Juvenile rheumatoid arthritis affected sibpairs: Extent of clinical phenotype concordance

38.3 Primary Immunodeficiencies: When is it not just "JIA"

Juvenile Idiopathic Arthritis (JIA) is sometimes considered a diagnosis of exclusion as the name signifies that no cause is evident for this form of arthritis. Despite this JIA has some classical clinical features and many categories are defined based on the phenotype. Since there is no diagnostic test for JIA, diseases that can mimic JIA, including Primary Immunodeficiencies (PID) can sometimes be misdiagnosed as JIA. The clues to suspecting PIDs are early age of onset, presence of family history, increased susceptibility to infections, unusual features like urticaria, interstitial lung disease, sensorineural hearing loss and poor response to conventional therapy, amongst others. This review will highlight the basics of PIDs and will discuss PIDs that can present with arthritis and hence can be confused with JIA.

Prevalence of familial autoimmune diseases in juvenile idiopathic arthritis: results from the international Pharmachild registry

BACKGROUND

Little is known about the disposition to autoimmune diseases (ADs) among children diagnosed with JIA. In this study, we provide a comprehensive overview of the prevalence of and factors associated with ADs in parents of children with juvenile idiopathic arthritis (JIA).

METHODS

Prevalence rates of ADs and 95% Poisson confidence intervals were calculated for parents of JIA patients from the international Pharmachild registry and compared with general population prevalence rates as reported in the literature. Demographic, clinical and laboratory features were compared between JIA patients with and without a family history of AD using χ² and Mann-Whitney U tests.

RESULTS

Eight thousand six hundred seventy three patients were included and the most common familial ADs were psoriasis, autoimmune thyroid disease, rheumatoid arthritis and ankylosing spondylitis. The prevalence of several ADs was higher in parents of the included JIA patients than in the general population. Clinical Juvenile Arthritis Disease Activity Scores at study entry and last follow-up were not significantly different between patients with (n = 1231) and without a family history of AD (n = 7442). Factors associated with familial AD were older age at JIA onset (P < 0.01), Scandinavian residence (P < 0.01), enthesitis-related arthritis, psoriatic arthritis and undifferentiated arthritis (P < 0.01), ANA positivity (P = 0.03) and HLA-B27 positivity (P < 0.01).

CONCLUSIONS

Familial AD proves to be a risk factor for JIA development and certain diseases should therefore not be overlooked during family health history at the diagnosis stage. A family history of AD is associated with the JIA category but does not influence the severity or disease course.

Examining Health Outcomes in Juvenile Idiopathic Arthritis: A Genetic Epidemiology Study

OBJECTIVE

Juvenile idiopathic arthritis (JIA) is the most common pediatric rheumatic disease; however, little is known about its wider health impacts. This study explores health outcomes associated with JIA genetic liability.

METHODS

We used publicly available genetic data sets to interrogate the genetic correlation between JIA and 832 other health-related traits using linkage disequilibrium score regression. Two-sample Mendelian randomization (2SMR) was used to examine four genetic correlates for evidence of causality.

RESULTS

We found robust evidence (adjusted P [P_adj ] < 0.05) of genetic correlation between JIA and rheumatoid arthritis (genetic correlation [r_g ] = 0.63, P_adj  = 0.029), hypothyroidism/myxedema (r_g  = 0.61, P_adj  = 0.041), celiac disease (CD) (r_g  = 0.58, P_adj  = 0.032), systemic lupus erythematosus (r_g  = 0.40, P_adj  = 0.032), coronary artery disease (CAD) (r_g  = 0.42, P_adj  = 0.006), number of noncancer illnesses (r_g  = 0.42, P_adj  = 0.016), paternal health (r_g  = 0.57, P_adj  = 0.032), and strenuous sports (r_g  = -0.52, P_adj  = 0.032). 2SMR analyses found robust evidence that genetic liability to JIA was causally associated with the number of noncancer illnesses reported by UK Biobank (UKBB) participants (increase of 0.03 noncancer illnesses per doubling odds of JIA, 95% confidence interval 0.01-0.05).

