Investigation of type 1 diabetes and coeliac disease susceptibility loci for association with juvenile idiopathic arthritis

A multi-phenotype analysis reveals 19 susceptibility loci for basal cell carcinoma and 15 for squamous cell carcinoma

Basal cell carcinoma and squamous cell carcinoma are the most common skin cancers, and have genetic overlap with melanoma, pigmentation traits, autoimmune diseases, and blood biochemistry biomarkers. In this multi-trait genetic analysis of over 300,000 participants from Europe, Australia and the United States, we reveal 78 risk loci for basal cell carcinoma (19 previously unknown and replicated) and 69 for squamous cell carcinoma (15 previously unknown and replicated). The previously unknown risk loci are implicated in cancer development and progression (e.g. CDKL1), pigmentation (e.g. TPCN2), cardiometabolic (e.g. FADS2), and immune-regulatory pathways for innate immunity (e.g. IFIH1), and HIV-1 viral load modulation (e.g. CCR5). We also report an optimised polygenic risk score for effective risk stratification for keratinocyte cancer in the Canadian Longitudinal Study of Aging (794 cases and 18139 controls), which could facilitate skin cancer surveillance e.g. in high risk subpopulations such as transplantees.

Prevalence of Inflammatory Pathways Over Immuno-Tolerance in Peripheral Blood Mononuclear Cells of Recent-Onset Type 1 Diabetes

Background

Changes in innate and adaptive immunity occurring in/around pancreatic islets had been observed in peripheral blood mononuclear cells (PBMC) of Caucasian T1D patients by some, but not all researchers. The aim of our study was to investigate whether gene expression patterns of PBMC of the highly admixed Brazilian population could add knowledge about T1D pathogenic mechanisms.

Methods

We assessed global gene expression in PBMC from two groups matched for age, sex and BMI: 20 patients with recent-onset T1D (≤ 6 months from diagnosis, in a time when the autoimmune process is still highly active), testing positive for one or more islet autoantibodies and 20 islet autoantibody-negative healthy controls.

Results

We identified 474 differentially expressed genes between groups. The most expressed genes in T1D group favored host defense, inflammatory and anti-bacterial/antiviral effects (LFT, DEFA4, DEFA1, CTSG, KCNMA1) and cell cycle progression. Several of the downregulated genes in T1D target cellular repair, control of inflammation and immune tolerance. They were related to T helper 2 pathway, induction of FOXP3 expression (AREG) and immune tolerance (SMAD6). SMAD6 expression correlated negatively with islet ZnT8 antibody. The expression of PDE12, that offers resistance to viral pathogens was decreased and negatively related to ZnT8A and GADA levels. The increased expression of long non coding RNAs MALAT1 and NEAT1, related to inflammatory mediators, autoimmune diseases and innate immune response against viral infections reinforced these data.

Conclusions

Our analysis suggested the activation of cell development, anti-infectious and inflammatory pathways, indicating immune activation, whereas immune-regulatory pathways were downregulated in PBMC from recent-onset T1D patients with a differential genetic profile.

Genetic aspects of idiopathic paediatric uveitis and juvenile idiopathic arthritis associated uveitis in Chinese Han

Background

Idiopathic paediatric uveitis (IPU) and juvenile idiopathic arthritis associated uveitis (JIA-U) are the two most common entities in paediatric uveitis. This study addressed the possible association of IPU and JIA-U with genes that had been shown earlier to be associated with juvenile idiopathic arthritis.

Methods

We carried out a case-control association study involving 286 IPU, 134 JIA-U patients and 743 healthy individuals. A total of 84 candidate single nucleotide polymorphisms (SNPs) in 60 genes were selected for this study. The MassARRAY platform and iPLEX Gold Genotyping Assay was used to genotype 83 candidate SNPs and the remaining SNP (rs27293) was analysed using the TaqMan SNP Genotyping Assay.

