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Objective: The increased risk of thrombosis in systemic lupus erythematosus (SLE) may be partially explained by interrelated genetic pathways for thrombosis and SLE. The present study was undertaken to investigate whether 33 established and novel single-nucleotide polymorphisms (SNPs) in 20 genes involved in hemostasis pathways that have been associated with deep venous thrombosis (DVT) in the general population are risk factors for SLE among Asian subjects., Methods: Patients in the discovery cohort were enrolled in 1 of 2 North American SLE cohorts. Patients in the replication cohort were enrolled in 1 of 4 Asian or 2 North American cohorts. We first genotyped 263 Asian patients with SLE and 357 healthy Asian control subjects for 33 SNPs in the discovery phase, and then genotyped 5 SNPs in up to an additional 1,496 patients and 993 controls in the replication phase. Patients were compared to controls for bivariate association with minor alleles. Principal components analysis was used to control for intra-Asian ancestry in the replication cohort., Results: Two genetic variants in the gene VKORC1 were highly significant in both the discovery and replication cohorts: rs9934438 (in the discovery cohort, odds ratio [OR] 2.45, P=2×10(-9); in the replication cohort, OR 1.54, P=4×10(-6)) and rs9923231 (in the discovery cohort, OR 2.40, P=6×10(-9); in the replication cohort, OR 1.53, P=5×10(-6)). These associations were significant in the replication cohort after adjustment for intra-Asian ancestry: for rs9934438, OR 1.34, P=0.0029; for rs9923231, OR 1.34, P=0.0032., Conclusion: Genetic variants in VKORC1, which are involved in vitamin K reduction and associated with DVT, correlate with SLE development in Asian subjects. These results suggest that there may be intersecting genetic pathways for the development of SLE and thrombosis., (Copyright © 2013 by the American College of Rheumatology.)

Objective: American Indian-Europeans, Asians, and African Americans have an excess morbidity from systemic lupus erythematosus (SLE) and a higher prevalence of lupus nephritis than do Caucasians. The aim of this study was to analyze the relationship between genetic ancestry and sociodemographic characteristics and clinical features in a large cohort of American Indian-European SLE patients., Methods: A total of 2,116 SLE patients of American Indian-European origin and 4,001 SLE patients of European descent for whom we had clinical data were included in the study. Genotyping of 253 continental ancestry-informative markers was performed on the Illumina platform. Structure and Admixture software were used to determine genetic ancestry proportions of each individual. Logistic regression was used to test the association between genetic ancestry and sociodemographic and clinical characteristics. Odds ratios (ORs) were calculated with 95% confidence intervals (95% CIs)., Results: The average American Indian genetic ancestry of 2,116 SLE patients was 40.7%. American Indian genetic ancestry conferred increased risks of renal involvement (P < 0.0001, OR 3.50 [95% CI 2.63- 4.63]) and early age at onset (P < 0.0001). American Indian ancestry protected against photosensitivity (P < 0.0001, OR 0.58 [95% CI 0.44-0.76]), oral ulcers (P < 0.0001, OR 0.55 [95% CI 0.42-0.72]), and serositis (P < 0.0001, OR 0.56 [95% CI 0.41-0.75]) after adjustment for age, sex, and age at onset. However, age and sex had stronger effects than genetic ancestry on malar rash, discoid rash, arthritis, and neurologic involvement., Conclusion: In general, American Indian genetic ancestry correlates with lower sociodemographic status and increases the risk of developing renal involvement and SLE at an earlier age., (Copyright © 2012 by the American College of Rheumatology.)

Objective: Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by autoantibody production and altered type I interferon expression. Genetic surveys and genome-wide association studies have identified >30 SLE susceptibility genes. One of these genes, TNIP1, encodes the ABIN1 protein. ABIN1 functions in the immune system by restricting NF-κB signaling. The present study was undertaken to investigate the genetic factors that influence association with SLE in genes that regulate the NF-κB pathway., Methods: We analyzed a dense set of genetic markers spanning TNIP1 and TAX1BP1, as well as the TNIP1 homolog TNIP2, in case-control populations of diverse ethnic origins. TNIP1, TNIP2, and TAX1BP1 were fine-mapped in a total of 8,372 SLE cases and 7,492 healthy controls from European-ancestry, African American, Hispanic, East Asian, and African American Gullah populations. Levels of TNIP1 messenger RNA (mRNA) and ABIN1 protein in Epstein-Barr virus-transformed human B cell lines were analyzed by quantitative reverse transcription-polymerase chain reaction and Western blotting, respectively., Results: We found significant associations between SLE and genetic variants within TNIP1, but not in TNIP2 or TAX1BP1. After resequencing and imputation, we identified 2 independent risk haplotypes within TNIP1 in individuals of European ancestry that were also present in African American and Hispanic populations. Levels of TNIP1 mRNA and ABIN1 protein were reduced among subjects with these haplotypes, suggesting that they harbor hypomorphic functional variants that influence susceptibility to SLE by restricting ABIN1 expression., Conclusion: Our results confirm the association signals between SLE and TNIP1 variants in multiple populations and provide new insight into the mechanism by which TNIP1 variants may contribute to SLE pathogenesis., (Copyright © 2012 by the American College of Rheumatology.)

