Akiko Suda

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.

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.

(18)F-FDG and (18)F-NaF PET/CT demonstrate coupling of inflammation and accelerated bone turnover in rheumatoid arthritis.

Objective. To compare the findings in rheumatoid arthritis (RA)-affected joints between 18F-fluorodeoxyglucose (FDG) and 18F-fluoride (NaF) positron emission tomography (PET)/computed tomography (CT). Methods. We enrolled twelve RA patients who started a new biologic agent (naïve 9 and switch 3). At entry, both hands were examined by 18F-FDG PET/CT, 18F-NaF PET/CT, and X-ray. Intensity of PET signals was determined by standardized uptake value max (SUVmax) in metacarpophalangeal (MCP), proximal interphalangeal (PIP), and ulnar, medial, and radial regions of the wrists. Hand X-rays were evaluated according to the Genant-modified Sharp score at baseline and 6 months. Results. Both 18F-FDG and 18F-NaF accumulated in RA-affected joints. The SUVmax of 18F-FDG correlated with that of 18F-NaF in individual joints (r = 0.65), though detail distribution was different between two tracers. 18F-NaF and 18F-FDG signals were mainly located in the bone and the surrounding soft tissues, respectively. The sum of SUVmax of 18F-NaF correlated with disease activity score in 28 joint (DAS28), modified health assessment questionnaire (MHAQ), and radiographic progression. 18F-FDG and 18F-NaF signals were associated with the presence of erosions, particularly progressive ones. Conclusion. Our data show that both 18F-FDG and 18F-NaF PET signals were associated with RA-affected joints, especially those with ongoing erosive changes.

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.

Association of a single nucleotide polymorphism in the SH2D1A intronic region with systemic lupus erythematosus.

SH2D1A, also known as signaling lymphocytic activation molecule (SLAM)-associated protein (SAP), is an adaptor protein. Recently, it was reported that SAP deficient mice were protected from systemic lupus erythematosus (SLE). In this study, we postulated SH2D1A gene to be a candidate susceptibility gene for SLE and analyzed its association with SLE. A case-control association study was conducted on 5 tag single nucleotide polymorphisms (SNPs) in SH2D1A region in 506 Japanese female SLE patients and 330 healthy female controls. The luciferase assay was performed to determine the functional role of the SNP associated with SLE. One SNP in the intron 2, rs2049995, showed association with SLE (p = 0.0110, odds ratio (OR) 1.97, 95% confidence interval (CI) 1.16–3.34, under the dominant model). The association of rs2049995 seemed to be stronger in the subset with the age of onset less than 20 years (p = 0.0067, OR 2.65, 95% CI 1.28–5.46). Functional evaluation of rs2049995 showed that reporter gene activity was increased 1.9-fold for the susceptible allele compared with the resistant allele. An intronic SNP of SH2D1A is associated with SLE.

Association of HLA-G 3’ Untranslated Region Polymorphisms with Systemic Lupus Erythematosus in a Japanese Population: A Case-Control Association Study

HLA-G plays a role in fetal-maternal tolerance as well as immunoregulation, and has been suggested to be involved in autoimmune diseases and cancers. HLA-G encodes two potentially functional polymorphisms in the 3’ untranslated region, 14bp insertion/deletion (14bp indel, rs371194629) and a single nucleotide polymorphism rs1063320, previously reported to affect HLA-G expression level or splicing isoform and to be associated with susceptibility to systemic lupus erythematosus (SLE). However, the results of SLE association studies are inconsistent, probably due to the small sample size of each study and lack of consideration of linkage disequilibrium (LD) with HLA-class II haplotypes in each population. In this study, we performed association studies of these polymorphisms on 843 patients with SLE and 778 healthy controls in a Japanese population, in many of whom HLA-DRB1 alleles have been genotyped at the four-digit level. LD was detected between DRB1*13:02, protective against multiple autoimmune diseases in the Japanese, and the rs1063320 G (D’ = 0.86, r2 = 0.02) and with 14bp del (D’ = 0.62, r2 = 0.01), but not between SLE-susceptible DRB1*15:01 and HLA-G. Although significant association with overall SLE was not detected, 14bp ins allele was significantly associated with SLE with the age of onset <20 years, when compared with healthy controls (P = 0.0067, PFDR = 0.039, OR 1.44, additive model) or with SLE patients with the age of onset ≥20 (P = 0.033, PFDR = 0.0495, OR 2.09, additive model). This association remained significant after conditioning on DRB1*13:02 or DRB1*15:01. On the other hand, significant association was detected between rs1063320 C and anti-RNP antibody and anti-Sm antibody positive SLE, which was dependent on negative LD with DRB1*13:02. eQTL analysis showed reduced HLA-G mRNA level in 14bp ins/ins individuals. In conclusion, our observations showed that HLA-G 14bp ins allele represents a genetic contribution on early-onset SLE independent of DRB1.

