and Non-HLA gene polymorphisms in autoimmune hepatitis patients of North Indian adults

Autoimmune hepatitis (AIH) is a chronic and progressive disease of the liver. This is a multifactorial autoimmune disease with both environmental factors and genetic factors playing a role in its pathogenesis. Certain environmental agents like viruses, drugs, etc., can trigger the disease in a genetically susceptible individual. The present study was aimed to explore the distribution of human leukocyte antigen (HLA)-DRB1, Protein tyrosine phosphatase non-receptor type 22 (PTPN22) and Cytotoxic T-Lymphocyte-associated protein 4 (CTLA-4) polymorphisms in North Indian adult AIH patients and their associations with clinical and pathological characteristics associated with the disease. A total of 147 subjects with 47 cases and 100 healthy controls were enrolled. Diagnosis of AIH was made by Revised International Autoimmune Hepatitis Group scoring system. HLA-DRB1 Typing was done by Luminex-based reverse Sequence-Specific Oligonucleotide Probing (SSOP). Single nucleotide variant (SNV) genotyping for CTLA-4 and PTPN22 was done by simple probe-based SNP arrays. Results indicated SLA positive AIH patients are poor responders to therapy. A significant predispositional association of HLA-DRB1*03 was observed in AIH patients from the North Indian population (p= 0.0001, OR=4.83 (2.30-10.15). The frequency of the GG genotype of CTLA-4 CT 60 was significantly increased in AIH patients compared to controls. Multinomial analysis showed that CTLA-4 CT 60 is an independent predictor for cases.

Altered PTPN22 and IL10 mRNA Expression Is Associated with Disease Activity and Renal Involvement in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a complex autoimmune disease with very heterogeneous clinical behavior between affected individuals. Therefore, the search for biomarkers clinically useful for the diagnosis, prognosis, and monitoring of the disease is necessary. Here, we determined the association between PTPN22, IL10, OAS2, and CD70 mRNA expression with the clinical characteristics and with the serum levels of IL-10, IFN-γ, and IL-17 in SLE patients. Forty patients with SLE and 34 control subjects (CS) were included, mRNA expression was determined by real-time qPCR and cytokine levels were quantified by a multiplex bead-based immunoassay. Compared to CS, SLE patients showed increased IL10 mRNA and high IL-10 and IL-17 serum levels; in contrast, PTPN22 mRNA and IFN-γ were decreased. PTPN22 and IL10 gene expression was negatively correlated with Mex-SLEDAI score and were notably downregulated in SLE patients with lupus nephritis. Interestingly, SLE patients with renal damage were the ones with the lowest levels of PTPN22 and IL10 mRNA and the highest SLEDAI scores. No associations were observed for OAS2 and CD70 mRNA and IL-10, IL-17, and IFN-γ. In conclusion, we suggest that the assessment of IL10 and PTPN22 mRNA could be useful for monitoring disease activity in SLE patients showing renal involvement.

Associations between deduced first islet specific autoantibody with sex, age at diagnosis and genetic risk factors in young children with type 1 diabetes

OBJECTIVES

We aimed to further characterize demography and genetic associations of type 1 diabetes "endotypes" defined by the first appearing islet specific autoantibodies.

RESEARCH DESIGN AND METHODS

We analyzed 3277 children diagnosed before the age of 10 years from the Finnish Pediatric Diabetes Register. The most likely first autoantibody could be deduced in 1636 cases (49.9%) based on autoantibody combinations at diagnosis. Distribution of age, sex, HLA genotypes and allele frequencies of 18 single nucleotide polymorphisms (SNPs) in non-HLA risk genes were compared between the endotypes.

RESULTS

Two major groups with either glutamic acid decarboxylase (GADA) or insulin autoantibodies (IAA) as the deduced first autoantibody showed significant differences in their demographic and genetic features. Boys and children diagnosed at young age had more often IAA-initiated autoimmunity whereas GADA-initiated autoimmunity was observed more frequently in girls and in subjects diagnosed at an older age. IAA as the first autoantibody was also most common in HLA genotype groups conferring high-disease risk while GADA first was seen more evenly and frequently in HLA groups associated with lower type 1 diabetes risk. The risk alleles in IKZF4 and ERBB3 genes were associated with GADA-initiated whereas those in PTPN22, INS and PTPN2 genes were associated with IAA-initiated autoimmunity.

CONCLUSIONS

The results support the assumption that in around half of the young children the first autoantibody can be deduced based on islet autoantibody combinations at disease diagnosis. Strong differences in sex and age distributions as well as in genetic associations could be observed between GADA- and IAA-initiated autoimmunity.

Non-HLA Gene Polymorphisms in the Pathogenesis of Type 1 Diabetes: Phase and Endotype Specific Effects

The non-HLA loci conferring susceptibility to type 1 diabetes determine approximately half of the genetic disease risk, and several of them have been shown to affect immune-cell or pancreatic β-cell functions. A number of these loci have shown associations with the appearance of autoantibodies or with progression from seroconversion to clinical type 1 diabetes. In the current study, we have re-analyzed 21 of our loci with prior association evidence using an expanded DIPP follow-up cohort of 976 autoantibody positive cases and 1,910 matched controls. Survival analysis using Cox regression was applied for time periods from birth to seroconversion and from seroconversion to type 1 diabetes. The appearance of autoantibodies was also analyzed in endotypes, which are defined by the first appearing autoantibody, either IAA or GADA. Analyzing the time period from birth to seroconversion, we were able to replicate our previous association findings at PTPN22, INS, and NRP1. Novel findings included associations with ERBB3, UBASH3A, PTPN2, and FUT2. In the time period from seroconversion to clinical type 1 diabetes, prior associations with PTPN2, CD226, and PTPN22 were replicated, and a novel association with STAT4 was observed. Analyzing the appearance of autoantibodies in endotypes, the PTPN22 association was specific for IAA-first. In the progression phase, STAT4 was specific for IAA-first and ERBB3 to GADA-first. In conclusion, our results further the knowledge of the function of non-HLA risk polymorphisms in detailing endotype specificity and timing of disease development.

