The association of PTPN22 rs2476601 with juvenile idiopathic arthritis is specific to females.

A preponderance of females develop autoimmune disease, including juvenile idiopathic arthritis (JIA), yet the reason for this bias remains elusive. Evidence suggests that genetic risk of disease may be influenced by sex. PTPN22 rs2476601 is associated with JIA and numerous other autoimmune diseases, and has been reported to show female-specific association with type 1 diabetes. We performed main effect and sex-stratified association analyses to determine whether a sex-specific association exists in JIA. As expected, rs2476601 was associated with JIA in our discovery (413 cases and 690 controls) and replication (1008 cases and 9284 controls) samples. Discovery sample sex-stratified analyses demonstrated an association specifically in females (odds ratio (OR)=2.35, 95% confidence interval (CI)=1.52-3.63, P=0.00011) but not males (OR=0.91, 95% CI=0.52-1.60, P=0.75). This was similarly observed in the replication sample. There was evidence for genotype-by-sex interaction (Pinteraction=0.009). The association between rs2476601 and JIA appears restricted to females, partly accounting for the predominance of females with this disease.

Short-term treatment with a gonadotropin-releasing hormone antagonist, cetrorelix, in rheumatoid arthritis (AGRA): a randomized, double-blind, placebo-controlled study.

OBJECTIVES: Gonadotropin-releasing hormone (GnRH) stimulates immune responses; therefore, antagonizing GnRH with cetrorelix may have anti-inflammatory effects. The aim of this study was to assess short-term cetrorelix therapy in rheumatoid arthritis (RA) patients. METHOD: In this proof-of-concept, randomized, double-blind study involving 99 patients with active, long-standing RA, 48 patients received subcutaneous cetrorelix (5 mg/day on days 1 and 2; 3 mg/day on days 3-5) and 51 received placebo. The primary end-point was the change in the 28-joint Disease Activity Score based on C-reactive protein (DAS28-CRP) by day 5, when the greatest GnRH suppression was anticipated. Secondary end-points included the change in tumour necrosis factor (TNF)-α, and achievement of American College of Rheumatology (ACR) responses and DAS28-CRP < 2.6 by day 5. Patients were followed up on days 10 and 15. RESULTS: By day 5, DAS28-CRP was non-significantly reduced by 0.82 in the cetrorelix group compared to a 0.57 reduction in the placebo group (p = 0.091), TNF-α (log pg/mL) was significantly reduced in the cetrorelix group compared with the placebo group [0.55, 95% confidence interval (CI) 0.08-1.01, p = 0.023], and more patients on cetrorelix achieved ACR20 responses (40% vs. 18%, p = 0.015) and DAS28-CRP < 2.6 (13% vs. 0%, p = 0.009). Inflammatory markers increased towards baseline levels after withdrawal of treatment. Rates of adverse events were similar in both groups. CONCLUSIONS: Although there was no significant difference in the primary end-point between groups, antagonizing GnRH led to significant improvements in key secondary end-points. Thus, GnRH antagonists may have rapid anti-inflammatory effects in RA, already occurring within 5 days. The data suggest a novel mode of action for TNF-α inhibition in RA, and potentially in other autoimmune diseases.

CIITA gene variants are associated with rheumatoid arthritis in Scandinavian populations.

