Systemic lupus erythematosus (SLE) is a multisystem, autoimmune disease that predominantly affects women. Previous findings that duplicated Toll-like receptor 7 (Tlr7) promotes lupus-like disease in male BXSB mice prompted us to evaluate TLR7 in human SLE. By using a candidate gene approach, we identified and replicated association of a TLR7 3′UTR SNP, rs3853839 (G/C), with SLE in 9,274 Eastern Asians (P combined = 6.5 × 10 −10 ), with a stronger effect in male than female subjects [odds ratio, male vs. female = 2.33 (95% CI = 1.64-3.30) vs. 1.24 (95% CI = 1.14-1.34); P = 4.1 × 10]. G-allele carriers had increased TLR7 transcripts and more pronounced IFN signature than C-allele carriers; heterozygotes had 2.7-fold higher transcripts of G-allele than C-allele. These data established a functional polymorphism in type I IFN pathway gene TLR7 predisposing to SLE, especially in Chinese and Japanese male subjects. functional polymorphism | disease susceptibility | autoimmunity | type I interferon S ystemic lupus erythematosus [SLE; Online Mendelian Inheritance in Man (OMIM) no. 152700] is a multisystem, autoimmune disease with strong genetic and environmental components (1). SLE predominantly affects women, with a female-to-male ratio of approximately 9:1. Male patients with SLE, although rare, tend to have more severe disease and poorer outcome (2), suggesting potential sex dimorphism in the disease development. Although the sex effect has often been attributed to sex hormones, the fact that XXY male subjects have approximately a 14-fold higher risk of developing SLE than 46 XY men indicates that X-linked genes may be risk factors for human SLE (3).Located at Xp22.2, Toll-like receptor 7 (TLR7; OMIM no. 300365) and its functionally related gene TLR8 (OMIM no. 300366) encode proteins that play critical roles in pathogen recognition and activation of innate immunity (4). They recognize endogenous RNA-containing autoantigens and induce the expression of type I IFN, a pivotal cytokine in the pathogenesis of SLE (5). In lupus-prone BXSB mice, the translocation of a segmental duplication of X chromosome to Y chromosome creates the Y-linked autoimmune accelerator (Yaa) locus, which was associated with autoreactive B cell responses to RNA-related antigens and exacerbation of glomerulonephritis in male mice (6). Although translocated X chromosome segment in Yaa may contain as many as 16 genes, the major gene for causation of the autoimmune phenotypes was identified to be TLR7 (7), making it a potential susceptibility gene for SLE. By using a candidate gene approach, we report herein that a functional polymorphism in 3′UTR of TLR7 is associated with SLE in Chinese and Japanese populations, with a stronger effect in male than female subjects. ResultsDiscovery and Replication of the Association of a TLR7 3′UTR SNP with SLE in Eastern Asian Population. We genotyped 27 SNPs from the TLR7-TLR8 region (12 in TLR7 and 15 in TLR8) in 1,434 SLE cases and 1,591 control subjects of Eastern Asian ancestry using the Beadstation Infinium II...

Toll-like receptors (TLRs), as innate immunity sensors, play critical roles in immune responses. Six SNPs of TLR3, TLR7, and TLR8 were genotyped to determine their associations with systemic lupus erythematosus (SLE) and clinical manifestations of SLE. TLR7 SNP rs3853839 was independently associated with SLE susceptibility in females (G vs. C: p = 0.0051). TLR7 rs3853839-G (G vs. C: p = 0.0100) and TLR8 rs3764880-G (recessive model: p = 0.0173; additive model: p = 0.0161) were associated with pericardial effusion in females relative to healthy females. Anti-SSA positive cases were more likely to have the dominant TLR7 rs179010-T allele than normal controls (p = 0.0435). TLR3 rs3775296-T was associated with photosensitivity (p = 0.0020) and anemia (p = 0.0082). The “G-G” haplotype of TLR7 rs3853839 and TLR8 rs3764880 increased risk of SLE in females (age adjusted p = 0.0032). These findings suggest that TLR variations that modify gene expression affect risk for SLE susceptibility, clinical phenotype development, and production of autoantibodies.

