Faculty Bibliography

Accurately measuring lupus disease activity has been a demanding and still unresolved task, considering the complex multisystem nature of the disease and its variability over time and between patients. Various available tools for measurement of lupus disease activity may detect clinical improvement and/or deterioration and can be global or organ-focused. Several measures have demonstrated validity, reliability, and sensitivity to change in observational studies, and some were found useful in randomized controlled trials. Evaluation of their content and metric properties and critical review of their strengths and weaknesses facilitates selection of the appropriate tool according to the outcome of interest, and forms the basis for their optimization. In this review, we highlight recent progress in lupus disease activity measures and point to future directions in this field, with a focus on novel composite measurements derived by combining outcome measures in ways that might compensate for their individual deficiencies.

Systemic lupus erythematosus is an autoimmune disease characterized by multi-system involvement and autoantibody production. Abnormal T cell DNA methylation and type-I interferon play an important role in the pathogenesis of lupus. We performed a genome-wide DNA methylation study in two independent sets of lupus patients and matched healthy controls to characterize the DNA methylome in naive CD4+ T cells in lupus. DNA methylation was quantified for over 485,000 methylation sites across the genome, and differentially methylated sites between lupus patients and controls were identified and then independently replicated. Gene expression analysis was also performed from the same cells to investigate the relationship between the DNA methylation changes observed and mRNA expression levels. We identified and replicated 86 differentially methylated CG sites between patients and controls in 47 genes, with the majority being hypomethylated. We observed significant hypomethylation in interferon-regulated genes in naive CD4+ T cells from lupus patients, including IFIT1, IFIT3, MX1, STAT1, IFI44L, USP18, TRIM22 and BST2, suggesting epigenetic transcriptional accessibility in these genetic loci. Indeed, the majority of the hypomethylated genes (21 out of 35 hypomethylated genes) are regulated by type I interferon. The hypomethylation in interferon-regulated genes was not related to lupus disease activity. Gene expression analysis showed overexpression of these genes in total but not naive CD4+ T cells from lupus patients. Our data suggest epigenetic "poising" of interferon-regulated genes in lupus naive CD4+ T cells, argue for a novel pathogenic implication for abnormal T cell DNA methylation in lupus, and suggest a mechanism for type-I interferon hyper-responsiveness in lupus T cells.

OBJECTIVE: Little is known about the genetic etiology of systemic lupus erythematosus (SLE) in individuals of African ancestry, despite its higher prevalence and greater disease severity. Overproduction of nitric oxide (NO) and reactive oxygen species are implicated in the pathogenesis and severity of SLE, making NO synthases and other reactive intermediate-related genes biological candidates for disease susceptibility. We analyzed variation in reactive intermediate genes for association with SLE in 2 populations with African ancestry. METHODS: A total of 244 single-nucleotide polymorphisms (SNP) from 53 regions were analyzed in non-Gullah African Americans (AA; 1432 cases and 1687 controls) and the genetically more homogeneous Gullah of the Sea Islands of South Carolina (133 cases and 112 controls). Single-marker, haplotype, and 2-locus interaction tests were computed for these populations. RESULTS: The glutathione reductase gene GSR (rs2253409; p = 0.0014, OR 1.26, 95% CI 1.09-1.44) was the most significant single SNP association in AA. In the Gullah, the NADH dehydrogenase NDUFS4 (rs381575; p = 0.0065, OR 2.10, 95% CI 1.23-3.59) and NO synthase gene NOS1 (rs561712; p = 0.0072, OR 0.62, 95% CI 0.44-0.88) were most strongly associated with SLE. When both populations were analyzed together, GSR remained the most significant effect (rs2253409; p = 0.00072, OR 1.26, 95% CI 1.10-1.44). Haplotype and 2-locus interaction analyses also uncovered different loci in each population. CONCLUSION: These results suggest distinct patterns of association with SLE in African-derived populations; specific loci may be more strongly associated within select population groups.