Functional Impact of Risk Gene Variants on the Autoimmune Responses in Type 1 Diabetes

Type 1 diabetes (T1D) is an autoimmune disease that develops in the interplay between genetic and environmental factors. A majority of individuals who develop T1D have a HLA make up, that accounts for 50% of the genetic risk of disease. Besides these HLA haplotypes and the insulin region that importantly contribute to the heritable component, genome-wide association studies have identified many polymorphisms in over 60 non-HLA gene regions that also contribute to T1D susceptibility.

Combining the risk genes in a score (T1D-GRS), significantly improved the prediction of disease progression in autoantibody positive individuals. Many of these minor-risk SNPs are associated with immune genes but how they influence the gene and protein expression and whether they cause functional changes on a cellular level remains a subject of investigation. A positive correlation between the genetic risk and the intensity of the peripheral autoimmune response was demonstrated both for HLA and non-HLA genetic risk variants. We also observed epigenetic and genetic modulation of several of these T1D susceptibility genes in dendritic cells (DCs) treated with vitamin D3 and dexamethasone to acquire tolerogenic properties as compared to immune activating DCs (mDC) illustrating the interaction between genes and environment that collectively determines risk for T1D. A notion that targeting such genes for therapeutic modulation could be compatible with correction of the impaired immune response, inspired us to review the current knowledge on the immune-related minor risk genes, their expression and function in immune cells, and how they may contribute to activation of autoreactive T cells, Treg function or β-cell apoptosis, thus contributing to development of the autoimmune disease.

Single-nucleotide polymorphisms as important risk factors of diabetes among Middle East population

Diabetes is a chronic metabolic disorder that leads to the dysfunction of various tissues and organs, including eyes, kidneys, and cardiovascular system. According to the World Health Organization, diabetes prevalence is 8.8% globally among whom about 90% of cases are type 2 diabetes. There are not any significant clinical manifestations in the primary stages of diabetes. Therefore, screening can be an efficient way to reduce the diabetic complications. Over the recent decades, the prevalence of diabetes has increased alarmingly among the Middle East population, which has imposed exorbitant costs on the health care system in this region. Given that the genetic changes are among the important risk factors associated with predisposing people to diabetes, we examined the role of single-nucleotide polymorphisms (SNPs) in the pathogenesis of diabetes among Middle East population. In the present review, we assessed the molecular pathology of diabetes in the Middle East population that paves the way for introducing an efficient SNP-based diagnostic panel for diabetes screening among the Middle East population. Since, the Middle East has a population of 370 million people; the current review can be a reliable model for the introduction of SNP-based diagnostic panels in other populations and countries around the world.

Coincidence of juvenile idiopathic arthritis and type 1 diabetes: a case-based review

The study was aimed to review a rare coexistence of type 1 diabetes (T1D) and juvenile idiopathic arthritis (JIA) regarding different clinical approaches to the management and treatment options. Medical complications of the two autoimmune disorders in children and adolescents have been evaluated, particularly in those treated with glucocorticosteroids (GCS) and insulin. A review of the literature regarding reports on concomitant T1D and JIA was conducted using resources available in Medline, Google Scholar, and Web of Science databases, with a specific focus on the combination of T1D and JIA in a pediatric population. The review was extended by our analysis of two patients treated in a single center for this comorbidity. Eligible reports of four cases were found, and including our two original records, a total of six pediatric patients (5 females) were analyzed, of which three had also other autoimmune diseases (thyroiditis, coeliac disease, autoimmune hepatitis), whereas four had been treated with a long-term GCS, and two were receiving biological therapy (etanercept or adalimumab). Only one of them had good metabolic control of diabetes. Diabetes in childhood may coexist with other autoimmune diseases, including rheumatologic conditions. Hyperglycemia can worsen JIA therapy by induction and maintaining inflammation. Using modern diabetes technologies (like personal insulin pumps and continuous glucose monitoring) helps to minimize the deteriorating effect of JIA exacerbations and the rheumatoid treatment on metabolic control of diabetes.

The Immunogenetics of Vitiligo: An Approach Toward Revealing the Secret of Depigmentation

Vitiligo is a hypomelanotic skin disease and considered to be of autoimmune origin due to breaching of immunological self-tolerance, resulting in inappropriate immune responses against melanocytes. The development of vitiligo includes a strong heritable component. Different strategies ranging from linkage studies to genome-wide association studies are used to explore the genetic factors responsible for the disease. Several vitiligo loci containing the respective genes have been identified which contribute to vitiligo and genetic variants for some of the genes are still unknown. These genes include mainly the proteins that play a role in immune regulation and a few other genes important for apoptosis and regulation of melanocyte functions. Despite the available data on genetic variants and risk alleles which influence the biological processes, only few immunological pathways have been found responsible for all ranges of severity and clinical manifestations of vitiligo. However, studies have concluded that vitiligo is of autoimmune origin and manifests due to complex interactions in immune components and their inappropriate response toward melanocytes. The genes involved in the immune regulation and processing the melanocytes antigen and its presentation can serve as effective immune-therapeutics that can target specific immunological pathways involved in vitiligo. This chapter highlights those immune-regulatory genes involved in vitiligo susceptibility and loci identified to date and their implications in vitiligo pathogenesis.

