Adolescent health care needs and relationship to disease in patients with childhood-onset systemic lupus erythematosus

OBJECTIVE

To characterize adolescent health and psychosocial issues in patients with childhood-onset systemic lupus erythematosus (cSLE) and evaluate demographic/disease characteristics associated with adolescent health.

METHODS

We retrospectively examined adolescents aged 12-18 years with cSLE seen at Toronto SickKids Hospital, meeting ACR/SLICC classification criteria, assessed by Adolescent Medicine in cSLE clinic between 2018-2020. Adolescent health issues were characterized using the HEADDSS framework (Home, Education/Employment, Activities, Diet/Drugs, Sexuality, Suicide/mood). Issues were classified as presenting and/or identified; adolescent health burden was tabulated as the number of distinct adolescent issues per patient. Multiple Poisson regression models examined associations between patient/disease characteristics (age, gender, material deprivation, disease activity, disease damage, and high-dose glucocorticoid exposure) and adolescent health issues.

RESULTS

108 of 181 (60%) adolescents with cSLE were seen by Adolescent Medicine, with a median of 2 (IQR 1,3) visits and a median of 2 adolescent health issues (IQR 1,5) during the study period. Common issues were mood (presenting in 21% vs. identified in 50%), sleep (27% vs. 2%), school/education (26% vs. 1%), and nonadherence (23% vs. 8%). Psychoeducation was provided by Adolescent Medicine to 54% of patients. High-dose glucocorticoids (RR=1.82, 95% CI 1.41-2.35, p<0.001), material deprivation (RR=1.17, 95% CI 1.04-1.30, p=0.007) and lower SLEDAI-2K scores (RR=0.95, 95% CI 0.92-0.98, p=0.004) were associated with higher adolescent health burden.

CONCLUSION

Adolescents with cSLE experience many adolescent issues, especially low mood. High-dose glucocorticoids and social marginalization are associated with greater adolescent health burden. This study highlights the importance of addressing adolescent health needs as part of routine care.

Genetics of longitudinal kidney function in children and adults with systemic lupus erythematosus

OBJECTIVES

Genome-wide association studies (GWAS) have identified loci associated with estimated glomerular filtration rate (eGFR). Few LN risk loci have been identified to date. We tested the association of SLE and eGFR polygenic risk scores (PRS) with repeated eGFR measures from children and adults with SLE.

METHODS

Patients from two tertiary care lupus clinics that met ≥4 ACR and/or SLICC criteria for SLE were genotyped on the Illumina MEGA or Omni1-Quad arrays. PRSs were calculated for SLE and eGFR, using published weighted GWA-significant alleles. eGFR was calculated using the CKD-EPI and Schwartz equations. We tested the effect of eGFR- and SLE-PRSs on eGFR mean and variance, adjusting for age at diagnosis, sex, ancestry, follow-up time, and clinical event flags.

RESULTS

We included 1158 SLE patients (37% biopsy-confirmed LN) with 36 733 eGFR measures over a median of 7.6 years (IQR: 3.9-15.3). LN was associated with lower within-person mean eGFR [LN: 93.8 (s.d. 26.4) vs non-LN: 101.6 (s.d. 17.7) mL/min per 1.73 m2; P < 0.0001] and higher variance [LN median: 157.0 (IQR: 89.5, 268.9) vs non-LN median: 84.9 (IQR: 46.9, 138.2) (mL/min per 1.73 m2)2; P < 0.0001]. Increasing SLE-PRSs were associated with lower mean eGFR and greater variance, while increasing eGFR-PRS was associated with increased eGFR mean and variance.

CONCLUSION

We observed significant associations between SLE and eGFR PRSs and repeated eGFR measurements, in a large cohort of children and adults with SLE. Longitudinal eGFR may serve as a powerful alternative outcome to LN categories for discovery of LN risk loci.

Maternal Anti-Ro Antibody Titers Obtained With Commercially Available Immunoassays Are Strongly Associated With Immune-Mediated Fetal Heart Disease

OBJECTIVE

Anti-Ro antibody-positive mothers are frequently referred for serial echocardiography due to the fetal risk of developing heart block and endocardial fibroelastosis. Little is known why only some and not all offspring develop these cardiac manifestations of neonatal lupus (CNL). This prospective study examined associations between anti-Ro antibody titers and fetal CNL.

METHODS

Antibody-positive mothers referred since 2018 for fetal echocardiography at risk of CNL (group 1; n = 240) or with CNL (group 2; n = 18) were included. Maternal antibody titers were measured with a chemiluminescent immunoassay (CIA). Additional testing on diluted serum samples was used to quantify anti-Ro 60 antibody titers above the analytical measuring range (AMR) of the standard CIA (≥1,375 chemiluminescent units [CU]).

RESULTS

Among 27 total mothers with a fetal diagnosis of CNL, all displayed anti-Ro 60 antibody titers that exceeded the AMR of the CIA at least 10-fold. Of 122 mothers in group 1 who underwent additional anti-Ro 60 antibody testing, event rates of CNL (n = 9) were 0% (0 of 45) among mothers with anti-Ro 60 antibody titers from 1,375-10,000 CU, 5% (3 of 56) among mothers with titers from 10,000-50,000 CU, but 29% (6 of 21) among mothers with titers >50,000 CU (odds ratio 13.1, P = 0.0008). Of mothers in group 2 with a primary diagnosis of CNL, 0% (0 of 18 mothers) had anti-Ro 60 antibody titers <10,000 CU, 44% (8 of 18 mothers) had titers from 10,000-50,000 CU, and 56% (10 of 18 mothers) had titers >50,000 CU.

CONCLUSION

CNL is associated with substantially higher anti-Ro antibody titers than are obtained using a standard CIA. Enhancing the assay measuring range allows an improved specificity of identifying pregnancies at risk of CNL.

Genetics of osteonecrosis in children and adults with systemic lupus erythematosus

OBJECTIVES

Genetics plays an important role in SLE risk, as well as osteonecrosis (ON), a significant and often debilitating complication of SLE. We aimed to identify genetic risk loci for ON in people with childhood-onset (cSLE) and adult-onset (aSLE) SLE.

METHODS

We enrolled participants from two tertiary care centres who met classification criteria for SLE. Participants had prospectively collected clinical data and were genotyped on a multiethnic array. Un-genotyped single nucleotide polymorphisms (SNPs) were imputed, and ancestry was inferred using principal components (PCs). Our outcome was symptomatic ON confirmed by imaging. We completed time-to-ON and logistic regression of ON genome-wide association studies (GWASs) with covariates for sex, age of SLE diagnosis, five PCs for ancestry, corticosteroid use and selected SLE manifestations. We conducted separate analyses for cSLE and aSLE and meta-analysed results using inverse-variance weighting. Genome-wide significance was P < 5 × 10-8.

RESULTS

The study included 940 participants with SLE, 87% female and 56% with cSLE. ON was present in 7.6% (n = 71). Median age of SLE diagnosis was 16.9 years (interquartile range [IQR]: 13.5, 29.3), with median follow-up of 8.0 years (IQR: 4.2, 15.7). Meta-GWAS of cSLE and aSLE time-to-ON of 4 431 911 SNPs identified a significant Chr.2 SNP, rs34118383 (minor allele frequency = 0.18), intronic to WIPF1 (hazard ratio = 3.2 [95% CI: 2.2, 4.8]; P = 1.0 × 10-8).

CONCLUSION

We identified an intronic WIPF1 variant associated with a 3.2 times increased hazard for ON (95% CI: 2.2, 4.8; P = 1.0 × 10-8) during SLE follow-up, independent of corticosteroid exposure. The effect of the SNP on time-to-ON was similar in cSLE and aSLE. This novel discovery represents a potential ON risk locus. Our results warrant replication.

Transmission disequilibrium analysis of whole genome data in childhood-onset systemic lupus erythematosus

Childhood-onset systemic lupus erythematosus (cSLE) patients are unique, with hallmarks of Mendelian disorders (early-onset and severe disease) and thus are an ideal population for genetic investigation of SLE. In this study, we use the transmission disequilibrium test (TDT), a family-based genetic association analysis that employs robust methodology, to analyze whole genome sequencing data. We aim to identify novel genetic associations in an ancestrally diverse, international cSLE cohort. Forty-two cSLE patients and 84 unaffected parents from 3 countries underwent whole genome sequencing. First, we performed TDT with single nucleotide variant (SNV)-based (common variants) using PLINK 1.9, and gene-based (rare variants) analyses using Efficient and Parallelizable Association Container Toolbox (EPACTS) and rare variant TDT (rvTDT), which applies multiple gene-based burden tests adapted for TDT, including the burden of rare variants test. Applying the GWAS standard threshold (5.0 × 10-8) to common variants, our SNV-based analysis did not return any genome-wide significant SNVs. The rare variant gene-based TDT analysis identified many novel genes significantly enriched in cSLE patients, including HNRNPUL2, a DNA repair protein, and DNAH11, a ciliary movement protein, among others. Our approach identifies several novel SLE susceptibility genes in an ancestrally diverse childhood-onset lupus cohort.

