Juvenile idiopathic arthritis classified by the ILAR criteria: HLA associations in UK patients

OBJECTIVE: To determine the HLA associations with juvenile idiopathic arthritis (JIA) and its subgroups as defined by the International League of Associations for Rheumatology (ILAR) classification criteria. METHODS: Five hundred and twenty-one UK Caucasian JIA patients and 537 UK Caucasian controls were typed for HLA class II alleles. Phenotype and haplotype frequencies were compared between all JIA cases and controls and between the seven ILAR-defined JIA subgroups. RESULTS: Three haplotypes (DRB1*08-DQA1*0401-DQB1*0402; DRB1*11-DQA1*05-DQB1*03; DRB1*1301-DQA1*01-DQB1*06) were associated with increased risk and one (DRB1*04-DQA1*03-DQB1*03) with decreased risk of JIA. However, in each case the frequencies also varied between JIA subgroups. CONCLUSION: This study categorically demonstrates that there are multiple HLA class II associations with JIA. It has also, for the first time, defined these associations in the seven different ILAR subgroups in UK JIA cases. Although there are a number of common associations, each ILAR subgroup exhibits different patterns of HLA associations, suggesting that the ILAR classification system does define genetically distinct groups of patients.     

Evidence for linkage of HLA loci in juvenile idiopathic oligoarthritis: independent effects of HLA-A and HLA-DRB1

OBJECTIVE: Although multiple associations between HLA loci and juvenile oligoarthritis have previously been documented, evidence for linkage of HLA loci in oligoarthritis in UK Caucasians with juvenile idiopathic arthritis (JIA) has not been described. The aim of this study was to investigate linkage of HLA-A, B, and DRB1 in UK Caucasian JIA patients with oligoarthritis. METHODS: One hundred forty-two families comprising affected offspring and their parents (45 with one parent available and 97 with both parents available) were typed for HLA-A, B, and DRB1 by polymerase chain reaction-sequence-specific oligonucleotide probe. Single-point and multipoint analyses were performed using various modifications of the extended transmission disequilibrium test. Linkage disequilibrium (LD) analysis was performed using the EH-Plus system. RESULTS: Linkage to HLA-A and HLA-DRB1 was seen in oligoarthritis and in the International League of Associations for Rheumatology-defined subgroups of persistent oligoarthritis and extended oligoarthritis. Linkage to HLA-A, B, and DRB1 was also observed in female patients with oligoarthritis. Linkage of the HLA loci seemed to be attributable to maternal preferential transmission of alleles. Furthermore, LD patterns between the HLA-A, B, and DRB1 loci were investigated. HLA-A and HLA-DRB1 were confirmed as independent susceptibility loci for oligoarthritis. CONCLUSION: This is the first study to establish linkage of HLA-A and HLA-DRB1 in oligoarthritis and to show that the 2 loci contribute independently to disease. Further studies are being performed to determine whether it is these loci or other genes in LD with them that are responsible for susceptibility to oligoarthritis in UK Caucasian patients with JIA.     

Prevalence and complications of uveitis in juvenile idiopathic arthritis in a population-based nation-wide study in Germany: suggested modification of the current screening guidelines

OBJECTIVES: To analyse the prevalence and complications of uveitis and their predictors in a large cohort of patients with juvenile idiopathic arthritis (JIA). METHODS: Data of 3271 JIA patients as classified by International League of Associations for Rheumatology (ILAR) criteria included in a national database during 1 yr were analysed. RESULTS: Uveitis prevalence was 12% of all JIA patients. The most frequent were oligoarthritis extended (25%) and persistent (16%). JIA patients with uveitis were significantly younger at onset of arthritis (3.8 vs 7.0 yrs) or ANA-positive (86% vs 42%) than the patients without uveitis. Predictors of uveitis included age at onset (P= 0.03) and ANA-positivity (P< 0.01) besides the presence of a certain JIA subgroup (P= 0.04). Uveitis was clinically silent in 75% of the oligoarthritis but in none of the enthesitis-related arthritis patients. The median onset of uveitis was 5.5 months after arthritis manifestation. In 73%, 77% and 90%, uveitis developed within 1, 2 and 4 yrs after arthritis, respectively. Anterior uveitis was the most common anatomic type of uveitis (83%). Uveitis complications at mean follow-up of 5.6 yrs were common (56%), and predictors for complications included presence of complications at first visit (P< 0.001) and uveitis manifestation before arthritis (P= 0.001), but not ANA positivity. CONCLUSIONS: The JIA subgroups markedly differ with respect to the prevalence and course of associated uveitis. Ophthalmological screening should be initiated early after arthritis onset and the intervals be related to the JIA subgroup. A modification of the current screening guidelines is suggested.     

