Shomi Oka

Association of human leukocyte antigen with interstitial lung disease in rheumatoid arthritis: a protective role for shared epitope.

Introduction Interstitial Lung Disease (ILD) is frequently associated with Rheumatoid Arthritis (RA) as one of extra-articular manifestations. Many studies for Human Leukocyte Antigen (HLA) allelic association with RA have been reported, but few have been validated in an RA subpopulation with ILD. In this study, we investigated the association of HLA class II alleles with ILD in RA. Methods An association study was conducted on HLA-DRB1, DQB1, and DPB1 in 450 Japanese RA patients that were or were not diagnosed with ILD, based on the findings of computed tomography images of the chest. Results Unexpectedly, HLA-DRB1*04 (corrected P [Pc] = 0.0054, odds ratio [OR] 0.57), shared epitope (SE) (P = 0.0055, OR 0.66) and DQB1*04 (Pc = 0.0036, OR 0.57) were associated with significantly decreased risk of ILD. In contrast, DRB1*16 (Pc = 0.0372, OR 15.21), DR2 serological group (DRB1*15 and *16 alleles) (P = 0.0020, OR 1.75) and DQB1*06 (Pc = 0.0333, OR 1.57, respectively) were significantly associated with risk of ILD. Conclusion HLA-DRB1 SE was associated with reduced, while DR2 serological group (DRB1*15 and *16) with increased, risk for ILD in Japanese patients with RA.

Protective effect of the HLA-DRB1*13:02 allele in Japanese rheumatoid arthritis patients.

Rheumatoid arthritis (RA) is a chronic systemic inflammatory disease. Certain HLA-DRB1 “shared-epitope” alleles are reported to be positively associated with increased RA susceptibility, whereas some of the other alleles may be negatively associated. However, studies on the latter are rare. Here, we focus on the protective effects of DRB1 alleles in Japanese RA patients in an association study. Relative predispositional effects (RPE) were analyzed by sequential elimination of carriers of each allele with the strongest association. The protective effects of DRB1 alleles were investigated in patients stratified according to whether they possessed anti-citrullinated peptide antibodies (ACPA). The DRB1*13:02 allele was found to be negatively associated with RA (P = 4.59×10−10, corrected P (Pc) = 1.42×10−8, odds ratio [OR] 0.42, 95% CI 0.32–0.55, P [RPE] = 1.27×10−6); the genotypes DRB1*04:05/*13:02 and *09:01/*13:02 were also negatively associated with RA. The protective effect of *13:02 was also present in ACPA-positive patients (P = 3.95×10−8, Pc = 1.22×10−6, OR 0.42, 95%CI 0.31–0.58) whereas *15:02 was negatively associated only with ACPA-negative RA (P = 8.87×10−5, Pc = 0.0026, OR 0.26, 95%CI 0.12–0.56). Thus, this study identified a negative association of DRB1*13:02 with Japanese RA; our findings support the protective role of DRB1*13:02 in the pathogenesis of ACPA-positive RA.

Human leukocyte antigens and systemic lupus erythematosus: a protective role for the HLA-DR6 alleles DRB1*13:02 and *14:03.

Many studies on associations between human leukocyte antigen (HLA) allele frequencies and susceptibility to systemic lupus erythematosus (SLE) have been performed. However, few protective associations with HLA-DRB1 alleles have been reported. Here, we sought protective, as well as predispositional, alleles of HLA-DRB1 in Japanese SLE patients. An association study was conducted for HLA-DRB1 in Japanese SLE patients. Relative predispositional effects were analyzed by sequential elimination of carriers of each allele with the strongest association. We also explored the association of DRB1 alleles with SLE phenotypes including the presence of autoantibody and clinical manifestations. Significantly different carrier frequencies of certain DRB1 alleles were found to be associated with SLE as follows: increased DRB1*15:01 (P = 5.48×10−10, corrected P (Pc) = 1.59×10−8, odds ratio [OR] 2.17, 95% confidence interval [CI] 1.69–2.79), decreased DRB1*13:02 (P = 7.17×10−5, Pc = 0.0020, OR 0.46, 95% CI 0.34–0.63) and decreased DRB1*14:03 (P = 0.0010, Pc = 0.0272, OR 0.34, 95% CI 0.18–0.63). Additionally, the “*15:01/*13:02 or *14:03” genotype tended to be negatively associated with SLE (P = 0.4209, OR 0.66), despite there being significant positive associations with *15:01 when present together with alleles other than *13:02 or *14:03 (P = 1.79×10−11, OR 2.39, 95% CI 1.84–3.10). This protective effect of *13:02 and *14:03 was also confirmed in SLE patients with different clinical phenotypes. To the best of our knowledge, this is the first report of a protective association between the carrier frequencies of HLA-DRB1*13:02 and *14:03 and SLE in the Japanese population.