Expression of the major autoimmune risk loci DRB1 and DQB1 is regulated by the class II MHC (major histocompatibility complex) transactivator (CIITA), making the CIITA gene a strong autoimmune risk locus candidate. A CIITA promoter single-nucleotide polymorphism (SNP), rs3087456 (-168 A/G), has indeed been associated with several autoimmune diseases, including rheumatoid arthritis (RA). Recently, an intronic SNP rs8048002 has been suggested as a better susceptibility marker in Addison's disease. Therefore, we tested both SNPs in a panel of autoimmune diseases, consisting of Norwegian patients with RA (n=819), juvenile idiopathic arthritis (JIA; n=524), or type 1 diabetes (T1D; n=1211), and 2149 controls. We also included an independent Swedish RA cohort (n=2503) and controls (n=1416). Both rs3087456 and rs8048002 were significantly associated with RA (combined Norwegian and Swedish patients P(corrected)=0.012 and P(corrected)=0.0016, respectively), but not with JIA or T1D. Meta-analysis of 16 RA cohorts confirmed rs3087456 with only marginal significance (P=0.016). However, results were stronger in the Scandinavian subgroup (4 cohorts, P=3.8 × 10(-4)), indicating a population-dependent effect. A similar pattern was observed in a meta-analysis of rs8048002. Our results support involvement of CIITA in RA, but imply that this is population dependent and that the aetiological variant is yet to be discovered.

Anti-CCP and RF IgM: predictors of impaired endothelial function in rheumatoid arthritis patients.

OBJECTIVE: To determine whether the presence of anti-cyclic citrullinated peptide (anti-CCP) antibodies and rheumatoid factor immunoglobulin M (RF IgM) is associated with endothelial dysfunction in patients with rheumatoid arthritis (RA). METHODS: We studied the presence of anti-CCP antibodies and RF IgM and endothelial function in terms of the reactive hyperaemic index (RHI) in 53 consecutive RA patients. Endothelial function was measured by using a finger plethysmograph. RESULTS: RHI was significantly lower in anti-CCP-positive RA patients (n = 33, RHI = 1.78, SD = 0.30) than in anti-CCP-negative RA patients (n = 20, RHI = 2.19, SD = 0.59; p = 0.008). A similar result was found in RF IgM-positive patients (n = 34, RHI = 1.77, SD = 0.30) vs. RF IgM-negative patients (n = 19, RHI = 2.23, SD = 0.58; p = 0.003). There were no significant differences between the groups regarding age, gender, traditional cardiovascular risk markers, Disease Activity Score using 28 joint counts (DAS28), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), extra-articular manifestations (EAMs), use of glucocorticosteroids, statins, angiotensin-converting enzyme (ACE) inhibitors, and non-steroidal anti-inflammatory drugs (NSAIDs). CONCLUSION: The presence of anti-CCP antibodies and RF IgM was related to impaired endothelial function independent of other cardiovascular risk factors in RA patients. Thus, these autoantibodies might reflect an early reversible stage of the atherosclerotic process, and may indicate increased risk of cardiovascular disease (CVD). Further studies are needed to explore whether anti-CCP antibodies and RF IgM may act directly or indirectly to cause endothelial dysfunction, or merely reflect endothelial dysfunction in RA patients.

Serological detection of variable region (Vh) subgroups of Ig heavy chains.

Serological test systems were established for determining the heavy-chain variable region (Vh) subgroups of immunoglobulin heavy chains. Myeloma proteins with known Vh subgroups based on amino acid sequence were utilized as the primary basis of reference for analysis by hemagglutination and hemagglutination inhibition. Good agreement between the chemical and serological typing was obtained and nonoverlapping systems established for the three major Vh subgroups. In a survey of 167 myeloma proteins, all except two were exclusively positive in one of the three systems. The two exceptions may represent a fourth subgroup. There was an overall incidence ratio of 1:2:3 for VhI:VhII:VhIII subgroups. Some differences in the overall ratios were encountered within the immunoglobulin classes. Certain advantages of the serological typing antisera were discussed with special emphasis on their use for studies of Vh antigens on the membranes of lymphocytes.

The association of luteinizing hormone and follicle-stimulating hormone with cytokines and markers of disease activity in rheumatoid arthritis: a case-control study.

