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Autoimmune Addison’s disease (AAD) is characterized by the autoimmune destruction of the adrenal cortex. Low prevalence and complex inheritance have long hindered successful genetic studies. We here report the first genome-wide association study on AAD, which identifies nine independent risk loci (P, Autoimmune Addison’s disease is a rare complex disease, which has not yet been characterized by non-biased genetic studies. Here, the authors perform the first GWAS for the disease, identifying nine loci including two coding variants in the gene Autoimmune Regulator (AIRE).

International audience; AIM: The aim of the present study was to replicate the association of five risk gene polymorphisms (PTPN22-rs2476601, STAT4-rs7574865, 6q23-rs6927172, IRF5-rs2004640 and TRAF1/C5-rs10818488) with RA in a specific population of the Western Algeria. MATERIAL AND METHODS: The study group comprised 110 patients with RA and 197 ethnically matched healthy control subjects. All polymorphisms were genotyped using predesigned TaqMan® assays. Allele and genotype frequencies in patients and control subjects were compared by chi-square test and odds ratios with 95% confidence intervals. Correction for multiple testing was carried out using the Bonferroni adjustment. RESULTS: Statistically significant associations with RA were detected. The strongest signal was obtained for PTPN22-rs2476601 with an allelic Pvalue 3.32 x 10(-11) (OR = 9.83, 95% CI [4.28 - 22.56]). A second significant association was obtained with STAT4-rs7574865 (allelic Pvalue = 4 x 10(-3); OR = 1.75, 95% CI [1.16 - 2.63]). The third SNP, 6q23-rs6927172, showed a significant result of association with RA, but missed our criteria for significance at allelic level after Bonferroni's correction (allelic Pvalue = 0.027; OR = 0.64, 95% CI [0.42 - 0.97]). Finally, IRF5-rs2004640 and TRAF1/C5-rs10818488 showed a significant association only at genotypic level (Pvalues: 3 x 10(-4) and 2.9 x 10(-3) respectively) but did not reach statistical significance when comparing allele frequencies (Pvalues: 0.96 and 0.21 respectively). CONCLUSIONS: From this initial study, we can conclude that PTPN22-rs2476601 and STAT4-rs7574865 polymorphisms are clearly associated with the risk of RA in the Western Algerian population.

RESUMEN Introducción. El lupus eritematoso sistémico es una enfermedad autoinmunitaria cuya gravedad varía según la raza, el sexo y la edad de aparición. Esta disparidad también se observa en los marcadores genéticos asociados con la enfermedad presentes en los genes PTPN22, VDR y TNF. La estratificación genética que presentan las diferentes poblaciones en el mundo puede influir en dicha variabilidad. Objetivo. Analizar la asociación de variantes genéticas de los genes PTPN22, VDR y TNF con nefritis lúpica en niños y su caracter de hereditarias en familias colombianas. Materiales y métodos. Se llevó a cabo un estudio basado en familias con 46 tríos (caso, padre y madre). Se hizo la genotipificación de las variantes rs2476601 de PTPN22, rs361525 y rs1800629 del TNF, y TaqI [rs731236], ApaI [rs7975232], BsmI [rs1544410] y FokI [rs2228570] del VDR, mediante reacción en cadena de la polimerasa cuantitativa (quantitative Polymerase Chain Reaction, qPCR). Se estimó el efecto de la transmisión del alelo de riesgo de padres a hijos y el desequilibrio de ligamiento de los loci VDR y TNF. Resultados. Se observó que el alelo A de rs2476601 en PTPN22 se distribuyó en 8,69 % (n=16) de los padres y en 19,5 % (n=18) de los casos, y que su transmisión de padres a hijos fue 17 veces mayor con relación al alelo G (p=0,028). Los polimorfismos de TNF y VDR no presentaron desequilibrio de transmisión. Las variantes TaqI, ApaI y BsmI del VDR presentaron desequilibrio de ligamiento. Conclusión. Estos hallazgos evidenciaron una asociación del polimorfismo rs2476601 de PTPN22 con la nefritis lúpica en niños, determinada por su transmisión en el grupo de familias estudiadas. ABSTRACT Introduction: Systemic lupus erythematosus is an autoimmune disease in which the severity varies according to race, sex and age of onset. This variation is also observed in the genetic markers associated with the disease, including PTPN22, VDR and TNF genes. The genetic stratification in different populations worldwide can influence the variability. Objective: To analyze the heritability of PTPN22, VDR and TNF genetic variants and their association with pediatric lupus nephritis in Colombian families. Materials and methods: We conducted a family-based study including 46 triads (case, father and mother). The variants rs2476601 of PTPN22; rs361525 and rs1800629 of TNF, and TaqI [rs731236], ApaI [rs7975232], BsmI [rs1544410] and FokI [rs2228570] of VDR were genotyped by qPCR. The effects of overtransmission of the risk allele from parents to children and linkage disequilibrium at the VDR and TNF loci were estimated. Results: We found that allele A of rs2476601 in PTPN22 was distributed among 8.69 % (n=16) of the parents and 19.5 % (n=18) of the cases; this allele was overtransmitted from parents to children 17 times more often than the G allele (p=0.028). TNF and VDR polymorphisms did not exhibit transmission disequilibrium. VDR TaqI, ApaI and BsmI variants exhibited linkage disequilibrium. Conclusion: These findings showed an association between the PTPN22 rs2476601 polymorphism and pediatric lupus nephritis due to its overtransmission in the group of families studied.