Proteomics and Organoid Culture Reveal the Underlying Pathogenesis of Hashimoto's Thyroiditis

Hashimoto’s thyroiditis (HT) is an autoimmune disease, and its incidence continues to rise. Although scientists have studied this disease for many years and discovered the potential effects of various proteins in it, the specific pathogenesis is still not fully comprehended. To understand HT and translate this knowledge to clinical applications, we took the mass spectrometric analysis on thyroid tissue fine-needle puncture from HT patients and healthy people in an attempt to make a further understanding of the pathogenesis of HT. A total of 44 proteins with differential expression were identified in HT patients, and these proteins play vital roles in cell adhesion, cell metabolism, and thyroxine synthesis. Combining patient clinical trial sample information, we further compared the transient changes of gene expression regulation in HT and papillary thyroid carcinoma (PTC) samples. More importantly, we developed patient-derived HT and PTC organoids as a promising new preclinical model to verify these potential markers. Our data revealed a marked characteristic of HT organoid in upregulating chemokines that include C-C motif chemokine ligand (CCL) 2 and CCL3, which play a key role in the pathogenesis of HT. Overall, our research has enriched everyone’s understanding of the pathogenesis of HT and provides a certain reference for the treatment of the disease.

Biomaterial-based immunotherapeutic strategies for rheumatoid arthritis

Rheumatoid arthritis (RA) is an extremely painful autoimmune disease characterized by chronic joint inflammation leading to the erosion of adjacent cartilage and bone. Rheumatoid arthritis pathology is primarily driven by inappropriate infiltration and activation of immune cells within the synovium of the joint. There is no cure for RA. As such, manifestation of symptoms entails lifelong management via various therapies that aim to generally dampen the immune system or impede the function of immune mediators. However, these treatment strategies lead to adverse effects such as toxicity, general immunosuppression, and increased risk of infection. In pursuit of safer and more efficacious therapies, many emerging biomaterial-based strategies are being developed to improve payload delivery, specific targeting, and dose efficacy, and to mitigate adverse reactions and toxicity. In this review, we highlight biomaterial-based approaches that are currently under investigation to circumvent the limitations of conventional RA treatments.

Association of the single nucleotide polymorphism C1858T of the PTPN22 gene with unexplained recurrent pregnancy loss: A case-control study

Background

Lymphoid-tyrosine-phosphatase which is encoded by the protein tyrosine phosphatase non-receptor 22 (PTPN22) gene plays a pivotal role in the regulation of immune responses by dephosphorylating several signaling intermediates of immune cells.

Objective

Since a balanced immune response has been shown to be important during pregnancy, the purpose of this research was to compare the frequency of the PTPN22 C1858T polymorphism in women with unexplained recurrent pregnancy loss (URPL) vs. in a control group for the first time.

Materials and Methods

Genomic DNA from 200 individuals with URPL and 200 individuals without URPL (the control group) at the infertility center in Yazd, Iran was isolated using the salting-out method. The PTPN22 C1858T polymorphism of the two groups was analyzed using polymerase chain reaction-restriction fragment length polymorphism. Genotype frequencies in the women with URPL and the fertile control group were compared using the Chi-square test.

Results

There were significant differences in the frequency of the PTPN22 1858T polymorphism in the URPL individuals vs. the healthy controls, i.e. 32.0% and 21.5%, respectively (p = 0.01).

Conclusion

Our findings suggest that the PTPN22 1858T polymorphism could play a role in recurrent pregnancy loss. Therefore, genotyping of the mentioned polymorphism can help clinicians to predict the probable risk of URPL.

Effect of PTPN22, FAS/FASL, IL2RA and CTLA4 genetic polymorphisms on the risk of developing alopecia areata: A systematic review of the literature and meta-analysis

Objectives

Genetic association studies on alopecia areata (AA) performed in various populations have shown heterogeneous results. The aim of the current review was to synthesize the results of said studies to estimate the impact of FAS, FASL, PTPN22, CTLA4 and IL2RA gene polymorphisms on AA susceptibility.

Design

A systematic literature search was conducted in the Medline, Web of Science, Scopus, EMBASE and LILACS databases. Studies published up to June 2020 were included. The results available in the grey literature including the Open Grey and Google Scholar databases were also used. The texts of potentially related studies were screened by individual reviewers. Evidence of publication bias was assessed using the Newcastle-Ottawa scale and the quality of evidence was assessed using the GRADE system. The quantitative synthesis was performed using the fixed effect model.

Results

Out of 1784 articles, we identified 18 relevant articles for the qualitative synthesis and 16 for the quantitative synthesis. In a study of rs2476601 polymorphism of PTPN22 gene, including 1292 cases and 1832 controls, a correlation was found with the risk of developing AA in the allelic model (OR1.49 [95% C:1.13–1.95]), the heterozygous codominant (OR1.44 [95% CI:1:19–1.76]) and dominant model (OR1.43 [95% CI:1.18–1.73]). No association was found between the presence of FASL, PTPN22, CTLA and IL2RA gene polymorphisms with AA susceptibility.

Conclusions

The results suggest that the T allele of the single nucleoid polymorphism (SNP) rs2476601 in PTPN22 gene is a risk factor for developing alopecia areata. However, more robust studies defining the ethnic background of the population of origin are required, so that the risk identified in the present study can be validated. Additionally, a greater number of studies is necessary to evaluate the role of the FAS, FASL, PTPN22, CTLA4 and IL2RA genetic variants, given the heterogenous results found in the literature.

DNA hypermethylation of PTPN22 gene promoter in children and adolescents with Hashimoto thyroiditis

PURPOSE

Protein tyrosine phosphatase non-receptor type 22 (PTPN22) is an inhibitor of T-cell activation, regulating intracellular signal transduction and thereby being implicated in the pathogenesis of autoimmune thyroid disease (AITD). The exact molecular mechanisms have not been fully elucidated. The aim of the present study was to quantitate DNA methylation within the PTPN22 gene promoter in children and adolescents with AITD and healthy controls.