Interferon and interferon-induced cytokines as markers of impending clinical progression in ANA+ individuals without a systemic autoimmune rheumatic disease diagnosis

BACKGROUND

Elevated levels of interferons (IFNs) are a characteristic feature of systemic autoimmune rheumatic diseases (SARDs) and may be useful in predicting impending symptomatic progression in anti-nuclear antibody-positive (ANA⁺) individuals lacking a SARD diagnosis. Typically, these are measured by their effect on gene expression in the blood, which has limited their utility in clinical settings. Here, we assessed whether the measurement of serum IFN-α or selected IFN-induced cytokines accurately mirrors IFN-induced gene expression in ANA⁺ individuals and investigated their utility as biomarkers of clinical progression.

METHODS

A total of 280 subjects were studied, including 50 ANA^- healthy controls, 160 ANA⁺ individuals without a SARD diagnosis (96 asymptomatic, 64 with undifferentiated connective tissue disease), and 70 SARD patients. IFN-induced gene expression was measured by nanoString and cytokine levels by ELISA or Simoa. ANA⁺ individuals lacking a SARD diagnosis who had the new onset of SARD criteria over the subsequent 2 years were defined as progressors.

RESULTS

Measurement of IFN-α levels by high-sensitivity ELISA or Simoa correlated much better with IFN-induced gene expression than measurement of CXCL-10 or Galectin-9 levels. Despite this, high CXCL-10 and Galectin-9 levels were better predictors of subsequent progression in ANA⁺ individuals than measures of IFN-α or IFN-induced gene expression with the optimal combination of predictive cytokines (CXCL-10 and IFN-α as measured by ELISA), resulting in a specificity and positive predictive value of 100%.

CONCLUSION

Easily performed ELISA assays for CXCL-10 and IFN-α can be used to predict ANA⁺ individuals at high risk of imminent symptomatic progression.

Case report: Novel variants in RELA associated with familial Behcet's-like disease

RELA haploinsufficiency is a recently described autoinflammatory condition presenting with intermittent fevers and mucocutaneous ulcerations. The RELA gene encodes the p65 protein, one of five NF-κB family transcription factors. As RELA is an essential regulator of mucosal homeostasis, haploinsufficiency leads to decreased NF-κB signaling which promotes TNF-driven mucosal apoptosis with impaired epithelial recovery. Thus far, only eight cases have been reported in the literature. Here, we report four families with three novel and one previously described pathogenic variant in RELA. These four families included 23 affected individuals for which genetic testing was available in 16. Almost half of these patients had been previously diagnosed with more common rheumatologic entities (such as Behcet's Disease; BD) prior to the discovery of their pathogenic RELA variants. The most common clinical features were orogenital ulcers, rash, joint inflammation, and fever. The least common were conjunctivitis and recurrent infections. Clinical variability was remarkable even among familial cases, and incomplete penetrance was observed. Patients in our series were treated with a variety of medications, and benefit was observed with glucocorticoids, colchicine, and TNF inhibitors. Altogether, our work adds to the current literature and doubles the number of reported cases with RELA-Associated Inflammatory Disease (RAID). It reaffirms the central importance of the NF-κB pathway in immunity and inflammation, as well as the important regulatory role of RELA in mucosal homeostasis. RELA associated inflammatory disease should be considered in all patients with BD, particularly those with early onset and/or with a strong family history.

Genome-wide Sequencing Identified Rare Genetic Variants for Childhood-onset Monogenic Lupus

Objective

Genetics play an important role in systemic lupus erythematosus (SLE) pathogenesis. We calculated the prevalence of rare variants in known monogenic lupus genes, among children suspected of monogenic lupus.

Methods

We completed paired end genome-wide sequencing (whole-genome or whole-exome) in patients suspected of monogenic lupus, and focused on 36 monogenic lupus genes. We prioritized rare (minor allele frequency <1%) nonsynonymous and splice variants with predicted pathogenicity classified as deleterious variants (CADD, Polyphen, SIFT scores). Additional filtering restricted to predicted damaging variants by considering reported zygosity. In those with WGS, n=69, we examined copy number variants (CNVs) >1kb in size. We created additive non-HLA and HLA SLE genetic risk scores (GRSs) using common SLE-risk SNPs. We tested the relationship between SLE-GRSs and the number of rare variants with multivariate logistic models, adjusted for sex, ancestry and age of diagnosis.

Results

The cohort included 71 patients, 80% female, with a mean age at diagnosis of 8.9 years (SD 3.2 years). We identified predicted damaging variants in 9 patients (13%) who were significantly younger at diagnosis compared to those without a predicted damaging variant (6.8 years [SD 2.1] vs. 9.2 years [SD 3.2], P=0.013). We did not identify damaging CNVs. There was no significant association between non-HLA or HLA SLE-GRSs and the odds of carrying one or more rare variant in multivariate analyses.

Conclusion

In a cohort of patients with suspected monogenic lupus who underwent genomewide sequencing, 13% carried rare variants for monogenic lupus. Additional studies are needed to validate our findings.

Altered Balance of Pro-Inflammatory Immune Cells to T Regulatory Cells Differentiates Symptomatic From Asymptomatic Individuals With Anti-Nuclear Antibodies

Systemic Autoimmune Rheumatic Diseases (SARDs) are characterized by the production of anti-nuclear antibodies (ANAs). ANAs are also seen in healthy individuals and can be detected years before disease onset in SARD. Both the immunological changes that promote development of clinical symptoms in SARD and those that prevent autoimmunity in asymptomatic ANA+ individuals (ANA+ NS) remain largely unexplored. To address this question, we used flow cytometry to examine peripheral blood immune populations in ANA+ individuals, with and without SARD, including 20 individuals who subsequently demonstrated symptom progression. Several immune populations were expanded in ANA+ individuals with and without SARD, as compared with ANA- healthy controls, particularly follicular and peripheral T helper, and antibody-producing B cell subsets. In ANA+ NS individuals, there were significant increases in T regulatory subsets and TGF-ß1 that normalized in SARD patients, whereas in SARD patients there were increases in Th2 and Th17 helper cell levels as compared with ANA+ NS individuals, resulting in a shift in the balance between inflammatory and regulatory T cell subsets. Patients with SARD also had increases in the proportion of pro-inflammatory innate immune cell populations, such as CD14+ myeloid dendritic cells, and intermediate and non-classical monocytes, as compared to ANA+ NS individuals. When comparing ANA+ individuals without SARD who progressed clinically over the subsequent 2 years with those who did not, we found that progressors had significantly increased T and B cell activation, as well as increased levels of LAG3+ T regulatory cells and TGF-ß1. Collectively, our findings suggest that active immunoregulation prevents clinical autoimmunity in ANA+ NS and that this becomes impaired in patients who progress to SARD, resulting in an imbalance favoring inflammation.

Hemophagocytic Lymphohistiocytosis Gene Variants in Childhood-Onset SLE with Macrophage Activation Syndrome

OBJECTIVE

Macrophage activation syndrome (MAS), a life-threatening complication of SLE, resembles familial hemophagocytic lymphohistiocytosis (fHLH), an inherited disorder of hyperinflammation. We compared the proportion of childhood-onset SLE (cSLE) patients with and without MAS, who carried low-frequency HLH non-synonymous variants.

METHODS

We enrolled patients from the Lupus Clinic at SickKids, Toronto. Demographic and clinical features were extracted from the lupus database and ancestry was genetically inferred using multiethnic genotyping array data. Patients with MAS (based on expert diagnosis) underwent either paired-end whole exome sequencing (read-depth:70-118X) or whole-genome sequencing. Non-MAS patients had whole-genome sequencing (read-depth:37-40X). In 16 HLH genes we prioritized low-frequency (minor allele frequency (MAF) <0.05) exonic nonsynonymous variants. We compared the proportion of patients with and without MAS carrying HLH variants (Fisher's exact test, P<0.05). MAFs were compared to an ancestrally-matched general population (TOPMed and gnomAD).

RESULTS

The study included 81 patients, 19 with MAS. We identified 47 unique low-frequency non-synonymous HLH variants. There was no difference in the proportion of MAS and non-MAS patients carrying ≥1 HLH variants (37% versus 47%, P=0.44). The MAS cohort did not carry more HLH variants when compared to an ancestrally-matched general population.

CONCLUSION

In a single-center multiethnic cSLE cohort, we found no difference in the proportion of MAS patients carrying non-synonymous HLH genetic variants compared to patients without MAS. This is the first study to examine the frequency of HLH genetic variants in relation to MAS among cSLE patients. Future studies are required to validate our findings.

Schizophrenia Genetics and Neuropsychiatric Features in Childhood-Onset Systemic Lupus Erythematosus

OBJECTIVE

We examined the association between schizophrenia genetic susceptibility loci and neuropsychiatric systemic lupus erythematosus (NPSLE) features in childhood-onset SLE (cSLE) participants.