CONCLUSION

This study illustrates genetic sharing between JIA and a diversity of health outcomes. The causal association between genetic liability to JIA and noncancer illnesses suggests a need for broader health assessments of patients with JIA to reduce their potential comorbid burden. The strength of genetic correlation with hypothyroidism and CD implies that patients with JIA may benefit from CD and thyroid function screening. Strong positive genetic correlation between JIA and CAD supports the need for cardiovascular risk assessment and risk factor modification.

Juvenile Idiopathic Arthritis Associated Uveitis

Juvenile idiopathic arthritis (JIA) is the most common childhood rheumatic disease. The development of associated uveitis represents a significant risk for serious complications, including permanent loss of vision. Initiation of early treatment is important for controlling JIA-uveitis, but the disease can appear asymptomatically, making frequent screening procedures necessary for patients at risk. As our understanding of pathogenic drivers is currently incomplete, it is difficult to assess which JIA patients are at risk of developing uveitis. Identification of specific risk factors for JIA-associated uveitis is an important field of research, and in this review, we highlight the genomic, transcriptomic, and proteomic factors identified as potential uveitis risk factors in JIA, and discuss therapeutic strategies.

Biological classification of childhood arthritis: roadmap to a molecular nomenclature

Chronic inflammatory arthritis in childhood is heterogeneous in presentation and course. Most forms exhibit clinical and genetic similarity to arthritis of adult onset, although at least one phenotype might be restricted to children. Nevertheless, paediatric and adult rheumatologists have historically addressed disease classification separately, yielding a juvenile idiopathic arthritis (JIA) nomenclature that exhibits no terminological overlap with adult-onset arthritis. Accumulating clinical, genetic and mechanistic data reveal the critical limitations of this strategy, necessitating a new approach to defining biological categories within JIA. In this Review, we provide an overview of the current evidence for biological subgroups of arthritis in children, delineate forms that seem contiguous with adult-onset arthritis, and consider integrative genetic and bioinformatic strategies to identify discrete entities within inflammatory arthritis across all ages.

New or vanishing frontiers: LACC1-associated juvenile arthritis

BACKGROUND

The classification and pathogenic basis of juvenile idiopathic arthritis (JIA) are a subject of some controversy. Essentially, JIA is an exclusion diagnosis that represents a phenotypically heterogeneous group of arthritis of unknown origin. Familial aggregation of JIA supports the concept of genetic influence in the pathogenesis of JIA.

OBJECTIVE

To present the spectrum of laccase domain-containing 1 (LACC1)-associated juvenile arthritis with clinical, biochemical, and molecular genetic data of a cohort of 43 patients, including 11 previously unpublished cases.

METHODS

We studied 11 patients with different categories of juvenile idiopathic arthritis from 5 consanguineous families, all from Saudi Arabia, except 2 patients who were of Jordanian ethnicity. Whole-exome sequencing was used to identify the disease-causing variant of LACC1. We also reviewed the clinical spectrum and molecular genetic data of previously published cases of LACC1-associated juvenile arthritis.

RESULTS

This study describes 43 (29 females, 14 males) patients from consanguineous multiplex families. Most of the included patients were of Arab origin with 86% having early onset disease. The most frequent categories were systemic (19 patients) and rheumatoid factor-negative polyarticular (19 patients). Thirty-seven (86%) had progressive erosive arthritis and 10 (23.3%) had persistent limb lymphedema. None of the patients had features of macrophage activation syndrome. Genetic analysis confirmed LACC1 variant in all patients; 22 patients had common founder mutation (LACC1: c.850T > C,p.C284R), while the others showed different LACC1 variants. All patients were treated aggressively with methotrexate and sequential biologic agents. Most of them showed a poor response to treatment.

CONCLUSION

This report expands the pathogenic variants of LACC1 and the clinical spectrum associated with this genetic subset of juvenile arthritis. The predominance of autosomal-recessive inheritance and strong genetic evidence allowed us to propose LACC1-associated juvenile arthritis as a distinct disorder.

Comorbidity of Type 1 Diabetes Mellitus in Patients with Juvenile Idiopathic Arthritis

OBJECTIVES

To determine the prevalence of type 1 diabetes mellitus (T1D) in patients with juvenile idiopathic arthritis (JIA) and to characterize patients having both.

STUDY DESIGN

Diabetes comorbidity was recorded in the National Pediatric Rheumatologic Database since 2012. Data from the North Rhine-Westphalian diabetes registry served as the reference population for the prevalence of diabetes in the general population. The National Pediatric Rheumatologic Database data were indirectly standardized for age and sex for comparison with the general population. The diabetes prevalence ratio was calculated using the Poisson regression model.

