Genetic dissection of HLA-DRB1*15:01 and XL9 region variants in Japanese patients with systemic lupus erythematosus: primary role for HLA-DRB1*15:01.

OBJECTIVE: Major histocompatibility complex strongly contributes to susceptibility to systemic lupus erythematosus (SLE). In the European populations, HLA-DRB1*03:01 and DRB1*15:01 are susceptibility alleles, but C4 locus was reported to account for the association of DRB1*03:01. With respect to DRB1*15:01, strong linkage disequilibrium with a variant rs2105898T in the XL9 region, located between DRB1 and DQA1 and regulates HLA-class II expression levels, was reported; however, the causative allele remains to be determined. Leveraging the genetic background of the Japanese population, where DRB1*15:01 and DRB1*15:02 are commonly present and only DRB1*15:01 is associated with SLE, this study aimed to distinguish the genetic contribution of DRB1*15:01 and XL9 variants. METHODS: Among the XL9 variants, two (rs2105898 and rs9271593) previously associated variants in the European populations and two (rs9271375 and rs9271378) which showed a trend towards association in a Japanese Genome-Wide Association Study were selected. Associations of the XL9 variants and HLA-DRB1 were examined in 442 Japanese SLE patients and 779 controls. Genotyping of the XL9 variants was performed by TaqMan SNP Genotyping Assay and direct sequencing. HLA-DRB1 alleles were determined by PCR-reverse sequence-specific oligonucleotide probes. RESULTS: Among the XL9 variants, associations of rs2105898T and rs9271593C were replicated in the Japanese population. However, these associations became no longer significant when conditioned on DRB1*15:01. In contrast, the association of DRB1*15:01 remained significant after conditioning on the XL9 variants. CONCLUSION: In the Japanese population, HLA-DRB1*15:01 was found to be primarily associated with SLE, and to account for the apparent association of XL9 region.

Clinical and Biomarker Responses to BI 655064, an Antagonistic Anti-CD40 Antibody, in Patients With Active Lupus Nephritis: A Randomized, Double-Blind, Placebo-Controlled, Phase II Trial.

OBJECTIVE: To characterize its dose-response relationship, BI 655064 (an anti-CD40 monoclonal antibody) was tested as an add-on to mycophenolate and glucocorticoids in patients with active lupus nephritis (LN). METHODS: A total of 121 patients were randomized (2:1:1:2) to receive placebo or BI 655064 120, 180, or 240 mg and received a weekly loading dose for 3 weeks followed by dosing every 2 weeks for the 120 and 180 mg groups, and 120 mg weekly for the 240 mg group. The primary endpoint was complete renal response (CRR) at week 52. Secondary endpoints included CRR at week 26. RESULTS: A dose-response relationship with CRR at week 52 was not shown (BI 655064 120 mg, 38.3%; 180 mg, 45.0%; 240 mg, 44.6%; placebo, 48.3%). At week 26, 28.6% (120 mg), 50.0% (180 mg), 35.0% (240 mg), and 37.5% (placebo) achieved CRR. The unexpected high placebo response prompted a post hoc analysis evaluating confirmed CRR (cCRR, at weeks 46 and 52). cCRR was achieved in 22.5% (120 mg), 44.3% (180 mg), 38.2% (240 mg), and 29.1% (placebo) of patients. Most patients reported ≥1 adverse event (BI 655064, 85.7-95.0%; placebo, 97.5%), most frequently infections and infestations (BI 655064 61.9-75.0%; placebo 60%). Compared with other groups, higher rates of serious (20% vs. 7.5-10%) and severe infections (10% vs. 4.8-5.0%) were reported with 240 mg BI 655064. CONCLUSION: The trial failed to demonstrate a dose-response relationship for the primary CRR endpoint. Post hoc analyses suggest a potential benefit of BI 655064 180 mg in patients with active LN.

Grafting of autologous concentrated bone marrow processed using a point-of-care device for patients with osteonecrosis of the femoral head: A phase 1 feasibility and safety study.