METHODS

Study participants from the Lupus Clinic at the Hospital for Sick Children, Toronto, met ≥4 of the ACR and/or SLICC SLE classification criteria and were genotyped using the Illumina MEGA or GSA arrays. Ungenotyped SNPs were imputed, and ancestry was genetically inferred. We calculated two additive schizophrenia weighted polygenic risk scores (PRSs) using: 1) genome-wide significant SNPs (P<5×10^-8) and 2) expanded list of SNPs with significance P<0.05. We defined two outcomes compared to absence of NPSLE features: 1) any NPSLE feature and 2) subtypes of NPSLE features: psychosis and non-psychosis NPSLE. We completed logistic and multinomial regressions, first adjusted for inferred ancestry only and second including variables significantly associated with NPSLE in our cohort (P<0.05).

RESULTS

We included 513 participants with cSLE. Median age at diagnosis was 13.8 years (IQR, 11.2-15.6), 83% were female, and 31% were of European ancestry. An increasing schizophrenia GWAS PRS was not significantly associated with NPSLE (OR=1.04, [95%CI 0.87,1.26];P=0.62), nor with NPSLE subtypes: psychosis (OR=0.97, [95%CI 0.73,1.29];P=0.84) and other non-psychosis NPSLE (OR=1.08, [95%CI 0.88,1.34];v=0.44) in ancestry adjusted models. Results were similar for the model including covariates (ancestry, malar rash, oral/nasal ulcers, arthritis, lymphopenia, Coombs-positive hemolytic anemia, lupus anticoagulant and anticardiolipin antibodies), and for the expanded PRS estimates.

CONCLUSION

We did not observe an association between known risk loci for schizophrenia and NPSLE in a multiethnic cSLE cohort. This work warrants further validation.

Nuclease deficiencies alter plasma cell-free DNA methylation profiles

The effects of DNASE1L3 or DNASE1 deficiency on cell-free DNA (cfDNA) methylation were explored in plasma of mice deficient in these nucleases and in DNASE1L3-deficient humans. Compared to wild-type cfDNA, cfDNA in DNASE1L3-deficient mice was significantly hypomethylated, while cfDNA in DNASE1-deficient mice was hypermethylated. The cfDNA hypomethylation in DNASE1L3-deficient mice was due to increased fragmentation and representation from open chromatin regions (OCRs) and CpG islands (CGIs). These findings were absent in DNASE1-deficient mice, demonstrating the preference of DNASE1 to cleave in hypomethylated OCRs and CGIs. We also observed a substantial decrease of fragment ends at methylated CpGs in the absence of DNASE1L3, thereby demonstrating that DNASE1L3 prefers to cleave at methylated CpGs. Furthermore, we found that methylation levels of cfDNA varied by fragment size in a periodic pattern, with cfDNA of specific sizes being more hypomethylated and enriched for OCRs and CGIs. These findings were confirmed in DNASE1L3-deficient human cfDNA. Thus, we have found that nuclease-mediated cfDNA fragmentation markedly affects cfDNA methylation level on a genome-wide scale. This work provides a foundational understanding of the relationship between methylation, nuclease biology, and cfDNA fragmentation.

Ethnicity and Neonatal Lupus Erythematosus Manifestations Risk in a Large Multiethnic Cohort

OBJECTIVE

To evaluate the association between ethnicity and neonatal lupus erythematosus (NLE), as well as specific NLE manifestations in a large multiethnic population.

METHODS

We conducted a cohort study of the children (≤ 1 yr of age) seen in the NLE clinic at The Hospital for Sick Children (SickKids), between January 2011 and April 2019. The cohort was divided into European, non-European, and mixed European-non-European groups according to parent-reported child's ethnicity (Canada Census categories). Outcomes were NLE and specific NLE manifestations (cardiac, cutaneous, cytopenias, transaminitis, and macrocephaly). The frequency of NLE and specific manifestations were compared between ethnic groups (Fisher exact test). We tested the association between ethnicity and (1) NLE risk, and (2) specific NLE manifestations with logistic regression models, including covariates for child's sex, maternal rheumatic disease status during pregnancy, and maternal use of antimalarials during pregnancy (multiple comparisons threshold P < 0.008).

RESULTS

We included 324 children born to 270 anti-Ro antibody-positive mothers. Median age at first visit was 1.8 (IQR 1.4-2.3) months, and median follow-up time was 12 (IQR 2-24) months. The majority was non-European (48%), with 34% European, and 18% mixed European-non-European. There was no significant association between non-European ethnicity (OR 1.18, 95% CI 0.71-1.94, P = 0.51), mixed European-non-European ethnicity (OR 1.13, 95% CI 0.59-2.16, P = 0.70), and NLE risk compared with European ethnicity. We also did not find an association between ethnicity and specific NLE manifestations in univariate or multivariable-adjusted models.

CONCLUSION

In a large multiethnic cohort, there was no association between a child's ethnicity and NLE risk or specific NLE manifestations.

Predicting Macrophage Activation Syndrome in Childhood-onset Systemic Lupus Erythematosus Patients at Diagnosis

OBJECTIVE

Macrophage activation syndrome (MAS), a life-threatening inflammatory complication, is increasingly recognized in childhood-onset systemic lupus erythematosus (cSLE). It can be a challenge to differentiate active cSLE from MAS. We generated decision rules for discriminating MAS from active cSLE in newly diagnosed patients.

METHODS

We conducted a retrospective cohort study of consecutive, newly diagnosed, active cSLE patients with fever, requiring hospital admission to The Hospital for Sick Children from January 2003 to December 2007 (cohort 1) and January 2008 to December 2013 (cohort 2). All patients met ≥ 4 American College of Rheumatology or Systemic Lupus International Collaborating Clinics criteria, and were steroid-naïve and infection-free. MAS was diagnosed based on expert opinion. Recursive partitioning was applied to each cohort to derive a decision rule based on clinical and laboratory features, distinguishing MAS from non-MAS cSLE. Each decision rule was applied to the alternate, independent cohort. Sensitivity and specificity of these decision rules were compared to existing criteria.

RESULTS

Cohort 1 (n = 34) and cohort 2 (n = 41) each had 10 patients with MAS. Recursive partitioning in cohort 1 identified ferritin ≥ 699 μg/L as the sole best discriminator between MAS and non-MAS patients (R² = 0.48), and in cohort 2, ferritin ≥ 1107 μg/L was the best discriminator for MAS, followed by lymphocytes < 0.72 × 10³/mm³ (R² = 0.52). Cross-validation of our decision rules maintained 90-100% sensitivity and 65-85% specificity.

CONCLUSION

Our decision rule demonstrated improved performance compared to preliminary guidelines for MAS in cSLE from the Lupus Working Group of the Paediatric Rheumatology European Society and familial hemophagocytic lymphohistiocytosis diagnostic criteria. Validation in independent cohorts is required.

Plasma DNA Profile Associated with DNASE1L3 Gene Mutations: Clinical Observations, Relationships to Nuclease Substrate Preference, and In Vivo Correction

Plasma DNA fragmentomics is an emerging area in cell-free DNA diagnostics and research. In murine models, it has been shown that the extracellular DNase, DNASE1L3, plays a role in the fragmentation of plasma DNA. In humans, DNASE1L3 deficiency causes familial monogenic systemic lupus erythematosus with childhood onset and anti-dsDNA reactivity. In this study, we found that human patients with DNASE1L3 disease-associated gene variations showed aberrations in size and a reduction of a "CC" end motif of plasma DNA. Furthermore, we demonstrated that DNA from DNASE1L3-digested cell nuclei showed a median length of 153 bp with CC motif frequencies resembling plasma DNA from healthy individuals. Adeno-associated virus-based transduction of Dnase1l3 into Dnase1l3-deficient mice restored the end motif profiles to those seen in the plasma DNA of wild-type mice. Our findings demonstrate that DNASE1L3 is an important player in the fragmentation of plasma DNA, which appears to act in a cell-extrinsic manner to regulate plasma DNA size and motif frequency.

Timing of Childhood-Onset Systemic Lupus Erythematosus Diagnosis Relative to Menarche and the Impact on Final Adult Height

OBJECTIVE

The aim of this study was to examine the impact of timing of a childhood-onset systemic lupus erythematosus (SLE) diagnosis relative to menarchal status, on final height, accounting for disease-associated factors.

METHODS

We conducted a cohort study of female patients age <18 years at childhood-onset SLE diagnosis, followed at a tertiary care pediatric center from July 1982 to March 2016, and restricted to patients with documented age of menarche and final height. We compared final height between patients diagnosed pre- and postmenarche. We tested the association of the timing of childhood-onset SLE diagnosis with final height, adjusted for ethnicity, in linear regression models. We performed subgroup analyses of patients with growth during follow-up, additionally adjusting for average daily corticosteroid dose and disease activity.