Objective: Systemic lupus erythematosus (SLE) is a heterogeneous autoimmune disease with significant immune system aberrations resulting from complex heritable genetics as well as environmental factors. We undertook to study the role of TRAF6 as a candidate gene for SLE, since it plays a major role in several signaling pathways that are important for immunity and organ development., Methods: Fifteen single-nucleotide polymorphisms (SNPs) across TRAF6 were evaluated in 7,490 SLE patients and 6,780 control subjects from different ancestries. Population-based case-control association analyses and meta-analyses were performed. P values, false discovery rate q values, and odds ratios (ORs) with 95% confidence intervals (95% CIs) were calculated., Results: Evidence of associations was detected in multiple SNPs. The best overall P values were obtained for SNPs rs5030437 and rs4755453 (P = 7.85 × 10(-5) and P = 4.73 × 10(-5) , respectively) without significant heterogeneity among populations (P = 0.67 and P = 0.50, respectively, in Q statistic). In addition, SNP rs540386, which was previously reported to be associated with rheumatoid arthritis (RA), was found to be in linkage disequilibrium with these 2 SNPs (r(2) = 0.95) and demonstrated evidence of association with SLE in the same direction (meta-analysis P = 9.15 × 10(-4) , OR 0.89 [95% CI 0.83-0.95]). The presence of thrombocytopenia improved the overall results in different populations (meta-analysis P = 1.99 × 10(-6) , OR 0.57 [95% CI 0.45-0.72], for rs5030470). Finally, evidence of family-based association in 34 African American pedigrees with the presence of thrombocytopenia was detected in 1 available SNP (rs5030437) with a Z score magnitude of 2.28 (P = 0.02) under a dominant model., Conclusion: Our data indicate the presence of association of TRAF6 with SLE, consistent with the previous report of association with RA. These data provide further support for the involvement of TRAF6 in the pathogenesis of autoimmunity., (Copyright © 2012 by the American College of Rheumatology.)

Objective: We previously reported an analysis of single-nucleotide polymorphisms (SNPs) in 3 validated European rheumatoid arthritis (RA) susceptibility loci, TAGAP, TNFAIP3, and CCR6, in African American patients with RA. Unexpectedly, the disease-associated alleles were different in African Americans from those in Europeans. In an effort to better define their contribution, we performed additional SNP genotyping in these genes., Methods: Seven SNPs were genotyped in 446 African American patients with RA and in 733 African American control subjects. Differences in minor allele frequency between the RA cases and controls were analyzed after controlling for the global proportion of European admixture, and pairwise linkage disequilibrium (LD) was estimated among the SNPs., Results: Three SNPs were significantly associated with RA: the TNFAIP3 rs719149 A allele (OR 1.22 [95% confidence interval (95% CI) 1.03-1.44], P = 0.02), the TAGAP rs1738074 G allele (OR 0.75 [95% CI 0.63-0.89, P = 0.0012), and the TAGAP rs4709267 G allele (OR 0.74 [95% CI 0.60-0.91], P = 0.004). Pairwise LD between the TAGAP SNPs was low (r(2) = 0.034). The haplotype containing minor alleles for both TAGAP SNPs was uncommon (4.5%). After conditional analysis of each TAGAP SNP, its counterpart remained significantly associated with RA (rs1738074 for rs4709267 P = 0.00001 and rs4709267 for rs1738074 P = 0.00005), suggesting independent effects., Conclusion: SNPs in regulatory regions of TAGAP and an intronic SNP (TNFAIP3) are potential susceptibility loci in African Americans. Pairwise LD, haplotype analysis, and SNP conditioning analysis suggest that these 2 SNPs in TAGAP are independent susceptibility alleles. Additional fine-mapping of this gene and functional genomic studies of these SNPs should provide further insight into the role of these genes in RA., (Copyright © 2012 by the American College of Rheumatology.)