OBJECTIVES: Disease activity in rheumatoid arthritis (RA) varies substantially during periods when luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels change, for example during pregnancy, postpartum, and menopause. We wanted to investigate whether small fluctuations in these hormones could be associated with similar fluctuations in cytokines and disease activity in RA. METHODS: Disease activity markers, serum LH, FSH, and 24 cytokines were assessed on days 1 and 8 in 20 RA patients (median age 58 years, six males) and 19 controls (median age 56 years, six males). RESULTS: Percentage changes in LH and FSH correlated positively with percentage changes in key proinflammatory cytokines such as tumour necrosis factor (TNF)alpha (LH r = 0.737, p = 0.0007; FSH r = 0.680, p = 0.001) and interleukin (IL)-1beta (LH r = 0.515, p = 0.050; FSH r = 0.749, p = 0.0008). Similar correlations were observed with IL-2, IL-2R, IL-8, monocyte chemoattractant protein (MCP)-1, macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, and eotaxin, but not with the anti-inflammatory cytokine IL-10, in RA and not in controls. Percentage changes in LH, FSH, and cytokines were not correlated with percentage changes of several disease activity markers but were correlated positively with cross-sectional levels of disease activity markers [erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), Visual Analogue Scale (VAS) pain, VAS global (physician/patient), and the modified Health Assessment Questionnaire (MHAQ)]. CONCLUSIONS: The significant associations between percentage changes in LH and FSH and percentage changes in key cytokines and several cross-sectional markers of disease activity may indicate that LH and FSH influence crucial points of the cytokine cascade in RA. This may help to explain, partially, why disease activity initiates or worsens during periods of increased LH and FSH, such as the postpartum period and the menopause.

A coding polymorphism in NALP1 confers risk for autoimmune Addison's disease and type 1 diabetes.

Variants in the gene encoding NACHT leucine-rich-repeat protein 1 (NALP1), an important molecule in innate immunity, have recently been shown to confer risk for vitiligo and associated autoimmunity. We hypothesized that sequence variants in this gene may be involved in susceptibility to a wider spectrum of autoimmune diseases. Investigating large patient cohorts from six different autoimmune diseases, that is autoimmune Addison's disease (n=333), type 1 diabetes (n=1086), multiple sclerosis (n=502), rheumatoid arthritis (n=945), systemic lupus erythematosus (n=156) and juvenile idiopathic arthritis (n=505), against 3273 healthy controls, we analyzed four single nucleotide polymorphisms (SNPs) in NALP1. The major allele of the coding SNP rs12150220 revealed significant association with autoimmune Addison's disease compared with controls (OR=1.25, 95% CI: 1.06-1.49, P=0.007), and with type 1 diabetes (OR=1.15, 95% CI: 1.04-1.27, P=0.005). Trends toward the same associations were seen in rheumatoid arthritis, systemic lupus erythematosus and, although less obvious, multiple sclerosis. Patients with juvenile idiopathic arthritis did not show association with NALP1 gene variants. The results indicate that NALP1 and the innate immune system may be implicated in the pathogenesis of many autoimmune disorders, particularly organ-specific autoimmune diseases.

Treatment of fibromyalgia at the Maharishi Ayurveda Health Centre in Norway. A six-month follow-up study.

BACKGROUND: Treatments offered at the Maharishi Ayurveda Health Centre in Norway are based on Maharishi Vedic medicine, which is also known as Maharishi Ayurveda. It is a consciousness based revival of the ancient Ayurvedic medicine tradition in India and is established by Maharishi Mahesh Yogi, the founder of the Transcendental Meditation (TM) technique. OBJECTIVE: To conduct a pilot study of the effect of the treatment program at the Health Centre on fibromyalgia patients. METHODS: Thirty-one women with diagnosed fibromyalgia received an individually designed Maharishi Vedic physiological purification therapy. All subjects received personal advice on diet based on Ayurvedic principles, including a novel approach to food into-lerance, and daily routines. In addition they were offered instruction in TM (for stress and pain management and personal development) (four subjects started), and recommended Ayurvedic herbal food products for home treatment. MAIN OUTCOME MEASURES: A modified Fibromyalgia Impact Questionnaire included a visual analogue scale for each of the seven outcomes: working ability, generalised pain, tiredness, stiffness, tiredness on arising, anxiety and depression. Pre-treatment scores were compared with scores at six-month follow-up for levels of statistical significance. RESULTS: Twenty-eight subjects (90%) completed the follow-up. The outcome measures were reduced by 25 to 46% by the study's endpoint: working ability (p<0.002), pain (p<0.001), tiredness (p<0.001), morning tiredness (p<0.001), stiffness (p<0.005), anxiety (p<0.136), and depression (p<0.001). A group of five excellent responders including all four participants who started to practise TM, had almost no symptoms by the endpoint. Compared to the non-meditating control group the TM-subgroup showed statistically significant improvements for all outcome measures except depression. CONCLUSIONS: In this pilot study fibromyalgia patients undergoing treatment at Maharishi Ayurveda Health Centre in Norway showed significant improvements six months post treatment. Because fibromyalgia is considered a treatment-resistant condition, these encouraging results warrant further research.