RESULTS

Of 401 female childhood-onset SLE patients in the study, 115 patients (29%) were diagnosed premenarche and 286 (71%) postmenarche. Patients diagnosed premenarche were older at menarche compared with patients diagnosed postmenarche (mean ± SD age 13.5 ± 1.4 versus 12.5 ± 1.3 years; P < 0.001). The mean ± SD final height for girls diagnosed postmenarche (161.4 ± 6.9 cm) was greater than for those diagnosed premenarche (158.8 ± 7.3 cm; P = 0.001). In regression analysis, those diagnosed postmenarche were significantly taller than those diagnosed premenarche, as adjusted for ethnicity and disease severity (mean ± SD β = 2.6 ± 0.7 cm; P = 0.0006).

CONCLUSION

In this large cohort study of girls with childhood-onset SLE, patients diagnosed postmenarche achieved a taller final height than those diagnosed premenarche, even after accounting for ethnicity and disease severity.

Association of systemic lupus erythematosus (SLE) genetic susceptibility loci with lupus nephritis in childhood-onset and adult-onset SLE

OBJECTIVE

LN is one of the most common and severe manifestations of SLE. Our aim was to test the association of SLE risk loci with LN risk in childhood-onset SLE (cSLE) and adult-onset SLE (aSLE).

METHODS

Two Toronto-based tertiary care SLE cohorts included cSLE (diagnosed <18 years) and aSLE patients (diagnosed ⩾18 years). Patients met ACR and/or SLICC SLE criteria and were genotyped on the Illumina Multi-Ethnic Global Array or Omni1-Quad arrays. We identified those with and without biopsy-confirmed LN. HLA and non-HLA additive SLE risk-weighted genetic risk scores (GRSs) were tested for association with LN risk in logistic models, stratified by cSLE/aSLE and ancestry. Stratified effect estimates were meta-analysed.

RESULTS

Of 1237 participants, 572 had cSLE (41% with LN) and 665 had aSLE (30% with LN). Increasing non-HLA GRS was significantly associated with increased LN risk [odds ratio (OR) = 1.26; 95% CI 1.09, 1.46; P = 0.0006], as was increasing HLA GRS in Europeans (OR = 1.55; 95% CI 1.07, 2.25; P = 0.03). There was a trend for stronger associations between both GRSs and LN risk in Europeans with cSLE compared with aSLE. When restricting cases to proliferative LN, the magnitude of these associations increased for both the non-HLA (OR = 1.30; 95% CI 1.10, 1.52; P = 0.002) and HLA GRS (OR = 1.99; 95% CI 1.29, 3.08; P = 0.002).

CONCLUSION

We observed an association between known SLE risk loci and LN risk in children and adults with SLE, with the strongest effect observed among Europeans with cSLE. Future studies will include SLE-risk single nucleotide polymorphisms specific to non-European ancestral groups and validate findings in an independent cohort.

Depressive and anxiety symptom prevalence in childhood-onset systemic lupus erythematosus: A systematic review

BACKGROUND

Depressive and anxiety symptoms are common in children and youth and may impact outcomes for individuals with childhood-onset systemic lupus erythematosus. Research into the prevalence of depressive and anxiety symptoms and childhood-onset systemic lupus erythematosus comorbidity has reported conflicting results.

OBJECTIVE

To synthesize current knowledge regarding the prevalence of depressive and anxiety symptoms in childhood-onset systemic lupus erythematosus.

METHODS

Studies were identified through a comprehensive search of MEDLINE, EMBASE, PsychINFO, LILACS and Web of Science (from database inception to July 2018) using MESH headings and keywords for 'lupus erythematosus', and 'depression' or 'anxiety'. Included studies measured depressive and/or anxiety symptoms prospectively among children and youth aged 8 to 21 years with a diagnosis of childhood-onset systemic lupus erythematosus. Neuropsychiatric systemic lupus erythematosus was included. Studies without use of validated screening tools for major depressive disorder or anxiety disorders were excluded, as were studies where diagnosis was by retrospective analysis of patient charts. Data were extracted by two independent coders and where discrepancies occurred, agreement was reached by consensus.

RESULTS

In total, 70 studies met the criteria for full text review and of these, 14 were included in the final analysis. The majority (70%) of studies were of cross-sectional design, with sample sizes ranging from 20 to 100 (mean = 48) participants. The mean age of participants was 15.9 years and participants were predominantly female. Prevalence rates for depressive symptoms ranged from 6.7% to 59%. Anxiety symptom prevalence was 34% to 37%. All studies employed self-report instruments to assess depressive and anxiety symptoms; none of the studies utilized a semi-structured diagnostic interview to make psychiatric diagnoses. Significant heterogeneity precluded meta-analysis of the data.

CONCLUSIONS

Depressive and anxiety symptoms may be common comorbidities of childhood-onset systemic lupus erythematosus; however, current research is limited by a paucity of studies, small sample sizes and an inability to confirm psychiatric diagnoses. Future research addressing these limitations is needed.

Genome-Wide Association Study of Diabetic Kidney Disease Highlights Biology Involved in Glomerular Basement Membrane Collagen

BACKGROUND

Although diabetic kidney disease demonstrates both familial clustering and single nucleotide polymorphism heritability, the specific genetic factors influencing risk remain largely unknown.

METHODS

To identify genetic variants predisposing to diabetic kidney disease, we performed genome-wide association study (GWAS) analyses. Through collaboration with the Diabetes Nephropathy Collaborative Research Initiative, we assembled a large collection of type 1 diabetes cohorts with harmonized diabetic kidney disease phenotypes. We used a spectrum of ten diabetic kidney disease definitions based on albuminuria and renal function.

RESULTS

Our GWAS meta-analysis included association results for up to 19,406 individuals of European descent with type 1 diabetes. We identified 16 genome-wide significant risk loci. The variant with the strongest association (rs55703767) is a common missense mutation in the collagen type IV alpha 3 chain (COL4A3) gene, which encodes a major structural component of the glomerular basement membrane (GBM). Mutations in COL4A3 are implicated in heritable nephropathies, including the progressive inherited nephropathy Alport syndrome. The rs55703767 minor allele (Asp326Tyr) is protective against several definitions of diabetic kidney disease, including albuminuria and ESKD, and demonstrated a significant association with GBM width; protective allele carriers had thinner GBM before any signs of kidney disease, and its effect was dependent on glycemia. Three other loci are in or near genes with known or suggestive involvement in this condition (BMP7) or renal biology (COLEC11 and DDR1).

CONCLUSIONS

The 16 diabetic kidney disease-associated loci may provide novel insights into the pathogenesis of this condition and help identify potential biologic targets for prevention and treatment.

Developing Reflection and Collaboration in Translational Medicine Toward Patients and Unmet Medical Needs

This perspective article aims to highlight the importance of values-driven personal reflection and collaboration for effective translational medicine training. We frame the dilemma in translational medicine and provide an approach for solution emphasizing collaboration and co-creation for innovative change in translational medicine. We cite the science in transition literature suggesting why personal reflection and a collaborative approach is important. We identify the problem with publication pressures and the bibliometric mindset. We focus on motivation to seek and find results that really matter for patients and individuals to maintain health in the real world. We review how the international EUREKA Institute for Translational Medicine (established in 2007) works with students, to harness their core values and develop personal growth skills to improve their leadership effectiveness, to work toward collaborative gain and potentially more meaningful results for patients and medical needs. We describe how the EUREKA Institute's unique setting, curriculum and hidden curriculum aspects effectively train program participants. The article highlights creating an immersive safe space, personal reflection, connection, structured brainstorming, group problem solving, collaboration and co-creation to facilitate innovation in translational medicine. The article relates program features to their theoretical underpinnings such as Theory U, Mediation Theory and Strategic Innovation Theory. The six authors from different global regions, ages, career stages, translational medicine contexts and years of attendance at the EUREKA Institute provide their reflections on training impact. Lessons learned and recommendations for research and application are discussed.

Comparison of Sensitivities of American College of Rheumatology and Systemic Lupus International Collaborating Clinics Classification Criteria in Childhood-onset Systemic Lupus Erythematosus

OBJECTIVE

Currently there are 2 different classification criteria for systemic lupus erythematosus (SLE): American College of Rheumatology (ACR) and Systemic Lupus International Collaborating Clinics (SLICC). The aim of this study was to compare the sensitivities of ACR and SLICC criteria in childhood-onset SLE (cSLE) using a large, multiethnic cohort.

METHODS

We conducted a retrospective study of 722 patients diagnosed with cSLE at The Hospital for Sick Children (SickKids). Prospectively collected data from SickKids' Lupus Database were reviewed/validated against medical records prior to ACR and SLICC scoring based on cumulative symptoms up to the last visit. Sensitivities were compared using McNemar's test. Descriptive statistics were used to identify SLE features unique to each set of criteria and autoantibodies not included in either.

RESULTS

ACR and SLICC sensitivities were as follows: 92.4% and 96.3% overall (p = 0.001); 82.5% and 91.3% (p = 0.01) in those scored ≤ 1 year from diagnosis; 92.7% and 97.9% (p = 0.02) in those scored 2-3 years from diagnosis. Forty-eight of 55 (87.3%) patients who did not meet ACR criteria met SLICC criteria through SLICC-specific criterion or renal biopsy. Twenty of 27 (74.1%) patients who did not meet SLICC criteria met ACR criteria as a result of photosensitivity (73.9%) and ACR lymphopenia criteria (26.1%). Six of 7 patients (85.7%) who were clinically diagnosed with cSLE but did not meet either SLICC or ACR criteria had anti-Ro antibodies.