METHODS

60 Patients with Hashimoto thyroiditis (HT), 25 patients with HT and type 1 diabetes (HT + T1D), 9 patients with Graves' disease (GD) and 55 healthy controls without any individual or family history of autoimmune disease were enrolled. Whole blood DNA extraction, DNA modification using sodium bisulfate and quantification of DNA methylation in the PTPN22 gene promoter, based on melting curve analysis of the selected DNA fragment using a Real-Time PCR assay, were implemented.

RESULTS

DNA methylation in the PTPN22 gene promoter was found to be significantly higher in HT patients (39.9 ± 3.1%) in comparison with other study groups (20.3 ± 2.4% for HT + T1D, 32.6 ± 7.8% for GD, 27.1 ± 2.4% for controls, p < 0.001). PTPN22 gene promoter DNA methylation was also associated marginally with thyroid autoimmunity in general (p = 0.059), as well as considerably with thyroid volume (p = 0.004) and the presence of goiter (p = 0.001) but not thyroid function tests.

CONCLUSIONS

This study demonstrates for the first time that a relationship between autoimmune thyroiditis and PTPN22 gene promoter DNA methylation state is present, thus proposing another possible etiological association between thyroiditis and abnormalities of PTPN22 function. Further expression studies are required to confirm these findings.

Proautoimmune Allele of Tyrosine Phosphatase, PTPN22, Enhances Tumor Immunity

The 1858C>T allele of the tyrosine phosphatase PTPN22 (causing amino acid substitution R620W in encoded protein lymphoid tyrosine phosphatase) is present in 5-10% of the North American population and is strongly associated with numerous autoimmune diseases. Although much research has been done to define how this allele potentiates autoimmunity, the influence PTPN22 and its proautoimmune allele have in tumor immunity is poorly defined. To interrogate the role this allele may have in the antitumor immune response, we used CRISPR/Cas9 to generate mice in which the ortholog of lymphoid tyrosine phosphatase, PEST domain-enriched protein (PEP), is mutated at position 619 to produce the relevant proautoimmune mutation (R619W). Results of this study show that mice homozygous for this alteration (PEP-619WW) resist tumor growth as compared with wild-type mice. Consistent with these results, tumors from PEP-619WW mice have more CD45 infiltrates containing more activated CD8 T cells and CD4 T cells. In addition, there are more conventional dendritic cell type 1 (cDC1) cells and fewer myeloid-derived suppressor cells in tumors from PEP-619WW mice. Interestingly, the tumor-infiltrating PEP-619WW cDC1 cells have decreased PD-L1 expression compared with cDC1 cells from PEP-wild-type mice. Taken together, our data show that the proautoimmune allele of Ptpn22 drives a strong antitumor response in innate and adaptive immune cells resulting in superior control of tumors.

LFA-1 in T cell priming, differentiation, and effector functions

The integrin LFA-1 is crucial for T cell entry into mammalian lymph nodes and tissues, and for promoting interactions with antigen-presenting cells (APCs). However, it is increasingly evident that LFA-1 has additional key roles beyond the mere support of adhesion between T cells, the endothelium, and/or APCs. These include roles in homotypic T cell-T cell (T-T) communication, the induction of intracellular complement activity underlying Th1 effector cell polarization, and the support of long-lasting T cell memory. Here, we briefly summarize current knowledge of LFA-1 biology, discuss novel cytoskeletal regulators of LFA-1 functions, and review new aspects of LFA-1 mechanobiology that are relevant to its function in immunological synapses and in specific pathologies arising from LFA-1 dysregulation.

The Role of Protein and Lipid Clustering in Lymphocyte Activation

Lymphocytes must strike a delicate balance between activating in response to signals from potentially pathogenic organisms and avoiding activation from stimuli emanating from the body's own cells. For cells, such as T or B cells, maximizing the efficiency and fidelity, whilst minimizing the crosstalk, of complex signaling pathways is crucial. One way of achieving this control is by carefully orchestrating the spatiotemporal organization of signaling molecules, thereby regulating the rates of protein-protein interactions. This is particularly true at the plasma membrane where proximal signaling events take place and the phenomenon of protein microclustering has been extensively observed and characterized. This review will focus on what is known about the heterogeneous distribution of proteins and lipids at the cell surface, illustrating how such distributions can influence signaling in health and disease. We particularly focus on nanoscale molecular organization, which has recently become accessible for study through advances in microscope technology and analysis methodology.

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.

Genetic Susceptibility to Joint Occurrence of Polycystic Ovary Syndrome and Hashimoto's Thyroiditis: How Far Is Our Understanding?

Polycystic ovary syndrome (PCOS) and Hashimoto’s thyroiditis (HT) are endocrine disorders that commonly occur among young women. A higher prevalence of HT in women with PCOS, relative to healthy individuals, is observed consistently. Combined occurrence of both diseases is associated with a higher risk of severe metabolic and reproductive complications. Genetic factors strongly impact the pathogenesis of both PCOS and HT and several susceptibility loci associated with a higher risk of both disorders have been identified. Furthermore, some candidate gene polymorphisms are thought to be functionally relevant; however, few genetic variants are proposed to be causally associated with the incidence of both disorders together.

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.

Recurrence of Graves' Disease: What Genetics of HLA and PTPN22 Can Tell Us

BACKGROUND

Approximately half of patients diagnosed with Graves' disease (GD) relapse within two years of thyreostatic drug withdrawal. It is then necessary to decide whether to reintroduce conservative treatment that can have serious side effects, or to choose a radical approach. Familial forms of GD indicate a significant genetic component. Our aim was to evaluate the practical benefits of HLA and PTPN22 genetic testing for the assessment of disease recurrence risk in the Czech population.

METHODS

In 206 patients with GD, exon 2 in the HLA genes DRB1, DQA1, DQB1 and rs2476601 in the gene PTPN22 were sequenced.