RESULTS

The analysis included 12 269 patients with JIA. A total of 58 patients had comorbid T1D, and the diabetes prevalence was 0.5%. The mean age was 11.6 years at the time of documentation, and the mean disease duration was 4.2 years. Compared with the general population, the prevalence of diabetes in patients with JIA was significantly increased (prevalence ratio 1.76 [95% CI 1.34; 2.28], P < .001). The onset of diabetes in patients with JIA was earlier than that reported in the reference data. Sixty-three percent of patients developed T1D before JIA. On average, diabetes onset was 56 months before the onset of JIA. Patients who first developed JIA developed T1D on average 40 months later. The majority of patients had not received disease-modifying antirheumatic drugs before diabetes onset.

CONCLUSIONS

T1D occurs more frequently in patients with JIA than in the general population. The likelihood of T1D occurrence appears to be slightly higher before JIA manifestation and without disease-modifying antirheumatic drug therapy after JIA onset.

A scoping review on the study of siblings in pediatric pain

Background: Sibling relationships are longstanding across an individual’s life and are influential in children’s development. The study of siblings in pediatric pain is, although in early stages, a growing field.

Aims: This scoping review sought to summarize and map the type of research available examining siblings and pediatric pain to identify gaps and directions for future research.

Methods: Studies were identified based on a search of PubMed, CINAHL, PsycInfo, Embase, and Web of Science (up to November 2016). We extracted data about study methods, the sample, outcome assessment, and the influence/relationships investigated.

Results: Thirty-five studies were included. Most studies used quantitative methods (n = 28), and participants typically included children (i.e., aged 6–12; n = 24) and adolescents (i.e., aged 13–18; n = 18). The majority of studies examined siblings in the context of chronic and disease-related pain (n = 30). Though quantitative studies primarily focused on the genetic influence of pain conditions (n = 18), qualitative and mixed-methods studies typically focused on exploring the impact of siblings with and without pain on one another (n = 2) and the impact of pain on the broader dyadic relationship/functioning (n = 4).

Conclusions: Sibling research in pediatric pain has been primarily focused on the biological/physical components of pain, using quantitative approaches. Conducting more studies using qualitative or mixed-methods designs, incorporating multiple assessment measures (e.g., observational, self-report) and multiple perspectives (e.g., siblings, health professionals), may provide an opportunity to gain richer and more comprehensive information regarding the experience of siblings.

The autoimmune burden in juvenile idiopathic arthritis

Background

Juvenile idiopathic arthritis (JIA) is a chronic inflammatory arthritis of unknown origin which can be considered an autoimmune disease (AD). The aim of this study is to analyse the presence of two or more autoimmune diseases (polyautoimmunity) in patients suffering from JIA and to evaluate the occurrence of ADs in their families.

Methods

Seventy-nine patients diagnosed with JIA aged 0–21 years, admitted to the Paediatric Rheumatology Unit, Sant’Orsola-Malpighi Hospital, Bologna were screened for ADs. Parents were asked about the presence of ADs in the living relatives of first and second degree.

Results

Twelve of 79 patients (15.2%) had at least 1 AD associated with JIA. Eight patients (10.1%) suffered from autoimmune thyroid disease (AITD), three patients had celiac disease, three patients suffered from psoriasis, one from alopecia and 1 from insulin-dependent diabetes mellitus. The average age at diagnosis was 13.2 years and the cumulative incidence of AITD was 36%. Seventy-six families were studied for a total of 438 relatives. The prevalence of ADs was 13%, greater in first-degree relatives (16.7%) than in second-degree ones (11.1%). The most common AD was AITD; there was no difference in JIA’s age of presentation between patients with positive and negative familiarity with ADs (p > 0.05).

Conclusion

Children and adolescents with JIA present a high autoimmunity burden, most commonly represented by AITD. Familial autoimmunity is not negligible in patients suffering from JIA (almost 50% of patients have at least one relative with an AD) and it should always be carefully examined.