Aims T1D has been found associated with PTPN22 and with ACP 1 –ADA 1 joint genotype. In the present note we have collected further data to evaluate the relative importance of the two systems and to search for possible interaction of PTPN22 with ACP 1 –ADA 1 joint genotype. Methods We have studied 314 children with T1D and 770 controls from the White population of Central Italy. ACP 1 , ADA 1 and PTPN22 genotypes were determined by DNA analysis. Chi square test of independence was performed by SPSS program and three way contingency analysis by a log-linear model. Results Both carriers of *T allele of PTPN22 and subjects with ACP 1 *A/*A and *A/*B genotypes carrying ADA 1 *2 allele show an increase of susceptibility to T1D. There is evidence of additive effect ( p = 0.0002) but not of epistatic interaction. The association of T1D with ACP 1 –ADA 1 joint genotype is stronger (OR = 2.494, 95% C.I. 1.509–4.122) as compared to that with PTPN22 (OR = 1.825, 95% C.I. 1.951–2.859). Conclusions It has been suggested that the *T variant of PTPN22 inhibits T cell receptor signaling leading to failure to delete autoreactive T cells during intrathymic selection resulting in increased susceptibility to autoimmune disorders. The joint genotype ACP 1 *A/*A and *A/*B carrying the ADA 1 *2 allele shows a decreased activity of ACP 1 resulting in a lowering of Zap70 activity that may decrease T cell receptor signaling with an additive effects to the inhibition due to the *T variant of PTPN22.

A gain-of-function mutant of the lymphoid phosphatase Lyp (PTPN22) has recently been implicated in type 1 diabetes and other autoimmune diseases, suggesting that small-molecule inhibitors of Lyp could be useful for the treatment of autoimmunity. Virtual ligand screening (VLS) was applied in the search for hit compounds. Two different docking algorithms, FlexX and ICM, were used to screen a library of 'drug-like' molecules against two different 3D structures, representing the catalytic site of Lyp in both the inactive 'open' and active 'closed' conformations. The top-scoring compounds of each VLS run were tested for their inhibitory activity against recombinant Lyp. Interestingly, VLS with both active and inactive conformations yielded very potent hits, with IC(50) values in the sub- and low-micromolar range. Moreover, many of these hits showed high docking scores only with one conformation. For instance, this was the case with several 2-benzamidobenzoic acid derivatives, which specifically docked into the inactive open form. Tryptophan fluorescence measurements further support a binding mode in which these compounds seem to stabilize the phosphatase in its inactive conformation.