CONCLUSION

SLICC criteria were significantly more sensitive than ACR criteria in cSLE classification, especially early in the disease course. Because of the extreme rarity of primary Sjögren syndrome in children, one may consider adding anti-Ro antibodies to the classification criteria for cSLE because they are present in ∼40% of patents with cSLE.

Canadian Rheumatology Association Recommendations for the Assessment and Monitoring of Systemic Lupus Erythematosus

OBJECTIVE

To develop recommendations for the assessment of people with systemic lupus erythematosus (SLE) in Canada.

METHODS

Recommendations were developed using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) approach. The Canadian SLE Working Group (panel of Canadian rheumatologists and a patient representative from Canadian Arthritis Patient Alliance) was created. Questions for recommendation development were identified based on the results of a previous survey of SLE practice patterns of members of the Canadian Rheumatology Association. Systematic literature reviews of randomized trials and observational studies were conducted. Evidence to Decision tables were prepared and presented to the panel at 2 face-to-face meetings and online.

RESULTS

There are 15 recommendations for assessing and monitoring SLE, with varying applicability to adult and pediatric patients. Three recommendations focus on diagnosis, disease activity, and damage assessment, suggesting the use of a validated disease activity score per visit and annual damage score. Strong recommendations were made for cardiovascular risk assessment and measuring anti-Ro and anti-La antibodies in the peripartum period and conditional recommendations for osteoporosis and osteonecrosis. Two conditional recommendations were made for peripartum assessments, 1 for cervical cancer screening and 2 for hepatitis B and C screening. A strong recommendation was made for annual influenza vaccination.

CONCLUSION

These are considered the first guidelines using the GRADE method for the monitoring of SLE. Existing evidence is largely of low to moderate quality, resulting in more conditional than strong recommendations. Additional rigorous studies and special attention to pediatric SLE populations and patient preferences are needed.

A Genome-Wide Association Study of Diabetic Kidney Disease in Subjects With Type 2 Diabetes

Identification of sequence variants robustly associated with predisposition to diabetic kidney disease (DKD) has the potential to provide insights into the pathophysiological mechanisms responsible. We conducted a genome-wide association study (GWAS) of DKD in type 2 diabetes (T2D) using eight complementary dichotomous and quantitative DKD phenotypes: the principal dichotomous analysis involved 5,717 T2D subjects, 3,345 with DKD. Promising association signals were evaluated in up to 26,827 subjects with T2D (12,710 with DKD). A combined T1D+T2D GWAS was performed using complementary data available for subjects with T1D, which, with replication samples, involved up to 40,340 subjects with diabetes (18,582 with DKD). Analysis of specific DKD phenotypes identified a novel signal near GABRR1 (rs9942471, P = 4.5 × 10^-8) associated with microalbuminuria in European T2D case subjects. However, no replication of this signal was observed in Asian subjects with T2D or in the equivalent T1D analysis. There was only limited support, in this substantially enlarged analysis, for association at previously reported DKD signals, except for those at UMOD and PRKAG2, both associated with estimated glomerular filtration rate. We conclude that, despite challenges in addressing phenotypic heterogeneity, access to increased sample sizes will continue to provide more robust inference regarding risk variant discovery for DKD.

Genomics of Systemic Lupus Erythematosus: Insights Gained by Studying Monogenic Young-Onset Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a systemic, autoimmune, multisystem disease with a heterogeneous clinical phenotype. Genome-wide association studies have identified multiple susceptibility loci, but these explain a fraction of the estimated heritability. This is partly because within the broad spectrum of SLE are monogenic diseases that tend to cluster in patients with young age of onset, and in families. This article highlights insights into the pathogenesis of SLE provided by these monogenic diseases. It examines genetic causes of complement deficiency, abnormal interferon production, and abnormalities of tolerance, resulting in monogenic SLE with overlapping clinical features, autoantibodies, and shared inflammatory pathways.

Features, Treatment, and Outcomes of Macrophage Activation Syndrome in Childhood-Onset Systemic Lupus Erythematosus

OBJECTIVE

To describe the features and treatment of macrophage activation syndrome (MAS) in a single-center cohort of patients with childhood-onset systemic lupus erythematosus (SLE), and to compare childhood-onset SLE manifestations and outcomes between those with and those without MAS.

METHODS

We included all patients with childhood-onset SLE followed up at The Hospital for Sick Children from 2002 to 2012, and identified those also diagnosed as having MAS. Demographic, clinical, and laboratory features of MAS and SLE, medication use, hospital and pediatric intensive care unit (PICU) admissions, as well as damage indices and mortality data were extracted from the Lupus database. Student's t-tests and Fisher's exact tests were used to compare continuous and categorical variables, respectively. We calculated incidence rate ratios of hospital and PICU admissions comparing patients with and those without MAS, using Poisson models. Kaplan-Meier survival analysis was used to examine the time to disease damage accrual.

RESULTS

Of the 403 patients with childhood-onset SLE, 38 (9%) had MAS. The majority (68%) had concomitant MAS and SLE diagnoses. Fever was the most common MAS clinical feature. The frequency of renal and central nervous system disease, hospital admissions, the average daily dose of steroids, and time to disease damage were similar between those with and those without MAS. We observed a higher mortality rate among those with MAS (5%) than those without MAS (0.2%) (P = 0.02).

CONCLUSION

MAS was most likely to develop concomitantly with childhood-onset SLE diagnosis. The majority of the MAS patients were successfully treated with corticosteroids with no MAS relapses. Although the numbers were small, there was a higher risk of death associated with MAS compared to SLE without MAS.

Serious Infection Rates Among Children With Systemic Lupus Erythematosus Enrolled in Medicaid

OBJECTIVE

To investigate the nationwide prevalence and incidence of serious infections among children with systemic lupus erythematosus (SLE) enrolled in Medicaid, the US health insurance program for low-income patients.

METHODS

From Medicaid claims (2000-2006) we identified children ages 5 to <18 years with SLE (≥3 International Classification of Diseases, Ninth Revision [ICD-9] codes of 710.0, each >30 days apart) and lupus nephritis (LN; ≥2 ICD-9 codes for kidney disease on/after SLE codes). From hospital discharge diagnoses, we identified infection subtypes (bacterial, fungal, and viral). We calculated incidence rates (IRs) per 100 person-years, mortality rates, and hazard ratios adjusted for sociodemographic factors, medications, and preventive care.

RESULTS

Among 3,500 children with identified SLE, 1,053 serious infections occurred over 10,108 person-years; the IR was 10.42 per 100 person-years (95% confidence interval [95% CI] 9.80-11.07) among all those with SLE and 17.65 per 100 person-years (95% CI 16.29-19.09) among those with LN. Bacterial infections were most common (87%, of which 39% were bacterial pneumonias). In adjusted models, African Americans and American Indians had higher rates of infections compared with white children, and those with comorbidities or receiving corticosteroids had higher infection rates than those without. Males had lower rates of serious infections compared to females. The 30-day postdischarge mortality rate was 4.4%.

CONCLUSION

Overall, hospitalized infections were very common in children with SLE, with bacterial pneumonia being the most common infection. Highest infection risks were among African American and American Indian children, those with LN, comorbidities, and those taking corticosteroids.

The Genetic Landscape of Renal Complications in Type 1 Diabetes

Diabetes is the leading cause of ESRD. Despite evidence for a substantial heritability of diabetic kidney disease, efforts to identify genetic susceptibility variants have had limited success. We extended previous efforts in three dimensions, examining a more comprehensive set of genetic variants in larger numbers of subjects with type 1 diabetes characterized for a wider range of cross-sectional diabetic kidney disease phenotypes. In 2843 subjects, we estimated that the heritability of diabetic kidney disease was 35% (P=6.4×10^-3). Genome-wide association analysis and replication in 12,540 individuals identified no single variants reaching stringent levels of significance and, despite excellent power, provided little independent confirmation of previously published associated variants. Whole-exome sequencing in 997 subjects failed to identify any large-effect coding alleles of lower frequency influencing the risk of diabetic kidney disease. However, sets of alleles increasing body mass index (P=2.2×10^-5) and the risk of type 2 diabetes (P=6.1×10^-4) associated with the risk of diabetic kidney disease. We also found genome-wide genetic correlation between diabetic kidney disease and failure at smoking cessation (P=1.1×10^-4). Pathway analysis implicated ascorbate and aldarate metabolism (P=9.0×10^-6), and pentose and glucuronate interconversions (P=3.0×10^-6) in pathogenesis of diabetic kidney disease. These data provide further evidence for the role of genetic factors influencing diabetic kidney disease in those with type 1 diabetes and highlight some key pathways that may be responsible. Altogether these results reveal important biology behind the major cause of kidney disease.