Lack of Association between STAT4 Single Nucleotide Polymorphisms and Iranian Juvenile Rheumatoid Arthritis Patients

Juvenile rheumatoid arthritis (JRA) is a common chronic systemic autoimmune disease in children. Single nucleotide polymorphisms (SNPs) of signal transducer and activator of transcription 4 (STAT4) gene are suspected to have association with the risk of autoimmune diseases. Previous investigations have indicated that the STAT4 rs7574865 T allele was significantly associated with rheumatoid arthritis. In this study, we aimed to evaluate the association of STAT4 SNPs with JRA in Iranian population. T allele of STAT4 rs7574865 SNP was less frequent in patients than in controls, and the difference was not significant (p = 0.19, OR = 0.72, 95% CI: 0.44 -1.17). In addition, G allele of this SNP was frequent but not significant in JRA patients (p = 0.19, OR = 1.38, 95% CI: 0.85-2.25). Neither alleles nor genotypes of rs7601754 SNP of STAT4 gene demonstrated associations with JRA. We recognize that gene variants of STAT4 did not affect JRA susceptibility in Iranian population.

Anti-cyclic citrullinated peptide antibodies in children with Juvenile Idiopathic Arthritis

AIM

The purpose of present study was to access the prevalence of anti-cyclic citrullinated peptide (anti-CCP) antibodies in children with Juvenile Idiopathic Arthritis (JIA), and to investigate the clinical significance and diagnostic value of the anti-CCP antibodies in correlation with age, sex & activity.

METHODS

This case-control study was performed on 50 patients with JIA in addition to 40 sex and age-matched children as a control group. The participants were recruited from rheumatology Outpatient Clinic of Cairo University Specialized Pediatric Hospital. Patients were subjected to full history taking, clinical examination, routine laboratory investigations and x-rays on involved joints. Both patients and controls underwent assay of anti-CCP antibodies by AxSYM Anti-CCP IgG Microparticle Enzyme Immunoassay (MEIA) which is a semi-quantitative determination of the IgG class of autoantibodies specific to cyclic citrullinated peptide (CCP) in patients' serum or plasma. Data were analyzed using Mann-Whitney U test, ANOVA, and independent-samples t-test by SPSS version 15.

RESULTS

Anti-CCP positivity was identified amongst patients with JIA, particularly those JIA patients experiencing RF positive polyarticular disease onset. Above all, it is important that anti-CCP positivity and bone erosions, degree of joint damage, and ESR levels were significantly correlated.

CONCLUSION

Anti-CCP could be utilized as a valuable marker in the polyarticular form of JIA to direct early, and could be aggressive therapeutic intervention.

Immunogenetics of juvenile idiopathic arthritis: A comprehensive review

Juvenile idiopathic arthritis (JIA) is the most common chronic inflammatory arthropathy of childhood. Juvenile idiopathic arthritis is believed to be a complex genetic trait influenced by both genetic and environmental factors. Twin and family studies suggest a substantial role for genetic factors in the predisposition to JIA. Describing the genetics is complicated by the heterogeneity of JIA; the International League of Associations for Rheumatology (ILAR) has defined seven categories of JIA based on distinct clinical and laboratory features. Utilizing a variety of techniques including candidate gene studies, the use of genotyping arrays such as Immunochip, and genome wide association studies (GWAS), both human leukocyte antigen (HLA) and non-HLA susceptibility loci associated with JIA have been described. Several of these polymorphisms (e.g. HLA class II, PTPN22, STAT4) are shared with other common autoimmune conditions; other novel polymorphisms that have been identified may be unique to JIA. Associations with oligoarticular and RF-negative polyarticular JIA are the best characterized. A strong association between HLA DRB1:11:03/04 and DRB1:08:01, and a protective effect of DRB1:15:01 have been described. HLA DPB1:02:01 has also been associated with oligoarticular and RF-negative polyarticular JIA. Besides PTPN22, STAT4 and PTPN2 variants, IL2, IL2RA, IL2RB, as well as IL6 and IL6R loci also harbor variants associated with oligoarticular and RF-negative polyarticular JIA. RF-positive polyarticular JIA is associated with many of the shared epitope encoding HLA DRB1 alleles, as well as PTPN22, STAT4 and TNFAIP3 variants. ERA is associated with HLA B27. Most other associations between JIA categories and HLA or non-HLA variants need confirmation. The formation of International Consortia to ascertain and analyze large cohorts of JIA categories, validation of reported findings in independent cohorts, and functional studies will enhance our understanding of the genetic underpinnings of JIA.