RESULTS

The risk HLA haplotype DRB1*03-DQA1*05-DQB1*02 was more frequent in our GD patients than in the general European population. During long-term retrospective follow-up (many-year to lifelong perspective), 87 patients relapsed and 26 achieved remission lasting over 2 years indicating a 23% success rate for conservative treatment of the disease. In 93 people, the success of conservative treatment could not be evaluated (thyroidectomy immediately after the first attack or ongoing antithyroid therapy). Of the examined genes, the HLA-DQA1*05 variant reached statistical significance in terms of the ability to predict relapse (p=0.03). Combinations with either both other HLA risk genes forming the risk haplotype DRB1*03-DQA1*05-DQB1*02 or with the PTPN22 SNP did not improve the predictive value.

CONCLUSION

the DQA1*05 variant may be a useful prognostic marker in patients with an unclear choice of treatment strategy.

The Role of Protein Tyrosine Phosphatases in Inflammasome Activation

Inflammasomes are multi-protein complexes that mediate the activation and secretion of the inflammatory cytokines IL-1β and IL-18. More than half a decade ago, it has been shown that the inflammasome adaptor molecule, ASC requires tyrosine phosphorylation to allow effective inflammasome assembly and sustained IL-1β/IL-18 release. This finding provided evidence that the tyrosine phosphorylation status of inflammasome components affects inflammasome assembly and that inflammasomes are subjected to regulation via kinases and phosphatases. In the subsequent years, it was reported that activation of the inflammasome receptor molecule, NLRP3, is modulated via tyrosine phosphorylation as well, and that NLRP3 de-phosphorylation at specific tyrosine residues was required for inflammasome assembly and sustained IL-1β/IL-18 release. These findings demonstrated the importance of tyrosine phosphorylation as a key modulator of inflammasome activity. Following these initial reports, additional work elucidated that the activity of several inflammasome components is dictated via their phosphorylation status. Particularly, the action of specific tyrosine kinases and phosphatases are of critical importance for the regulation of inflammasome assembly and activity. By summarizing the currently available literature on the interaction of tyrosine phosphatases with inflammasome components we here provide an overview how tyrosine phosphatases affect the activation status of inflammasomes.

Beyond the HLA polymorphism: A complex pattern of genetic susceptibility to pemphigus

Pemphigus is a group of autoimmune bullous skin diseases that result in significant morbidity. As for other multifactorial autoimmune disorders, environmental factors may trigger the disease in genetically susceptible individuals. The goals of this review are to summarize the state of knowledge about the genetic variation that may affect the susceptibility and pathogenesis of pemphigus vulgaris and pemphigus foliaceus – both the endemic and the sporadic forms –, to compare and discuss the possible meaning of the associations reported, and to propose recommendations for new research initiatives. Understanding how genetic variants translate into pathogenic mechanisms and phenotypes remains a mystery for most of the polymorphisms that contribute to disease susceptibility. However, genetic studies provide a strong foundation for further developments in this field by generating testable hypotheses. Currently, results still have limited influence on disease prevention and prognosis, drug development, and clinical practice, although the perspectives for future applications for the benefit of patients are encouraging. Recommendations for the continued advancement of our understanding as to the impact of genetic variation on pemphigus include these partially overlapping goals: (1) Querying the functional effect of genetic variants on the regulation of gene expression through their impact on the nucleotide sequence of cis regulatory DNA elements such as promoters and enhancers, the splicing of RNA, the structure of regulatory RNAs and proteins, binding of these regulatory molecules to regulatory DNA elements, and alteration of epigenetic marks; (2) identifying key cell types and cell states that are implicated in pemphigus pathogenesis and explore their functional genomes; (3) integrating structural and functional genomics data; (4) performing disease-progression longitudinal studies to disclose the causal relationships between genetic and epigenetic variation and intermediate disease phenotypes; (5) understanding the influence of genetic and epigenetic variation in the response to treatment and the severity of the disease; (6) exploring gene-gene and genotype-environment interactions; (7) developing improved pemphigus-prone and non-prone animal models that are appropriate for research about the mechanisms that link genotypes to pemphigus. Achieving these goals will demand larger samples of patients and controls and multisite collaborations.

Prediction of Relapse After Antithyroid Drugs Withdrawal: A Narrative Review

Context: Antithyroid drugs (ATD) are the first-line treatment for Graves’ disease (GD); however, relapse following treatment is approximately 30% - 40% in the first year, and 50% - 60% in the long term. Identification of risk factors that predict relapse, after discontinuing ATD, plays an important role in guiding therapeutic options. Evidence Acquisition: PubMed was used to search for studies published in English between 1995 and 2019. The following search terms were used: Graves’ disease, antithyroid drugs, relapse, recurrence, and outcome. The reference lists from review articles were also included in the search in order to find older journals. Results: Factors associated with a high recurrence rate, as reported in most studies, were divided into phenotype and genotype predictors. Phenotype factors included large goiter size, persistence of high TSH receptor antibody (TRAb), severe hyperthyroidism, smoking, younger age, male sex, and prior history of recurrence. Genotype factors included human leukocyte antigen (HLA), CD40, CTLA-4, PTPN22, Tg, and TSHR genes. In a subgroup analysis by age, genetic factors were better predictors in the younger group, while clinical signs were more useful in the older group. The reliability of using individual baseline risk factors to predict subsequent relapse is poor; however, predictive scores calculated by grouping single risk factors might help to predict future outcomes. Conclusions: Longer normalization time of TRAb, the persistence of a palpable goiter, and harboring genetic risk factors in younger patients are associated with high recurrence rate of GD. Multi-marker prediction models have been proposed and validated to improve the predictive value of relapse after ATD withdrawal.