Results

No evidence was found for an association of the candidate polymorphisms tested with IPU. Six SNPs (PRM1/rs11074967, JAZF1/rs73300638, IRF5/rs2004640, MEFV/rs224217, PSMA3/rs2348071 and PTPN2/rs7234029) showed an association with JIA-U (p<1.0×10⁻²).

Conclusion

Our findings showed associations of six SNPs (PRM1/rs11074967, JAZF1/rs73300638, IRF5/rs2004640, MEFV/rs224217, PSMA3/rs2348071 and PTPN2/rs7234029) with JIA-U. No association was detected between the 84 tested SNPs and IPU.

Endothelial Dysfunction in Children with Juvenile Psoriatic Arthritis

BACKGROUND

To evaluate the presence of endothelial dysfunction in Slovak children with juvenile psoriatic arthritis in the absence of classic cardiovascular risk factors in order to assess its relationship to the disease activity and disability.

METHODS

25 juvenile psoriatic arthritis patients (JPSA) and 25 healthy controls aged 6-19 years were enrolled into this study. In all subjects vascular measurements over a period of three years (January 2013 - January 2016) were performed, in accordance with the guidelines for ultrasonographic evaluation of FMD% (flow-mediated endothelial dependent vasodilatation) of the brachial artery. The measured items were compared to the variables reflecting the disease activity and disability.

RESULTS

Significantly lower FMD% values in patients with JPSA when compared to healthy controls {mean(SD), median, range: 5.49% (3.77), 3.55, 0.3-13.0 vs. 9.28% (1.72), 9.3, 6.4-13.1} (p < 0.001) have been documented. Strong correlations between FMD% values and disease duration (p < 0.01), non-specific inflammatory markers levels (p < 0.001) or functional disability (p < 0.01) have been observed. Significantly lower FMD% values in patients with an early disease onset (JPSA onset < 5 years of age) when compared to the rest of JPSA group {mean (SD), median, range: 4.39% (2.47), 4.45, 0.9-13.2 vs. 6.38% (1.42), 6.3, 3.2-12.1} (p < 0.01) have also been detected.

CONCLUSION

Study is the only one addressing endothelial dysfunction development in Slovak children with psoriatic arthritides. We state that endothelial dysfunction is present in these patients even during childhood and in the absence of classic cardiovascular risk factors. Its development seems to be related to an early disease onset as well as to the increased disease activity and disability. Potential genetic predictors have also been identified.

Fertility and Ovarian Reserve among Women with Rheumatoid Arthritis

OBJECTIVE

We sought to identify causes for infertility in women with and without rheumatoid arthritis (RA).

METHODS

Women with RA were matched to healthy controls. Differences in anti-Müllerian hormone (AMH) and anovulation were analyzed.

RESULTS

Women with RA had lower AMH (β -1.05, 95% CI -2.09 to -0.005), but no difference was observed when AMH was log-transformed. No difference in anovulation was observed. Infertility prevalence was similar between groups, primarily attributable to polycystic ovary syndrome in healthy controls but largely unexplained in women with RA.

CONCLUSION

AMH was lower in women with RA, but reasons for infertility among women with RA remain unknown.

Genetic Polymorphisms Associated with the Neutrophil⁻Lymphocyte Ratio and Their Clinical Implications for Metabolic Risk Factors