Quantification of the familial contribution to juvenile idiopathic arthritis

OBJECTIVE

We previously demonstrated that there is familial aggregation of juvenile idiopathic arthritis (JIA). Using a large JIA cohort, we sought to identify additional clusters of JIA cases and to calculate robust estimates of the relative risk (RR) of JIA in the siblings and cousins of JIA probands. We also estimated the population attributable risk (PAR) of familial factors in JIA.

METHODS

A probabilistic record-linking analysis was performed by matching the records of 862 patients with JIA with the records of approximately 7 million individuals in the Utah Population Database (UPDB), a computerized genealogic database. For each patient, 5 control subjects matched for birth year and sex were selected from the UPDB. Specialized software was used to test for familial aggregation of disease, to estimate the magnitude of familial risks, and to identify families at high risk of disease.

RESULTS

We identified 22 founders who had significantly more descendants with JIA than expected (5-13 descendants; P values ranged from <0.0001 to <0.008). The PAR of familial factors for JIA was approximately 13%. The RR of JIA in the siblings of patients was significantly increased (11.6, 95% confidence interval [95% CI] 4.9-27.5, P < 2.59 x 10(-8)). The RR of JIA in first cousins was also increased (5.82, 95% CI 2.5-13.8, P < 6.07 x 10(-5)).

CONCLUSION

We have identified the largest sets of JIA pedigrees described to date. Approximately 13% of cases of JIA can be attributed to familial factors. Siblings and first cousins of probands with JIA have an increased risk of JIA. The observed decline in the magnitude of risk between siblings and cousins suggests that JIA is influenced by shared genetic factors.

The clinical relevance of genetic susceptibility to osteoarthritis

Osteoarthritis is a major musculoskeletal cause of disability in the elderly, but current therapeutic approaches are insufficient to prevent initiation and progression of the disease. Genetic studies in humans have identified molecules involved in signalling cascades that are important for the pathology of the joint components. These include the bone morphogenetic protein (BMP) signalling, the wingless-type signalling and the thyroid pathway as well as apoptotic-related molecules. There is emerging evidence indicating that inflammatory molecules related to cytokine production, prostaglandin and arachidonic acid metabolism are also involved in susceptibility to osteoarthritis. All of these pathways are likely targets for pharmacological intervention. Genetic variation also affects pain due to osteoarthritis highlighting molecular mechanisms for pain relief. Moreover, combinations of genetic markers can be used to identify individuals at high risk of osteoarthritis and risk of total joint arthroplasty failure, which should facilitate the application of preventive and disease management strategies.

Susceptibility to JRA/JIA: complementing general autoimmune and arthritis traits

Juvenile rheumatoid arthritis (JRA), also known as juvenile idiopathic arthritis (JIA), includes the most common chronic autoimmune arthropathies of childhood. These two nomenclatures for classification include components representing the major subclasses of disease. The chromosomal regions and the genes involved in these complex genetic traits are being elucidated, with findings often specific for a particular disease subtype. With the advent of new SNP technologies, progress is being made at an ever-increasing pace. This review discusses the difficulties of deciphering the genetic components in complex disorders, while demonstrating the similarities that JRA shares with other autoimmune disorders. Particular emphasis has been placed on positive findings either for candidate genes that have been replicated independently in JRA/JIA, or findings in JRA for which consistent results have been reported in other forms of autoimmunity.

The contribution of genes to osteoarthritis

Osteoarthritis (OA) is the most prevalent form of arthritis in the elderly. A large body of evidence, including familial aggregation and classic twin studies, indicates that primary OA has a strong hereditary component that is likely polygenic in nature. Traits related to OA, such as longitudinal changes in cartilage volume and progression of radiographic features, are also under genetic control. In recent years several linkage analyses and candidate gene studies have been performed and unveiled some of the specific genes involved in disease risk, such as FRZB and GDF5. This article discusses the impact that future genome-wide association scans can have on our understanding of the pathogenesis of OA and on identifying individuals at high risk for developing severe OA.