Genome, epigenome and transcriptome analyses of a pair of monozygotic twins discordant for systemic lupus erythematosus.

Information to distinguish genetic and environmental factors in the pathogenesis of multifactorial diseases can be obtained by investigation of disease development in monozygotic twins. Recent reports have shown that there are genomic and epigenomic differences between monozygotic twins. Genomic/epigenomic and gene expression analyses were performed in monozygotic twins discordant for systemic lupus erythematosus (SLE) to find the genes playing important roles in SLE pathogenesis. Single nucleotide polymorphism (SNP) and copy number variation (CNV) typing, CpG methylation and gene expression were analyzed. The discordances in SNPs and CNVs were not confirmed. Both CpG methylation and gene expression levels were different for 10 genes. There were no genomic differences between monozygotic twins discordant for SLE, but epigenomic and gene expression differences were detected. These findings provide information for better understanding of SLE pathogenesis.

Association of Increased Frequencies of HLA-DPB1*05∶01 with the Presence of Anti-Ro/SS-A and Anti-La/SS-B Antibodies in Japanese Rheumatoid Arthritis and Systemic Lupus Erythematosus Patients

Introduction Autoantibodies to ribonucleoprotein are associated with a variety of autoimmune diseases, including rheumatoid arthritis (RA). Many studies on associations between human leukocyte antigen (HLA) alleles and RA have been reported, but few have been validated in RA subpopulations with anti-La/SS-B or anti-Ro/SS-A antibodies. Here, we investigated associations of HLA class II alleles with the presence of anti-Ro/SS-A or anti-La/SS-B antibodies in RA. Methods An association study was conducted for HLA-DRB1, DQB1, and DPB1 in Japanese RA and systemic lupus erythematosus (SLE) patients that were positive or negative for anti-Ro/SS-A and/or anti-La/SS-B antibodies. Results An increased prevalence of certain class II alleles was associated with the presence of anti-Ro/SS-A antibodies as follows: DRB1*08∶03 (Pc = 3.79×10−5, odds ratio [OR] 3.06, 95% confidence interval [CI] 1.98–4.73), DQB1*06∶01 (Pc = 0.0106, OR 1.70, 95%CI 1.26–2.31), and DPB1*05∶01 (Pc = 0.0040, OR 1.55, 95%CI 1.23–1.96). On the other hand, DRB1*15∶01 (Pc = 0.0470, OR 3.14, 95%CI 1.63–6.05), DQB1*06∶02 (Pc = 0.0252, OR 3.14, 95%CI 1.63–6.05), and DPB1*05∶01 (Pc = 0.0069, OR 2.27, 95% CI 1.44–3.57) were associated with anti-La/SS-B antibodies. The DPB1*05∶01 allele was associated with anti-Ro/SS-A (Pc = 0.0408, OR 1.69, 95% CI 1.19–2.41) and anti-La/SS-B antibodies (Pc = 2.48×10−5, OR 3.31, 95%CI 2.02–5.43) in SLE patients. Conclusion HLA-DPB1*05∶01 was the only allele associated with the presence of both anti-Ro/SS-A and anti-La/SS-B antibodies in Japanese RA and SLE patients.

