Genetics of Neonatal Lupus Erythematosus Risk and Specific Manifestations.

OBJECTIVE: Neonatal lupus erythematosus (NLE) is a passively acquired autoimmune disease of infants born to anti-Ro and/or La autoantibody positive mothers. Genetics may impact NLE risk. We analyzed the genetics of infants and anti-Ro antibody positive mothers, with NLE and NLE specific manifestations. METHODS: Infants and mothers from a tertiary care clinic underwent genotyping on the Global Screening Array. We created additive non-HLA and HLA polygenic risk scores (PRSs) for systemic lupus erythematosus (SLE), from one of the largest genome wide association studies. Outcomes were any NLE manifestations, cardiac NLE, and cutaneous NLE. We tested the association between SLE-PRSs in the infant, mother, and the PRS difference between the mother and infant with NLE outcomes, in logistic regression and generalized linear mixed models (Bonferroni P<0.02). We also performed HLA-wide analyses for the outcomes (P<5.00x10-8). RESULTS: The study included 332 infants, 270 anti-Ro antibody positive mothers, and 253 mother-infant pairs. A large proportion of mothers (40.3%) and infants (41.3%) were European, and 50.0% of infants were female. More than half of the infants had NLE (53.0%), including 7.2% with cardiac NLE and 11.7% with cutaneous NLE. We did not identify significant associations between infant, maternal, or maternal-infant PRSs and any NLE outcomes. HLA-wide analyses did not identify NLE risk alleles. CONCLUSION: In a multiethnic cohort of infants and anti-Ro antibody positive mothers, we did not identify a significant association between SLE genetics and risk of NLE outcomes.

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.

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 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.

High-sensitivity cardiac troponin T in infants exposed to anti-Ro antibodies.

OBJECTIVES: Cardiac involvement in neonatal lupus erythematosis (NLE) can present as myocarditis/endocardial fibroelastosis (EFE). It is unknown whether high-sensitivity cardiac troponin T (hs-cTnT) is useful in identifying subclinical myocardial inflammation in infants exposed prenatally to anti-Ro antibodies. This study reports hs-cTnT levels in infants exposed to anti-Ro antibodies with/without cardiac NLE and reports cardiac MRI (CMR) findings in a subset of these children. METHODS: The study included 45 consecutive infants exposed prenatally to anti-Ro antibodies with (n = 7) or without (n = 38) cardiac NLE, who were seen at the SickKids NLE Clinic between 2012 and 2014. Hs-cTnT levels were measured at least once, and those infants with values of ≥30 ng/l were offered the opportunity to undergo CMR. Descriptive statistics were performed. RESULTS: Of 38 infants without cardiac NLE, 25 had a hs-cTnT level of ≥30 ng/l (including 1 of >113 ng/l); of these, 8 underwent CMR (all without myocarditis/EFE). All 7 infants with cardiac NLE had at least one hs-cTnT level of ≥30 ng/l, but only 2/7 had a level of >113 ng/l; 4/7 infants with cardiac NLE had CMR (all without myocarditis/EFE); 6/7 infants with cardiac NLE had their steroid treatment adjusted based on the trend in their hs-cTnT levels. CONCLUSION: Only 3/45 anti-Ro antibodies-exposed infants had hs-cTnT values outside the reference range reported in healthy infants. None of 12 infants who had CMR had subclinical myocarditis/EFE. Routine measurement of hs-cTnT in every anti-Ro antibody-exposed infant is not indicated. Further studies are needed to define the role of hs-cTnT as a biomarker for cardiac NLE.

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.

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 ß = 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.

Evaluation of self-report screening measures in the detection of depressive and anxiety disorders among children and adolescents with systemic lupus erythematosus.