Introduction: Along with the accumulating reports of autologous concentrated bone marrow (CBM) grafting for osteonecrosis of the femoral head (ONFH), the related medical device, a "point-of-care device" has also been recently developed. However, no study has confirmed the feasibility, safety, and efficiency of CBM grafting using a specific point-of-care device. Materials and methods: We designed this phase I, prospective clinical study to evaluate the feasibility and safety of autologous CBM grafting processed using a point-of-care device, the BioCUE system, in patients with ONFH. The primary outcomes were the safety and adverse event (AE), the secondary outcomes included pain score; hip function score; ONFH stage using X-ray; and the volume of the osteonecrotic area on 3T MRI. Besides, safety quality tests on the final product of concentrated bone marrow were performed. Results: Two patients (a 34-year-old man and a 33-year-old woman; three hips) with systemic lupus erythematosus were included. The incidence of AEs was 100% such as pain or transient fever after the operation, but all AEs were nonserious. No peri-operative complications were observed. Pain and hip function score remained unchanged from the preoperative to the postoperative observational periods. Safety quality test demonstrated were all negative or under the threshold. Conclusion: The feasibility and safety of grafting of concentrated autologous CBM in patients with ONFH using a point-of-care device were confirmed. A further clinical study aiming for the authorization of this procedure should be conducted in the future.

Branched chain amino acids in the treatment of polymyositis and dermatomyositis: a phase II/III, multi-centre, randomized controlled trial.

OBJECTIVES: To assess the efficacy and safety of branched chain amino acids (BCAAs) in the treatment of PM/DM prior to official approval of their use in Japan. METHODS: Treatment naïve adults with PM/DM were enrolled in a randomized, double-blind trial to receive either TK-98 (drug name of BCAAs) or placebo in addition to conventional treatment. After 12 weeks, patients with an average manual muscle test (MMT) score <9.5 were enrolled in an open label extension study for a further 12 weeks. The primary endpoint was the change of the MMT score at 12 weeks. The secondary endpoints were the clinical response and the change of functional index (FI). RESULTS: Forty-seven patients were randomized either to the TK-98 (n = 24) or placebo (n = 23) group. The changes of MMT scores at 12 weeks were 0.70 (0.19) [mean (s.e.m.)] and 0.69 (0.18), respectively (P = 0.98). Thirteen patients from the TK-98 group and 12 from the placebo group were enrolled in the extension study. The MMT scores in both groups improved similarly. The increase of the FI scores of the shoulder flexion at 12 weeks was significantly greater in the TK-98 group [27.9 (5.67) vs 12.8 (5.67) for the right shoulder flexion, and 27.0 (5.44) vs 13.4 (5.95) for the left shoulder; P < 0.05]. Frequencies of adverse events up to 12 weeks were similar. CONCLUSION: BCAAs showed no effect on the improvement of the muscle strength evaluated by MMT and the clinical response. However, they were partly effective for improving dynamic repetitive muscle functions. TRIAL REGISTRATION: UMIN-CTR Clinical Trial, https://center6.umin.ac.jp/, UMIN000016233.

Anti-TLR7 Antibody Protects Against Lupus Nephritis in NZBWF1 Mice by Targeting B Cells and Patrolling Monocytes.

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by autoantibody production and multiple organ damage. Toll-like receptor 7 (TLR7), an innate immune RNA sensor expressed in monocytes/macrophages, dendritic cells (DCs), and B cells, promotes disease progression. However, little is known about the cellular mechanisms through which TLR7 drives lupus nephritis. Here, we show that the anti-mouse TLR7 mAb, but not anti-TLR9 mAb, protected lupus-prone NZBWF1 mice from nephritis. The anti-TLR7 mAb reduced IgG deposition in glomeruli by inhibiting the production of autoantibodies to the RNA-associated antigens. We found a disease-associated increase in Ly6Clow patrolling monocytes that expressed high levels of TLR7 and had upregulated expression of lupus-associated IL-10, CD115, CD31, and TNFSF15 in NZBWF1 mice. Anti-TLR7 mAb abolished this lupus-associated increase in patrolling monocytes in the circulation, spleen, and glomeruli. These results suggested that TLR7 drives autoantibody production and lupus-associated monocytosis in NZBWF1 mice and, that anti-TLR7 mAb is a promising therapeutic tool targeting B cells and monocytes/macrophages.