Objective: To determine the therapeutic efficacy and immunomodulatory effect of an anti-human death receptor 5 (DR5) antibody, TRA-8, in eliminating macrophage subsets in a mouse model of type II collagen-induced arthritis (CIA)., Methods: A human/mouse-chimeric DR5-transgenic mouse, under the regulation of a mouse 3-kb promoter and a loxP-flanked STOP cassette, was generated and crossed with an ubiquitous Cre (Ubc.Cre) mouse and a lysozyme M-Cre (LysM.Cre)-transgenic mouse to achieve inducible or macrophage-specific expression. Chicken type II collagen was used to induce CIA in mice, which were then treated with an anti-human DR5 antibody, TRA-8. Clinical scores, histopathologic severity, macrophage apoptosis and depletion, and T cell subset development were evaluated., Results: In human/mouse DR5-transgenic Ubc.Cre mice with CIA, transgenic DR5 was most highly expressed on CD11b+ macrophages, with lower expression on CD4+ T cells. In human/mouse DR5-transgenic LysM.Cre mice, transgenic DR5 was restrictively expressed on macrophages. Both in vivo near-infrared imaging of caspase activity and TUNEL staining demonstrated that TRA-8 rapidly induced apoptosis of macrophages in inflamed synovium. Depletion of pathogenic macrophages by TRA-8 led to significantly reduced clinical scores for arthritis; decreased macrophage infiltration, synovial hyperplasia, osteoclast formation, joint destruction, cathepsin activity, and inflammatory cytokine expression in joints; reduced numbers of Th17 cells; and an increased number of Treg cells in draining lymph nodes., Conclusion: The anti-human DR5 antibody TRA-8 was efficacious in reducing the severity of arthritis via targeted depletion of macrophages and immunomodulation. Our data provide preclinical evidence that TRA-8 is a potential novel biologic agent for rheumatoid arthritis therapy., (Copyright © 2012 by the American College of Rheumatology.)

Objective: Several confirmed genetic susceptibility loci for lupus have been described. To date, no clear evidence for genetic epistasis in lupus has been established. The aim of this study was to test for gene-gene interactions in a number of known lupus susceptibility loci., Methods: Eighteen single-nucleotide polymorphisms tagging independent and confirmed lupus susceptibility loci were genotyped in a set of 4,248 patients with lupus and 3,818 normal healthy control subjects of European descent. Epistasis was tested by a 2-step approach using both parametric and nonparametric methods. The false discovery rate (FDR) method was used to correct for multiple testing., Results: We detected and confirmed gene-gene interactions between the HLA region and CTLA4, IRF5, and ITGAM and between PDCD1 and IL21 in patients with lupus. The most significant interaction detected by parametric analysis was between rs3131379 in the HLA region and rs231775 in CTLA4 (interaction odds ratio 1.19, Z = 3.95, P = 7.8 × 10(-5) [FDR ≤0.05], P for multifactor dimensionality reduction = 5.9 × 10(-45)). Importantly, our data suggest that in patients with lupus, the presence of the HLA lupus risk alleles in rs1270942 and rs3131379 increases the odds of also carrying the lupus risk allele in IRF5 (rs2070197) by 17% and 16%, respectively (P = 0.0028 and P = 0.0047, respectively)., Conclusion: We provide evidence for gene-gene epistasis in systemic lupus erythematosus. These findings support a role for genetic interaction contributing to the complexity of lupus heritability., (Copyright © 2012 by the American College of Rheumatology.)

Objective: Candidate gene and genome-wide association studies have identified several disease susceptibility loci in lupus patients. These studies have largely been performed in lupus patients who are Asian or of European ancestry. This study was undertaken to examine whether some of these same susceptibility loci increase lupus risk in African American individuals., Methods: Single-nucleotide polymorphisms tagging 15 independent lupus susceptibility loci were genotyped in a set of 1,724 lupus patients and 2,024 healthy controls of African American descent. The loci examined included PTPN22, FCGR2A, TNFSF4, STAT4, CTLA4, PDCD1, PXK, BANK1, MSH5 (HLA region), CFB (HLA region), C8orf13-BLK region, MBL2, KIAA1542, ITGAM, and MECP2/IRAK1., Results: We found the first evidence of genetic association between lupus in African American patients and 5 susceptibility loci (C8orf13-BLK, BANK1, TNFSF4, KIAA1542, and CTLA4; P = 8.0 × 10⁻⁶, P = 1.9 × 10⁻⁵, P = 5.7 × 10⁻⁵, P = 0.00099, and P = 0.0045, respectively). Further, we confirmed the genetic association between lupus and 5 additional lupus susceptibility loci (ITGAM, MSH5, CFB, STAT4, and FCGR2A; P = 7.5 × 10⁻¹¹, P = 5.2 × 10⁻⁸, P = 8.7 × 10⁻⁷ , P = 0.0058, and P = 0.0070, respectively), and provided evidence, for the first time, of genome-wide significance for the association between lupus in African American patients and ITGAM and MSH5 (HLA region)., Conclusion: These findings provide evidence of novel genetic susceptibility loci for lupus in African Americans and demonstrate that the majority of lupus susceptibility loci examined confer lupus risk across multiple ethnicities., (Copyright © 2011 by the American College of Rheumatology.)