[Abstract] INTRODUCTION: Approximately 100 loci have been definitively associated with rheumatoid arthritis (RA) susceptibility. However, they explain only a fraction of RA heritability. Interactions between polymorphisms could explain part of the remaining heritability. Multiple interactions have been reported, but only the shared epitope (SE) × protein tyrosine phosphatase nonreceptor type 22 (PTPN22) interaction has been replicated convincingly. Two recent studies deserve attention because of their quality, including their replication in a second sample collection. In one of them, researchers identified interactions between PTPN22 and seven single-nucleotide polymorphisms (SNPs). The other showed interactions between the SE and the null genotype of glutathione S-transferase Mu 1 (GSTM1) in the anti-cyclic citrullinated peptide-positive (anti-CCP+) patients. In the present study, we aimed to replicate association with RA susceptibility of interactions described in these two high-quality studies. METHODS: A total of 1,744 patients with RA and 1,650 healthy controls of Spanish ancestry were studied. Polymorphisms were genotyped by single-base extension. SE genotypes of 736 patients were available from previous studies. Interaction analysis was done using multiple methods, including those originally reported and the most powerful methods described. RESULTS: Genotypes of one of the SNPs (rs4695888) failed quality control tests. The call rate for the other eight polymorphisms was 99.9%. The frequencies of the polymorphisms were similar in RA patients and controls, except for PTPN22 SNP. None of the interactions between PTPN22 SNPs and the six SNPs that met quality control tests was replicated as a significant interaction term--the originally reported finding--or with any of the other methods. Nor was the interaction between GSTM1 and the SE replicated as a departure from additivity in anti-CCP+ patients or with any of the other methods. CONCLUSIONS: None of the interactions tested were replicated in spite of sufficient power and assessment with different assays. These negative results indicate that whether interactions are significant contributors to RA susceptibility remains unknown and that strict standards need to be applied to claim that an interaction exists. Instituto de Salud Carlos III; 11/01048 Instituto de Salud Carlos III; 12/01909 Instituto de Salud Carlos III; RD12/0009/0008

OBJECTIVE: The PTPN22 rs2476601 polymorphism is associated with rheumatoid arthritis (RA); nonetheless, the association is weaker or absent in some southern European populations. The aim of the study was to evaluate the association between the PTPN22 rs2476601 polymorphism and RA in Italian subjects and to compare our results with those of other European countries, carrying out a meta-analysis of European data. METHODS: A total of 396 RA cases and 477 controls, all of Italic ancestry, were genotyped for PTPN22 rs2476601 polymorphism. Patients were tested for autoantibodies positivity. The meta-analysis was performed on 23 selected studies. RESULTS: The PTPN22 T1858 allele was significantly more frequent in RA patients compared to controls (5.7% vs. 3.7%, p = 0.045). No clear relationship arose with the autoantibodies tested. The 1858T allele frequency in Italian RA patients was lower than the one described in northern European populations and similar to the frequency found in Spain, Turkey, Greece, Tunisia. A clear-cut North-South gradient arose from the analysis. CONCLUSIONS: The PTPN22 T1858 allele is associated with RA in the Italian population. A North-South gradient of the allele frequency seems to exist in Europe, with a lower prevalence of the mutation in the Mediterranean area.

A missense C1858T single nucleotide polymorphism in the PTPN22 gene recently emerged as a major risk factor for human autoimmunity. PTPN22 encodes the lymphoid tyrosine phosphatase (LYP), which forms a complex with the kinase Csk and is a critical negative regulator of signaling through the T cell receptor. The C1858T single nucleotide polymorphism results in the LYP-R620W variation within the LYP-Csk interaction motif. LYP-W620 exhibits a greatly reduced interaction with Csk and is a gain-of-function inhibitor of signaling. Here we show that LYP constitutively interacts with its substrate Lck in a Csk-dependent manner. T cell receptor-induced phosphorylation of LYP by Lck on an inhibitory tyrosine residue releases tonic inhibition of signaling by LYP. The R620W variation disrupts the interaction between Lck and LYP, leading to reduced phosphorylation of LYP, which ultimately contributes to gain-of-function inhibition of T cell signaling.

One of the most severe and important complication in the treatment of patients with haemophilia A is the formation of neutralizing antibodies (FVIII inhibitors) that inhibit the clotting activity of substituted FVIII. Both genetic and environmental factors influence the susceptibility of patients to develop inhibitors. The objective of this study was to evaluate whether polymorphisms in different genes involved in the regulation of the immune system may confer susceptibility to inhibitor development in patients with HA. We analysed the distribution of polymorphisms in the CTLA4, PTPN22, IL10, TNFalpha, FOXP3 and IRF5 genes that have been reported to be associated with a number of autoimmune disease. In addition, we evaluated the distribution of IL10 haplotypes in haemophilic patients and healthy controls to assess whether specific polymorphisms in IL10 gene were associated to the risk of inhibitor development. We focused on a cohort of Italian unrelated haemophilic patients with and without a history of inhibitors. Genotyping was carried out with standard methods including RFLP, real time PCR and direct DNA sequencing. Our data show that, considering single nucleotide variations, genotype frequencies in patients with inhibitors were not significantly different from those observed in patients without inhibitors, suggesting a lack of association between these polymorphisms and the development of inhibitors. Moreover, no relationship was found between specific combinations of IL10 alleles and the antibody production. Previous contradictory association studies may depend on the different genetic background of the population examined. Further studies may contribute to a clearer understanding of this process.