2020 guide for the diagnosis and treatment of interstitial lung disease associated with connective tissue disease.

The prognosis of patients with connective tissue disease (CTD) has improved significantly in recent years, but interstitial lung disease (ILD) associated with connective tissue disease (CTD-ILD) remains a refractory condition, which is a leading cause of mortality. Because it is an important prognostic factor, many observational and interventional studies have been conducted to date. However, CTD is a heterogeneous group of conditions, which makes the clinical course, treatment responses, and prognosis of CTD-ILD extremely diverse. To summarize the current understanding and unsolved questions, the Japanese Respiratory Society and the Japan College of Rheumatology collaborated to publish the world's first guide focusing on CTD-ILD, based on the evidence and expert consensus of pulmonologists and rheumatologists, along with radiologists, pathologists, and dermatologists. The task force members proposed a total of 27 items, including 7 for general topics, 9 for disease-specific topics, 3 for complications, 4 for pharmacologic treatments, and 4 for non-pharmacologic therapies, with teams of 2-4 authors and reviewers for each item to prepare a consensus statement based on a systematic literature review. Subsequently, public opinions were collected from members of both societies, and a critical review was conducted by external reviewers. Finally, the task force finalized the guide upon discussion and consensus generation. This guide is expected to contribute to the standardization of CTD-ILD medical care and is also useful as a tool for promoting future research by clarifying unresolved issues.

Combining maintenance therapy with hydroxychloroquine increases LLDAS achievement rates in individuals with stable systemic lupus erythematosus.

BACKGROUND: Hydroxychloroquine (HCQ) has been positioned as an anchor drug for systemic lupus erythematosus (SLE). There is evidence supporting the benefits of HCQ; however, the effect of additional HCQ in maintenance therapy remains unclear. METHODS: Thirty patients with SLE who visited Juntendo University Hospital were receiving maintenance therapy before HCQ treatment and were able to complete more than 104 weeks of HCQ treatment were analyzed. Anti-DNA antibody titers, IgG and CH50 levels, the maintenance dose of corticosteroids, the SLE disease activity index (SLEDAI), and the achievement of the Lupus Low Disease Activity State (LLDAS) were evaluated at baseline and at 12, 24, 52, and 104 weeks after HCQ initiation. RESULTS: We observed improvements in the anti-DNA antibody titers, IgG and CH50 levels, maintenance dose of corticosteroids, and SLEDAI at week 104 relative to baseline. Moreover, the LLDAS achievement rate increased over time from 10% at baseline to 43% and 80% at week 52 and week 104, respectively. CONCLUSION: Two years of continuous HCQ treatment led to improvements in SLE disease activity and corticosteroid dose and an increase in LLDAS achievement, thereby demonstrating the significance of the maintenance dose of HCQ for the management of SLE.

First external validation of sensitivity and specificity of the European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) classification criteria for idiopathic inflammatory myopathies with a Japanese cohort.