Objective: T cells from patients with systemic lupus erythematosus (SLE) express increased amounts of PP2Ac, which contributes to decreased production of interleukin-2 (IL-2). Because IL-2 is important in the regulation of several aspects of the immune response, it has been proposed that PP2Ac contributes to the expression of SLE. This study was designed to determine whether genetic variants of PPP2AC are linked to the expression of SLE and specific clinical manifestations and account for the increased expression of PP2Ac., Methods: We conducted a trans-ethnic study of 8,695 SLE cases and 7,308 controls of 4 different ancestries. Eighteen single-nucleotide polymorphisms (SNPs) across PPP2CA were genotyped using an Illumina custom array. PPP2CA expression in SLE and control T cells was analyzed by real-time polymerase chain reaction., Results: A 32-kb haplotype comprising multiple SNPs of PPP2CA showed significant association with SLE in Hispanic Americans, European Americans, and Asians, but not in African Americans. Conditional analyses revealed that SNP rs7704116 in intron 1 showed consistently strong association with SLE across Asian, European American, and Hispanic American populations (odds ratio 1.3 [95% confidence interval 1.14-1.31], meta-analysis P=3.8×10(-7)). In European Americans, the largest ethnic data set studied, the risk A allele of rs7704116 was associated with the presence of renal disease, anti-double-stranded DNA, and anti-RNP antibodies. PPP2CA expression was ∼2-fold higher in SLE patients carrying the rs7704116 AG genotype than those carrying the GG genotype (P=0.007)., Conclusion: Our data provide the first evidence of an association between PPP2CA polymorphisms and elevated PP2Ac transcript levels in T cells, which implicates a new molecular pathway for SLE susceptibility in European Americans, Hispanic Americans, and Asians., (Copyright © 2011 by the American College of Rheumatology.)

Objective: The overexpression of interferon (IFN)-inducible genes is a prominent feature of systemic lupus erythematosus (SLE); it serves as a marker for active and more severe disease, and is also observed in other autoimmune and inflammatory conditions. This study was undertaken to investigate the genetic variations responsible for sustained activation of IFN-responsive genes in SLE., Methods: We systematically evaluated association of SLE with a total of 1,754 IFN pathway-related genes, including IFN-inducible genes known to be differentially expressed in SLE patients and their direct regulators. We used a 3-stage study design in which 2 cohorts (total of 939 SLE cases and 3,398 controls) were analyzed independently and jointly for association with SLE, and the results were adjusted for the number of comparisons., Results: A total of 15,166 single-nucleotide polymorphisms (SNPs) passed all quality control filters; 305 of these SNPs demonstrated replicated association with SLE in both cohorts. Nine variants were further genotyped for confirmation in an average of 1,316 independent SLE cases and 3,215 independent controls. Association with SLE was confirmed for several genes, including those for the transmembrane receptor CD44 (CD44 [rs507230]; P = 3.98 × 10⁻¹²), the cytokine pleiotrophin (PTN [rs919581]; P = 5.38 × 10⁻⁴), the heat-shock protein DnaJ (DNAJA1 [rs10971259]; P = 6.31 × 10⁻³), and the nuclear import protein karyopherin α1 (KPNA [rs6810306]; P = 4.91 × 10⁻²)., Conclusion: This study expands the number of candidate genes that have been shown to be associated with SLE and highlights potential of pathway-based approaches for gene discovery. Identification of the causal alleles will help elucidate the molecular mechanisms responsible for activation of the IFN system in SLE., (Copyright © 2011 by the American College of Rheumatology.)

Objective: Genetic association of the IL2/IL21 region at chromosome 4q27 has previously been reported in lupus and a number of autoimmune and inflammatory diseases. This study was undertaken to determine whether this genetic effect could be localized, using a very large cohort of lupus patients and controls., Methods: We genotyped 45 tag single-nucleotide polymorphisms (SNPs) across the IL2/IL21 locus in 2 large independent lupus sample sets. We studied a set of subjects of European descent consisting of 4,248 lupus patients and 3,818 healthy controls, and an African American set of 1,569 patients and 1,893 healthy controls. Imputation in 3,004 additional controls from the Wellcome Trust Case Control Consortium was also performed. Genetic association between the genotyped markers was determined, and pairwise conditional analysis was performed to localize the independent genetic effect in the IL2/IL21 locus in lupus., Results: We established and confirmed the genetic association between IL2/IL21 and lupus. Using conditional analysis and transethnic mapping, we localized the genetic effect in this locus to 2 SNPs in high linkage disequilibrium: rs907715 located within IL21 (odds ratio 1.16 [95% confidence interval 1.10-1.22], P=2.17×10(-8)) and rs6835457 located in the 3'-untranslated flanking region of IL21 (odds ratio 1.11 [95% confidence interval 1.05-1.17], P=9.35×10(-5))., Conclusion: Our findings establish the genetic association between lupus and IL2/IL21 with a genome-wide level of significance. Further, our findings indicate that this genetic association within the IL2/IL21 linkage disequilibrium block is localized to IL21. If other autoimmune IL2/IL21 genetic associations are similarly localized, then the IL21 risk alleles would be predicted to operate by a fundamental mechanism that influences the course of a number of autoimmune disease processes., (Copyright © 2011 by the American College of Rheumatology.)