Chest abnormalities in juvenile-onset mixed connective tissue disease: assessment with high-resolution computed tomography and pulmonary function tests.

BACKGROUND: Mixed connective tissue disease (MCTD) is associated with several chest manifestations. Only a few studies have focused on chest manifestations in juvenile-onset MCTD (jMCTD), and the true prevalence of pulmonary abnormalities on high-resolution computed tomography (HRCT) in these patients is unknown. PURPOSE: To investigate the occurrence of pulmonary abnormalities in jMCTD with particular reference to interstitial lung disease (ILD), and to evaluate a possible association between pulmonary findings and disease-related variables. MATERIAL AND METHODS: Twenty-four childhood-onset MCTD patients with median disease duration of 10.5 years (range 1-21 years) were investigated in a cross-sectional study by means of HRCT, pulmonary function tests (PFT), and clinical assessment. RESULTS: Discrete ILD was identified in six patients (25%). Median extent of ILD was 2.0%, and all except one of the patients had very mild disease in which 5% or less of the parenchyma was affected. The CT features of fibrosis were mainly microcystic and fine intralobular. The most frequently abnormal PFT was carbon monoxide uptake from the lung, which was abnormal in 33% of the patients. PFT and disease duration were not significantly associated with HRCT findings of ILD. CONCLUSION: The prevalence of ILD in childhood-onset MCTD patients was lower than previously believed. In most of the patients with ILD, the findings were subtle and without clinical correlation. The results suggest a low extent of ILD in childhood-onset MCTD, even after long-term disease duration.

Everolimus in patients with rheumatoid arthritis receiving concomitant methotrexate: a 3-month, double-blind, randomised, placebo-controlled, parallel-group, proof-of-concept study.

OBJECTIVES: Everolimus, a proliferation signal inhibitor with disease-modifying properties, may be useful in treating rheumatoid arthritis (RA). This proof-of-concept study assessed efficacy and safety of everolimus in combination with methotrexate (MTX) in patients with refractory RA. METHODS: A multi-centre, randomised, double-blind, placebo-controlled trial was performed in 121 patients with active RA receiving MTX. Patients were randomised to receive everolimus (6 mg/day) or placebo. The primary endpoint was the American College of Rheumatology criteria for a 20% improvement in measures of disease activity (ACR20) at 12 weeks. RESULTS: There was a rapid onset of action and at 12 weeks the ACR20 response rate was significantly higher in the everolimus group (36.1%) than in the placebo group (16.7%; p = 0.022). Improvements from baseline in tender and swollen joint counts, patient's assessment of pain, and patient's and physician's global assessment of disease activity were significantly greater after treatment with everolimus. The most common adverse events (AEs) in the everolimus group were gastrointestinal (52.5% vs 31.7% in the placebo group), skin (29.5% vs 8.3%), and nervous system disorders (21.3% vs 10.0%); AEs leading to treatment discontinuation were reported for 16.4% and 10.0% of patients, respectively. Changes in haematological parameters, liver function tests, and lipid levels occurred more frequently with everolimus compared to placebo, but were mild and reversible. CONCLUSIONS: The study indicates that everolimus plus MTX provides clinical benefit with an acceptable safety and tolerability profile. It may offer a new treatment option in RA patients with inadequate response to MTX.