Objective. To investigate the possible association of the Fc␥ receptor IIb (Fc␥RIIb) Ile/Thr187 transmembrane domain polymorphism, which significantly affects receptor signaling, with susceptibility to systemic lupus erythematosus (SLE) in Taiwanese patients.Methods. We used matrix-assisted laser desorption ionization؊time-of-flight mass spectrometry to genotype 351 Taiwanese SLE patients and 372 age-and sex-matched healthy individuals from the same geographic area. Allele frequencies and genotype distributions were compared between the patients and controls, both as an aggregate and as stratified by sex, autoantibody profile, and clinical parameters. A combined analysis was conducted to assess the FCGR2B Thr187 allele as a common risk factor in different ethnic populations.Results. The minor Thr187 allele was significantly associated with SLE in Taiwanese Fc␥RIIb exhibits several apparent inhibitory activities in modulating the immune system, but not all the inhibitory activities are dependent on its distinct ITIM. Coengagement of Fc␥RIIb and other receptors containing an immunoreceptor tyrosine-based activation motif (ITAM) leads to tyrosine phosphorylation of the ITIM by Lyn kinase, recruitment of SH2 domain-containing inositol phosphatase (SHIP), inhibition of ITAMtriggered calcium mobilization, and arrest of cellular proliferation (3). Inhibition of calcium mobilization requires the phosphatase activity of SHIP to hydrolyze phosphatidylinositol 3,4,5-trisphosphate (PIP 3 ), and the

IntroductionAnkylosing spondylitis (AS) is a familial, heritable disease specified by syndesmophyte formation leading to an ankylosed spine. Endoplasmic reticulum aminopeptidase 1 (ERAP1) genetic variations have been widely proved to be associated with AS in several ethnic populations. The aim of this study was to investigate whether ERAP1 single nucleotide polymorphisms (SNPs) are associated with AS susceptibility and disease severity in Taiwanese.MethodsFour ERAP1 SNPs (rs27037, rs27980, rs27044 and rs30187) were genotyped in 797 Taiwanese AS patients and 1,150 healthy controls. Distributions of genotype and alleles were compared between AS patients and healthy controls, and among AS patients stratified by clinical parameters.ResultsThe SNP rs27037T allele appeared to be a risk factor for AS susceptibility (P = 5.5 × 10-5, OR 1.30, 95% CI: 1.15 to 1.48; GT+TT vs. GG P = 9.3 × 10-5, OR 1.49, 95% CI: 1.22 to 1.82). In addition, the coding SNP (cSNP) rs27044G allele (P = 1.5 × 10-4, OR 1.28, 95% CI: 1.13 to 1.46; CG+GG vs. CC, P = 1.7 × 10-3, OR 1.44, 95% CI: 1.15 to 1.81) and the cSNP rs30187T allele (P = 1.7 × 10-3, OR 1.23, 95% CI: 1.08 to 1.40; CT+TT vs. CC P = 6.1 × 10-3, OR 1.38, 95% CI: 1.10 to 1.74) were predisposing factors for AS. Notably, the rs27044G allele carriers (CG+GG vs. CC, P = 0.015, OR 1.59, 95% CI: 1.33 to 2.30) and rs30187T allele carriers (CT+TT vs. CC, P = 0.011, OR 1.63, 95% CI: 1.12 to 2.38) were susceptible to syndesmophyte formation in AS patients. Furthermore, two cSNPs (rs27044 and rs30187) strongly associated with HLA-B27 positivity in AS patients. Finally, the ERAP1 SNP haplotype TCG (rs27037T/rs27980C/rs27044G) is a major risk factor for AS (adjusted P <0.00001, OR 1.38, 95% CI: 1.12 to 1.58) in Taiwanese.ConclusionsThis study provides the first evidence of ERAP1 SNPs involving syndesmophyte formation. The interactions between ERAP1 SNPs and HLA-B27 play critical roles in pMHC I pathway processing contributing to the pathogenesis of AS in multiple populations.