Association of Functional Polymorphisms in Interferon Regulatory Factor 2 (IRF2) with Susceptibility to Systemic Lupus Erythematosus: A Case-Control Association Study

Interferon regulatory factor 2 (IRF2) negatively regulates type I interferon (IFN) responses, while it plays a role in induction of Th1 differentiation. Previous linkage and association studies in European-American populations suggested genetic role of IRF2 in systemic lupus erythematosus (SLE); however, this observation has not yet been confirmed. No studies have been reported in the Asian populations. Here we investigated whether IRF2 polymorphisms contribute to susceptibility to SLE in a Japanese population. Association study of 46 IRF2 tag single nucleotide polymorphisms (SNPs) detected association of an intronic SNP, rs13146124, with SLE. When the association was analyzed in 834 Japanese patients with SLE and 817 healthy controls, rs13146124 T was significantly increased in SLE compared with healthy controls (dominant model, P = 5.4×10−4, Bonferroni-corrected P [Pc] = 0.026, odds ratio [OR] 1.48, 95% confidence interval [CI] 1.18–1.85). To find causal SNPs, resequencing was performed by next-generation sequencing. Twelve polymorphisms in linkage disequilibrium with rs13146124 (r2: 0.30–1.00) were identified, among which significant association was observed for rs66801661 (allele model, P = 7.7×10−4, Pc = 0.037, OR 1.53, 95%CI 1.19–1.96) and rs62339994 (dominant model, P = 9.0×10−4, Pc = 0.043, OR 1.46, 95%CI 1.17–1.82). The haplotype carrying both of the risk alleles (rs66801661A–rs62339994A) was significantly increased in SLE (P = 9.9×10−4), while the haplotype constituted by both of the non-risk alleles (rs66801661G–rs62339994G) was decreased (P = 0.0020). A reporter assay was carried out to examine the effect of the IRF2 haplotypes on the transcriptional activity, and association of the IRF2 risk haplotype with higher transcriptional activity was detected in Jurkat T cells under IFNγ stimulation (Tukeys test, P = 1.2×10−4). In conclusion, our observations supported the association of IRF2 with susceptibility to SLE, and the risk haplotype was suggested to be associated with transcriptional activation of IRF2.

HLA-DRB1*08:02 Is Associated with Bucillamine-Induced Proteinuria in Japanese Rheumatoid Arthritis Patients

Background Drug-induced proteinuria can occur in rheumatoid arthritis (RA) patients treated with d-penicillamine, gold salts, or bucillamine (Buc), and represents a drug hypersensitivity reaction. Striking associations of human leukocyte antigen (HLA) alleles with adverse reactions have recently been reported for many drugs. Methods We investigated the association of HLA class II with Buc-induced proteinuria (BI-Pro) in 485 Japanese RA patients treated with Buc, of whom 25 had developed BI-Pro. Results and Conclusion This preliminary study showed a highly significant association of DRB1*08:02 with BI-Pro (P = 1.09 × 10−6, corrected P [Pc] = 1.96 × 10−5, odds ratio [OR] 25.17, 95% confidence interval [CI] 7.98-79.38). DQB1*04:02 was also significantly associated with increased risk of BI-Pro (P = 2.44 × 10−5, Pc = 2.69 × 10−4, OR 10.35, 95%CI 3.99–26.83). These findings provide useful information for promoting personalized medicine for RA.