The FCRL3 -169T>C polymorphism is associated with rheumatoid arthritis and shows suggestive evidence of involvement with juvenile idiopathic arthritis in a Scandinavian panel of autoimmune diseases.

BACKGROUND AND OBJECTIVES: The Fc receptor-like 3 (FCRL3) gene -169T>C single nucleotide polymorphism (SNP) has been reported to be associated with several autoimmune diseases (AIDs) in Japanese populations. However, association results in other populations have been conflicting. Therefore, we investigated this SNP in a Scandinavian panel of AIDs. METHODS: We genotyped patients with rheumatoid arthritis (RA; n = 708), juvenile idiopathic arthritis (JIA; n = 524), systemic lupus erythaematosus (SLE; n = 166), ulcerative colitis (UC; n = 335), primary sclerosing cholangitis (PSC; n = 365), Crohn disease (CD; n = 149), a healthy control group (n = 1030) and 425 trio families with type 1 diabetes (T1D). Statistical analysis consisted of case-control and family-based association tests. RESULTS: RA was associated with the C allele (odds ratio (OR) = 1.16, 95% CI 1.01 to 1.33) and the CC genotype (OR = 1.30, 95% CI 1.01 to 1.67) of the FCRL3 -169T>C SNP in our material. Suggestive evidence for association was also found for JIA (CC genotype: OR = 1.30, 95% CI 0.99 to 1.70), and clinical subgroup analysis indicated that this was connected to the polyarticular subgroup. No significant association was found with SLE, UC, CD, PSC or T1D. In patients with RA, we found no significant interaction between the FCRL3 -169T>C and PTPN22 1858C>T SNPs, nor between the FCRL3 -169CC genotype and IgM-rheumatoid factor or anti-cyclic citrullinated peptide titre levels. CONCLUSION: We found an association between the FCRL3 -169T>C SNP and RA, and suggestive evidence for involvement with JIA, in a Norwegian population. These findings lend support for a role for this SNP in RA across ethnically diverse populations, and warrant follow-up studies in JIA.

Rheumatoid factors isolated from patients with autoimmune disorders are derived from germline genes distinct from those encoding the Wa, Po, and Bla cross-reactive idiotypes.

To better understand the structural basis for rheumatoid factor activity, the nucleotide sequence of the light chain variable regions of nine human monospecific IgM rheumatoid factors were analyzed. Rheumatoid factors were isolated from three patients with rheumatoid arthritis, a patient with systemic lupus erythematosus, and a normal individual. The VL gene segments used by these rheumatoid factors are not as restricted as previous work on mixed cryoglobulin rheumatoid factors had suggested. Each of the different VK families is represented and there are two examples where a V lambda gene segment is used. Molecules with structures similar to those of the Wa and Po CRI, characteristic of mixed cryoglobulin rheumatoid factors, are not common among these rheumatoid factors isolated from patients with rheumatoid arthritis. While there are clear examples of rheumatoid factors that are direct copies of germline genes, most of the sequence data suggest that the processes of antigenic selection and somatic mutation contribute significantly to the generation of monospecific rheumatoid factors in patients with autoimmune disease.

The complete nucleotide sequences of the heavy chain variable regions of six monospecific rheumatoid factors derived from Epstein-Barr virus-transformed B cells isolated from the synovial tissue of patients with rheumatoid arthritis. Further evidence that some autoantibodies are unmutated copies of germ line genes.