The contribution of genes to osteoarthritis

Osteoarthritis (OA) is the most prevalent form of arthritis in the elderly. A large body of evidence, including familial aggregation and classic twin studies, indicates that primary OA has a strong hereditary component that is likely polygenic in nature. Furthermore, traits related to OA, such as longitudinal changes in cartilage volume and progression of radiographic features, are also under genetic control. In recent years, several linkage analysis and candidate gene studies have been performed and have unveiled some of the specific genes involved in disease risk, such as FRZB and GDF5. The authors discuss the impact that future genome-wide association scans can have on our understanding of the pathogenesis of OA and on identifying individuals at high risk for developing severe OA.

A comprehensive review of the genetics of juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is the most common chronic arthropathy of childhood which is believed to be influenced by both genetic and environmental factors. The progress in identifying genes underlying JIA susceptibility using candidate gene association studies has been slow. Several associations between JIA and variants in the genes encoding the human leukocyte antigens (HLA) have been confirmed and replicated in independent cohorts. However it is clear that genetic variants outside the HLA also influence susceptibility to JIA. While a large number of non-HLA candidate genes have been tested for associations, only a handful of reported associations such as PTPN22 have been validated. In this review we discuss the principles behind genetic studies of complex traits like JIA, and comprehensively catalogue non-HLA candidate-gene association studies performed in JIA to date and review several validated associations. Most candidate gene studies are underpowered and do not detect associations, and those that do are often not replicated. We also discuss the principles behind genome-wide association studies and discuss possible implications for identifying genes underlying JIA. Finally we discuss several genetic variants underlying multiple clinically distinct autoimmune phenotypes.

Systemic juvenile idiopathic arthritis: diagnosis, management, and outcome

Systemic juvenile idiopathic arthritis is a heterogeneous form of arthritis in childhood and represents 10-20% of all juvenile idiopathic arthritides in the Caucasian populations of Northern America and Europe. Up to 30% of patients will still have active disease after 10 years, and morbidity within this group is high. Secondary complications (e.g. growth failure, osteoporosis, deformities, and loss of function) and amyloidosis are the medical sequelae, but there are also serious developmental and social consequences. The medical treatment of patients who are at the more severe end of the disease spectrum is unsatisfactory; however, new therapies that might improve prognosis, such as autologous stem-cell transplantation and approaches for blocking interleukin-6 signaling, are currently being assessed in clinical trials.

Genomic progress in pediatric arthritis: recent work and future goals

PURPOSE OF REVIEW

Pediatric arthritis is a heterogeneous group of chronic arthropathies that are influenced by complex genetic and perhaps environmental factors. Interacting genetic traits may one day be identified that provide the basis for predicting disease risk and other characteristics such as course, age of onset, and disease severity. The purpose of this review is to describe the recent progress towards identifying the multiple genes related to pediatric arthritis and understand how they relate to each other and to disease pathology.

RECENT FINDINGS

Candidate gene studies are by far the most widely reported type of genetic studies to date for juvenile arthritis with only one genome-wide screen for juvenile rheumatoid/idiopathic arthritis published. Particular attention is paid to studies of candidate genes with potential immunological roles and those associated with other forms of autoimmunity.

SUMMARY

Genomic studies may perhaps one day provide information to allow future classification systems of childhood arthritis to include molecular biomarkers as a complement to clinical observations, as well as understand how these genes or proteins relate to each other and to disease pathogenesis.

Juvenile idiopathic arthritis

One of the most enigmatic problems in rheumatology has been juvenile idiopathic arthritis (JIA). Firstly, the classification has often depended on clinical features that have variations between patients. Secondly, there are different classification schemes in usage and there are few objective serologic tests that help to resolve the differences between the criteria sets. Thirdly, only recently have significant advances been made in understanding the immunology and immunopathology of JIA and, in particular, new treatment options. In this review, we will define the historical basis of JIA and emphasize not only the clinical features, but also the immunological characteristics, the pathogenesis, and treatment options. We will also discuss, in particular, quality of life, psychosocial functioning, socioeconomic outcomes and the difficult area of mortality. Finally, this review will attempt to bridge genetic observations with clinical presentation. JIA represents a relatively common syndrome of pediatric onset rheumatologic disease and a better understanding of the clinical definition, the relationship to autoimmunity, and novel treatments with biologic agents are critical for improved patient care.