PEGylated-carbon nanotubes (PNTs) were evaluated as nanocarriers of antisense oligonucleotides into T-cells using protein tyrosine phosphatase N22 (PTPN22) as a model target gene. PTPN22 is an important predisposing gene and drug target in type 1 diabetes and several other human autoimmune diseases. Here, we generated the first anti-PTPN22 20-mer antisense oligonucleotides (ASOs) and tethered them to PNTs through a cleavable disulfide bond. Spectroscopic and atomic force microscopy analyses were used to determine the loading of ASO onto PNTs, whereas the cleavable nature of the disulfide bond connecting the oligonucleotide to the nanocarrier was confirmed by incubation with dithiothreitol followed by agarose gel electrophoresis. PNT-conjugated ASOs achieved efficient (>50%) knockdown of PTPN22 expression in T-lymphocytes in culture at the mRNA and protein level, as measured by quantitative real-time PCR and Western blotting, respectively. Considering the high biocompatibility and low in vivo toxicity of PNTs, we expect that our approach will be easily translated to achieve in vivo knockdown of PTPN22 and other T lymphocyte targets, thus enabling novel ASO-mediated immunotherapies for type 1 diabetes and other autoimmune diseases.

A gain-of-function R620W polymorphism in the PTPN22 gene, encoding the lymphoid tyrosine phosphatase LYP, has recently emerged as an important risk factor for human autoimmunity. Here we report that another missense substitution (R263Q) within the catalytic domain of LYP leads to reduced phosphatase activity. High-resolution structural analysis revealed the molecular basis for this loss of function. Furthermore, the Q263 variant conferred protection against human systemic lupus erythematosus, reinforcing the proposal that inhibition of LYP activity could be beneficial in human autoimmunity.

The missense PTPN22 C1858T polymorphism recently emerged as an important population-independent risk factor for type 1 diabetes (T1D) and other autoimmune diseases. The PTPN22 gene encodes the lymphoid tyrosine phosphatase (LYP), a negative regulator of signal transduction through the T-cell receptor. Although the frequency of the polymorphism is variable among different ethnic groups, the association between PTPN22 *T1858 and T1D has been replicated in several populations. Here, we contribute the first replication of the association between PTPN22 and T1D in populations from continental Italy, carried out in two independent samples of T1D patients (N = 216 and 82) and controls (N = 271 and 89). Our data also suggest that T1D carriers of the *T1858 allele could be at increased risk for other comorbid autoimmune disorders.

International audience

PTPN22 is currently one of the few known shared-autoimmunity genes and is therefore a candidate marker for endometriosis. Our data show that female carriers of the PTPN22( *)T variant are significantly more susceptible to endometriosis than controls.

The tyrosine phosphatase PTPN22 allele 1858T has been associated with rheumatoid arthritis (RA) and other autoimmune diseases. RA is the most frequent of those multifactorial diseases. The RA association was usually restricted to serum rheumatoid factor positive disease (RF + ). No interaction was shown with HLA-DRB1 , the first RA gene. Many case-control studies replicated the RA association, showing an allele frequency increase of ≈5% on average and large variations of population allele frequencies (2.1–15.5%). In multifactorial diseases, the final proof for a new susceptibility allele is provided by departure from Mendel's law (50% transmission from heterozygous parents). For PTPN22–1858T allele, convincing linkage proof was available only for type 1 diabetes. We aimed at providing this proof for RA. We analyzed 1,395 West European Caucasian individuals from 465 “trio” families. We replicated evidence for linkage, demonstrating departure from Mendel's law in this subset of early RA onset patients. We estimated the overtransmission of the 1858T allele in RF + families: T = 63%, P < 0.0007. The 1858T allele frequency increased from 11.0% in controls to 17.4% in RF + RA for the French Caucasian population and the susceptibility genotype ( 1858T / T or T / C ) from 20.2% to 31.6% [odds ratio (OR) = 1.8 (1.2–2.8)]. In conclusion, we provided the linkage proof for the PTPN22–1858T allele and RF + RA. With diabetes and RA, PTPN22 is therefore a “linkage-proven” autoimmunity gene. PTPN22 accounting for ≈1% of the RA familial aggregation, many new genes could be expected that are as many leads to definitive therapy for autoimmune diseases.