Background: The neutrophil–lymphocyte ratio (NLR) is a valuable prognostic or predictive biomarker in various diseases, but the genetic factors that underlie the NLR have not been studied. We attempted to investigate polymorphisms related to NLR phenotype and analyze their ability to predict metabolic risks. Methods: A genome-wide association study was performed with log-transformed NLR using an Affymetrix Axiom™ KORV1.1-96 Array. Regression models for metabolic risk status were designed using the identified significant single-nucleotide polymorphisms (SNPs). Results: We identified four SNPs near the TMEM116, NAA25, and PTPN11 genes that were associated with the NLR. The top SNP associated with the log-transformed NLR was rs76181728 in TMEM116. A case–control study was performed to analyze the metabolic risks associated with each SNP after adjusting for age, sex, and body mass index (BMI). Three SNPs displayed significant odds ratios (ORs) for increased blood pressure and increased waist circumference. In the regression model for metabolic syndrome, rs76181728 showed a significant association (OR = 1.465, 95% confidence interval (CI) = 1.091–1.969, P = 0.011) after adjustment for the NLR phenotype. Conclusions: We identified four novel SNPs that are associated with the NLR in healthy Koreans. SNPs in relevant genes might therefore serve as biomarkers for metabolic risks.

Clinical Applications of Regulatory T cells in Adoptive Cell Therapies

Interest in adoptive T-cell therapies has been ignited by the recent clinical success of genetically-modified T cells in the cancer immunotherapy space. In addition to immune targeting for malignancies, this approach is now being explored for the establishment of immune tolerance with regulatory T cells (Tregs). Herein, we will summarize the basic science and clinical results emanating from trials directed at inducing durable immune regulation through administration of Tregs. We will discuss some of the current challenges facing the field in terms of maximizing cell purity, stability and expansion capacity, while also achieving feasibility and GMP production. Indeed, recent advances in methodologies for Treg isolation, expansion, and optimal source materials represent important strides toward these considerations. Finally, we will review the emerging genetic and biomaterial-based approaches on the horizon for directing Treg specificity to augment tissue-targeting and regenerative medicine.

HLA genotyping as first-line screening tool for coeliac disease in children with juvenile idiopathic arthritis

OBJECTIVES

Coeliac disease (CD) and juvenile idiopathic arthritis (JIA) often coexist. This association warrants assessment for CD in patients with JIA. We evaluated the clinical relevance and cost-effectiveness of human leucocyte antigen (HLA) genotyping in first-line screening for development of CD in children with JIA.

PATIENTS AND INTERVENTIONS

95 patients with JIA were screened for CD using CD-specific antibodies. In case of positivity, a small intestinal biopsy was performed to confirm diagnosis. In addition, HLA genotyping was performed. 110 age-matched and sex-matched Caucasian children from the same geographical area served as controls.

RESULTS

CD was diagnosed in 4 of 95 patients with JIA (4.2%), a rate significantly higher compared with controls (p<0.02) and 14 times higher than in the general population. Twenty-six patients (27.4%) had one of the variants of the risk genotypes. All four patients diagnosed with CD had a HLA-DQ2.5 genotype: one was homozygote, the remainder heterozygote. Twenty-two patients are, judging by their HLA genotypes, at risk of developing CD and require repeated serological screening. None of the 69 patients without HLA-DQ2/DQ8 genotypes had CD-specific antibodies. Screening with HLA genotyping becomes cheaper than screening without after the second determination.

CONCLUSIONS

In our cohort of patients with JIA, lack of HLA-DQ2/DQ8 genotypes identified a majority not at risk of CD in whom repeated serological testing is unnecessary. Genotyping is nowadays the most efficient and cost-effective way to screen for CD risk in JIA.

Exceptional manifestation of polyautoimmunity in a very young girl - a case report

Polyautoimmunity is defined as the presence of more than one autoimmune disease in a single patient. The exact pathogenic mechanisms responsible for the coexistence of distinct autoimmune diseases within an individual have not been clearly explained. We report a case of a very young girl with the extremely rare co-existence of four distinct autoimmune diseases i.e. juvenile idiopathic arthritis, type 1 diabetes mellitus, coeliac disease and autoimmune hepatitis, recognized based on validated international classification criteria. The best to our knowledge there has been no case reporting coexistence of these particular four disorders in an individual. Moreover, all these diseases occurred during first three years of life, which also cause that case unique. Molecular studies of human leukocyte antigen (HLA) class II in our patient showed the presence of the HLA DRB1*01, HLA DRB1*03, HLA DQB1*02, HLA DQB1*05 molecules, which may suggest immunogenetic links between those autoimmune diseases. The presented case highlights the importance of active screening for other autoimmune diseases, if a patient with one autoimmune disease manifests with new or nonspecific symptoms.