Serum biomarker analysis of collagen disease patients with acute-onset diffuse interstitial lung disease

BackgroundInterstitial lung disease (ILD) is frequently associated with collagen diseases. The prognosis of acute-onset diffuse ILD (AoDILD) occurring in collagen disease patients is very poor. Here, we investigated serum biomarker profiles of AoDILD to find markers predicting outcome in patients with collagen diseases.MethodsA solid-phase antibody array was used for screening 274 biomarkers in pooled sera from collagen disease patients in the AoDILD state and in the stable state. Biomarkers in individual sera were detected without pooling by bead-based immunoassay.ResultsThe serum levels of matrix metalloproteinase (MMP)-1, tissue inhibitor of metalloproteinase (TIMP)-1, osteopontin, interleukin (IL)-2 receptor α(IL-2Rα), and IL-1 receptor antagonist were significantly increased in AoDILD, but TIMP-2, MMP-3, and eotaxin 2 levels were decreased. The MMP-3 to MMP-1 ratio was reduced in AoDILD state. This tendency was also observed in RA patients with AoDILD. Moreover, serum IL-6 level was significantly increased in the AoDILD state in patients with acute exacerbation of ILD (AE-ILD). Serum TIMP-1 and IL-2Rα levels were significantly increased in the AoDILD state in patients with drug-induced ILD (DI-ILD), whereas TIMP-2, MMP-3, and eotaxin 2 levels were decreased. The MMP-3 to MMP-1 ratio was reduced in AoDILD state in patients with DI-ILD. The serum TIMP-3,MMP-9, osteopontin, IL-2Rα, MMP-1, and MMP-8 levels were significantly increased in the AoDILD state in patients who subsequently died, whereas TIMP-2 and MMP-3 levels were decreased in those who survived. The MMP-3 to MMP-1 ratio was reduced in AoDILD state in patients who died, but not in those who survived.ConclusionsSerum biomarker profiles could represent prognosis markers for AoDILD in collagen diseases.

Human leukocyte antigen polymorphisms and personalized medicine for rheumatoid arthritis

Human leukocyte antigen (HLA) polymorphisms are the most important genetic risk factors for rheumatoid arthritis (RA), a chronic systemic inflammatory disease of unknown etiology. Certain HLA-DRB1 alleles, known as shared epitope (SE) alleles because they have the same amino-acid sequence at positions 70–74, are associated with susceptibility to RA. A gene dosage effect is present for RA-predisposing SE alleles, and protective alleles show epistasis. An important role of amino-acid polymorphisms at positions 11 and 13 of the HLA-DRβ chain was also reported recently. Rheumatoid factor and anticitrullinated peptide antibodies are present in many RA patients. Similar to extra-articular manifestations, the presence of these autoantibodies is also associated with certain DRB1 alleles. Different frequencies of RA risk alleles in different ethnicities explain the varying prevalence of RA in different populations and suggest genetic heterogeneity of RA with regard to phenotype and population subsets. Some drug-induced hypersensitivity reactions due to disease-modifying antirheumatic drugs are also associated with HLA alleles. Understanding the role of HLA as the most important genetic factor relevant to RA susceptibility may help in determining its pathogenesis and pave the way to personalized medicine.

Human Leukocyte Antigen and Systemic Sclerosis in Japanese: The Sign of the Four Independent Protective Alleles, DRB1*13:02, DRB1*14:06, DQB1*03:01, and DPB1*02:01.

Objective Several studies on associations between human leukocyte antigen (HLA) allele frequencies and susceptibility to systemic sclerosis (SSc) have been reported. Anti-centromere antibodies (ACA) and anti-topoisomerase I antibodies (ATA) are found in SSc patients. Here, we sought to identify HLA alleles associated with SSc in Japanese, and explored their associations with SSc phenotypes including the presence of autoantibodies. Methods Associations of HLA-DRB1, DQB1, and DPB1 were analyzed in 463 Japanese SSc patients and 413 controls. Results We found that DRB1*13:02 (P = 0.0011, Pc = 0.0319, odds ratio [OR] 0.46, 95% confidence interval [CI] 0.29–0.73), DRB1*14:06 (P = 6.60X10-5, Pc = 0.0020, OR 0.05, 95%CI 0.01–0.41), DQB1*03:01 (P = 0.0009, Pc = 0.0150, OR 0.56, 95%CI 0.40–0.79), and DPB1*02:01 (P = 5.16X10-6, Pc = 8.77X10-5, OR 0.52, 95%CI 0.39–0.69) were protectively associated with SSc. In addition, these four alleles seemed to be independently associated with the protection against the susceptibility of SSc. On the other hand, we could not find predisposing alleles for overall SSc. With respect to SSc subsets, a tendency for these four alleles to be protectively associated was observed. However, there was a significant association between DRB1*01:01, DRB1*10:01, DQB1*05:01, and DPB1*04:02 and the susceptibility to SSc with ACA. On the other hand, the presence of DRB1*15:02, DQB1*06:01, DPB1*03:01, and DPB1*09:01 was associated with SSc with ATA. Conclusion Thus, the present study has identified protective associations of the four HLA class II alleles with overall Japanese SSc and predisposing associations of HLA class II alleles with Japanese SSc subsets.