Mutation screening of the macrophage migration inhibitory factor gene: positive association of a functional polymorphism of macrophage migration inhibitory factor with juvenile idiopathic arthritis

OBJECTIVE: To determine if polymorphisms of the macrophage migration inhibitory factor (MIF) gene are associated with juvenile idiopathic arthritis (JIA). METHODS: Denaturing high-performance liquid chromatography was used to screen the MIF gene in 32 UK Caucasian controls and 88 UK Caucasian JIA patients. Ninety-two healthy UK Caucasian controls were then genotyped for each of the polymorphic positions identified. A panel of 526 UK Caucasian JIA patients and 259 UK Caucasian controls were subsequently genotyped for a single-nucleotide polymorphism (SNP) identified in the 5'-flanking region of the gene, using SNaPshot ddNTP primer extension and capillary electrophoresis. The functional significance of this polymorphism was also studied using luciferase-based reporter gene assays in human T lymphoblast and epithelial cell lines. RESULTS: A tetranucleotide repeat CATT((5-7)) beginning at nucleotide position -794 and 3 SNPs at positions -173 (G to C), +254 (T to C), and +656 (C to G) of the MIF gene were identified. No JIA-specific mutations were found. Allele and genotype frequencies differed significantly between the controls and the JIA patients for the MIF-173 polymorphism. Individuals possessing a MIF-173*C allele had an increased risk of JIA (34.8% versus 21.6%) (odds ratio 1.9, 95% confidence interval 1.4-2.7; P = 0.0002). Furthermore, the MIF-173* G and C variants resulted in altered expression of MIF in a cell type-specific manner. Serum levels of MIF were also significantly higher in individuals who carried a MIF-173*C allele (P = 0.04). CONCLUSION: The -173-MIF*C allele confers increased risk of susceptibility to JIA. Our data suggest a cell type-specific regulation of MIF, which may be central to understanding its role in inflammation.     

Neuroendocrine gene polymorphisms and susceptibility to juvenile idiopathic arthritis

OBJECTIVE: To investigate the involvement of neuroendocrine candidate genes in the aetiopathogenesis of juvenile idiopathic arthritis (JIA). METHODS: Single-nucleotide polymorphisms and intragenic microsatellite markers within five neuroendocrine candidate genes (CRH, CBG, CYP19, ESR1, PRL) were investigated in 463 clinically characterized UK Caucasian JIA patients and a panel of 276 unrelated, healthy UK Caucasian controls. RESULTS: None of the polymorphisms investigated showed any statistically significant associations with JIA. CONCLUSIONS: The lack of association with polymorphisms of these neuroendocrine genes suggests that they are not involved in susceptibility to JIA.     

HLA class II haplotype and autoantibody associations in children with juvenile dermatomyositis and juvenile dermatomyositis-scleroderma overlap