Structural studies of human monoclonal rheumatoid factors (RF) derived from patients with monoclonal gammapathies have revealed a restriction in the usage of heavy and light chain variable regions. These studies have suggested that germline genes with little if any somatic mutation can generate RF specificity. However, there is no information presently available regarding the primary structure and genetic origin of RF in rheumatoid arthritis. In this study, we have isolated and sequenced the VH regions of six monoclonal RF derived from the synovial membranes of two patients with rheumatoid arthritis and one with the juvenile polyarticular form of the disease. We found the same VH families as previously reported among monoclonal paraproteins with RF activity. However, our sample was diverse regarding the VH, DH, and JH gene segments used. Among VHI RF there was conservation in the length of CDRIII as well as restriction in the amino acid generated at the V-D junction, as opposed to VHIII RF and non-RF VHI molecules that are highly heterogeneous in these two aspects. We also found that different JH gene segments may contribute to RF specificity. The VH, DH, and JH elements of one RF in our study all had clearly identifiable germline counterparts. This RF displays a nearly germline configuration throughout its entire heavy chain and represents another example of an autoantibody encoded by one of the VH gene segments from the preimmune fetal repertoire.

Pulmonary involvement in patients with childhood-onset systemic lupus erythematosus.

OBJECTIVE: Pulmonary involvement is a common finding in adults with systemic lupus erythematosus (SLE). The aim of this study was to investigate the frequency of pulmonary abnormalities in patients with childhood-onset SLE, with particular reference to interstitial lung disease (ILD), and to examine any association between pulmonary abnormalities and other disease-related variables. METHODS: A cohort of 60 Norwegian patients with childhood-onset SLE was examined in a cross-sectional study by high-resolution computed chest tomography (HRCT) and pulmonary function tests (PFT). Median disease duration was 11.2 years. Disease activity, cumulative organ damage and immunological markers were also assessed. RESULTS: Five patients (8%) had abnormal HRCT findings, including micronodules in four patients and bronchiectasis in one. None of the patients had radiographic evidence of ILD. PFT results were impaired in 37% of the patients, the most frequent pulmonary dysfunction was reduced carbon monoxide diffusing capacity (26%). HRCT findings, disease activity or serology did not correlate with PFTs. Reduced diffusion capacity was associated with smoking (p-value < 0.05). CONCLUSION: Lung function was moderately impaired, while the frequency of pulmonary parenchymal involvement was low. There was no radiographic evidence of ILD, which is an unexpected finding given the high frequencies reported in adult SLE patients assessed with HRCT. The results suggests that PFT values are often abnormal, but these are infrequently associated with development of ILD or other substantial parenchymal alterations in childhood-onset SLE, and do not require further HRCT investigation in asymptomatic patients.

Preformed ribozyme destroys tumour necrosis factor mRNA in human cells.

Maintaining RNA stability is a major problem in the delivery of preformed inhibitory RNA to target cells. In this study, we delivered a hammerhead ribozyme directed against tumour necrosis factor alpha into human promyelocytic leukaemia cells by cationic liposome-mediated transfection. Delivering a ribozyme in this manner reduced by 90% and 85% tumour necrosis factor alpha mRNA and protein, respectively. A modified ribozyme with a bacteriophage T7 transcription terminator at its 3' end was more stable than one lacking this sequence. This indicates that ribozyme stability can be improved by the addition of terminal sequences expected to protect against cellular nucleases.

Disease duration, hypertension and medication requirements are associated with organ damage in childhood-onset systemic lupus erythematosus.

