Nationwide collaborative study of HLA class II associations with distinct types of juvenile chronic arthritis (JCA) in Greece

Controversies in juvenile idiopathic arthritis-associated uveitis

Abstract Juvenile idiopathic arthritis-associated uveitis (JIAU) accounts for a sizable proportion of uveitis cases in children and is an important cause of ocular morbidity in uveitis patients in this age group. The authors present the results of a survey conducted to obtain a better understanding of the current views and practices of ophthalmologists involved in the care of children with JIAU. A detailed questionnaire consisting of 54 questions addressing epidemiology, diagnosis, and therapy of JIAU was distributed to 67 uveitis specialists. The responses from 37 completed questionnaires were tabulated for this report. While the experts often agreed on aspects of the epidemiologic and clinical features of JIAU and its complications, considerable diversity of responses was noted-particularly with regard to practice patterns. Regarding diagnostics and disease monitoring, all experts favored ANA testing, whereas two-thirds also suggested HLA-B27 typing. Laser flare photometry was available to and routinely used by almost one-third of the experts. Optical coherence tomography (OCT) was used by more than half. The survey revealed an overall consensus on therapeutic strategies, including the use of both conventional immunosuppressive and biologic agents. Methotrexate was the initial choice for immunosuppression by most respondents. Most would add an anti-TNF-alpha agent following failure of traditional immunosuppressive therapy, and adalimumab was favored by almost half of the experts. Questions addressing the management of individual situations, such as the treatment of macular edema and perioperative management, revealed considerable differences in therapeutic approaches. The results of this survey support the development of international guidelines for the management of JIAU.

Balancing selection and heterogeneity across the classical human leukocyte antigen loci: a meta-analytic review of 497 population studies

This paper presents a meta-analysis of high-resolution human leukocyte antigen (HLA) allele frequency data describing 497 population samples. Most of the datasets were compiled from studies published in eight journals from 1990 to 2007; additional datasets came from the International Histocompatibility Workshops and from the AlleleFrequencies.net database. In all, these data represent approximately 66,800 individuals from throughout the world, providing an opportunity to observe trends that may not have been evident at the time the data were originally analyzed, especially with regard to the relative importance of balancing selection among the HLA loci. Population genetic measures of allele frequency distributions were summarized across populations by locus and geographic region. A role for balancing selection maintaining much of HLA variation was confirmed. Further, the breadth of this meta-analysis allowed the ranking of the HLA loci, with DQA1 and HLA-C showing the strongest balancing selection and DPB1 being compatible with neutrality. Comparisons of the allelic spectra reported by studies since 1990 indicate that most of the HLA alleles identified since 2000 are very-low-frequency alleles. The literature-based allele-count data, as well as maps summarizing the geographic distributions for each allele, are available online.

Immunogenetics of ocular inflammatory disease

Ocular inflammatory disease comprises of a diverse group of clinical entities that may result from autoimmune processes, infections, or both. While many individual ocular inflammatory diseases are quite rare, ocular inflammation is one of the more common causes of visual disability, including blindness, in the developed world. Better understanding of ocular inflammatory disease is an important step in designing more sophisticated therapies that may help prevent loss of visual function for these patients.

Lack of association between mannose-binding lectin gene polymorphisms and juvenile idiopathic arthritis in a Han population from the Hubei province of China

Many studies have reported that polymorphisms of the mannose-binding lectin (MBL) gene are associated with autoimmune disease. Here, we investigate the relationship between MBL gene polymorphisms and susceptibility to juvenile idiopathic arthritis (JIA) in a Han-nationality population from the Hubei province of China. PCR-restriction fragment length polymorphism was used to investigate polymorphisms of codons 54 and 57 in exon 1 of the MBL gene in 93 patients with JIA and 48 control children. Neither group showed codon 57 polymorphisms. There was no significant difference in the genotypic frequencies of codon 54 between patients with JIA and healthy controls (wild type, 71.0% versus 75.0%, respectively; heterozygous type, 25.8% versus 25.0%, respectively; and homozygous type, 3.2% versus 0.0%, respectively). In addition, no association was found between the subgroups of patients with JIA and control individuals. Our results provide no evidence for a relationship between MBL gene mutation and susceptibility to JIA.