OBJECTIVES: To investigate a large cohort of children with juvenile dermatomyositis (JDM), and those with JDM-scleroderma (JDM-SSc) overlap, using detailed serological analysis, HLA class II genotyping and clinical characterization. METHODS: Children (114) with JDM were recruited, and clinical data collected, through the JDM National Registry and Repository (UK and Ireland). Sera were assayed for ANA using standard immunofluorescence techniques and specific antibodies characterized using ELISA, immunodiffusion and radioimmunoprecipitation. Patients and controls (n = 537) were genotyped at the HLA-DRB1 and DQB1 loci, and then the DQA1 locus data was derived. RESULTS: Over 70% of the patients were ANA-positive. Clear differences in serological and genetic data were demonstrated between JDM and JDM-SSc overlap groups. Strong associations were seen for HLA-DRB1*03 (all cases vs controls, P(corr) = 0.02; JDM-SSc vs controls, P(corr) = 0.001) and HLA-DQA1*05 (all cases vs controls, P(corr) = 0.01; JDM-SSc vs controls, P(corr) = 0.005). The frequency of the HLA-DRB1*03-DQA1*05-DQB1*02 haplotype was significantly increased in the JDM-SSc (P = 0.003) and anti-PM-Scl antibody (P = 0.002) positive groups. All anti-U1-RNP antibody-positive patients had at least one copy of HLA-DRB1*04-DQA1*03-DQB1*03 haplotype. Associations were observed between serology and specific clinical features. CONCLUSIONS: We present clinical data, HLA genotyping and serological profiling on a large cohort of JDM patients and a carefully characterized subset of patients with JDM-SSc overlap. The results confirm known HLA associations and extend the knowledge by stratification of data in serological and clinical subgroups. In the future, a combination of serological and genetic typing may allow for better prediction of clinical course and disease subtype in JDM.     

Autoinflammatory genes and susceptibility to psoriatic juvenile idiopathic arthritis

OBJECTIVE: To investigate the association of NLRP3, NOD2, MEFV, and PSTPIP1, genes that cause 4 of the autoinflammatory hereditary periodic fever syndromes (HPFS), with juvenile idiopathic arthritis (JIA). METHODS: Fifty-one single-nucleotide polymorphisms (SNPs) across the 4 loci were investigated using MassArray genotyping in 950 Caucasian patients with JIA living in the UK and 728 ethnically matched healthy controls. RESULTS: Prior to Bonferroni correction for multiple testing, significant genotype associations between 6 SNPs in MEFV and JIA were observed and, in subgroup analysis, associations between 12 SNPs across all 4 loci and the subgroup of patients with psoriatic JIA were found. After Bonferroni correction for multiple testing, 2 genotype associations remained significant in the subgroup of patients with psoriatic JIA (MEFV SNP rs224204 [corrected P = 0.025] and NLRP3 SNP rs3806265 [corrected P = 0.04]). CONCLUSION: These findings support the use of monogenic loci as candidates for investigating the genetic component of complex disease and provide preliminary evidence of association between SNPs in autoinflammatory genes and psoriatic JIA. Our findings raise the interesting possibility of a shared disease mechanism between the HPFS and psoriatic JIA, potentially involving abnormal production of interleukin-1beta.     

Prevalence and outcome of juvenile idiopathic arthritis-associated uveitis and relation to articular disease

OBJECTIVE: To determine prevalence and complications of juvenile idiopathic arthritis (JIA)-associated uveitis, and to evaluate risk factors for uveitis and its relation to articular disease. METHODS: Records of 309 patients with JIA (244 female, 65 male, mean age at onset 4.9 yrs) were retrospectively reviewed. Occurrence of uveitis and complications were assessed among oligoarticular-onset JIA (193 patients), polyarticular-onset JIA (66 patients), and systemic-onset JIA (50 patients). The presence of antinuclear antibodies (ANA) was determined in patients with oligoarticular-onset JIA. Therapy and relapses of uveitis and arthritis were recorded at each visit during the followup (mean followup 7.6 yrs). RESULTS: Sixty-two patients developed uveitis (20.1%); 57 patients had oligoarticular-, 3 polyarticular-, and 2 systemic-onset JIA. Uveitis was asymptomatic in 56/62 cases. Fifty-five of the 62 patients (88.7%) developed uveitis within 4 years from disease onset. In patients with oligoarticular-onset JIA, an early age at disease onset and the presence of ANA (p < 0.05) and DRB1*11 (p < 0.03) were the best predictors of uveitis, while a polyarticular course was not associated to uveitis (p > 0.05). Active arthritis was present at the first episode of uveitis in 46/62 patients. Forty-four of the 62 patients experienced relapses of uveitis: in 20/62, relapses were concomitant to arthritis relapses; in 24/62 relapses presented without active arthritis. Complications of uveitis developed in 35.5% of the patients (22/62), leading to visual impairment in 13 patients. CONCLUSION: Current guidelines provide early identification of uveitis in 90% of patients. With the exception of the first episode of uveitis, uveitis and arthritis seem to run different courses; close ophthalmologic scrutiny then should also be maintained during arthritis remission.     