OBJECTIVE: To investigate the frequency of organ damage in childhood-onset systemic lupus erythematosus (SLE) and to identify disease variables and patient characteristics related to organ damage. METHODS: A cohort of 71 patients was examined in a cross-sectional study after a mean disease duration of 10.8+/-8.2 years (mean age 26.4+/-9.8 years). The occurrence of organ damage was measured by the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI). Factors analysed as possible explanatory variables of organ damage were the following: demographic variables, clinical variables at diagnosis and during disease course, as well as medication use. Growth and self-reported health status were also measured. RESULTS: The most frequent areas of organ damage were in the neuropsychiatric (28%), renal (13%) and musculoskeletal (13%) organ systems. Forty-three patients (61%) had evidence of damage. The mean SDI score was 1.3 for the whole study population. Hypertension, longer disease duration and use of cyclophosphamide were factors significantly related to an increasing SDI score in multiple linear regression analyses. Furthermore, patients with damage (SDI > or =1) compared to those without damage (SDI = 0) had a significantly higher cumulative corticosteroid dose (24.7 g versus 10.6 g) and more frequently required high-dose prednisolone at diagnosis (68% versus 43%). CONCLUSION: Evidence of organ damage was found in 61% of all patients. Long disease duration, known hypertension and use of cylophosphamide were significantly associated with an increasing SDI score. Furthermore high-dose prednisolone at diagnosis and cumulative prednisolone dose were significantly related to the presence of organ damage.

Studies on the binding of proteins to the human platelet surface: relation to platelet activation.

Several antibody fractions and sera from patients with rheumatoid arthritis, systemic lupus erythematosus and chronic idiopathic thrombocytopenic purpura were examined for their ability to bind to normal platelets using immunofluorescent staining techniques. Platelet aggregometry was used to study the activating capacity of the samples. Both C1q, C1s, C1 inactivator, fibrinogen, factor VIII-related antigen, alpha 1-acid glycoprotein, alpha 1-antitrypsin, beta 2-microglobulin and isoantigens A and B, as well as fibronectin and plasminogen were found on the platelet surface. Only antibodies to C1q, C1s and beta 2-microglobulin were able to induce platelet aggregation. Sera containing immune complexes or platelet autoantibodies revealed positive surface staining for IgG, or for IgG and IgM. There sera also induced aggregation of platelets. Sera not containing immune complexes or autoantibodies gave negative staining and aggregation results. Thus, only some of the ligand receptor interactions were able to induce platelet aggregation.

Association to HLA-DRB1*08, HLA-DPB1*0301 and homozygosity for an HLA-linked proteasome gene in juvenile ankylosing spondylitis.

To assess the role of HLA genes other than those encoding B27 in predisposing to JAS and AAS, we analyzed the distribution of B*4001, as well as the DRB1, DPB1, and LMP2 alleles, using PCR-based techniques in 63 JAS and 44 AAS patients (all B27 positive). The NBMDR (N = 4724) provided a source of controls matched with the patients for B27 (or other markers when necessary). We found an increase of the B*4001, DRB1*08, and DPB1*0301 alleles, as well as the LMP2 b/b genotype (the latter was most pronounced among patients with acute iridocyclitis), in JAS compared to B27-positive controls. The increase of DRB1*08 and DPB1*0301 was due to an increase of DRB1*08 and DPB1*0301 in combination, whereas the association with B*4001 could be due to linkage disequilibrium with LMP2b. None of these associations were detected in AAS. We conclude that in JAS, in addition to the association to B27, there are also weaker but distinct associations to the DRB1*08, DPB1*0301 alleles and homozygosity for LMP2b.

Polymorphism of human major histocompatibility complex-encoded transporter associated with antigen processing (TAP) genes and susceptibility to juvenile rheumatoid arthritis.

The TAP1 and TAP2 genes encode a peptide transporter supplying peptides for binding to HLA class I molecules. Both genes are located in the class II region of the HLA complex and are polymorphic. Here we report the distribution of TAP alleles in a group of 285 JRA patients (including various subsets), 165 random controls, and 82 DR8-positive controls. We found a pronounced increase of TAP1B and TAP2C/D in patients, compared with controls. The difference was, however, mainly secondary to a strong linkage disequilibrium between these TAP alleles and DR8, which is significantly increased in JRA. When we compared patients and controls after stratification for DR8 the differences decreased, although an increase of TAP1B in DR8-negative patients remained significant. We conclude that a primary association of JRA with given TAP allels cannot explain the HLA class II associations in JRA. However, we cannot exclude the possibility that TAP1B acts as an additive susceptibility factor in JRA.