Distinct HLA and non-HLA associations in different subtypes of ANCA-associated vasculitides in North India

AIM

Antineutrophil cytoplasmic antibody-associated vasculitis (AAV) is an autoimmune disease characterized by necrotizing small vessel vasculitis that can affect various organs and present multiple symptoms. Susceptibility to AAV is multifactorial and most likely caused by an amalgamation of genetic and environmental factors. The aim of the present study was to explore the distribution of human leukocyte antigen (HLA)-DRB1/DQB1, protein tyrosine phosphatase non-receptor type 22 (PTPN22) and cytotoxic T-Lymphocyte-associated protein 4 (CTLA-4) polymorphisms in North Indian AAV patients and their associations with clinical and pathological characteristics associated with the disease.

METHODS

A total of 150 AAV patients and 150 healthy controls were recruited. The clinical classification showed 128 as granulomatosis with polyangiitis (GPA) and 21 as microscopic polyangiitis. Only 1 case of eosinophilic granulomatosis with polyangiitis was encountered, which was excluded from analysis. HLA-DRB1/DQB1 alleles were determined by polymerase chain reaction-sequence-specific primer (PCR-SSP) method and single nucleotide variant genotyping for CTLA-4 and PTPN22 was done by simple probe-based SNP arrays.

RESULTS

A significant predispositional association of DRB1*03 and DQB1*02 alleles, were confirmed in proteinase 3 (PR3)-AAV patients, whereas DRB1*10, DRB1*14 and DQB1*05 were protective alleles in AAV, PR3-AAV and GPA patients. GG genotype of CTLA-4 + 49A/G was increased in patients as compared to controls and showed an association with AAV, PR3-AAV and GPA patients.

CONCLUSION

The study indicated strong genetic associations were linked with PR3 antineutrophil cytoplasmic antibody specificity and it appears that PR3-AAV and MPO-AAV have distinct genetic backgrounds.

Protein tyrosine phosphatase nonreceptor type 22 gene polymorphism in alopecia areata: Does it have an association with disease severity?

BACKGROUND

Alopecia areata is a condition involving hair loss from certain or all areas of the body. It has been considered as an immune-mediated disease, characterized by the infiltration of CD4+ and CD8+ lymphocytes in the hair follicles.

AIM OF THE STUDY

The study aimed to assess whether protein tyrosine phosphatase nonreceptor type 22 gene single nucleotide polymorphism 1858C/T has any relationship with alopecia areata in Egyptian patients and whether it is associated with disease severity or not.

SUBJECTS AND METHODS

Protein tyrosine phosphatase nonreceptor type 22 (PTPN22) C1858T gene polymorphism was identified using polymerase chain reaction-restriction fragment length polymorphism analysis technique in 60 patients suffering from alopecia areata and 30 age- and sex-matched healthy controls. Disease severity was assessed using SALT score.

RESULTS

CT and TT genotypes were significantly higher in the patients' group (P = .005), OR = 4.38 95% CI [1.48-12.96], with significant statistical predominance of T allele in patients, P = .003, OR = 3.86, 95% CI [1.52-9.77]. There was also a positive significant relationship between protein tyrosine phosphatase nonreceptor type 22 genotype CT and SALT score.

CONCLUSION

PTPN22 1858T allele is associated with the development and severity of alopecia areata in Egyptians.

Understanding Idiosyncratic Toxicity: Lessons Learned from Drug-Induced Liver Injury

Idiosyncratic adverse drug reactions (IADRs) encompass a diverse group of toxicities that can vary by drug and patient. The complex and unpredictable nature of IADRs combined with the fact that they are rare makes them particularly difficult to predict, diagnose, and treat. Common clinical characteristics, the identification of human leukocyte antigen risk alleles, and drug-induced proliferation of lymphocytes isolated from patients support a role for the adaptive immune system in the pathogenesis of IADRs. Significant evidence also suggests a requirement for direct, drug-induced stress, neoantigen formation, and stimulation of an innate response, which can be influenced by properties intrinsic to both the drug and the patient. This Perspective will provide an overview of the clinical profile, mechanisms, and risk factors underlying IADRs as well as new approaches to study these reactions, focusing on idiosyncratic drug-induced liver injury.

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.

Clinical and genetic correlates of islet-autoimmune signatures in juvenile-onset type 1 diabetes

AIMS/HYPOTHESIS

Heterogeneity in individuals with type 1 diabetes has become more generally appreciated, but has not yet been extensively and systematically characterised. Here, we aimed to characterise type 1 diabetes heterogeneity by creating immunological, genetic and clinical profiles for individuals with juvenile-onset type 1 diabetes in a cross-sectional study.

METHODS

Participants were HLA-genotyped to determine HLA-DR-DQ risk, and SNP-genotyped to generate a non-HLA genetic risk score (GRS) based on 93 type 1 diabetes-associated SNP variants outside the MHC region. Islet autoimmunity was assessed as T cell proliferation upon stimulation with the beta cell antigens GAD65, islet antigen-2 (IA-2), preproinsulin (PPI) and defective ribosomal product of the insulin gene (INS-DRIP). Clinical parameters were collected retrospectively.

RESULTS

Of 80 individuals, 67 had proliferation responses to one or more islet antigens, with vast differences in the extent of proliferation. Based on the multitude and amplitude of the proliferation responses, individuals were clustered into non-, intermediate and high responders. High responders could not be characterised entirely by enrichment for the highest risk HLA-DR3-DQ2/DR4-DQ8 genotype. However, high responders did have a significantly higher non-HLA GRS. Clinically, high T cell responses to beta cell antigens did not reflect in worsened glycaemic control, increased complications, development of associated autoimmunity or younger age at disease onset. The number of beta cell antigens that an individual responded to increased with disease duration, pointing to chronic islet autoimmunity and epitope spreading.

CONCLUSIONS/INTERPRETATION

Collectively, these data provide new insights into type 1 diabetes disease heterogeneity and highlight the importance of stratifying patients on the basis of their genetic and autoimmune signatures for immunotherapy and personalised disease management.