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.

The prevalence of human leukocyte antigen (HLA) DR/DQ/DP alleles in Kuwaiti children with oligoarticular juvenile idiopathic arthritis

We have determined the prevalence of human leukocyte antigen (HLA)-DR, DQ and DP alleles in Kuwaiti children with oligoarticular juvenile idiopathic arthritis (OA-JIA) and healthy controls using the PCR-SSP (sequence specific primers) method. The analysis took into account the presence of antinuclear antibodies and chronic anterior uveitis. DRB1*03 (RR 2.20, P<0.001), DRB1*08 (RR 5.280, P<0.026), DQA1*0501 (RR 1.930, P<0.001), DQB1*0304 (RR 7.920, P<0.002), DQB1*0501 (RR 3.080, P<0.007) and DPB1*0101 (RR 8.8, P<0.001) were the main HLA alleles associated with OA-JIA in Kuwaiti Arabs in this study. DRB1*03 was detected in 71% of children with positive ANA, and in 50% of children with anterior uveitis. DQA1 alleles *0501, *0103 and *0105 (P<0.001; 0.029 and 0.024 respectively) were found to be associated with OA-JIA. In contrast, DQA1*0301 and DQA1*0302 alleles appear to be protective in Kuwaiti children (RR 0.153, P<0.001 and RR 0.278, P<0.016 respectively). The DQB1 alleles *0304 and *0501 were associated with OA-JIA (P<0.002 and P<0.007 respectively). In the case of DPB1, only one allele (*0101) was associated with OA-JIA (P<0.001). Most Kuwaiti Arab patients with OA-JIA who carried a DQ or DP susceptibility allele also had an accompanying DRB1*03 or *8 allele.

Intraocular inflammation in autoimmune diseases

BACKGROUND

The uveal tract represents the vascular organ of the eye. In addition to providing most of the blood supply to the intraocular structures, it acts as a conduit for immune cells, particularly lymphocytes, to enter the eye. Consequently, the uveal tract is represented in many intraocular inflammatory processes. Uveitis is probably a misnomer unless antigens within the uvea are the direct targets of the inflammatory process. A better term of the condition is "intraocular inflammation" (IOI).

OBJECTIVES

To review the presence of IOI in autoimmune diseases, the immunopathogenic mechanisms leading to disease, and treatment.

METHODS

We reviewed the English medical literature by using MEDLINE (1984-2003) employing the terms "uveitis," "intraocular inflammation," and "autoimmune diseases."

RESULTS

An underlying autoimmune disease was identified in up to 40% of patients with IOI, and included spondyloarthropathies, Behcets disease, sarcoidosis, juvenile chronic arthritis, Vogt-Koyanagi-Harada syndrome (an inflammatory syndrome including uveitis with dermatologic and neurologic manifestations), immune recovery syndrome, and uveitis with tubulointerstitial disease. The immunopathogenesis of IOI involves enhanced T-cell response. Recently, guidelines for the use of immunosuppressive drugs for inflammatory eye disease were established and include: corticosteroids, azathioprine, methotrexate, mycophenolate mofetil, cyclosporine, tacrolimus, cyclophosphamide, and chlorambucil. New therapies with limited experience include the tumor necrosis factor alpha inhibitors, interferon alfa, monoclonal antibodies against lymphocyte surface antigens, intravenous immunoglobulin (IVIG), and the intraocular delivery of immunosuppressive agents.

CONCLUSION

An underlying autoimmune disease was identified in up to 40% of patients with IOI. Immunosuppressive drugs, biologic agents, and IVIG are employed for the treatment of IOI in autoimmune diseases.