OBJECTIVE: To externally validate the performance of the new European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) classification criteria set for idiopathic inflammatory myopathies (IIM) with a Japanese cohort. METHODS: This study included 420 IIM and 402 non-IIM cases. Probability of having IIM in each patient was calculated using the collected data set. The cut-off probability was set at 55%, as recommended by EULAR/ACR. Patients classified as IIM by the criteria were further subclassified with classification trees. RESULTS: When the probability cut-off was set at 55%, the sensitivity/specificity of the new criteria to diagnose IIM were 89.3%/91.0% in the total cohort, 88.1%/95.1% without muscle biopsy data and 90.4%/65.5% with biopsy data. The cohort included 12 overlap syndrome patients with biopsy data, who were included as non-IIM cases in accordance with traditional Japanese methods. When they were included in the IIM cases, the specificity in patients with biopsy increased to 74.4%. The sensitivity/specificity of the new criteria to diagnose polymyositis/dermatomyositis (PM/DM) plus juvenile and amyopathic DM in the Japanese cohort was 87.4%/92.4%, which were greater than those of the Tanimoto's criteria revised to enable classification of amyopathic DM (ADM) (71.2%/87.8%) and were comparable with those of Bohan & Peter's criteria to diagnose those diseases except for ADM (88.4%/88.3%). CONCLUSIONS: Our study externally validated high specificity of the new criteria for the first time, although with several limitations, including low percentage of child patients. The new criteria have higher sensitivity and/or specificity in classification of PM/DM than the previously reported criteria, demonstrating its usefulness for interethnic patients.

A Critical Role for Mucosal-Associated Invariant T Cells as Regulators and Therapeutic Targets in Systemic Lupus Erythematosus.

Mucosal-associated invariant T (MAIT) cells are a subset of innate-like lymphocytes that are restricted by major histocompatibility complex-related molecule 1 (MR1). In this study, we investigated the role of MAIT cells in the pathogenesis of lupus in FcγRIIb-/-Yaa mice, a spontaneous animal model of lupus. Using two approaches of MAIT cell deficiency, MR1 knockout animals and a newly synthesized inhibitory MR1 ligand, we demonstrate that MAIT cells augment the disease course of lupus by enhancing autoantibody production and tissue inflammation. MR1 deficiency reduced germinal center responses and T cell responses in these mice. Suppression of MAIT cell activation by the inhibitory MR1 ligand reduced autoantibody production and lupus nephritis in FcγRIIb-/-Yaa mice. MAIT cells directly enhanced autoantibody production by B cells in vitro. Our results indicate the contribution of MAIT cells to lupus pathology and the potential of these cells as novel therapeutic targets for autoimmune diseases such as lupus.

Association of NCF1 polymorphism with systemic lupus erythematosus and systemic sclerosis but not with ANCA-associated vasculitis in a Japanese population.

Genome-wide association studies of systemic lupus erythematosus (SLE) in Chinese and Korean populations demonstrated strong association of single nucleotide polymorphisms (SNPs) located in the GTF2I-NCF1 region, rs73366469 (GTF2I), rs117026326 (GTF2I), rs80346167(GTF2IRD1) and rs201802880 (NCF1). This region has also been associated with susceptibility to Sjögren syndrome and rheumatoid arthritis; however, association studies with systemic sclerosis (SSc) and ANCA-associated vasculitis (AAV) have not been reported. Here we made an attempt to confirm their associations with SLE in the Japanese population, to find the primarily associated SNP, and to investigate whether these SNPs are also associated with susceptibility to SSc and AAV. By genotyping these four SNPs on 842 SLE, 467 SSc, 477 AAV patients and 934 healthy controls, striking association was confirmed in Japanese SLE. In addition, these SNPs were significantly associated with susceptibility to SSc, but not with AAV. Conditional logistic regression analysis revealed that the association of NCF1 rs201802880, a missense SNP encoding p.Arg90His, can account for the association of other SNPs by linkage disequilibrium. These results suggested that GTF2I-NCF1 region is associated with susceptibility to multiple autoimmune rheumatic diseases but not with AAV, and the primarily associated variant may be the missense SNP in NCF1.

FcγRIIb on B Cells and Myeloid Cells Modulates B Cell Activation and Autoantibody Responses via Different but Synergistic Pathways in Lupus-Prone Yaa Mice.