Objective: Large-scale genetic association studies have identified >20 rheumatoid arthritis (RA) risk alleles among individuals of European ancestry. The influence of these risk alleles has not been comprehensively studied in African Americans. We therefore sought to examine whether these validated RA risk alleles are associated with RA risk in an African American population., Methods: Twenty-seven candidate single-nucleotide polymorphisms (SNPs) were genotyped in 556 autoantibody-positive African Americans with RA and 791 healthy African American control subjects. Odds ratios (ORs) and 95% confidence intervals (95% CIs) for each SNP were compared with previously published ORs for RA patients of European ancestry. We then calculated a composite genetic risk score (GRS) for each individual based on the sum of all risk alleles., Results: Overlap of the ORs and 95% CIs between the European and African American populations was observed for 24 of the 27 candidate SNPs. Conversely, 3 of the 27 SNPs (CCR6 rs3093023, TAGAP rs394581, and TNFAIP3 rs6920220) demonstrated ORs in the opposite direction from those reported for RA patients of European ancestry. The GRS analysis indicated a small but highly significant probability that African American patients relative to control subjects were enriched for the risk alleles validated in European RA patients (P = 0.00005)., Conclusion: The majority of RA risk alleles previously validated for RA patients of European ancestry showed similar ORs in our population of African Americans with RA. Furthermore, the aggregate GRS supports the hypothesis that these SNPs are risk alleles for RA in the African American population. Future large-scale genetic studies are needed to validate these risk alleles and identify novel RA risk alleles in African Americans., (Copyright © 2010 by the American College of Rheumatology.)

Objective: Interleukin-21 (IL-21) is a member of the type I cytokine superfamily that has a variety of effects on the immune system, including B cell activation, plasma cell differentiation, and immunoglobulin production. The expression of IL-21 receptor (IL-21R) is reduced in the B cells of patients with systemic lupus erythematosus (SLE), while serum IL-21 levels are increased both in lupus patients and in some murine lupus models. We recently reported that polymorphisms within the IL21 gene are associated with increased susceptibility to SLE. The aim of this study was to examine the genetic association between single-nucleotide polymorphisms (SNPs) within IL21R and SLE., Methods: We genotyped 17 SNPs in the IL21R gene in 2 large cohorts of lupus patients (a European-derived cohort and a Hispanic cohort) and in ethnically matched healthy controls., Results: We identified and confirmed the association between rs3093301 within the IL21R gene and SLE in the 2 cohorts (meta-analysis odds ratio 1.16 [95% confidence interval 1.08-1.25], P=1.0x10(-4))., Conclusion: Our findings indicate that IL21R is a novel susceptibility gene for SLE.

Objective: Both genetic and epigenetic factors play an important role in the pathogenesis of lupus. The aim of this study was to examine methyl-CpG-binding protein 2 gene (MECP2) polymorphisms in a large cohort of patients with lupus and control subjects, and to determine the functional consequences of the lupus-associated MECP2 haplotype., Methods: We genotyped 18 single-nucleotide polymorphisms within MECP2, located on chromosome Xq28, in a large cohort of patients with lupus and control subjects of European descent. We studied the functional effects of the lupus-associated MECP2 haplotype by determining gene expression profiles in B cell lines in female lupus patients with and those without the lupus-associated MECP2 risk haplotype., Results: We confirmed, replicated, and extended the genetic association between lupus and genetic markers within MECP2 in a large independent cohort of lupus patients and control subjects of European descent (odds ratio 1.35, P = 6.65 x 10(-11)). MECP2 is a dichotomous transcription regulator that either activates or represses gene expression. We identified 128 genes that are differentially expressed in lupus patients with the disease-associated MECP2 haplotype; most ( approximately 81%) were up-regulated. Genes that were up-regulated had significantly more CpG islands in their promoter regions compared with genes that were down-regulated. Gene ontology analysis using the differentially expressed genes revealed significant association with epigenetic regulatory mechanisms, suggesting that these genes are targets for MECP2 regulation in B cells. Furthermore, at least 13 of the 104 up-regulated genes are regulated by interferon. The disease-risk MECP2 haplotype was associated with increased expression of the MECP2 transcription coactivator CREB1 and decreased expression of the corepressor histone deacetylase 1., Conclusion: Polymorphism in the MECP2 locus is associated with lupus and, at least in part, contributes to the interferon signature observed in lupus patients.