Association of LPP and TAGAP Polymorphisms with Celiac Disease Risk: A Meta-Analysis

Background: Lipoma preferred partner (LPP) and T-cell activation Rho GTPase activating protein (TAGAP) polymorphisms might influence the susceptibility to celiac disease. Therefore, we performed a meta-analysis by identifying relevant studies to estimate the risks of these polymorphisms on celiac disease. Methods: The PubMed, Web of Science and Embase databases were searched (up to October 2016) for LPP rs1464510 and TAGAP rs1738074 polymorphisms. Results: This meta-analysis included the same 7 studies for LPP rs1464510 and TAGAP rs1738074. The minor risk A allele at both rs1464510 and rs1738074 carried risks (odds ratios) of 1.26 (95% CI: 1.22-1.30) and 1.17 (95% CI: 1.14-1.21), respectively, which contributed to increased risks in all celiac disease patients by 10.72% and 6.59%, respectively. The estimated lambdas were 0.512 and 0.496, respectively, suggesting that a co-dominant model would be suitable for both gene effects. Conclusions: This meta-analysis provides robust estimates that polymorphisms in LPP and TAGAP genes are potential risk factors for celiac disease in European and American. Prospective studies and more genome-wide association studies (GWAS) are needed to confirm these findings, and some corresponding molecular biology experiments should be carried out to clarify the pathogenic mechanisms of celiac disease.

Coexistence of endocrinopathies in children with rheumatic diseases

Background and objectives

To examine the frequency of endocrinopathies in children with systemic lupus erythematosus (SLE) and juvenile idiopathic arthritis (JIA).

Design and setting

A cross-sectional study.

Patients and methods

A study was conducted in Saudi children with SLE and JIA who were seen at King Faisal Specialist Hospital and Research Centre, Riyadh, between September 2013 and April 2015. All enrolled patients completed the clinical evaluation, which included information about family history of autoimmune disease, growth parameters and tanner stage, as well as the following assessments: vitamin D profile (parathyroid hormone and 25-OH vitamin D levels), TSH, FT4 and total T3, thyroglobulin antibodies, thyroperoxidase antibodies, random blood sugar, Hb_A1C, IGF₁, IGF_BP-3, LH, and FSH.

Results

A total of 42 patients, 22 with JIA and 20 with SLE, were included in the study. The mean participant age was 12.2 ± 5.3 years with a mean disease duration of 3.2 ± 3.4 years. Female gender was predominant (17 SLE, 13 JIA) in the patient population. Fifteen patients (35.7%) presented with a family history of autoimmune disease. The most frequently detected endocrinopathies were vitamin D insufficiency (35%) and thyroid disease (31%). Eight JIA patients and 7 SLE patients exhibited low vitamin D levels; 10 patients presented with hyperparathyroidism. Thyroid dysfunction was observed in 13 patients (8 SLE, 5 JIA), and 2 patients were found to be euthyroid (normal TSH, FT4) with positive thyroid autoantibodies. Furthermore, 7 patients presented with subclinical hypothyroidism (high TSH, normal FT4), and 4 patients presented with overt hypothyroidism (high TSH, low FT4). Seven patients (4 SLE and 3 JIA) presented with short stature due to growth hormone insufficiency (low IGF₁, IGF_BP-3). Two patients exhibited delayed puberty accompanied by low LH levels. Diabetes mellitus was more frequently observed in patients with JIA (4 patients) than in patients with SLE (1 patient).