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.

Autoimmune thyroid disease and type 1 diabetes mellitus: same pathogenesis; new perspective?

Autoimmune thyroid disease (AITD) and type 1 diabetes mellitus (T1DM) are two common autoimmune diseases that can occur concomitantly. In general, patients with diabetes have a high risk of AITD. It has been proposed that a complex genetic basis together with multiple nongenetic factors make a variable contribution to the pathogenesis of T1DM and AITD. In this paper, we summarize current knowledge in the field regarding potential pathogenic factors of T1DM and AITD, including human leukocyte antigen, autoimmune regulator, lymphoid protein tyrosine phosphatase, forkhead box protein P3, cytotoxic T lymphocyte-associated antigen, infection, vitamin D deficiency, and chemokine (C-X-C motif) ligand. These findings offer an insight into future immunotherapy for autoimmune diseases.

PTPN22 Acts in a Cell Intrinsic Manner to Restrict the Proliferation and Differentiation of T Cells Following Antibody Lymphodepletion

Lymphopenic insult has been shown to precipitate the initiation of autoimmune disease in murine models such as the Non-obese diabetic mouse. Similarly, in man lymphopenia induced by mAb therapy, for instance Alemtuzumab as treatment for Multiple Sclerosis, can precipitate development of secondary autoimmune disease in up to 30 % of patients. We asked whether an identified autoimmune susceptibility locus might increase the risk of developing autoimmunity in the context of mAb-induced lymphopenia in a mouse model. A single nucleotide polymorphism (SNP) in the gene encoding the tyrosine phosphatase PTPN22 (R620W) is associated with multiple human autoimmune diseases, and PTPN22 has been shown to modulate T cell responses, particularly to weak antigens. In keeping with this, PTPN22-deficient or PTPN22 R619W mutant murine T cells adoptively transferred into immunodeficient lymphopenic hosts showed a higher lymphopenia-induced proliferation rate than WT cells. We induced lymphopenia by treating wild-type or PTPN22 knock-out mice with T cell depleting antibodies and monitored reconstitution of the T cell pool. We found that PTPN22 deficient T cells acquired a more activated effector phenotype, with significantly more IFNγ producing cells. This resulted from expansion driven by self-peptide MHC, as it was evident when the contribution of IL-7 to lymphopenic expansion was blocked with IL-7R Ab. Interestingly, Foxp3⁺ Tregs were also considerably expanded in PTPN22-deficient and PTPN22 R619W mice, as was the frequency of both CD25⁺ and CD25^- CD4 T cells that produce IL-10. Using bone marrow chimeric mice, we showed that PTPN22 influenced development of both regulatory and effector T cell functions in a cell-intrinsic manner. Overall the expansion of Tregs is likely to keep the expanded T effector populations in check and sparing Treg during therapeutic mAb depletion may be a useful strategy to prevent occurrence of secondary autoimmunity.

Phosphatase PTPN22 Regulates Dendritic Cell Homeostasis and cDC2 Dependent T Cell Responses

Dendritic cells (DCs) are specialized antigen presenting cells that instruct T cell responses through sensing environmental and inflammatory danger signals. Maintaining the homeostasis of the multiple functionally distinct conventional dendritic cells (cDC) subsets that exist in vivo is crucial for regulating immune responses, with changes in numbers sufficient to break immune tolerance. Using Ptpn22^-/- mice we demonstrate that the phosphatase PTPN22 is a highly selective, negative regulator of cDC2 homeostasis, preventing excessive population expansion from as early as 3 weeks of age. Mechanistically, PTPN22 mediates cDC2 homeostasis in a cell intrinsic manner by restricting cDC2 proliferation. A single nucleotide polymorphism, PTPN22^R620W, is one of the strongest genetic risk factors for multiple autoantibody associated human autoimmune diseases. We demonstrate that cDC2 are also expanded in mice carrying the orthologous PTPN22^619W mutation. As a consequence, cDC2 dependent CD4⁺ T cell proliferation and T follicular helper cell responses are increased. Collectively, our data demonstrate that PTPN22 controls cDC2 homeostasis, which in turn ensures appropriate cDC2-dependent T cell responses under antigenic challenge. Our findings provide a link between perturbations in DC development and susceptibility to a broad spectrum of PTPN22^R620W associated human autoimmune diseases.

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.

Differential nanoscale organisation of LFA-1 modulates T-cell migration

Effector T-cells rely on integrins to drive adhesion and migration to facilitate their immune function. The heterodimeric transmembrane integrin LFA-1 (αLβ2 integrin) regulates adhesion and migration of effector T-cells through linkage of the extracellular matrix with the intracellular actin treadmill machinery. Here, we quantified the velocity and direction of F-actin flow in migrating T-cells alongside single-molecule localisation of transmembrane and intracellular LFA-1. Results showed that actin retrograde flow positively correlated and immobile actin negatively correlated with T-cell velocity. Plasma membrane-localised LFA-1 forms unique nano-clustering patterns in the leading edge, compared to the mid-focal zone, of migrating T-cells. Deleting the cytosolic phosphatase PTPN22, loss-of-function mutations of which have been linked to autoimmune disease, increased T-cell velocity, and leading-edge co-clustering of pY397 FAK, pY416 Src family kinases and LFA-1. These data suggest that differential nanoclustering patterns of LFA-1 in migrating T-cells may instruct intracellular signalling. Our data presents a paradigm where T-cells modulate the nanoscale organisation of adhesion and signalling molecules to fine tune their migration speed, with implications for the regulation of immune and inflammatory responses.This article has an associated First Person interview with the first author of the paper.

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.

Autoimmune Polyendocrinopathy

CONTEXT

This mini-review offers an update on the rare autoimmune polyendocrinopathy (AP) syndrome with a synopsis of recent developments.