Subtyping of juvenile idiopathic arthritis using latent class analysis. British Paediatric Rheumatology Group

OBJECTIVE: To use statistical techniques to identify underlying subtypes of juvenile idiopathic arthritis (JIA) that best explain the observed relationships of clinical and laboratory variables, and to compare the statistically derived subtypes with those defined by the International League of Associations for Rheumatology (ILAR) criteria and examine them for HLA associations. METHODS: Information on 572 patients diagnosed as having JIA was summarized by 10 clinical and laboratory categorical variables (age at onset, large joint involvement, small joint involvement, polyarthritis, symmetric arthritis, spinal pain, fever, psoriasis, antinuclear antibodies [ANA], and rheumatoid factor). Latent class analysis (LCA) was used to identify underlying ("latent") classes that explained the relationships among the observed variables. Statistical models incorporating 5-8 latent classes were applied to the data. RESULTS: The 7-class model was the most appropriate. Patterns of joint involvement and the presence of ANA were influential in determining latent classes. There was some correspondence between the latent classes and the ILAR categories, but they did not coincide completely. Significant differences between the latent classes were seen for 3 HLA haplotypes (DRB1*04-DQA1*03-DQB1*03, DRB1*13-DQA1*01-DQB1*06, and DRB1*08-DQA1*0401-DQB1*0402). CONCLUSION: LCA provides a novel approach to the task of identifying homogeneous subtypes within the umbrella of JIA. In further work, the identified latent classes will be examined for associations with other candidate genes and for differences in outcome.     

HLA-DRB1 antigens in Taiwanese patients with juvenile-onset systemic lupus erythematosus

OBJECTIVE: This study was done to investigate the frequency of HLA-DRB1 antigens in juvenile-onset systemic lupus erythematosus (SLE) in the Taiwanese population. PATIENTS AND METHODS: Thirty-four Taiwanese patients with juvenile onset SLE and 200 unrelated healthy controls were studied. HLA-DRB1 typing was performed with polymerase chain reaction (PCR) and the sequence-specific oligonucleotide probe (SSO) typing method. RESULT: Among the 14 investigated DRB1 alleles, the frequency of HLA-DRB1*1602 was higher in juvenile onset SLE patients than the controls (15.15% vs 4.50%, odds ratio 3.66, 95% confidence interval 1.15-11.68, Pc = 0.04). Although there were differences in the frequencies of DRB1*0301, DRB1*0803, and DRB1*1501 between patients and controls, the associations were statistically insignificant. CONCLUSION: The frequency of HLA-DRB1*1602 was significantly higher in patients with juvenile onset SLE than in healthy controls. This finding differs from those in the previous studies in Caucasian and Japanese adult onset SLE patients.     

Major histocompatility complex haplotypic associations in Felty's syndrome and large granular lymphocyte syndrome are secondary to allelic association with HLA-DRB1 *0401

OBJECTIVE: To investigate the role of HLA class I in susceptibility to Felty's syndrome (FS) and large granular lymphocyte (LGL) syndrome. METHODS: Fifty caucasoid FS patients, and 55 patients with LGL syndrome, of whom 26 had arthritis and 29 did not, were studied. Complete HLA class I and HLA-DR typing including, where relevant, DRB1*04 subtyping was carried out by molecular methods. Comparison was made with 78 unselected healthy caucasoid controls and a further 29 DRB1*0401+ individuals. RESULTS: A significant association was found between HLA-A*02 and FS [odds ratio (OR) 3.9, 95% confidence interval (95% CI) 1.8-8.4, P = 0.0004]. At the B locus, there was an association between B*44 and LGL with arthritis [OR 3.5 (1.3-9.2), P = 0.01]. For HLA-Cw*0501, there was an association with FS [OR 4 (1. 7-9.2) P = 0.0008]. For both FS and LGL with arthritis, the extended haplotype HLA-A*02;B*44;Cw*0501;DRB1*0401 was significantly associated [OR 9.5 (2.6-35), P = 0.0001; OR 4.6 (1-22.4), P = 0.05, respectively]. There was no association between HLA class I or II and LGL without arthritis. All the allelic and haplotypic associations were lost on comparison with HLA-DRB1*0401+ controls. The strongest HLA association was with HLA-DRB1*0401 for FS [OR 27.9 (10.3-75.5), P = 10(-13)], and LGL with arthritis [OR 35.4 (9.6-131. 3), P = 10(-10)]. CONCLUSIONS: The major histocompatibility locus (MHC) associations with FS reported here are due to linkage disequilibrium with HLA-DRB1*0401. LGL syndrome with arthritis shows identical class II associations with FS, although there may be subtle immunogenetic differences between the two in the class I region. One of the extended haplotypes reported in a number of studies for FS and rheumatoid arthritis (summarized as HLA-A*02;Cw*0501; B*44;TNFb5;TNFa6;TNFd4;C4A*3;C4BQ*0;DRB1*0 401;DQB1*0301) is likely to be attributable to strong primary association with HLA-DRB1*0401, rather than to epistatic interaction between these loci.     