Conclusion

Our findings demonstrated that coexistence of endocrinopathies is not uncommon in children diagnosed with JIA and SLE. Abnormal thyroid function occurs frequently and at a similar rate in children diagnosed with SLE and JIA. Thus, screening for endocrinopathies, namely thyroid disease, during the assessment of childhood SLE and JIA is worth consideration.

Genome-wide association study identifies 14 novel risk alleles associated with basal cell carcinoma

Basal cell carcinoma (BCC) is the most common cancer worldwide with an annual incidence of 2.8 million cases in the United States alone. Previous studies have demonstrated an association between 21 distinct genetic loci and BCC risk. Here, we report the results of a two-stage genome-wide association study of BCC, totalling 17,187 cases and 287,054 controls. We confirm 17 previously reported loci and identify 14 new susceptibility loci reaching genome-wide significance (P<5 × 10(-8), logistic regression). These newly associated SNPs lie within predicted keratinocyte regulatory elements and in expression quantitative trait loci; furthermore, we identify candidate genes and non-coding RNAs involved in telomere maintenance, immune regulation and tumour progression, providing deeper insight into the pathogenesis of BCC.

Contemporary management of TMJ involvement in JIA patients and its orofacial consequences

Juvenile idiopathic arthritis is the most common chronic rheumatic condition during childhood. Temporomandibular joint arthritis is frequently asymptomatic. When it takes place during childhood, it may affect condylar growth; therefore, these children are at risk of unfavorable long-term outcomes from the associated joint damage. The etiology is not completely understood, but it is considered as multifactorial with both genetic and environmental factors involved.

The standardized examination and imaging protocols serve important purpose to diagnose temporomandibular joint (TMJ) arthritis not only to establish an early interventional strategy but also to assess craniofacial growth and the progression of signs and symptoms in those patients. Although the treatment of juvenile idiopathic arthritis (JIA) has changed dramatically over the last decades due to new therapeutic options, TMJ arthritis still can develop during the course of the disease. In clinical experience, TMJs appear to respond less well to the standard of care used to treat other joints. More individualized approach to the patient’s treatment serves as the main goal of personalized medicine. It could be achieved by adopting new methods of medical imaging such as conebeam computer tomography as well as developing reliable biomarkers which may assist with predicting disease type, course, or severity and predicting response to medication.

This article provides an overview of current information on orofacial complications in JIA and its management. Based on information provided in this review, more precise diagnosis, proper tools for recognizing people at risk, and more efficient treatment approaches could be implemented. This may lead to more personalized treatment management strategies of TMJ complications of JIA patients.

Influence of Genetic Variants in EGF and Other Genes on Hematological Traits in Korean Populations by a Genome-Wide Approach

Hematological traits are important health indicators and are used as diagnostic clinical parameters for human disorders. Recently, genome-wide association studies (GWAS) identified many genetic loci associated with hematological traits in diverse ethnic groups. However, additional GWAS are necessary to elucidate the breadth of genetic variation and the underlying genetic architecture represented by hematological metrics. To identify additional genetic loci influencing hematological traits (such as hematocrit, hemoglobin concentration, white blood cell count, red blood cell count, and platelet count), we conducted GWAS and meta-analyses on data from 12,509 Korean individuals grouped into population-based cohorts. Of interest is EGF, a factor plays a role in the proliferation and differentiation of hematopoietic progenitor cells. We identified a novel EGF variant, which associated with platelet count in our study (P_combined = 2.44 × 10⁻¹⁵). Our study also replicated 16 genetic associations related to five hematological traits with genome-wide significance (P < 5 × 10⁻⁸) that were previously established in other ethnic groups. Of these, variants influencing platelet count are distributed across several genes and have pleiotropic effects in coronary artery disease and dyslipidemia. Our findings may aid in elucidating molecular mechanisms underlying not only hematopoiesis but also inflammatory and cardiovascular diseases.

12q24 locus association with type 1 diabetes: SH2B3 or ATXN2?