Objectives Human complement C4 is sophisticatedly complex with multiple layers of diversity. This study aims to elucidate the CNVs of C4A and C4B in disease risk of SLE, and compare the basis of race-specific C4A-deficiency in East-Asians (EA) and Europeans. Patients and Methods Our EA study-population included 999 SLE patients and 1,347 healthy subjects. Variations in gene copy-numbers (GCNs) for total C4, C4A, C4B, long and short genes were determined and validated rigorously by independent genotyping technologies. Genomic regions with C4B96 were investigated to determine the basis of the most basic C4B protein that is concurrent with C4A-deficiency. Results In EA, strong protective effects of high GCNs for total C4 and C4A against SLE were notable; low and medium GCNs for total C4 and C4A, and the absence of short genes were risk factors of SLE. Homozygous C4A-deficiency was infrequent but had an odds-ratio (OR) of 12.4 (p=0.0015). Patients who experienced very-low serum complement were associated with low GCNs of total C4 (OR=3.27, p=7.0×10−7) and C4B (OR=2.55, p=2.5×10−5). Patients with low complement had high frequencies of anti-dsDNA (OR=4.96, p=9.7×10−17), hemolytic anemia (OR=3.89, p=3.6×10−10) and renal disease (OR=2.18, p=8.5×10−6). The monomodular-short haplotype with C4A-deficiency and in linkage-disequilibrium with HLA-DRB1*0301 prevalent in European was scarce in EA. Instead, most EA-subjects with C4A-deficiency shared a recombinant haplotype with bimodular-LS encoding C4B1 and C4B96, which was linked to HLA-DRB1*1501. DNA sequencing revealed the E920K polymorphism for C4B96. Conclusion C4 CNVs and C4A-deficiency are important in the risk and manifestations of East-Asian and European SLE.

ObjectiveTo determine whether copy number variations (CNVs) in FCGR3A and FCGR3B are associated with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) in Taiwanese individuals.MethodsFCGR3A and FCGR3B CNV genotypes were determined in 846 patients with SLE, 948 patients with RA, and 1,420 healthy control subjects, using custom TaqMan CNV assays. The FCGR3A and FCGR3B CNV genotypes were compared between healthy control subjects and patients and among patients stratified according to clinical characteristics.ResultsA low (<2) FCGR3A copy number was significantly associated with SLE (for <2 copies versus 2 copies, P = 5.06 × 10−4, false discovery rate–corrected P [PFDR] = 0.001, odds ratio [OR] 3.26, 95% confidence interval [95% CI] 1.68−6.35) and RA (for <2 copies versus 2 copies, P = 5.83 × 10−4, PFDR = 0.0012, OR 2.82, 95% CI 1.56−5.1). A low FCGR3B copy number was also significantly associated with SLE (for <2 copies versus 2 copies, P = 0.0032, PFDR = 0.0032, OR 1.59, 95% CI 1.17−2.18). Notably, a high (>2) FCGR3A copy number was also associated with SLE (for >2 copies versus 2 copies, P = 0.003, PFDR = 0.0061, OR 1.6, 95% CI 1.17−2.18). Additionally, the FCGR3A low copy number genotype was significantly enriched in subsets of patients with SLE (those with ulcer, arthritis, rash, discoid rash, photosensitivity, nephritis, leukopenia, thrombocytopenia, depressed complement levels, and autoantibody positivity) and patients with RA (those positive for rheumatoid factor) compared with healthy control subjects. The FCGR3B low copy number genotype was also significantly enriched in SLE patients with ulcer, rash, discoid rash, photosensitivity, ascites, nephritis, complement level depression, and anti–double-stranded DNA antibody positivity compared with control subjects. However, FCGR3B CNVs were not associated with RA susceptibility (for <2 copy numbers versus 2 copy numbers, P = 0.3584, OR 1.15, 95% CI 0.85–1.55) and clinical characteristics.ConclusionIn Taiwanese individuals, a low FCGR3A copy number is a common risk factor for SLE and RA, while a low FCGR3B copy number confers a risk of SLE but not RA.