The role of common protective alleles HLA-DRB1*13 among systemic autoimmune diseases

Associations between human leukocyte antigen (HLA) and susceptibility to systemic autoimmune diseases have been reported. The predisposing alleles are variable among ethnic groups and/or diseases. On the other hand, some HLA alleles are associated with resistance to systemic autoimmune diseases, including systemic sclerosis, systemic lupus erythematosus and rheumatoid arthritis. Interestingly, DRB1*13 alleles are the protective alleles shared by multiple autoimmune diseases. DRB1*13:01 allele is protective in European populations and DRB1*13:02 in Japanese. Because alleles in multiple HLA loci are in strong linkage disequilibrium, it is difficult to determine which of the protective alleles is functionally responsible for the protective effects. Thus far, association studies suggested that DRB1*13:02 represents at least one of the causally associated protective factors against multiple systemic autoimmune diseases in the Japanese population. The protective effect of DRB1*13 alleles appears to overcome the predisposing effect of the susceptible alleles in heterozygous individuals of DRB1*13 and the susceptible allele. A gene dosage effect was observed in the associations of DRB1*13:02 with the protection from systemic autoimmune diseases; thus homozygous individuals are more effectively protected from the systemic autoimmune diseases than heterozygotes. DRB1*13:02 also confers protection against organ-specific autoimmune diseases and some infectious diseases. Several hypotheses can be proposed for the molecular mechanisms of the protection conferred by DRB1*13, some of which can explain the dominant effect of DRB1*13 molecules over the susceptible alleles, but the actual protective function of DRB1*13 requires further study. Understanding of the protective mechanisms of DRB1*13 may lead to the identification of targets for the curative treatment of systemic autoimmune diseases.

Association of human leukocyte antigen alleles with chronic lung diseases in rheumatoid arthritis

OBJECTIVES Chronic lung diseases including interstitial lung disease and airway disease (AD) occur in RA patients. Interstitial lung disease and AD in RA are extra-articular manifestations that influence the prognosis quoad vitam of RA. Studies on associations of HLA alleles with RA have been carried out, and shared epitopes of several alleles are reported to be associated with RA susceptibility. Few association studies in RA subpopulations with chronic lung diseases have been conducted. The aim of the study was to identify HLA alleles predisposing to RA phenotypes including the presence of AD. METHODS Associations of HLA-DRB1 and DQB1 alleles with chronic lung diseases in RA were analysed. RESULTS A positive association was found between the DR4 serological group and resistance to usual interstitial pneumonia [P = 0.0250, odds ratio (OR) 0.62, 95% CI: 0.41, 0.93]. The DR2 serological group was associated with susceptibility to usual interstitial pneumonia (P = 0.0036, OR = 1.86, 95% CI: 1.23, 2.81). An association was found for shared epitopes alleles with bronchiolitic AD (P = 0.0040, OR = 2.06, 95% CI: 1.24, 3.41). DQB1*03:01 was associated with bronchiectatic AD (P = 0.0021, corrected P-value (Pc) = 0.0315, OR = 1.99, 95% CI: 1.30, 3.06), as well as with emphysema (P = 0.0007, Pc = 0.0104, OR = 2.43, 95% CI: 1.49, 3.95). In combined analysis, a predisposing association of DQB1*03:01 (P = 1.94 ×10(-5), Pc = 0.0003, OR = 2.16, 95% CI: 1.53, 3.06) and a negative association of DQB1*03:02 (P = 0.0008, Pc = 0.0117, OR = 0.33, 95% CI: 0.17, 0.67) with bronchiectatic AD or emphysema were observed in RA. CONCLUSION The present study identified an association of HLA-DQB1*03:01 with predisposition to, and DQB1*03:02 with resistance to, bronchiectatic AD or emphysema in RA.