Genetic linkage analyses, genome-wide association studies of single nucleotide polymorphisms, copy number variation surveys, and mutation screenings found the human chromosomal 12q24 locus, with the genes SH2B3 and ATXN2 in its core, to be associated with an exceptionally wide spectrum of disease susceptibilities. Hematopoietic traits of red and white blood cells (like erythrocytosis and myeloproliferative disease), autoimmune disorders (like type 1 diabetes, coeliac disease, juvenile idiopathic arthritis, rheumatoid arthritis, thrombotic antiphospholipid syndrome, lupus erythematosus, multiple sclerosis, hypothyroidism and vitiligo), also vascular pathology (like kidney glomerular filtration rate deficits, serum urate levels, plasma beta-2-microglobulin levels, retinal microcirculation problems, diastolic and systolic blood pressure and hypertension, cardiovascular infarction), furthermore obesity, neurodegenerative conditions (like the polyglutamine-expansion disorder spinocerebellar ataxia type 2, Parkinson’s disease, the motor-neuron disease amyotrophic lateral sclerosis, and progressive supranuclear palsy), and finally longevity were reported. Now it is important to clarify, in which ways the loss or gain of function of the locally encoded proteins SH2B3/LNK and ataxin-2, respectively, contribute to these polygenic health problems. SH2B3/LNK is known to repress the JAK2/ABL1 dependent proliferation of white blood cells. Its null mutations in human and mouse are triggers of autoimmune traits and leukemia (acute lymphoblastic leukemia or chronic myeloid leukemia-like), while missense mutations were found in erythrocytosis-1 patients. Ataxin-2 is known to act on RNA-processing and trophic receptor internalization. While its polyglutamine-expansion mediated gain-of-function causes neuronal atrophy in human and mouse, its deletion leads to obesity and insulin resistance in mice. Thus, it is conceivable that the polygenic pathogenesis of type 1 diabetes is enhanced by an SH2B3-dysregulation-mediated predisposition to autoimmune diseases that conspires with an ATXN2-deficiency-mediated predisposition to lipid and glucose metabolism pathology.

The history of genetics in inflammatory bowel disease

The influence of genetics in the etiology of inflammatory bowel disease (IBD) was initially demonstrated by epidemiological data, including differences in prevalence among different ethnic groups, familial aggregation of IBD, concordance in twins, and association with genetic syndromes. These early observations paved the way to molecular genetics in IBD, and culminated in the identification of nucleotide-binding oligomerization domain containing 2 (NOD2) gene as an IBD risk gene in 2001. As in other complex diseases, the advent of Genome Wide Association studies has dramatically improved the resolution of the IBD genome and our understanding of the pathogenesis of IBD. However, the complexity of the genetic puzzle in IBD seems more pronounced today than ever previously. In total, 163 risk genes/loci have been identified, and the corresponding number of possible causal variants is challenging. The great majority of these loci are associated with both Crohn's disease and ulcerative colitis, suggesting that nearly all of the biological mechanisms involved in one disease play some role in the other. Interestingly, a large proportion of the IBD risk loci are also shared with other immune-mediated diseases, primary immunodeficiencies and mycobacterial diseases.

A genome- and phenome-wide association study to identify genetic variants influencing platelet count and volume and their pleiotropic effects