Objective: To examine the clinical and genetic correlates of hemolytic anemia and its impact on damage accrual and mortality in systemic lupus erythematosus (SLE) patients., Methods: SLE patients (American College of Rheumatology [ACR] criteria) of Hispanic (Texan or Puerto Rican), African American, and Caucasian ethnicity from the LUMINA (LUpus in MInorities, NAture versus nurture) cohort were studied. Hemolytic anemia was defined as anemia with reticulocytosis (ACR criterion). The association between degrees of hemolytic anemia and socioeconomic/demographic, clinical, pharmacologic, immunologic, psychological, and behavioral variables was examined by univariable and multivariable (proportional odds model) analyses. Genetic variables (FCGR and Fas/Fas ligand polymorphisms) were examined by 2 degrees of freedom test of association and Cochran-Armitage trend tests. The impact of hemolytic anemia on damage accrual and mortality was examined by multivariable linear and Cox regression analyses, respectively., Results: Of 628 patients studied, 90% were women, 19% were Texan Hispanic, 16% were Puerto Rican Hispanic, 37% were African American, and 28% were Caucasian. Sixty-five (10%) patients developed hemolytic anemia at some time during the disease course, 83% at or before diagnosis. Variables independently associated with degrees of hemolytic anemia were African American ethnicity, thrombocytopenia, and the use of azathioprine. Hemolytic anemia was associated with damage accrual after adjusting for variables known to affect this outcome; however, hemolytic anemia was not associated with mortality., Conclusion: The association of hemolytic anemia with thrombocytopenia suggests a common mechanism in their pathophysiology. Hemolytic anemia is an early disease manifestation and is associated with African American ethnicity and the use of azathioprine; it appears to exert an impact on damage but not on mortality.

Objective: Systemic lupus erythematosus (SLE) is a systemic autoimmune disease that predominantly affects women. Despite isolated reports of patients with coexisting Klinefelter's syndrome (47,XXY) and SLE, no association of Klinefelter's syndrome with SLE or any other autoimmune disease has been established. The present study was undertaken to investigate the prevalence of Klinefelter's syndrome in a large population of patients with SLE., Methods: Sex chromosome genotyping was performed in 981 SLE patients, of whom 213 were men. A first group of 844 SLE patients from 378 multiplex families and a second group of 137 men with nonfamilial SLE were evaluated. In selected cases, chromosomes were enumerated by fluorescence in situ hybridization (FISH) and karyotyping in transformed B cell lines., Results: Of 213 men with SLE, 5 had Klinefelter's syndrome (1 in 43). Four of them were heterozygous at X markers, and Klinefelter's syndrome was confirmed by FISH and karyotyping in the fifth. An overall rate of 47,XXY of 235 per 10,000 male SLE patients was found (95% confidence interval 77-539), a dramatic increase over the known prevalence of Klinefelter's syndrome in an unselected population (17 per 10,000 live male births). Asking men with SLE about fertility was highly sensitive (100%) for Klinefelter's syndrome. All 768 women with SLE were heterozygous at X., Conclusion: The frequency of Klinefelter's syndrome (47,XXY), often subclinical, is increased in men with SLE by approximately 14-fold compared with its prevalence in men without SLE. Diagnostic vigilance for 47,XXY in male patients with SLE is warranted. These data are the first to show an association of Klinefelter's syndrome with an autoimmune disease found predominantly in women. The risk of SLE in men with Klinefelter's syndrome is predicted to be similar to the risk in normal women with 46,XX and approximately 14-fold higher than in men with 46,XY, consistent with the notion that SLE susceptibility is partly explained by an X chromosome gene-dose effect.

Objective: To determine whether there is an increase in the number of TLR7 gene copies in patients diagnosed as having systemic lupus erythematosus (SLE) and whether gene amplification influences the autoantibody profiles in SLE patients, as has recently been reported in the BXSB/Yaa mouse model of lupus., Methods: We used a modified real-time quantitative polymerase chain reaction protocol to calculate the relative TLR7 gene copy number according to the comparative 2(-DeltaDeltaC(t) ) method in 99 SLE patients and 91 healthy controls matched for sex and ethnicity. Autoantibody profiles were determined by standard methods., Results: The relative number of TLR7 gene copies in SLE patients and healthy controls varied; however, no significant concordance between the number of relative gene copies and the SLE phenotype was found. There was also no difference in variation by ethnic group. Comparison of the relative gene copy numbers according to the presence or absence of antinuclear antibodies (ANAs), the ANA staining patterns, and the presence or absence of anti-RNA-associated antigen antibody showed no statistically significant difference in the SLE patients., Conclusion: We determined that although the relative gene copy number of TLR7 varied in both SLE patients and healthy controls, it was not significantly increased among our SLE patients as compared with our controls. We found no detectable trend for an association between the relative gene copy number and the autoantibody profile in SLE patients.