The CTLA4+49A/G and CT60 polymorphisms and chronic inflammatory arthropathies in Northern Ireland

Rheumatoid and juvenile idiopathic arthritis (RA, JIA) are chronic inflammatory arthropathies with an autoimmune background. The cytotoxic T-lymphocyte antigen-4 (CTLA-4) protein plays a key role in the down-regulation of T cell activation. We analyzed the CTLA4 +49A/G and CT60 polymorphisms in cohorts of Northern Irish RA and JIA patients and healthy control subjects using restriction fragment length polymorphism methods. The +49 A allele was increased in RA (61.2%; P=0.02; OR=1.28; 95% C.I.=1.04-1.58) and JIA (61.8%; P=0.14) patients compared to the control population (55.3%). No significant association was observed for the CT60 polymorphism. Haplotype analysis revealed a significantly different distribution of +49 A/G-CT60 haplotypes in RA and JIA patients compared to controls (P value<0.00001 and 0.030 for comparison of RA and JIA patients with controls, respectively). Our results suggest that the CTLA-4 gene is involved in predisposition to inflammatory arthropathies in the Northern Irish population.

Pediatric clinical research

PURPOSE OF REVIEW

This review will focus on childhood-onset systemic lupus erythematosus, juvenile idiopathic arthritis, and juvenile dermatomyositis, with special interest on strategies to improve the health-related quality of life in these conditions.

RECENT FINDINGS

The contribution of plasma insulin levels, lipoproteins, markers of oxidized state (including nitric oxide metabolites, isoprostanes) and autoantibodies to oxidized low-density lipoprotein to risk for atherosclerosis has been studied in childhood-onset systemic lupus erythematosus. Elevated serum levels of myeloid-related protein-8 (also called S100A8) and myeloid-related protein-14 (S100A9) in children with juvenile idiopathic arthritis can indicate clinically occult disease activity. Serum levels of S100A12 correlate with disease activity in juvenile idiopathic arthritis. Magnetic resonance imaging T2 relaxation times in weight-bearing cartilage in patients with juvenile idiopathic arthritis may help with early detection of cartilage changes. Quantitative computed tomography commonly shows decreased muscle mass and abnormal bone geometry in juvenile idiopathic arthritis patients. In patients with juvenile idiopathic arthritis who do not respond to oral methotrexate, subcutaneous methotrexate dosing was frequently successful. Duration of inactive disease while a patient is receiving methotrexate does not decrease the frequency of flaring of disease once methotrexate is discontinued. Residual synovial inflammation seems to be a stronger influence on the rate of relapse. In juvenile dermatomyositis, the quantitative magnetic resonance imaging T2 relaxation time and overexpression of Class I major histocompatibility complex in early juvenile dermatomyositis are reported. Intravenous cyclophosphamide in refractory juvenile dermatomyositis and tacrolimus ointment for the dermatologic manifestations of juvenile dermatomyositis seem promising.

SUMMARY

Progress has been made in the diagnosis and treatment of childhood-onset systemic lupus erythematosus, juvenile idiopathic arthritis, and juvenile dermatomyositis.

Familial aggregation of juvenile idiopathic arthritis

OBJECTIVE

To estimate the degree of familial aggregation of juvenile idiopathic arthritis (JIA), determine whether the aggregation of JIA and the aggregation of type 1 diabetes mellitus (type 1 DM) overlap, and identify multiplex JIA pedigrees.

METHODS

Records of individuals with JIA or type 1 DM were probabilistically linked with records in the Utah Population Database (UPDB), a large computerized family history database. For each case of JIA or type 1 DM, 10 matched controls or 5 matched controls, respectively, were selected. All familial relationships among cases of JIA or type 1 DM were established. A familial risk score was calculated for each subject. For various levels of familial exposure to JIA or type 1 DM, one's risk (odds ratio [OR]) of developing JIA or type 1 DM was established (cases compared with controls). Recurrence risks for JIA were computed for relatives of JIA cases compared with relatives of controls. Extended JIA families were identified from a list of common ancestors.

RESULTS

Records of a total of 443 patients were linked with the UPDB. Of these, 381 (86.0%) met criteria for JIA. An increased risk for JIA was observed among relatives of probands with JIA. The prevalence of type 1 DM among JIA cases was higher than the US prevalence of type 1 DM (P < 0.003). The recurrence risk for JIA was significantly elevated among first-degree relatives of cases with JIA (OR 30.4). The overall prevalence of JIA was 28/100,000. Four extended JIA pedigrees were identified.