HLA-DRB1 alleles and HLA-DRB1 shared epitopes are markers for juvenile rheumatoid arthritis subgroups in Colombian mestizos

We studied the association of human leukocyte antigen (HLA)-DRB1 and HLA-DQB1 alleles and HLA haplotypes with juvenile rheumatoid arthritis (JRA) in 65 patients and 65 controls from Colombia. The JRA subsets were distinguished on the basis of criteria established by the American College of Rheumatology. Two alleles were associated with protection, HLA-DRB1*1501 (p = 0.002) and HLA-DRB1*1402 (p = 0.01). HLA-DRB1*1602 (p = 0.0000002) was associated with susceptibility for systemic JRA and HLA-DRB1*1104 (p = 0.0002) for pauciarticular JRA. Amino acid sequences at residues 70-74 of DRB1 chain shared by HLA-DRB1 alleles (shared epitomes) were also informative. The polyarticular JRA subset revealed association with (70)QRRAA(74), which includes HLA-DRB1*04, 01, and (70)DRRAA(74), which includes DRB1*1601, 1602, 1101, and 1104. Two new findings of interest were the association of the haplotypes DRB1*1104, DQB1*0301(p = 0.0002) with pauciarticular JRA and DRB1*1602, DQB1*0301 (p = 0.0000002) association with systemic JRA. The DRB1 alleles of these two haplotypes share the epitope (70)DRRAA(74)and were associated with both the pauciarticular and the systemic subset of JRA. Our results suggest that studies of disease susceptibility in populations of admixed genetic background should take into account the contribution of different ethnic groups or nationalities in the recruitment of controls and patients studied in order to rule out genetic stratification.

Juvenile rheumatoid arthritis

Progress in achieving international consensus concerning the classification of juvenile idiopathic arthritis has been made, although further refinement and validation of these criteria is needed. It is hoped that this will facilitate more effective international collaboration in the study of these diseases, because much remains to be learned about genetic susceptibility, causation, pathogenesis, and treatment. Attention to the unique aspects of chronic arthritis in children such as impaired growth and macrophage activation syndrome may help to reduce disease-related morbidity and mortality. New biologic agents have substantially enhanced the treatment of JRA. The identification of reliable predictors of disease course and outcome is important in the rational and timely application of new therapies.

Polymorphism of the human retinoid X receptor beta and linkage disequilibrium with HLA-DPB1

The human retinoid X receptor beta (RXRB) gene is localized in the major histocompatibility complex (MHC) region between DPB1 and RING2. The RXRB gene sequence reported by different investigators suggests that the gene may be polymorphic. In this study, we confirmed one polymorphism by sequencing genomic DNA from four Caucasian individuals. We also developed a restriction fragment length polymorphism (RFLP) analysis to detect this specific polymorphism. Linkage analysis studies between RXRB alleles and a number of HLA markers showed significant linkage disequilibrium between RXRB*T and HLA-DPB1*0401.

Juvenile rheumatoid arthritis

A satisfactory classification of arthritis in childhood has still to be defined, and a system that can facilitate communication among physicians has been proposed by an international committee. The immunopathogenesis of the diseases that are encompassed by the term juvenile rheumatoid arthritis is complex, and many studies have investigated the role of genetic and cytokine balance abnormalities. HLA associations have been confirmed in multiple series, and there is evidence that non-major histocompatibility complex genes might also contribute to disease pathogenesis. Recent studies have added knowledge to the diverse clinical features of the disease, including joint distribution at presentation, association with Turner syndrome, presence of arthritis mutilans, and alterations in mandibulofacial development. Medical treatment remains a challenge. For cases recalcitrant to conventional therapy autologous hemopoietic stem-cell transplantation has been attempted; the risks of this procedure must however be carefully balanced in individual patients.

Juvenile spondyloarthropathies

This paper reviews the recent literature on the juvenile spondyloarthropathies. Several case reports emphasized clinical characteristics of the spondyloarthropathies including reactive arthritis. MR imaging seemed to enhance the detection of sacroiliitis in children with spondyloarthropathies. The presence of different cytokines in various forms of juvenile arthritis including the juvenile spondyloarthropathies was investigated and suggested a role for the anti-inflammatory cytokines in milder disease. Evidence for the association of low-molecular-weight polypeptide gene polymorphism with susceptibility to acute anterior uveitis was found in a Mexican population of patients with spondyloarthropathies, including 80 with juvenile spondyloarthropathy. A review of therapeutic use of sulfasalazine in children with chronic arthritis, including those with juvenile spondyloarthropathy, concluded that it was safe and effective. Last, a study assessed aerobic fitness and physical activity in patients with juvenile spondyloarthropathy in remission and suggested a decline in physical fitness in older patients.