Uveitis in sibling pairs with juvenile idiopathic arthritis

OBJECTIVE: To ascertain the occurrence and characteristics of uveitis in sibling pairs affected with juvenile idiopathic arthritis (JIA). METHODS: The sibling series comprised 80 JIA patients from 37 families with two or three JIA children, seen at the paediatric department of the Rheumatism Foundation Hospital in Heinola, Finland. An ophthalmologist examined the children for uveitis two to four times a year and the course of the condition was recorded during the follow-up. RESULTS: Uveitis was diagnosed in 21 of the 80 patients (26%). Three pairs (3.4 pairs expected) were concordant for the presence of asymptomatic uveitis. Two patients with enthesitis-related arthritis had acute unilateral uveitis. Among the remaining cases, uveitis was chronic and continuously active at the end of follow-up in 13 instances, but in spite of this only one patient had impaired vision. HLA allele B27 occurred more frequently in patients with uveitis than in those without uveitis (52 vs 30%, P=0.073) and all six subjects in the pairs concordant for chronic uveitis carried this allele. CONCLUSIONS: The observed concordance rate for uveitis did not differ from that expected. Although the uveitis was chronic in most instances, its course was usually mild.     

A functional promoter haplotype of macrophage migration inhibitory factor is linked and associated with juvenile idiopathic arthritis

OBJECTIVE: To establish linkage and replicate the association of macrophage migration inhibitory factor (MIF) with juvenile idiopathic arthritis (JIA). METHODS: Three hundred twenty-one Caucasian simplex families from the UK were genotyped for polymorphisms of MIF using SNaPshot ddNTP primer extension, or by a fluorescently labeled primer method, and capillary gel electrophoresis. The functional significance of the promoter polymorphisms was studied using luciferase-based reporter gene assays in human T lymphoblast and epithelial cell lines. RESULTS: MIF was linked and associated with JIA (P = 0.0016). Specifically, a 2-point promoter haplotype, CATT(7)-MIF-173*C, was found to be transmitted in excess (38 transmitted: 21 not transmitted) in the JIA patients. Conditional extended transmission disequilibrium test and pairwise extended transmission disequilibrium test predicted functional interaction between the 2 polymorphic positions. The interaction of the CATT repeat with MIF-173*G/C was found to be specific to the cell type. CONCLUSION: Replication of an association and linkage of MIF with JIA has been established. Functional interaction between the polymorphic positions on the linked haplotype has also been shown. The molecular mechanism of this interaction is currently being investigated.     

Uveitis in young adults with juvenile idiopathic arthritis: a clinical evaluation of 123 patients

OBJECTIVE: To examine the prevalence and characteristics of uveitis in young adults with juvenile idiopathic arthritis (JIA). METHODS: The study population consisted of 123 JIA patients born between 1976 and 1980 whose arthritis had been diagnosed and treatment first started at the Rheumatism Foundation Hospital in 1976 to 1995. A clinical re-evaluation was carried out by an ophthalmologist and a paediatric rheumatologist 16 years later on average. RESULTS: The mean age of the patients was 23.5 years, 72% were women, and 63% had oligoarthritis. During the course of the disease, diagnosis of uveitis had been made in 25 patients (20%). Arthritis in the 19 patients with asymptomatic uveitis was more often ongoing than in the 98 patients without uveitis (p = 0.032). Asymptomatic uveitis was persistent in eight of the 19 cases (42%), and arthritis was active in seven of these. Four of the six patients with attacks of symptomatic uveitis had parallel treatment for arthritis. In three of 19 patients with asymptomatic uveitis and in five of six with acute uveitis the eye inflammation had started after the age of 16. At the onset of arthritis the patients with asymptomatic uveitis were younger than those without uveitis (p = 0.002). Complications of uveitis developed in six patients but their sight remained good. CONCLUSIONS: Asymptomatic uveitis continued into adulthood in almost half the uveitis patients. Most also had ongoing arthritis. Acute uveitis was often associated with persistent arthritis.     