Objective: To investigate the possible association of the Fcgamma receptor IIb (FcgammaRIIb) 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 subjects (P = 0.017, odds ratio [OR] 1.989 [95% confidence interval (95% CI) 1.119-3.553]). Interestingly, male SLE patients showed enrichment of the Thr/Thr187 genotype (24%; 7 of 29) as compared with female SLE patients (10%; 32 of 322) (P = 0.043, OR 2.884 [95% CI 1.028-7.839]). Additionally, SLE patients with Thr/Thr187 and Ile/Thr187 genotypes were more likely to have pleural effusions (P = 0.038, OR 1.874 [95% CI 1.033-3.411]) and anti-SSA/Ro antibody production (P = 0.046, OR 2.221 [95% CI 1.013-4.897]). Combined analysis of 4 groups of Asian patients strongly supported the association of the FCGR2B Thr187 allele with the lupus phenotype (P = 0.000159)., Conclusion: The FcgammaRIIb transmembrane polymorphism is a strong disease susceptibility candidate in epistasis with other genetic effects in Taiwanese and other Asian populations. It may also play a more prominent role in male patients with SLE.

Objective: To examine the roles of specific genetic polymorphisms as predictors of response to treatment of early rheumatoid arthritis (RA)., Methods: Subjects included 457 patients with early RA (duration of < or =3 years) who participated in a randomized controlled trial comparing weekly methotrexate and 2 dosages of etanercept (10 mg twice weekly and 25 mg twice weekly). Our primary outcome measure was achievement of 50% improvement in disease activity according to the criteria of the American College of Rheumatology (ACR50 response) after 12 months of treatment. Subjects were genotyped for HLA-DRB1 alleles and polymorphisms in the following genes: TNF, LTA, TNFRSF1A, TNFRSF1B, FCGR2A, FCGR3A, and FCGR3B. Univariate and multivariate analyses were performed to define the impact of specific polymorphisms and haplotypes on response to treatment. Covariates for the multivariate analyses included sex, ethnicity, age, disease duration, and baseline values for rheumatoid factor and the tender and swollen joint counts., Results: The presence of 2 HLA-DRB1 alleles encoding the shared epitope (SE) (compared with 1 or 0 copies) was associated with response to treatment with standard-dose etanercept (odds ratio [OR] 4.3, 95% confidence interval [95% CI] 1.8-10.3). Among Caucasian patients, 2 extended haplotypes that included the HLA-DRB1 alleles *0404 and *0101 (both of which encode the SE) and 6 single-nucleotide polymorphisms in the LTA-TNF region were associated with response to treatment. In a multivariate model that included treatment received and the aforementioned covariates, the ORs for the association of these haplotypes with achievement of an ACR50 response at 12 months were 2.5 (95% CI 0.8-7.3) and 4.9 (95% CI 1.5-16.1) for the *0404- and *0101-containing haplotypes, respectively., Conclusion: Genetic variation in the HLA-DRB1 and the LTA-TNF regions is significantly associated with response to treatment of early RA. These findings may have clinical application through the identification of patients who are most likely to benefit from treatment with methotrexate or etanercept.

Objective: Serum B lymphocyte stimulator (BLyS) is increased in autoimmune diseases, both in animal models and in humans. This study examined the effect of BLyS blockade in 3 animal models of lupus., Methods: Antibodies and lupus-like disease manifestations were examined in mice after administration of a single injection of an adenoviral construct for the transmembrane activator and CAML interactor receptor (AdTACI) that produces high serum levels of TACI-Fc fusion protein., Results: In C57BL/6 (B6) lpr/lpr mice (B6.lpr/lpr), which were used to model autoimmunity in the absence of severe disease, treatment of younger mice with AdTACI prevented the development of hypergammaglobulinemia. In contrast, use of AdTACI for BLyS blockade had only transient effects on the levels of IgG in normal B6 mice. AdTACI blocked the development of autoantibodies in younger B6.lpr/lpr mice and reversed the production of autoantibodies in older B6.lpr/lpr mice, and also reduced the numbers of splenic plasma cells. In MRL.lpr/lpr mice, which were used to examine disease manifestations, AdTACI reduced the extent of glomerulonephritis and proteinuria and improved survival, but had little effect on T cell infiltration and interstitial nephritis. However, in (NZB x NZW)F(1) mice, AdTACI induced neutralizing anti-TACI antibodies and failed to reduce the numbers of B cells., Conclusion: BLyS blockade has little effect on IgG levels in normal mice, but reverses the production of spontaneously produced IgM and IgG autoantibodies in the setting of established autoimmunity. Blockade of BLyS ameliorates B cell-dependent disease manifestations even in the MRL.lpr/lpr model, but its effectiveness on autonomous T cell aspects of the disease is limited. Moreover, its effectiveness is neutralized by anti-TACI antibodies when present. These results provide a basis for understanding the potential effects of BLyS blockade in human disease.