C57BL/6 (B6).FcγRIIb-/- Yaa mice spontaneously develop lethal lupus nephritis. To define the cell type-specific role of FcγRIIb in Yaa-associated lupus, we established B cell- (CD19Cre Yaa), myeloid cell- (C/EBPαCre Yaa), and dendritic cell- (DC) (CD11cCre Yaa) specific FcγRIIb-deficient B6.Yaa mouse strains. CD19Cre Yaa mice developed milder lupus than B6.FcγRIIb-/- Yaa mice, indicating that FcγRIIb deficiency on B cells is not sufficient for the development of severe disease. Surprisingly, C/EBPαCre Yaa mice also showed autoantibody production and mild lupus similar to that in CD19Cre Yaa mice, whereas CD11cCre Yaa mice stayed disease free. These observations indicate that FcγRIIb deficiency in B cells and myeloid cells, but not DCs, contributes to the severe disease in B6.FcγRIIb-/- Yaa mice. Flow cytometric analysis showed that the frequency of peripheral Gr-1- but not Gr-1+ monocyte was increased in B6.FcγRIIb-/- Yaa and C/EBPαCre Yaa but not CD19Cre Yaa mice, suggesting a link between FcγRIIb deficiency on myeloid cells and the high frequency of Gr-1- monocytes. RNA sequencing revealed that compared with Gr-1+ monocytes, Gr-1- monocytes expressed higher levels of the B cell-stimulating cytokines BSF-3, IL-10, and IL-1ß, the DC markers CD11c, CD83, and Adamdec1, and the antiapoptotic factors Bcl2 and Bcl6. In conclusion, in Yaa-associated lupus nephritis, FcγRIIb on B cells and myeloid cells modulates B cell activation via different but synergistic pathways. Gr-1- monocytes are the most likely candidate myeloid cells involved.

Anti-CD11b antibody treatment suppresses the osteoclast generation, inflammatory cell infiltration, and autoantibody production in arthritis-prone FcγRIIB-deficient mice.

BACKGROUND: Previously we established an arthritis-prone FcγRIIB-deficient mouse strain (designated KO1). Anti-mouse CD11b mAb (5C6) has been reported to inhibit the recruitment of peripheral CD11b+ myelomonocytic cells from the blood to the inflammatory site. These cells include neutrophils and monocytes, both of which play important roles in the development of arthritis. Here we treated KO1 mice with 5C6 mAb in order to study its effect on arthritis development. METHODS: To evaluate the disease-preventive effect of 5C6, 4-month-old preclinical KO1 mice were divided into three groups: the first treated with 5C6 for 6 months, the second treated with normal rat IgG for 6 months, as a control, and the third left untreated. Arthritis severity and immunological abnormalities were compared among the groups, along with transcriptional levels of several important arthritis-related factors in ankle joints, spleen, and peripheral blood cells. RESULTS: The 5C6 treatment ameliorated arthritis in KO1 mice, showing decreases in inflammatory cell infiltration and osteoclast formation. Analysis of transcriptional levels in ankle joints revealed that compared with the two control groups, the 5C6-treated group showed downregulated expression of RANK, RANKL, MCP-1, RANTES, TNFα, and IL-6, and at the same time showed significantly up-regulated expression of the decoy receptor for RANKL, i.e. osteoprotegerin. In addition, the disease suppression was associated with the lower serum levels of autoantibodies, and the decreased frequencies of activated B cells and plasma cells. The expression levels of B cell activation/differentiation-related cytokines were suppressed in spleen and peripheral leukocytes of the 5C6-treated mice. Intriguingly, while untreated KO1 mice spontaneously developed marked monocytosis, the 5C6-treated mice showed the significantly down-regulated frequency of monocytes. CONCLUSIONS: The outcome of 5C6 treatment was complex, in which the 5C6-mediated disease-preventive effect is likely due on one hand to the decrease in the recruitment of inflammatory cells and osteoclast precursor monocytes from the periphery into the joints, and on the other hand to the suppression of B cell activation/maturation and of autoantibody production via the suppression of B cell stimulating cytokine production. The lower levels of these cytokines may be the secondary effect of the lower frequency of monocytes, since monocytes/macrophages are the major producers of these cytokines.

Splicing variant of WDFY4 augments MDA5 signalling and the risk of clinically amyopathic dermatomyositis.