Review: Measuring permanent damage in pediatric systemic lupus erythematosus

The survival rates in pediatric systemic lupus erythematosus (pSLE) have improved greatly over recent decades. Increased life expectancy has meant that more children are growing up with the consequences of chronic disease and prolonged therapy. Assessing complications of disease and its therapy becomes an important outcome measure by which to evaluate our therapeutic interventions and appraise quality of life.

In this paper we review the development of the Systemic Lupus International Collaborative Clinics (SLICC)/American College of Rheumatology (ACR) Damage Index (SDI) and its application to the pSLE population. We examine the profile of damage in pSLE as identified by the SDI. However we also critically appraise its application and identify potential limitations in the SDI as a measure of permanent disease damage in children. In this paper we put forth suggestions for additional domains addressing pediatric specific issues such as decreased final height and delayed puberty. We also suggest modifications to domains of gonadal failure, diabetes mellitus, cognitive impairment and osteonecrosis in the SDI to make it more reflective of the damage phenomenon observed in pediatrics. Lupus (2007) 16: 657—662.

New Locus for Skin Intrinsic Fluorescence in Type 1 Diabetes Also Associated With Blood and Skin Glycated Proteins

Skin fluorescence (SF) noninvasively measures advanced glycation end products (AGEs) in the skin and is a risk indicator for diabetes complications. N-acetyltransferase 2 (NAT2) is the only known locus influencing SF. We aimed to identify additional genetic loci influencing SF in type 1 diabetes (T1D) through a meta-analysis of genome-wide association studies (N = 1,359) including Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) and Wisconsin Epidemiologic Study of Diabetic Retinopathy (WESDR). A locus on chromosome 1, rs7533564 (P = 1.9 × 10(-9)), was associated with skin intrinsic fluorescence measured by SCOUT DS (excitation 375 nm, emission 435-655 nm), which remained significant after adjustment for time-weighted HbA1c (P = 1.7 × 10(-8)). rs7533564 was associated with mean HbA1c in meta-analysis (P = 0.0225), mean glycated albumin (P = 0.0029), and glyoxal hydroimidazolones (P = 0.049), an AGE measured in skin biopsy collagen, in DCCT. rs7533564 was not associated with diabetes complications in DCCT/EDIC or with SF in subjects without diabetes (nondiabetic [ND]) (N = 8,721). In conclusion, we identified a new locus associated with SF in T1D subjects that did not show similar effect in ND subjects, suggesting a diabetes-specific effect. This association needs to be investigated in type 2 diabetes.

Genome-wide Association Studies Identify Genetic Loci Associated With Albuminuria in Diabetes

Elevated concentrations of albumin in the urine, albuminuria, are a hallmark of diabetic kidney disease and are associated with an increased risk for end-stage renal disease and cardiovascular events. To gain insight into the pathophysiological mechanisms underlying albuminuria, we conducted meta-analyses of genome-wide association studies and independent replication in up to 5,825 individuals of European ancestry with diabetes and up to 46,061 without diabetes, followed by functional studies. Known associations of variants in CUBN, encoding cubilin, with the urinary albumin-to-creatinine ratio (UACR) were confirmed in the overall sample (P = 2.4 × 10(-10)). Gene-by-diabetes interactions were detected and confirmed for variants in HS6ST1 and near RAB38/CTSC. Single nucleotide polymorphisms at these loci demonstrated a genetic effect on UACR in individuals with but not without diabetes. The change in the average UACR per minor allele was 21% for HS6ST1 (P = 6.3 × 10(-7)) and 13% for RAB38/CTSC (P = 5.8 × 10(-7)). Experiments using streptozotocin-induced diabetic Rab38 knockout and control rats showed higher urinary albumin concentrations and reduced amounts of megalin and cubilin at the proximal tubule cell surface in Rab38 knockout versus control rats. Relative expression of RAB38 was higher in tubuli of patients with diabetic kidney disease compared with control subjects. The loci identified here confirm known pathways and highlight novel pathways influencing albuminuria.

Serious infections among adult Medicaid beneficiaries with systemic lupus erythematosus and lupus nephritis

OBJECTIVE

To examine the epidemiology of serious infections, a significant cause of morbidity and mortality in systemic lupus erythematosus (SLE), in a nationwide cohort of SLE and lupus nephritis (LN) patients.

METHODS

Using the Medicaid Analytic eXtract database for the years 2000-2006, we identified patients ages 18-64 years who had SLE and the subset who had LN. We ascertained cases of serious hospitalized infections using validated algorithms, and we determined 30-day mortality rates. Poisson regression was used to calculate infection incidence rates and multivariable Cox proportional hazards models were used to calculate hazard ratios (HRs) for the first infection, adjusted for sociodemographic variables, medication use, and an SLE-specific risk adjustment index.

RESULTS

We identified 33,565 patients with SLE, 7,113 of whom had LN. There were 9,078 serious infections in 5,078 SLE patients and 3,494 infections in 1,825 LN patients. The infection incidence rate per 100 person-years was 10.8 in the SLE cohort and 23.9 in the LN subcohort. In adjusted models for the SLE cohort, we observed increased risks of infection in men as compared to women (HR 1.33 [95% confidence interval (95% CI) 1.20-1.47]), in blacks as compared to whites (HR 1.14 [95% CI 1.06-1.21]), and in users of glucocorticoids (HR 1.51 [95% CI 1.43-1.61]) and immunosuppressive drugs (HR 1.11 [95% CI 1.03-1.20]) as compared to never users. Hydroxychloroquine users had a reduced risk of infection as compared to never users (HR 0.73 [95% CI 0.68-0.77]). The 30-day mortality rate per 1,000 person-years among those hospitalized with infections was 21.4 in the SLE cohort and 38.6 in the LN subcohort.

CONCLUSION

In this diverse, nationwide cohort of SLE patients, we observed a substantial burden of serious infections with many subsequent deaths, particularly among those with LN.

Contributions of familial rheumatoid arthritis or lupus and environmental factors to risk of rheumatoid arthritis in women: a prospective cohort study

OBJECTIVE

We assessed the contributions of familial rheumatoid arthritis (RA) or lupus and environmental factors to the risk of RA.

METHODS

Among 121,700 women in the Nurses' Health Study, 65,457 provided data on familial RA/lupus. Among these, 493 RA cases (301 seropositive and 192 seronegative) were validated. We estimated hazard ratios (HRs) for RA comparing those with and without familial RA/lupus, adjusting for environmental factors (smoking, alcohol, body mass index [BMI], parity, breastfeeding, menopause, hormone use, early menarche, and menstrual regularity) using Cox proportional hazards models. Population attributable risks (PARs) for RA within this cohort were calculated for familial RA/lupus, smoking, alcohol, BMI, parity, and breastfeeding.

RESULTS

Familial RA/lupus was significantly associated with RA (HR 3.67), seropositive RA (HR 3.90), and seronegative RA (HR 3.95). After adjusting for environmental factors, familial RA/lupus was significantly associated with RA (HR 3.59, 95% confidence interval 2.94-4.37). Smoking >10 pack-years, overweight, BMI, and premenopause status remained significantly associated with RA after adjusting for familial RA/lupus. For RA in this cohort, the PAR for smoking, BMI, alcohol, parity, or breastfeeding collectively was 41%; the PAR due to heredity from familial RA/lupus was 21%.

CONCLUSION

In this large, prospective cohort, women with familial RA/lupus had a 4-fold increased risk for RA that remained significant after adjusting for environmental factors. A large proportion of RA risk was attributable to environmental factors, even among those with familial RA/lupus.

Circulating 25-hydroxyvitamin D level and risk of developing rheumatoid arthritis

OBJECTIVE

The aim of this study was to examine the relationship between preclinical circulating 25-hydroxyvitamin D [25(OH)D] and RA in two nested case-control studies within the prospective cohort Nurses' Health Study (NHS) and NHS II (NHSII).

METHODS

We included 166 women with RA and blood specimens collected 3 months to 16 years prior to the first RA symptom and 490 matched controls (3:1, matched on age, date of blood draw, hormonal factors). We calculated the odds ratio (OR) and 95% CI for incident RA using conditional logistic regression multivariable adjusted models, including additional covariates for smoking status, parity and breastfeeding, alcohol consumption, BMI, median income and region of residence in the USA. We repeated analyses stratified by time from blood draw to RA diagnosis (3 months to <4 years or ≥4 years) and meta-analysed estimates from the two cohorts using fixed effects models.

RESULTS

Incident RA was confirmed in 120 NHS [mean age 63.8 years (s.d. 8.2)] and 46 NHSII participants [mean age 48.5 years (s.d. 4.7)]. Mean time from blood draw to RA diagnosis was 7.8 years (s.d. 4.2) for NHS and 4.2 years (s.d. 2.0) for NHSII participants. Meta-analysis of crude and multivariable-adjusted conditional logistic models did not show significant associations between circulating 25(OH)D and RA. However, among NHSII women with blood drawn between 3 months and <4 years prior to RA diagnosis, there was a 20% decreased risk of RA associated with each 1 ng/ml increase in 25(OH)D [OR 0.80 (95% CI 0.64, 0.99)].