BackgroundType III interferons (IFNs) or IFN-λs are the newly discovered cytokines that primarily target the cells of epithelial and myeloid lineages, which are major components of kidneys. The current study aimed to investigate whether IFN-λs are involved in the pathogenesis of systemic lupus erythematosus (SLE) and lupus nephritis.MethodsTaqMan allele discrimination assays were used to determine IFNL3/4 SNP genotypes of 1620 healthy controls and 1013 SLE patients (two independent cohorts consisting of 831 and 182 subjects, respectively) from Taiwan. The distributions of IFNL3/4 SNP genotypes and allele frequencies were compared between SLE patients and healthy controls and among SLE patients stratified by clinical phenotypes. ELISA was used to determine the serum IFN-λ3 concentrations of SLE patients.ResultsAll major IFN3/4 SNP alleles were significantly associated with the risk for lupus nephritis (rs8099917T, PFDR = 0.0021, OR 1.75, 95% CI 1.24–2.47; rs12979860C, PFDR = 0.0034, OR 1.65, 95% CI 1.18–2.30; rs4803217C, PFDR = 0.0021, OR 1.76, 95% CI 1.25–2.48; and ss469415590TT, PFDR = 0.0021, OR 1.73, 95% CI 1.23–2.42) among SLE patients. Similarly, the major IFNL3/4 SNP haplotype rs8099917T-ss469415590TT-rs12979860C-rs4803217C (or T-TT-C-C) was a significant risk factor for lupus nephritis (P = 0.0015, OR 1.68, 95% CI 1.22–2.32). Additionally, all minor IFN3/4 SNP alleles were significantly associated with SLE susceptibility in nephritis-negative SLE patients as compared to normal healthy controls (rs8099917G, PFDR = 0.00177, OR 1.68, 95% CI 1.24–2.28; rs12979860T, PFDR = 0.00299, OR 1.58, 95% CI 1.18–2.32; rs4803217A, PFDR = 0.00176, OR 1.65, 95% CI 1.22–2.23; and ss469415590ΔG, PFDR = 0.00176, OR 1.70, 95% CI 1.26–2.29). Furthermore, the elevated serum levels of IFN-λ3 were significantly correlated with the complement depression and the high SLE disease activities in SLE patients.ConclusionsIFN-λ3/4 genetic variants play a unique role in the development of lupus nephritis and SLE.Electronic supplementary materialThe online version of this article (10.1186/s13075-018-1683-z) contains supplementary material, which is available to authorized users.

Ankylosing spondylitis (AS) is a chronic inflammatory disease that leads to spinal ankylosis. The receptor activator of the nuclear factor-kappa (RANK), RANK ligand, and osteoprotegerin (OPG) (RANK/RANKL/OPG) pathway plays critical roles in bone metabolism and the immune system. The current study was aimed at investigating whether six single-nucleotide polymorphisms (SNPs) within the RANK, RANKL, and OPG genes essential for bone homeostasis are associated with AS. Genotype distributions, allele and haplotype frequencies, were compared between 1120 AS patients and 1435 healthy controls and among AS patients with stratification by syndesmophyte formation, onset age, and HLA-B27 positivity. We found that RANKL SNPs were associated with AS syndesmophyte formation. Notably, the RANKL SNP haplotype rs7984870C/rs9533155G/rs9525641C was negatively associated with AS susceptibility and appeared to protect against syndesmophyte formation in AS. Functionally, RANKL promoter SNPs (rs9525641 C/T and rs9533155 G/C) affected DNA-protein complex formation and promoter activity in promoter reporter analyses. The OPG SNP haplotype rs2073618G/rs3102735T was significantly associated with HLA-B27 negativity in AS patients. Furthermore, AS patients with syndesmophyte formation had significantly lower levels of soluble RANKL levels than those without syndesmophyte formation. Our data suggested a role for RANKL in AS susceptibility and severity.