OBJECTIVES: Idiopathic inflammatory myopathies (IIMs) are a heterogeneous group of rare autoimmune diseases in which both genetic and environmental factors play important roles. To identify genetic factors of IIM including polymyositis, dermatomyositis (DM) and clinically amyopathic DM (CADM), we performed the first genome-wide association study for IIM in an Asian population. METHODS: We genotyped and tested 496 819 single nucleotide polymorphism for association using 576 patients with IIM and 6270 control subjects. We also examined the causal mechanism of disease-associated variants by in silico analyses using publicly available data sets as well as by in in vitro analyses using reporter assays and apoptosis assays. RESULTS: We identified a variant in WDFY4 that was significantly associated with CADM (rs7919656; OR=3.87; P=1.5×10-8). This variant had a cis-splicing quantitative trait locus (QTL) effect for a truncated WDFY4isoform (tr-WDFY4), with higher expression in the risk allele. Transexpression QTL analysis of this variant showed a positive correlation with the expression of NF-κB associated genes. Furthermore, we demonstrated that both WDFY4 and tr-WDFY4 interacted with pattern recognition receptors such as TLR3, TLR4, TLR9 and MDA5 and augmented the NF-κB activation by these receptors. WDFY4 isoforms also enhanced MDA5-induced apoptosis to a greater extent in the tr-WDFY4-transfected cells. CONCLUSIONS: As CADM is characterised by the appearance of anti-MDA5 autoantibodies and severe lung inflammation, the WDFY4 variant may play a critical role in the pathogenesis of CADM.

Evaluation of the alternative classification criteria of systemic lupus erythematosus established by Systemic Lupus International Collaborating Clinics (SLICC).

OBJECTIVE: To evaluate the performance of the 2012 Systemic Lupus International Collaborating Clinics criteria (SLICC-12) on classifying systemic lupus erythematosus (SLE) in an uncontrolled multi-centered study with real-life scenario of the patients in Japan. METHODS: This study comprised 495 patients with SLE or non-SLE rheumatic diseases and allied conditions from 12 institutes in Japan. Chart review of each patient was performed by the 27 expert rheumatologists and diagnosis of 487 cases reached to the consensus. Value of the SLICC-12 on SLE classification was analyzed comparing with the 1997 revised American College of Rheumatology SLE classification criteria (ACR-97) employing the expert-consented diagnoses. RESULTS: Compared to the ACR-97, the SLICC-12 had a higher sensitivity (ACR-97 vs. SLICC-12: 0.88 vs. 0.99, p < .01) and comparable specificity (0.85 vs. 0.80). The rate of misclassification (0.14 vs. 0.11) or the area under the receiver operating characteristic curves (0.863 vs. 0.894) was not statistically different. In the cases that diagnoses corresponded in high rates among experts, both criteria showed high accordance of SLE classification over 85% with the expert diagnoses. CONCLUSION: Although employment of SLICC-12 for the classification for SLE should be carefully considered, the SLICC-12 showed the higher sensitivity on classifying SLE in Japanese population.

Disease flare patterns and predictors of systemic lupus erythematosus in a monocentric cohort of 423 Japanese patients during a long-term follow-up: The JUDE study.

OBJECTIVE: To clarify the clinical features of systemic lupus erythematosus (SLE) patients, factors associated with flares, and changes over time. METHODS: Patients having SLE with a visiting history were entered into the Juntendo University Database of Erythematosus. We included 423 cases in the long-term follow-up analysis, and 383 cases were followed for 10 years after the initiation of any therapeutic intervention (comparative analysis: 1973-1982, 82 cases; 1983-1992, 141, and 1993-2002, 160). We assessed changes in the patients' background characteristics, disease symptoms, flare rates, etc. RESULTS: Among the 423 cases, the mean follow-up period was 25.9 years, and mean number of flares was 0.51. Of those, 31.9% had ≥1 flares. Thrombocytopenia at onset contributed to the flares. For disease symptoms at onset, a recent trend in increasing thrombocytopenia was observed. The combination rate of immunosuppressive agents for diseases other than lupus nephritis was slightly increased, and there was no improvement until the first flare or in the flare rate. CONCLUSIONS: Thrombocytopenia at onset is predictive factor for flares. Since SLE is a diverse disease with varying symptoms at recurrence, the treatment guidelines should be improved for thrombocytopenia from a long-term perspective.