Co-stimulatory molecules help to regulate interactions between T cells and antigen-presenting cells and may play an important role in the pathogenesis of lupus. Both work in murine models and some early studies in human lupus support further examination of these molecules as therapeutic targets. Complexities of lupus clinical trial variables may have hampered progress in this area but recent developments in the field may make interventional trials more feasible in the near future. To date biologics which provide direct blockade of interactions between CD40 and CD154, B7RP-1 and ICOS, and CD80 or CD86 with CD28 have been assessed in multicenter clinical trials. These data will be reviewed and critiqued.

We previously established an 80 kb haplotype upstream of TNFSF4 as a susceptibility locus in the autoimmune disease SLE. SLE-associated alleles at this locus are associated with inflammatory disorders, including atherosclerosis and ischaemic stroke. In Europeans, the TNFSF4 causal variants have remained elusive due to strong linkage disequilibrium exhibited by alleles spanning the region. Using a trans-ancestral approach to fine-map the locus, utilising 17,900 SLE and control subjects including Amerindian/Hispanics (1348 cases, 717 controls), African-Americans (AA) (1529, 2048) and better powered cohorts of Europeans and East Asians, we find strong association of risk alleles in all ethnicities; the AA association replicates in African-American Gullah (152,122). The best evidence of association comes from two adjacent markers: rs2205960-T (P=1.71 x 10(-34) , OR=1.43[1.26-1.60]) and rs1234317-T (P=1.16 x 10(-28) , OR=1.38[1.24-1.54]). Inference of fine-scale recombination rates for all populations tested finds the 80 kb risk and non-risk haplotypes in all except African-Americans. In this population the decay of recombination equates to an 11 kb risk haplotype, anchored in the 5' region proximal to TNFSF4 and tagged by rs2205960-T after 1000 Genomes phase 1 (v3) imputation. Conditional regression analyses delineate the 5' risk signal to rs2205960-T and the independent non-risk signal to rs1234314-C. Our case-only and SLE-control cohorts demonstrate robust association of rs2205960-T with autoantibody production. The rs2205960-T is predicted to form part of a decameric motif which binds NF-kappaBp65 with increased affinity compared to rs2205960-G. ChIP-seq data also indicate NF-kappaB interaction with the DNA sequence at this position in LCL cells. Our research suggests association of rs2205960-T with SLE across multiple groups and an independent non-risk signal at rs1234314-C. rs2205960-T is associated with autoantibody production and lymphopenia. Our data confirm a global signal at TNFSF4 and a role for the expressed product at multiple stages of lymphocyte dysregulation during SLE pathogenesis. We confirm the validity of trans-ancestral mapping in a complex trait.

Protein tyrosine phosphatase non-receptor type 22 (PTPN22) is a negative regulator of T-cell activation associated with several autoimmune diseases, including systemic lupus erythematosus (SLE). Missense rs2476601 is associated with SLE in individuals with European ancestry. Since the rs2476601 risk allele frequency differs dramatically across ethnicities, we assessed robustness of PTPN22 association with SLE and its clinical sub-phenotypes across four ethnically diverse populations. Ten SNPs were genotyped in 8220 SLE cases and 7369 controls from in European-Americans (EA), African-Americans (AA), Asians (AS), and Hispanics (HS). We performed imputation-based association followed by conditional analysis to identify independent associations. Significantly associated SNPs were tested for association with SLE clinical sub-phenotypes, including autoantibody profiles. Multiple testing was accounted for by using false discovery rate. We successfully imputed and tested allelic association for 107 SNPs within the PTPN22 region and detected evidence of ethnic-specific associations from EA and HS. In EA, the strongest association was at rs2476601 (P = 4.7 x 10(-9), OR = 1.40 (95% CI = 1.25-1.56)). Independent association with rs1217414 was also observed in EA, and both SNPs are correlated with increased European ancestry. For HS imputed intronic SNP, rs3765598, predicted to be a cis-eQTL, was associated (P = 0.007, OR = 0.79 and 95% CI = 0.67-0.94). No significant associations were observed in AA or AS. Case-only analysis using lupus-related clinical criteria revealed differences between EA SLE patients positive for moderate to high titers of IgG anti-cardiolipin (aCL IgG >20) versus negative aCL IgG at rs2476601 (P = 0.012, OR = 1.65). Association was reinforced when these cases were compared to controls (P = 2.7 x 10(-5), OR = 2.11). Our results validate that rs2476601 is the most significantly associated SNP in individuals with European ancestry. Additionally, rs1217414 and rs3765598 may be associated with SLE. Further studies are required to confirm the involvement of rs2476601 with aCL IgG.