Positive family history of psoriasis does not affect the clinical expression and course of juvenile idiopathic arthritis patients with oligoarthritis

OBJECTIVE: In the 1997 revision of the International League of Associations for Rheumatology (ILAR) criteria for juvenile idiopathic arthritis (JIA), a family history of psoriasis is an exclusion for the oligoarthritis category. We investigated whether psoriasis in a first or second degree relative influences the clinical expression and course of JIA patients with oligoarthritis. METHODS: In a cross-sectional study, consecutive oligoarticular-onset JIA patients were investigated. Clinical evaluations included confirmation of a family history of psoriasis and assessment of nail abnormalities, dactylitis, psoriatic rash, variables of JIA activity, and laboratory indicators of inflammation. Retrospective assessments included sex, onset age, disease duration, antinuclear antibodies, HLA-B27, uveitis, ocular complications, second-line therapies, intraarticular corticosteroid injections, radiographic joint lesions, joint involvement over time, and laboratory investigations at disease presentation and first observation. RESULTS: A total of 185 patients were included. Thirty-three had a positive family history of psoriasis (group 2) and 139 did not (group 1). Thirteen patients fulfilled the ILAR criteria for juvenile psoriatic arthritis (group 3). Patients in groups 1 and 2 were comparable for all parameters, except for a higher frequency of females in group 1 (P = 0.04). As compared with group 2, patients in group 3 were less frequently antinuclear antibody positive and had a more severe arthritis and a different distribution of joint involvement. CONCLUSION: We found close similarities in the clinical features and course among patients with oligoarthritis who had a positive family history for psoriasis and those who did not. These findings argue against the exclusion of the former patients from the oligoarthritis category of JIA.     

Evidence for a novel rheumatoid arthritis susceptibility locus on chromosome 6p

OBJECTIVE: To investigate whether the large linkage peak on chromosome 6p harbors rheumatoid arthritis (RA) susceptibility loci in addition to the well-characterized HLA-DRB1 gene. METHODS: DNA samples obtained from 377 UK RA affected sibling pair (ASP) families, comprising test (181 ASPs) and replication (196 ASPs) cohorts, were used for linkage analysis. Three hundred eighty-four patients with RA derived from a subset of 192 ASPs were compared with a panel of 288 unrelated healthy controls for association studies. Samples were genotyped for 35 microsatellites and 25 single-nucleotide polymorphisms (SNPs). RESULTS: In the test cohort, the maximum logarithm of odds (LOD) score was obtained over D6S1260 (LOD 7.1). Evidence for linkage to the telomeric portion of the peak was increased in subsets of ASPs in which both individuals had erosive disease or both carried 2 copies of the shared epitope. HLA-A, HLA-DRB1, and 8 additional markers showed evidence of linkage in the presence of association with RA (using the extended transmission disequilibrium test [ETDT]). The positive ETDT result for 2 adjacent markers (D6S1665 and 210901-4) mapping to the telomeric end of the linked region ( approximately 11 Mb from DRB1) was replicated (for D6S1665) in the second cohort of ASPs. Haplotypic overtransmission of pairwise combinations between D6S1665*7 and 210901-4*4 was identified through the TDTPhase program. Multipoint conditional analysis showed this effect to be independent of HLA-DRB1. SNP-based association studies of the region identified a 4-marker haplotype in the DEK gene that was significantly associated with RA (P = 0.009). CONCLUSION: Evidence has been presented for an RA susceptibility locus mapping under the linkage peak on 6p, 11 Mb telomeric of HLA-DRB1. Preliminary association data implicate the gene DEK.     