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.

Second-to-fourth Digit Ratio in Systemic Lupus Erythematosus.

OBJECTIVE: Systemic lupus erythematosus (SLE) occurs predominantly in women, and sex hormones play an important role in SLE. Variation in the second-to-fourth digit ratio (2D4D ratio) is attributed to sex hormone exposure. Therefore, we evaluated the relationship between sex hormones and SLE by measuring 2D4D ratios. METHODS: We measured 2D4D ratios in 100 patients with SLE and 200 normal healthy controls (NHC). RESULTS: Patients with SLE had a lower 2D4D ratio than NHC. CONCLUSION: Our study suggests that patients with SLE have experienced high prenatal testosterone and low prenatal estrogen. To our knowledge, this is the first study evaluating the association between 2D4D ratio and SLE.

IL-6 signal blockade ameliorates the enhanced osteoclastogenesis and the associated joint destruction in a novel FcγRIIB-deficient rheumatoid arthritis mouse model.

OBJECTIVE: We earlier found that TNFα but not interleukin (IL)-17 is indispensable in the pathogenesis of spontaneously occurring rheumatoid arthritis (RA)-like disease in our newly established FcγRIIB-deficient C57BL/6 (B6) mouse model, designated KO1. Here, we examined the role of IL-6 in the pathogenesis of RA features in KO1, with particular reference to cartilage and bone destruction in arthritic joints. METHODS: To evaluate the preventive effect of MR16-1, a rat anti-mouse IL-6 receptor (IL-6R) mAb, 4-month-old preclinical KO1 mice were divided into three groups: the first treated with MR16-1 for 6 months, the second treated with normal rat IgG, as a control, and the third left untreated. The incidence and severity of arthritis, immunological abnormalities, and transcription levels of receptor activator of NF-κB ligand (RANKL), osteoprotegerin (OPG), and inflammatory cytokines/chemokines in ankle joint tissues were compared among the three groups. The therapeutic effect of MR16-1 was examined by treating 7-month-old KO1 mice in the early stages of arthritis for 2 months. RESULTS: Compared with the findings in the KO1 mice left untreated or treated with normal rat IgG, the development of arthritis was markedly suppressed in mice with MR16-1 treatment started from preclinical stages. The suppression was associated with the decrease in production of autoantibodies, rheumatoid factors (RF), and anti-cyclic citrullinated peptide (CCP). Histologically, marked synovitis, pannus formation, and cartilage and bone destruction associated with the increase in tartrate-resistant acid phosphatase (TRAP)-positive osteoclast generation were evident in the two control groups; however, these findings were virtually absent in MR16-1-treated mice. Real-time PCR analysis revealed that the up-regulated expression levels of MCP-1, IL-6, and TNFα, and the aberrantly high RANKL/OPG expression ratio in synovial joint tissues from the two control groups of mice with overt arthritis were significantly suppressed in MR16-1-treated mice. In mice with therapeutic MR16-1 treatment, there was no progression in arthritis score and the RANKL/OPG ratio in joint tissues was significantly suppressed. CONCLUSIONS: Administration of an anti-IL-6R mAb ameliorated spontaneously occurring RA-like disease features, indicating that IL-6, as well as TNFα, plays a pivotal role in the pathogenesis of RA in KO1 mice. Current studies showed that, in addition to the role in enhancing autoantibody production, IL-6 promotes synovial tissue inflammation and osteoclastogenesis, leading to the severe synovitis with pannus formation and the progressive cartilage and bone destruction in multiple joints.

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 (Tukey's 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.