CONCLUSION

There is familial aggregation of JIA in the Intermountain West region of the US. We have demonstrated that multiplex JIA pedigrees can be identified using a genealogic database.

Antibodies against cyclic citrullinated peptide are associated with HLA-DR4 in simplex and multiplex polyarticular-onset juvenile rheumatoid arthritis

OBJECTIVE

Anti-cyclic citrullinated peptide (anti-CCP) antibodies have been detected in patients with juvenile rheumatoid arthritis (JRA), particularly in those with polyarticular, rheumatoid factor (RF)-positive JRA. Our objectives were to determine whether anti-CCP antibodies are associated with HLA-DR4 in children with polyarticular JRA, whether anti-CCP antibodies are associated with clinical features of disease, and whether affected sibling pairs (ASPs) with JRA are concordant for this antibody.

METHODS

Stored serum samples obtained from 230 HLA-typed patients with JRA (77 with polyarticular-onset disease and 153 with pauciarticular- or systemic-onset disease), 100 JRA ASPs, and 688 healthy children were tested for anti-CCP antibodies and RF.

RESULTS

Thirteen percent of the patients with polyarticular-onset JRA and 2% of the other JRA patients exhibited anti-CCP antibodies, compared with only 0.6% of the controls. Fifty-seven percent of RF-positive patients with polyarticular-onset JRA had anti-CCP antibodies. HLA-DR4-positive patients with polyarticular-onset JRA were more likely to have anti-CCP antibodies than were those without HLA-DR4 alleles (odds ratio [OR] 5.20, 95% confidence interval [95% CI] 1.30-20.9). Anti-CCP antibodies were associated with polyarticular onset (OR 7.46, 95% CI 1.99-28.0), a polyarticular disease course (OR 9.78, 95% CI 1.25-76.7), and erosive disease (OR 14.3, 95% CI 3.01-67.9). Concordance rates for anti-CCP antibodies among ASPs were statistically significant.

CONCLUSION

These data demonstrate increased anti-CCP antibody formation in HLA-DR4-positive patients with polyarticular-onset JRA. The overall prevalence of anti-CCP antibodies in JRA is low, but a substantial proportion of RF-positive patients with polyarticular-onset JRA have these antibodies. Anti-CCP antibodies in JRA are associated with polyarticular onset, a polyarticular course, and erosive disease.

A genome-wide scan for juvenile rheumatoid arthritis in affected sibpair families provides evidence of linkage

OBJECTIVE

Juvenile rheumatoid arthritis (JRA) represents a heterogeneous group of disorders with a complex genetic component. A genome scan was performed to detect linkage to JRA in 121 families containing 247 affected children in North America (the JRA Affected Sibpair [ASP] Registry).

METHODS

Genotype data collected for HLA-DR and 386 microsatellite markers were subjected to multipoint nonparametric linkage analysis. Following analysis of the entire set of families, additional analyses were performed after a priori stratification by disease onset type, age at onset, disease course, and selected HLA-DRB1 alleles.

RESULTS

Linkage of JRA to the HLA region was confirmed (logarithm of odds [LOD] score 2.26). Additional evidence supporting linkage of JRA was observed at 1p36 (D1S214; LOD 1.65), 19p13 (D19S216; LOD 1.72), and 20q13 (D20S100; LOD 1.75). For early-onset polyarticular disease, evidence of linkage was found at chromosome 7q11 (D7S502; LOD 3.47). For pauciarticular disease, evidence supporting linkage was observed on chromosome 19p13 (D19S216; LOD 2.98), the same marker that supported linkage to the "JRA" phenotype. Other regions supporting linkage with JRA disease subtype included 20q13, 4q24, 12q24, and Xp11. Stratification of families based on the presence of the HLA-DR8 allele in affected siblings resulted in significant linkage observed at 2p25 (D2S162/D2S305; LOD 6.0).

CONCLUSION

These data support the hypothesis that multiple genes, including at least 1 in the HLA region, influence susceptibility to JRA. These findings for JRA are consistent with findings for other autoimmune diseases and support the notion that common genetic regions contribute to an autoimmune phenotype.