HLA class II alleles, genotypes, haplotypes, and amino acids in primary biliary cirrhosis: a large-scale study

Twin and family studies suggest there is a significant genetic component to primary biliary cirrhosis (PBC). However, the inability to replicate reported associations has been a recurring problem, with the only consistently reported genetic association that between PBC and HLA-DRB1*0801. However, recently even this has been questioned, and a number of novel associations have also been reported. We reinvestigated HLA class II DRB1, DQA1, and DQB1 alleles and haplotypes in a total of 492 well-characterized PBC patients, 412 from the United Kingdom and an additional 80 patients from northern Italy. There was a clear and significant association with HLA-DRB1*0801 in both groups of patients compared to population-specific healthy controls (12% versus 4% in the UK patients, P=.00087, OR=3.05; and 18% versus 6% in the Italian patients, P=.021, OR=3.15). There were also significant protective associations with DRB1*11 in the Italian patients (28% versus 47%, P=.0071, OR=0.42), but not in the UK patients (8% versus 8%) and a protective association with DRB1*13 in both series (14% versus 20%, P=.042, OR=0.65 in the UK patients; and 10% versus 31%, P=.00092, OR=0.25 in the Italian patients). In conclusion, a complex relationship exists between HLA and PBC, and some genetic associations may be population specific.     

Analysis of single-nucleotide polymorphisms in Japanese rheumatoid arthritis patients shows additional susceptibility markers besides the classic shared epitope susceptibility sequences

OBJECTIVE: To examine the entire HLA region for loci (other than the DRB1 locus) associated with rheumatoid arthritis (RA) susceptibility, by typing HLA-DRB1 alleles and multiple single-nucleotide polymorphisms (SNPs) in the Japanese population. METHODS: The HLA-DRB1 alleles and 88 SNPs distributed over the HLA gene complex were genotyped, for 828 patients with RA and 1,032 control subjects. The data were evaluated for linkage disequilibrium, and case-control associations were analyzed in 2 ways, in the presence or absence of the disease-susceptibility DRB1 allele, to detect loci independent of the DRB1 allele. RESULTS: HLA-DRB1 alleles *0405, *0401, *0901, *0101, *1401, *1602, *0403, and *1405 were significantly associated with RA in the Japanese population. The smallest P value (P = 1.4 x 10(-27)) was observed in association with an intronic SNP of the NOTCH4 gene, which was due to strong linkage disequilibrium with the HLA-DRB1 allele. A strong association that was independent of HLA-DRB1 shared epitope alleles was observed in 2 SNPs: one in the intron of the MICA gene, the other in the intron of the HLA-DQB2 gene. Their association with RA, independent of HLA-DRB1 shared epitope alleles, was suggestive (P = 0.0024 [corrected P (P(corr)) = 0.068, and P = 0.00037 [P(corr) = 0.012], respectively). CONCLUSION: These findings suggest that 1 or more other loci besides the HLA-DRB1 or other DRB1 (non-shared epitope, non-*0901) alleles are involved in RA susceptibility/protection.     

Genetic loci contributing to hemophagocytic lymphohistiocytosis do not confer susceptibility to systemic-onset juvenile idiopathic arthritis

OBJECTIVE: To investigate whether single-nucleotide polymorphisms (SNPs) within the genes PRF1, GZMB, UNC13D, and Rab27a, which are involved in natural killer cell dysfunction and known to contribute to the risk of hemophagocytic lymphohistiocytosis (HLH), confer an increased risk of susceptibility to systemic-onset juvenile idiopathic arthritis (JIA). METHODS: Four SNPs across the PRF1 gene locus, 5 for GZMB, 7 for UNC13D, and 11 for Rab27a were investigated using MassArray genotyping in 133 UK Caucasian patients with systemic-onset JIA and 384 ethnically matched unrelated control subjects. Additional control genotypes were accessed from the data generated by the Wellcome Trust Case Control Consortium. RESULTS: No significant association was found between any SNP within the 4 selected loci and systemic-onset JIA, by either single-point or haplotype analysis. CONCLUSION: The results of this study demonstrate that genes involved in HLH do not confer a significant risk of association with systemic-onset JIA.