CONCLUSION

We did not observe a significant association between circulating 25(OH)D levels and RA, except for among a small subset of NHSII women with levels measured closest to RA diagnosis.

Being overweight or obese and risk of developing rheumatoid arthritis among women: a prospective cohort study

OBJECTIVES

To examine the relationship between being overweight or obese and developing rheumatoid arthritis (RA) in two large prospective cohorts, the Nurses' Health Study (NHS) and Nurses' Health Study II (NHSII).

METHODS

We followed 109 896 women enrolled in NHS and 108 727 in NHSII who provided lifestyle, environmental exposure and anthropometric information through biennial questionnaires. We assessed the association between time-varying and cumulative Body Mass Index (BMI) in WHO categories of normal, overweight and obese (18.5-<25, 25.0-<30, ≥30.0 kg/m(2)) and incident RA meeting the 1987 American College of Rheumatology (ACR) criteria. We estimated HRs for overall RA and serologic subtypes with Cox regression models adjusted for potential confounders. We repeated analyses restricted to RA diagnosed at age 55 years or younger.

RESULTS

During 2 765 195 person-years of follow-up (1976-2008) in NHS and 1 934 518 person-years (1989-2009) in NHSII, we validated 1181 incident cases of RA (826 in NHS, 355 in NHSII). There was a trend toward increased risk of all RA among overweight and obese women (HR (95% CI) 1.37 (0.95 to 1.98) and 1.37 (0.91, 2.09), p for trend=0.068). Among RA cases diagnosed at age 55 years or younger, this association appeared stronger (HR 1.45 (1.03 to 2.03) for overweight and 1.65 (1.34 to 2.05) for obese women (p trend <0.001)). Ten cumulative years of being obese, conferred a 37% increased risk of RA at younger ages (HR 1.37 (1.11 to 1.69)).

CONCLUSIONS

Risks of seropositive and seronegative RA were elevated among overweight and obese women, particularly among women diagnosed with RA at earlier ages.

Improved performance of epidemiologic and genetic risk models for rheumatoid arthritis serologic phenotypes using family history

OBJECTIVE

To develop and validate rheumatoid arthritis (RA) risk models based on family history, epidemiologic factors and known genetic risk factors.

METHODS

We developed and validated models for RA based on known RA risk factors, among women in two cohorts: the Nurses' Health Study (NHS, 381 RA cases and 410 controls) and the Epidemiological Investigation of RA (EIRA, 1244 RA cases and 971 controls). Model discrimination was evaluated using the area under the receiver operating characteristic curve (AUC) in logistic regression models for the study population and for those with positive family history. The joint effect of family history with genetics, smoking and body mass index (BMI) was evaluated using logistic regression models to estimate ORs for RA.

RESULTS

The complete model including family history, epidemiologic risk factors and genetics demonstrated AUCs of 0.74 for seropositive RA in NHS and 0.77 for anti-citrullinated protein antibody (ACPA)-positive RA in EIRA. Among women with positive family history, discrimination was excellent for complete models for seropositive RA in NHS (AUC 0.82) and ACPA-positive RA in EIRA (AUC 0.83). Positive family history, high genetic susceptibility, smoking and increased BMI had an OR of 21.73 for ACPA-positive RA.

CONCLUSIONS

We developed models for seropositive and seronegative RA phenotypes based on family history, epidemiological and genetic factors. Among those with positive family history, models using epidemiologic and genetic factors were highly discriminatory for seropositive and seronegative RA. Assessing epidemiological and genetic factors among those with positive family history may identify individuals suitable for RA prevention strategies.

Joint effects of colorectal cancer susceptibility loci, circulating 25-hydroxyvitamin D and risk of colorectal cancer

Background

Genome wide association studies (GWAS) have identified several SNPs associated with colorectal cancer (CRC) susceptibility. Vitamin D is also inversely associated with CRC risk.

Methods

We examined main and joint effects of previously GWAS identified genetic markers of CRC and plasma 25-hydroxyvitamin D (25(OH)D) on CRC risk in three prospective cohorts: the Nurses' Health Study (NHS), the Health Professionals Follow-up Study (HPFS), and the Physicians' Health Study (PHS). We included 1895 CRC cases and 2806 controls with genomic DNA. We calculated odds ratios and 95% confidence intervals for CRC associated with additive genetic risk scores (GRSs) comprised of all CRC SNPs and subsets of these SNPs based on proximity to regions of increased vitamin D receptor binding to vitamin D response elements (VDREs), based on published ChiP-seq data. Among a subset of subjects with additional prediagnostic 25(OH)D we tested multiplicative interactions between plasma 25(OH)D and GRS's. We used fixed effects models to meta-analyze the three cohorts.

Results

The per allele multivariate OR was 1.12 (95% CI, 1.06–1.19) for GRS-proximalVDRE; and 1.10 (95% CI, 1.06–1.14) for GRS-nonproxVDRE. The lowest quartile of plasma 25(OH)D compared with the highest, had a multivariate OR of 0.63 (95% CI, 0.48–0.82) for CRC. We did not observe any significant interactions between any GRSs and plasma 25(OH)D.

Conclusions

We did not observe evidence for the modification of genetic susceptibility for CRC according to vitamin D status, or evidence that the effect of common CRC risk alleles differed according to their proximity to putative VDR binding sites.

Chicken or the egg: anorexia nervosa and systemic lupus erythematosus in children and adolescents

Systemic lupus erythematosus (SLE) frequently has neuropsychiatric involvement including affective disorders, psychosis, and cognitive dysfunction. Evidence suggests that anorexia nervosa (AN) in adolescents with SLE may be triggered by steroid-induced changes in weight and body shape. We propose that AN may be another manifestation of neuropsychiatric SLE and should be considered in this patient population. A retrospective chart review identified 7 children/adolescents diagnosed with SLE and the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition diagnostic criteria for AN, restrictive subtype, at the Hospital for Sick Children in Toronto between January 1989 and January 2011. One patient developed AN 15 months after being diagnosed with SLE that was attributed to prednisone-induced weight gain and cushingoid appearance. Of the remaining 6 patients, the median age at onset of AN symptoms was 12.2 years and diagnosis of AN was 13.6 years. The median age at SLE diagnosis was 14.2 years with median time after onset of AN symptoms of 20 months (7.5-32 months). All patients had evidence of joint symptoms and a positive antinuclear antibody, and 50% had lymphopenia at the time of SLE diagnosis. Treatment of SLE resulted in improvement of AN in all patients. The timing of the clinical presentation of AN in relation to the diagnosis of SLE and response to SLE treatment suggests that AN may be a novel presentation of neuropsychiatric SLE. Patients with AN who present with or develop joint symptoms, a positive antinuclear antibody, or lymphopenia should be investigated and followed for possible SLE.

Genetic predictors of circulating 25-hydroxyvitamin d and risk of colorectal cancer

BACKGROUND

Experimental evidence has demonstrated an antineoplastic role for vitamin D in the colon, and higher circulating 25-hydroxyvitamin D [25(OH)D] levels are consistently associated with a lower risk of colorectal cancer. Genome-wide association studies have identified loci associated with levels of circulating 25(OH)D. The identified single-nucleotide polymorphisms (SNPs) from four gene regions collectively explain approximately 5% of the variance in circulating 25(OH)D.

METHODS

We investigated whether five polymorphisms in GC, CYP2R1, CYP24A1, and DHCR7/NADSYN1, genes previously shown to be associated with circulating 25(OH)D levels, were associated with colorectal cancer risk in 10,061 cases and 12,768 controls drawn from 13 studies included in the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO) and Colon Cancer Family Registry (CCFR). We conducted a meta-analysis of crude and multivariate-adjusted logistic regression models to calculate odds ratios and associated confidence intervals for SNPs individually, SNPs simultaneously, and for a vitamin D additive genetic risk score (GRS).

RESULTS

We did not observe a statistically significant association between the 25(OH)D-associated SNPs and colorectal cancer marginally, conditionally, or as a GRS, or for colon or rectal cancer separately.

CONCLUSIONS

Our findings do not support an association between SNPs associated with circulating 25(OH)D and risk of colorectal cancer. Additional work is warranted to investigate the complex relationship between 25(OH)D and colorectal cancer risk.

IMPACT

There was no association observed between genetic markers of circulating 25(OH)D and colorectal cancer. These genetic markers account for a small proportion of the variance in 25(OH)D.

Epidemiology and sociodemographics of systemic lupus erythematosus and lupus nephritis among US adults with Medicaid coverage, 2000-2004

OBJECTIVE

Systemic lupus erythematosus (SLE) and lupus nephritis (LN) disproportionately affect individuals who are members of racial/ethnic minority groups and individuals of lower socioeconomic status (SES). This study was undertaken to investigate the epidemiology and sociodemographics of SLE and LN in the low-income US Medicaid population.