The genetic factors underlying the pathogenesis of lupus nephritis associated with systemic lupus erythematosus are largely unknown, although animal studies indicate that nuclear factor (NF)-kappaB is involved. We reported previously that a knockin mouse expressing an inactive form of ABIN1 (ABIN1[D485N]) develops lupus-like autoimmune disease and demonstrates enhanced activation of NF-kappaB and mitogen-activated protein kinases in immune cells after toll-like receptor stimulation. In the current study, we show that ABIN1[D485N] mice develop progressive GN similar to class III and IV lupus nephritis in humans. To investigate the clinical relevance of ABIN1 dysfunction, we genotyped five single-nucleotide polymorphisms in the gene encoding ABIN1, TNIP1, in samples from European-American, African American, Asian, Gullah, and Hispanic participants in the Large Lupus Association Study 2. Comparing cases of systemic lupus erythematosus with nephritis and cases of systemic lupus erythematosus without nephritis revealed strong associations with lupus nephritis at rs7708392 in European Americans and rs4958881 in African Americans. Comparing cases of systemic lupus erythematosus with nephritis and healthy controls revealed a stronger association at rs7708392 in European Americans but not at rs4958881 in African Americans. Our data suggest that variants in the TNIP1 gene are associated with the risk for lupus nephritis and could be mechanistically involved in disease development via aberrant regulation of NF-kappaB and mitogen-activated protein kinase activity.

OBJECTIVE: Patients with systemic lupus erythematosus (SLE) are at increased risk of herpes zoster (HZ). Although a vaccine for HZ has been approved by the US Food and Drug Administration, its use in immunocompromised individuals remains controversial because it is a live-attenuated virus vaccine. We performed a pilot study of the immunogenicity of the HZ vaccine (Zostavax) in patients with SLE. METHODS: Ten patients with SLE and 10 control subjects >/= age 50 years participated in this open-label vaccination study. All were seropositive for varicella zoster virus (VZV). Patients with SLE were excluded for SLE Disease Activity Index (SLEDAI) > 4, or use of mycophenolate mofetil, cyclophosphamide, biologics, or > 10 mg prednisone daily. Followup visits occurred at 2, 6, and 12 weeks. Clinical outcomes included the development of adverse events, particularly HZ or vesicular lesions, and SLE flare. Immunogenicity was assessed with VZV-specific interferon-gamma-producing enzyme-linked immunospot (ELISPOT) assays and with antibody concentrations. RESULTS: All subjects were women. Patients with SLE were slightly older than controls (60.5 vs 55.3 yrs, p < 0.05). Median baseline SLEDAI was 0 (range 0-2) for patients with SLE. No episodes of HZ, vesicular rash, serious adverse events, or SLE flares occurred. Three injection site reactions occurred in each group: mild erythema or tenderness. The proportion of subjects with a > 50% increase in ELISPOT results following vaccination was comparable between both groups, although absolute SLE responses were lower than controls. Antibody titers increased only among controls following vaccination (p < 0.05). CONCLUSION: The HZ vaccination yielded a measurable immune response in this cohort of patients with mild SLE taking mild-moderate immunosuppressive medications. No herpetiform lesions or SLE flares were seen in this small cohort of patients. ClinicalTrials.gov ID:NCT01474720.