DESIGN AND RESULTS

Systematic search for studies related to pathogenesis, immunogenetics, screening, diagnosis, clinical spectrum, and epidemiology of AP. AP (orphan code ORPHA 282196) is defined as the autoimmune-induced failure of at least two glands. AP is divided into the rare juvenile type I and the adult types II to IV. The prevalence is 1:100,000 and 1:20,000 for types I and types II to IV, respectively. Whereas type I (ORPHA 3453) is a monogenetic syndrome with an autosomal recessive transmission related to mutations in the autoimmune regulator (AIRE) gene, types II to IV are genetically complex multifactorial syndromes that are strongly associated with certain alleles of HLA genes within the major histocompatibility complex located on chromosome 6, as well as the cytotoxic T lymphocyte antigen 4 and the protein tyrosine phosphatase nonreceptor type 22 genes. Addison disease is the major endocrine component of type II (ORPHA 3143), whereas the coexistence of type 1 diabetes and autoimmune thyroid disease is characteristic for type III (ORPHA 227982). Genetic screening for the AIRE gene is useful in patients with suspected type I, whereas serological screening (i.e., diabetes/adrenal antibodies) is required in patients with monoglandular autoimmunity and suspected AP. If positive, functional endocrine testing of the antibody-positive patients as well as serological screening of their first-degree relatives is recommended.

CONCLUSION

Timely diagnosis, genetic counseling, and optimal long-term management of AP is best offered in specialized centers.

PTPN22 Gene Polymorphisms Are Associated with Susceptibility to Large Artery Atherosclerotic Stroke and Microembolic Signals

Large artery atherosclerotic stroke (LAAS) is the most common ischemic stroke (IS) subtype, and microemboli may be clinically important for indicating increased risk of IS. The inflammatory process of atherosclerosis is well known, and lymphoid phosphatase (Lyp), which is encoded by the protein tyrosine phosphatase nonreceptor type 22 (PTPN22) gene, plays an important role in the inflammatory response. Our study was intended to evaluate the relationship between PTPN22 gene and LAAS and microembolic signals (MES). Three loci of the PTPN22 gene (rs2476599, rs1217414, and rs2488457) were analyzed in 364 LAAS patients and 369 control subjects. A genotyping determination was performed using the TaqMan assay. The G allele of rs2488457 might be related to a higher risk for developing LAAS and MES (odds ratio (OR) = 1.456, 95% confidence interval (CI) 1.156-1.833, P = 0.001; OR = 1.652, 95% CI 1.177-2.319, P = 0.004, respectively). In the LAAS group, the prevalence of the GTG haplotype was higher (P < 0.001) and the prevalence of the GCC haplotype was lower (P = 0.001). An interaction analysis of rs2488457 with smoking showed that smokers with the CG/GG genotypes had a higher risk of LAAS, compared to nonsmokers with the rs2488457 CC genotype (OR = 2.492, 95% CI 1.510–4.114, P < 0.001). Our research indicated that the PTPN22 rs2488457 might be related to the occurrence of LAAS and MES in the Han Chinese population. In addition, the rs2488457 polymorphism and the environmental factor of smoking jointly influenced the susceptibility of LAAS.

Non-receptor tyrosine kinase signaling in autoimmunity and therapeutic implications

Autoimmune diseases are characterized by impaired immune tolerance towards self-antigens, leading to enhanced immunity to self by dysfunctional B cells and/or T cells. The activation of these cells is controlled by non-receptor tyrosine kinases (NRTKs), which are critical mediators of antigen receptor and cytokine receptor signaling pathways. NRTKs transduce, amplify and sustain activating signals that contribute to autoimmunity, and are counter-regulated by protein tyrosine phosphatases (PTPs). The function of and interaction between NRTKs and PTPs during the development of autoimmunity could be key points of therapeutic interference against autoimmune diseases. In this review, we summarize the current state of knowledge of the functions of NRTKs and PTPs involved in B cell receptor (BCR), T cell receptor (TCR), and cytokine receptor signaling pathways that contribute to autoimmunity, and discuss their targeting for therapeutic approaches against autoimmune diseases.

The association between rs2476601 polymorphism in PTPN22 gene and risk of alopecia areata: A meta-analysis of case-control studies

BACKGROUND

The single nucleotide polymorphism (SNP) rs2476601 of the protein tyrosine phosphatase, nonreceptor type 22 (PTPN22) gene has been presented to implicate in the pathogenesis of alopecia areata (AA) in a few association investigations with limited sample size and inconsistent conclusions.

METHODS

The aim of the current meta-analysis was to assess and synthesize the presently available data on the connection between rs2476601 and AA vulnerability. Six electronic databases, including EMBASE, PubMed, Web of Science, the Cochrane Library, Wanfang data, and the China National Knowledge Infrastructure database (CNKI), were systematically retrieved for relevant observational studies published previous to November 2018. Total odds ratios (ORs) and corresponding 95% confidence intervals (95% CIs) were analyzed to evaluate the correlation between PTPN22 polymorphism and AA. Risk of bias was estimated according to the Newcastle-Ottawa Scale (NOS). Sensitivity analyses were carried out using the RevMan 5.3 software.

RESULTS

In general, 5 case-control studies including 1129 AA patients and 1702 healthy control individuals were obtained for this meta-analysis. The pooled results suggested that rs2476601 SNP was significantly associated with AA susceptibility under allelic model (C vs T, OR = 0.77, 95% CI, 0.64-0.92, P = .003) and recessive model (CC vs CT + TT, OR = 0.73, 95% CI, 0.60-0.88, P = .001).

CONCLUSION

On the basis of the results of the current research, the rs2476601 polymorphism of PTPN22 gene is significantly correlated with AA susceptibility. The C-allele and CC-genotype carriers at this locus have a lower risk of AA.