METHODS

We utilized Medicaid Analytic eXtract data, with billing claims from 47 states and Washington, DC, for 23.9 million individuals ages 18-65 years who were enrolled in Medicaid for >3 months in 2000-2004. Individuals with SLE (≥3 visits >30 days apart with an International Classification of Diseases, Ninth Revision [ICD-9] code of 710.0) and with LN (≥2 visits with an ICD-9 code for glomerulonephritis, proteinuria, or renal failure) were identified. We calculated SLE and LN prevalence and incidence, stratified by sociodemographic category, and adjusted for number of American College of Rheumatology (ACR) member rheumatologists in the state and SES using a validated composite of US Census variables.

RESULTS

We identified 34,339 individuals with SLE (prevalence 143.7 per 100,000) and 7,388 (21.5%) with LN (prevalence 30.9 per 100,000). SLE prevalence was 6 times higher among women, nearly double in African American compared to white women, and highest in the US South. LN prevalence was higher among all racial/ethnic minority groups compared to whites. The areas with lowest SES had the highest prevalence; areas with the fewest ACR rheumatologists had the lowest prevalence. SLE incidence was 23.2 per 100,000 person-years and LN incidence was 6.9 per 100,000 person-years, with similar sociodemographic trends.

CONCLUSION

In this nationwide Medicaid population, there was sociodemographic variation in SLE and LN prevalence and incidence. Understanding the increased burden of SLE and its complications in this low-income population has implications for resource allocation and access to subspecialty care.

Dietary intake of vitamin D during adolescence and risk of adult-onset systemic lupus erythematosus and rheumatoid arthritis

OBJECTIVE

Vitamin D has immunomodulatory properties with potential etiologic implications for autoimmune diseases. The relevant exposure time during which vitamin D may influence disease risk is unknown. Our objective was to examine the relationship between reported vitamin D intake during adolescence and adult-onset rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) incidence in prospective cohort studies of women, the Nurses' Health Study (NHS) and the Nurses' Health Study II (NHSII).

METHODS

Food frequency questionnaires concerning high school diet completed by 73,629 NHS (1986) and 45,544 NHSII (1998) participants were used to calculate nutrient intakes during adolescence. Incident RA and SLE cases prior to 2006 (NHS) and 2007 (NHSII) were confirmed by medical record review. Cox proportional hazards models calculated relative risks and 95% confidence intervals of incident RA and SLE according to quintile cutoffs of vitamin D intake. Age- and calorie-adjusted and multivariable-adjusted (including sun exposure factors) analyses were completed. Random-effects models were used to meta-analyze estimates of association from the 2 cohorts.

RESULTS

Incident RA was confirmed in 652 NHS and 148 NHSII participants and SLE was confirmed in 122 NHS and 54 NHSII participants over a mean followup time of 351 months (NHS) and 209 months (NHSII). Age- and calorie-adjusted and multivariable-adjusted models did not show significant associations between adolescent vitamin D intake and risk of adult-onset RA or SLE.

CONCLUSION

We did not find associations between adolescent dietary vitamin D intake and adult RA or SLE risk among NHS and NHSII women, suggesting that other time periods during the life course should be studied.

Causal relationship between obesity and vitamin D status: bi-directional Mendelian randomization analysis of multiple cohorts

BACKGROUND

Obesity is associated with vitamin D deficiency, and both are areas of active public health concern. We explored the causality and direction of the relationship between body mass index (BMI) and 25-hydroxyvitamin D [25(OH)D] using genetic markers as instrumental variables (IVs) in bi-directional Mendelian randomization (MR) analysis.

METHODS AND FINDINGS

We used information from 21 adult cohorts (up to 42,024 participants) with 12 BMI-related SNPs (combined in an allelic score) to produce an instrument for BMI and four SNPs associated with 25(OH)D (combined in two allelic scores, separately for genes encoding its synthesis or metabolism) as an instrument for vitamin D. Regression estimates for the IVs (allele scores) were generated within-study and pooled by meta-analysis to generate summary effects. Associations between vitamin D scores and BMI were confirmed in the Genetic Investigation of Anthropometric Traits (GIANT) consortium (n = 123,864). Each 1 kg/m(2) higher BMI was associated with 1.15% lower 25(OH)D (p = 6.52×10⁻²⁷). The BMI allele score was associated both with BMI (p = 6.30×10⁻⁶²) and 25(OH)D (-0.06% [95% CI -0.10 to -0.02], p = 0.004) in the cohorts that underwent meta-analysis. The two vitamin D allele scores were strongly associated with 25(OH)D (p≤8.07×10⁻⁵⁷ for both scores) but not with BMI (synthesis score, p = 0.88; metabolism score, p = 0.08) in the meta-analysis. A 10% higher genetically instrumented BMI was associated with 4.2% lower 25(OH)D concentrations (IV ratio: -4.2 [95% CI -7.1 to -1.3], p = 0.005). No association was seen for genetically instrumented 25(OH)D with BMI, a finding that was confirmed using data from the GIANT consortium (p≥0.57 for both vitamin D scores).

CONCLUSIONS

On the basis of a bi-directional genetic approach that limits confounding, our study suggests that a higher BMI leads to lower 25(OH)D, while any effects of lower 25(OH)D increasing BMI are likely to be small. Population level interventions to reduce BMI are expected to decrease the prevalence of vitamin D deficiency.

Prevalence, incidence, and demographics of systemic lupus erythematosus and lupus nephritis from 2000 to 2004 among children in the US Medicaid beneficiary population

OBJECTIVE

To investigate the nationwide prevalence, incidence, and sociodemographics of systemic lupus erythematosus (SLE) and lupus nephritis among children in the US Medicaid beneficiary population.

METHODS

Children ages 3 years to <18 years with a diagnosis of SLE (defined as ≥3 claims with an International Classification of Diseases, Ninth Revision [ICD-9] code of 710.0 for SLE, each >30 days apart) were identified from the US Medicaid Analytic eXtract database from 2000 to 2004. This database contains all inpatient and outpatient Medicaid claims for 47 US states and the District of Columbia. Lupus nephritis was identified from ≥2 ICD-9 billing codes for glomerulonephritis, proteinuria, or renal failure, each recorded >30 days apart. The prevalence and incidence of SLE and lupus nephritis were calculated among Medicaid-enrolled children overall and within sociodemographic groups.

RESULTS

Of the 30,420,597 Medicaid-enrolled children during these years, 2,959 were identified as having SLE. The prevalence of SLE was 9.73 (95% confidence interval [95% CI] 9.38-10.08) per 100,000 Medicaid-enrolled children. Among the children with SLE, 84% were female, 40% were African American, 25% were Hispanic, 21% were White, and 42% resided in the South region of the US. Moreover, of the children with SLE, 1,106 (37%) had lupus nephritis, representing a prevalence of 3.64 (95% CI 3.43-3.86) per 100,000 children. The average annual incidence of SLE was 2.22 cases (95% CI 2.05-2.40) and that of lupus nephritis was 0.72 cases (95% CI 0.63-0.83) per 100,000 Medicaid enrollees per year. The prevalence and incidence rates of SLE and lupus nephritis increased with age, were higher in girls than in boys, and were higher in all non-White racial/ethnic groups.

CONCLUSION

In the current study, the prevalence and incidence rates of SLE among Medicaid-enrolled children in the US are high compared to studies in other populations. In addition, these data represent the first population-based estimates of the prevalence and incidence of lupus nephritis in the US to date.

Exploring the genetic architecture of circulating 25-hydroxyvitamin D

The primary circulating form of vitamin D is 25-hydroxy vitamin D (25(OH)D), a modifiable trait linked with a growing number of chronic diseases. In addition to environmental determinants of 25(OH)D, including dietary sources and skin ultraviolet B (UVB) exposure, twin- and family-based studies suggest that genetics contribute substantially to vitamin D variability with heritability estimates ranging from 43% to 80%. Genome-wide association studies (GWAS) have identified single nucleotide polymorphisms (SNPs) located in four gene regions associated with 25(OH)D. These SNPs collectively explain only a fraction of the heritability in 25(OH)D estimated by twin- and family-based studies. Using 25(OH)D concentrations and GWAS data on 5,575 subjects drawn from five cohorts, we hypothesized that genome-wide data, in the form of (1) a polygenic score comprised of hundreds or thousands of SNPs that do not individually reach GWAS significance, or (2) a linear mixed model for genome-wide complex trait analysis, would explain variance in measured circulating 25(OH)D beyond that explained by known genome-wide significant 25(OH)D-associated SNPs. GWAS identified SNPs explained 5.2% of the variation in circulating 25(OH)D in these samples and there was little evidence additional markers significantly improved predictive ability. On average, a polygenic score comprised of GWAS-identified SNPs explained a larger proportion of variation in circulating 25(OH)D than scores comprised of thousands of SNPs that were on average, nonsignificant. Employing a linear mixed model for genome-wide complex trait analysis explained little additional variability (range 0-22%). The absence of a significant polygenic effect in this relatively large sample suggests an oligogenetic architecture for 25(OH)D.