Immunoregulatory cytokine interleukin-10 (IL-10) is elevated in sera from patients with systemic lupus erythematosus (SLE) correlating with disease activity. The established association of IL10 with SLE and other autoimmune diseases led us to fine map causal variant(s) and to explore underlying mechanisms. We assessed 19 tag SNPs, covering the IL10 gene cluster including IL19, IL20 and IL24, for association with SLE in 15,533 case and control subjects from four ancestries. The previously reported IL10 variant, rs3024505 located at 1 kb downstream of IL10, exhibited the strongest association signal and was confirmed for association with SLE in European American (EA) (P = 2.7x10(-)(8), OR = 1.30), but not in non-EA ancestries. SNP imputation conducted in EA dataset identified three additional SLE-associated SNPs tagged by rs3024505 (rs3122605, rs3024493 and rs3024495 located at 9.2 kb upstream, intron 3 and 4 of IL10, respectively), and SLE-risk alleles of these SNPs were dose-dependently associated with elevated levels of IL10 mRNA in PBMCs and circulating IL-10 protein in SLE patients and controls. Using nuclear extracts of peripheral blood cells from SLE patients for electrophoretic mobility shift assays, we identified specific binding of transcription factor Elk-1 to oligodeoxynucleotides containing the risk (G) allele of rs3122605, suggesting rs3122605 as the most likely causal variant regulating IL10 expression. Elk-1 is known to be activated by phosphorylation and nuclear localization to induce transcription. Of interest, phosphorylated Elk-1 (p-Elk-1) detected only in nuclear extracts of SLE PBMCs appeared to increase with disease activity. Co-expression levels of p-Elk-1 and IL-10 were elevated in SLE T, B cells and monocytes, associated with increased disease activity in SLE B cells, and were best downregulated by ERK inhibitor. Taken together, our data suggest that preferential binding of activated Elk-1 to the IL10 rs3122605-G allele upregulates IL10 expression and confers increased risk for SLE in European Americans.

OBJECTIVE: To examine the frequency and characteristics of headaches and their association with global disease activity and health-related quality of life (HRQOL) in patients with systemic lupus erythematosus (SLE). METHODS: A disease inception cohort was assessed annually for headache (5 types) and 18 other neuropsychiatric (NP) events. Global disease activity scores (SLE Disease Activity Index 2000 [SLEDAI-2K]), damage scores (Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index [SDI]), and Short Form 36 (SF-36) mental and physical component summary scores were collected. Time to first headache and associations with SF-36 scores were analyzed using Cox proportional hazards and linear regression models with generalized estimating equations. RESULTS: Among the 1,732 SLE patients enrolled, 89.3% were female and 48.3% were white. The mean +/- SD age was 34.6 +/- 13.4 years, duration of disease was 5.6 +/- 5.2 months, and length of followup was 3.8 +/- 3.1 years. At enrollment, 17.8% of patients had headache (migraine [60.7%], tension [38.6%], intractable nonspecific [7.1%], cluster [2.6%], and intracranial hypertension [1.0%]). The prevalence of headache increased to 58% after 10 years. Only 1.5% of patients had lupus headache, as identified in the SLEDAI-2K. In addition, headache was associated with other NP events attributed to either SLE or non-SLE causes. There was no association of headache with SLEDAI-2K scores (without the lupus headache variable), SDI scores, use of corticosteroids, use of antimalarials, use of immunosuppressive medications, or specific autoantibodies. SF-36 mental component scores were lower in patients with headache compared with those without headache (mean +/- SD 42.5 +/- 12.2 versus 47.8 +/- 11.3; P < 0.001), and similar differences in physical component scores were seen (38.0 +/- 11.0 in those with headache versus 42.6 +/- 11.4 in those without headache; P < 0.001). In 56.1% of patients, the headaches resolved over followup. CONCLUSION: Headache is frequent in SLE, but overall, it is not associated with global disease activity or specific autoantibodies. Although headaches are associated with a lower HRQOL, the majority of headaches resolve over time, independent of lupus-specific therapies.