Objective: The low-affinity receptor Fcgamma receptor IIb (FcgammaRIIb), with an immunoreceptor tyrosine-based inhibitory motif (ITIM) in the cytoplasmic domain, down-regulates humoral immune responses and modulates the risk of autoimmunity in animal models. The transmembrane domain of FcgammaRIIb may also contribute to receptor signaling. Therefore, we investigated the biologic significance of single-nucleotide polymorphisms (SNPs) throughout the coding region., Methods: Discovery of SNPs in FCGR2B was performed by direct cycle sequencing of complementary DNA samples derived by reverse transcriptase-polymerase chain reaction. To assess the biologic significance of the nonsynonymous transmembrane SNP, we studied 3 functions influenced by the FcgammaRIIb transmembrane domain: tyrosine dephosphorylation of CD19, inhibition of B cell receptor (BCR)-induced calcium response, and modulation of BCR- or anti-Fas-induced apoptosis., Results: The nonsynonymous C-to-T transition in the first cytoplasmic exon, originally reported in the Raji cell line, was not found in either the African-American or the Caucasian population, but a nonsynonymous T-to-C transition at nucleotide 775 in exon 4 of FCGR2B, which changes isoleucine to threonine at residue 187 in the transmembrane domain, was significantly more common in African Americans. Using the FcgammaRIIb-negative mouse B cell line IIA1.6, we expressed both allelic forms as both full-length and truncated cytoplasmic domain constructs. The FCGR2B-187T allele mediated a higher level of CD19 dephosphorylation (P = 0.029) and a greater degree of inhibition of the calcium response (P = 0.003) when co-engaged with BCR than did FCGR2B-187I, independent of the presence of the ITIM. In contrast, FcgammaRIIb modulation of BCR-induced and anti-Fas antibody-induced cell death rates were similar in IIA1.6 cells expressing either the 187I or the 187T allelic form., Conclusion: The differential activity of FCGR2B alleles suggests a novel mechanism of FcgammaRIIb regulation that may influence the risk of autoimmune disease.

Objective: Although low-affinity alleles of human Fcgamma receptor types IIA and IIIA (FcgammaRIIA and FcgammaRIIIA, respectively) polymorphisms have been associated with systemic lupus erythematosus (SLE) in case-control studies, the relative contribution of these genes to SLE susceptibility has not been resolved., Methods: We analyzed the distribution of alleles of FcgammaRIIA, FcgammaRIIIA, and FcgammaRIIIB in 126 multiplex-SLE pedigrees and FcgammaRIIA and FcgammaRIIIA in a case-control replication study, using allele-specific polymerase chain reaction and direct sequencing of genomic DNA. Statistical tests of association were performed to detect evidence of linkage between the single nucleotide polymorphisms and SLE., Results: We found evidence for linkage at both the FcgammaRIIIA (single-point nonparametric linkage [NPL] 1.8, P = 0.038; multipoint NPL 2.7, P = 0.004) and the FcgammaRIIA (single-point NPL 2.0, P = 0.021; multipoint NPL 2.6, P = 0.006) loci, but not the FcgammaRIIIB locus. Family-based tests of association demonstrated increased transmission of the low-affinity F176 allele at the FcgammaRIIIA locus (odds ratio [OR] 2.18, P = 0.0005 by transmission disequilibrium test and P = 0.002, by pedigree disequilibrium test [PDT]), but little evidence of preferential transmission of alleles at FcgammaRIIA (P = 0.089 by PDT). Stratification by ethnicity showed preferential transmission of the associated FcgammaRIIIA allele both in families of African American ancestry and in those of European American ancestry. Despite significant linkage disequilibrium between these genes, 2- and 3-locus haplotype analysis of the extended Fcgamma receptor cluster did not reveal any significant association beyond that observed with FcgammaRIIIA alone. In a large case-control replication study of 438 patients with SLE and 219 controls, FcgammaRIIIA provided the strongest evidence of an FcgammaR-SLE association (additive model: V/V 176 versus V/F 176 OR 1.51, V/V 176 versus F/F 176 OR 1.98, P = 0.007)., Conclusion: To our knowledge, these data are the first to demonstrate linkage and both family-based and case-control-based association of FcgammaRIIIA with SLE. These data provide genetic evidence supporting a role for the physiologically relevant single nucleotide polymorphism of the FcgammaRIIIA gene in the pathophysiology of this complex genetic disease.