Platelets are enucleated cell fragments derived from megakaryocytes that play key roles in hemostasis and in the pathogenesis of atherothrombosis and cancer. Platelet traits are highly heritable and identification of genetic variants associated with platelet traits and assessing their pleiotropic effects may help to understand the role of underlying biological pathways. We conducted an electronic medical record (EMR)-based study to identify common variants that influence inter-individual variation in the number of circulating platelets (PLT) and mean platelet volume (MPV), by performing a genome-wide association study (GWAS). We characterized genetic variants associated with MPV and PLT using functional, pathway and disease enrichment analyses; we assessed pleiotropic effects of such variants by performing a phenome-wide association study (PheWAS) with a wide range of EMR-derived phenotypes. A total of 13,582 participants in the electronic MEdical Records and GEnomic network had data for PLT and 6,291 participants had data for MPV. We identified five chromosomal regions associated with PLT and eight associated with MPV at genome-wide significance (P < 5E-8). In addition, we replicated 20 SNPs [out of 56 SNPs (α: 0.05/56 = 9E-4)] influencing PLT and 22 SNPs [out of 29 SNPs (α: 0.05/29 = 2E-3)] influencing MPV in a published meta-analysis of GWAS of PLT and MPV. While our GWAS did not find any new associations, our functional analyses revealed that genes in these regions influence thrombopoiesis and encode kinases, membrane proteins, proteins involved in cellular trafficking, transcription factors, proteasome complex subunits, proteins of signal transduction pathways, proteins involved in megakaryocyte development, and platelet production and hemostasis. PheWAS using a single-SNP Bonferroni correction for 1,368 diagnoses (0.05/1368 = 3.6E-5) revealed that several variants in these genes have pleiotropic associations with myocardial infarction, autoimmune, and hematologic disorders. We conclude that multiple genetic loci influence interindividual variation in platelet traits and also have significant pleiotropic effects; the related genes are in multiple functional pathways including those relevant to thrombopoiesis.

Independent replication analysis of genetic loci with previous evidence of association with juvenile idiopathic arthritis

BACKGROUND

Over the last five years, there have been numerous reports of association of juvenile idiopathic arthritis with single nucleotide polymorphisms (SNPs) at various loci outside the major histocompatibility complex (MHC) region. However, the majority of these association findings have been generated using a limited number of international cohorts, and thus there is benefit in further independent replication. To address this, we examined a total of 56 SNPs in 42 non-MHC gene regions previously reported to be associated with JIA, in the ChiLdhood Arthritis Risk factor Identification sTudY (CLARITY), a new Australian collection of cases and healthy child controls.

FINDINGS

Genotyping was performed on a total of 324 JIA cases (mean age 9.7 years, 67.3% female) and 568 controls (mean age 7.8 years, 40.7% female). We demonstrated clear evidence for replication of association of JIA with SNPs in or around c12orf30, c3orf1, PTPN22, STAT4, and TRAF1-C5, confirming the involvement of these loci in disease risk. Further, we generated evidence supportive of replication of association of JIA with loci containing AFF3, CD226, MBL2, PSTPIP1, and RANTES (CCL5). These results were robust to sensitivity analyses for ethnicity.

CONCLUSION

We have provided valuable independent data as to the underlying genetic architecture of this understudied pediatric autoimmune disease, further confirming five loci outside the MHC, and supporting a role for a further five loci in determining disease risk.

Investigation of rheumatoid arthritis susceptibility loci in juvenile idiopathic arthritis confirms high degree of overlap

OBJECTIVES

Rheumatoid arthritis (RA) shares some similar clinical and pathological features with juvenile idiopathic arthritis (JIA); indeed, the strategy of investigating whether RA susceptibility loci also confer susceptibility to JIA has already proved highly successful in identifying novel JIA loci. A plethora of newly validated RA loci has been reported in the past year. Therefore, the aim of this study was to investigate these single nucleotide polymorphisms (SNP) to determine if they were also associated with JIA.

METHODS

Thirty-four SNP that showed validated association with RA and had not been investigated previously in the UK JIA cohort were genotyped in JIA cases (n=1242), healthy controls (n=4281), and data were extracted for approximately 5380 UK Caucasian controls from the Wellcome Trust Case-Control Consortium 2. Genotype and allele frequencies were compared between cases with JIA and controls using PLINK. A replication cohort of 813 JIA cases and 3058 controls from the USA was available for validation of any significant findings.

RESULTS

Thirteen SNP showed significant association (p<0.05) with JIA and for all but one the direction of association was the same as in RA. Of the eight loci that were tested, three showed significant association in the US cohort.

CONCLUSIONS

A novel JIA susceptibility locus was identified, CD247, which represents another JIA susceptibility gene whose protein product is important in T-cell activation and signalling. The authors have also confirmed association of the PTPN2 and IL2RA genes with JIA, both reaching genome-wide significance in the combined analysis.

Simultaneous Juvenile Idiopathic Arthritis and Diabetes Mellitus Type 1 — A Finnish Nationwide Study

Objective.

To describe the occurrence and main clinical and laboratory findings of patients having both juvenile idiopathic arthritis (JIA) and diabetes mellitus type 1 (DM-1) in a period of 30 years.

Methods.

Eighty-two patients having simultaneous JIA and DM-1 were identified in the reimbursement registers of the Finnish National Institute of Insurance during the period 1976–2005. Data on their clinical histories were collected from patient files.

Results.

Occurrence of simultaneous JIA and DM-1 increased 4.5-fold between the first (1976-85) and the last (1996–2005) decade. Prevalence of uveitis was 7%, of rheumatoid factor seropositivity 15%; 22% of patients had a third autoimmune disease [autoimmune disease (AID)], and 16% had serious psychiatric problems.

Conclusion.

The occurrence of patients with the 2 diseases, JIA and DM-1, increased over 3 decades. The prevalence of uveitis was low, the number of seropositive patients was high, and further cases of AID were frequent. Patients had multiple additional problems necessitating multiprofessional care.

Nonsegmental vitiligo and autoimmune mechanism

Nonsegmental vitiligo is a depigmented skin disorder showing acquired, progressive, and depigmented lesions of the skin, mucosa, and hair. It is believed to be caused mainly by the autoimmune loss of melanocytes from the involved areas. It is frequently associated with other autoimmune diseases, particularly autoimmune thyroid diseases including Hashimoto's thyroiditis and Graves' disease, rheumatoid arthritis, type 1 diabetes, psoriasis, pernicious anemia, systemic lupus erythematosus, Addison's disease, and alopecia areata. This indicates the presence of genetically determined susceptibility to not only vitiligo but also to other autoimmune disorders. Here, we summarize current understanding of autoimmune pathogenesis in non-segmental vitiligo.

The adaptor Lnk (SH2B3): an emerging regulator in vascular cells and a link between immune and inflammatory signaling

A better knowledge of the process by which inflammatory extracellular signals are relayed from the plasma membrane to specific intracellular sites is a key step to understand how inflammation develops and how it is regulated. This review focuses on Lnk (SH2B3) a member, with SH2B1 and SH2B2, of the SH2B family of adaptor proteins that influences a variety of signaling pathways mediated by Janus kinase and receptor tyrosine kinases. SH2B adaptor proteins contain conserved dimerization, pleckstrin homology, and SH2 domains. Initially described as a regulator of hematopoiesis and lymphocyte differentiation, Lnk now emerges as a key regulator in hematopoeitic and non hematopoeitic cells such as endothelial cells (EC) moderating growth factor and cytokine receptor-mediated signaling. In EC, Lnk is a negative regulator of TNF signaling that reduce proinflammatory phenotype and prevent EC from apoptosis. Lnk is a modulator in integrin signaling and actin cytoskeleton organization in both platelets and EC with an impact on cell adhesion, migration and thrombosis. In this review, we discuss some recent insights proposing Lnk as a key regulator of bone marrow-endothelial progenitor cell kinetics, including the ability to cell growth, endothelial commitment, mobilization, and recruitment for vascular regeneration. Finally, novel findings also provided evidences that mutations in Lnk gene are strongly linked to myeloproliferative disorders but also autoimmune and inflammatory syndromes where both immune and vascular cells display a role. Overall, these studies emphasize the importance of the Lnk adaptor molecule not only as prognostic marker but also as potential therapeutic target.