BACKGROUND: There are no validated screening measures for depressive or anxiety disorders in childhood Systemic Lupus Erythematosus (cSLE). We investigated cross-sectionally (1) the prevalence of depressive and anxiety disorder in cSLE. (2) the validity of the Centre for Epidemiologic Studies Depression Scale for Children (CES-DC) and the Screen for Childhood Anxiety and Related Disorders (SCARED) measures in identifyingthese disorders. METHODS: Participants 8-18 years with cSLE/incipient cSLE completed CES-DC, SCARED, and Quality OfMy Life (QOML) measures. Parents completed the SCARED-Parent measure. Diagnosis was by gold-standard psychiatric interview and determined prevalence of psychiatric disorder. Receiver Operating Characteristics Area under the Curve (ROCAUC) evaluated screening measure diagnostic performance. RESULTS: Ofseventy-two parent-child dyads, 56 interviews were completed. Mean screen scores were: CES-DC = 15 (range 1-49, SD 12), SCARED-C = 22 (range 2-61, SD 14), SCARED-P = 13 (range 0-36, SD 8). Depressive disorder screen positivity (CES-DC ≥ 15) was 35% (vs. prevalence 5%). Anxiety disorder screen positivity (SCARED ≥ 25) was 39% (vs. prevalence 16%). CES-DC ROCAUC = 0.98 and SCARED-C ROCAUC = 0.7 (cut-points 38 and 32 respectively). CONCLUSIONS: Diagnostic thresholds for depressive and anxiety disorderscreening measures are high for both CES-DC and SCARED-C in cSLE. Brief focused interview should follow to determine whether psychiatric evaluation is warranted.

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.

Relationship Between Genetic Risk and Age of Diagnosis in Systemic Lupus Erythematosus.

OBJECTIVE: Specific risk alleles for childhood-onset systemic lupus erythematosus SLE (cSLE) vs adult-onset SLE (aSLE) patients have not been identified. The aims of this study were to determine if there is an association (1) between non-HLA-related genetic risk score (GRS) and age of SLE diagnosis, and (2) between HLA-related GRS and age of SLE diagnosis. METHODS: Genomic DNA was obtained from 2001 multiethnic patients and genotyped using the Immunochip. Following quality control, genetic risk counting (GRCS), weighted (GRWS), standardized counting (GRSCS), and standardized weighted (GRSWS) scores were calculated based on independent single-nucleotide polymorphisms from validated SLE loci. Scores were analyzed in a regression model and adjusted by sex and ancestral population. RESULTS: The analyzed cohort consisted of 1540 patients: 1351 females and 189 males (675 cSLE and 865 aSLE). There were significant negative associations between all non-HLA GRS and age of SLE diagnosis: P = 0.011 and r2 = 0.175 for GRWS; P = 0.008 and r2 = 0.178 for GRSCS; P = 0.002 and r2 = 0.176 for GRSWS (higher GRS correlated with lower age of diagnosis.) All HLA GRS showed significant positive associations with age of diagnosis: P = 0.049 and r2 = 0.176 for GRCS; P = 0.022 and r2 = 0.176 for GRWS; P = 0.022 and r2 = 0.176 for GRSCS; P = 0.011 and r2 = 0.177 for GRSWS (higher GRS correlated with higher age of diagnosis). CONCLUSION: Our data suggest that there is a linear relationship between genetic risk and age of SLE diagnosis and that HLA and non-HLA GRS are associated with age of diagnosis in opposite directions.

Efficacy and Safety of Tocilizumab for Polyarticular-Course Juvenile Idiopathic Arthritis in the Open-Label Two-Year Extension of a Phase III Trial.

OBJECTIVE: To report the 2-year efficacy and safety of tocilizumab (TCZ) in patients with polyarticular-course juvenile idiopathic arthritis (JIA). METHODS: Patients ages 2-17 years with active polyarticular-course JIA, in whom treatment with methotrexate was unsuccessful, received 16 weeks of open-label intravenous TCZ in part 1 (once every 4 weeks: 8 mg/kg or 10 mg/kg for body weight [BW] <30 kg; 8 mg/kg for BW ≥30 kg). Assessments were based on the JIA-American College of Rheumatology (ACR) response (defined as percentage of improvement in ≥3 of the 6 JIA core response variables [CRVs]). Patients with at least a JIA-ACR30 response (defined as ≥30% improvement in ≥3 of the 6 JIA CRVs without worsening in >1 of the remaining JIA CRVs by >30%) at week 16 were randomly assigned (1:1) to receive TCZ or placebo in part 2. Patients remained in part 2 until either week 40 or the occurrence of JIA flare. Upon starting part 3, all patients received open-label TCZ. At week 104 of the study, efficacy was assessed using JIA-ACR50/70/90 response rates (defined as 50%, 70%, or 90% improvement, respectively), achievement of inactive disease, and the Juvenile Arthritis Disease Activity Score in 71 joints (JADAS-71). Safety was assessed in the all-exposure population per 100 patient-years of exposure. RESULTS: Overall, 188 patients entered part 1, 166 patients entered part 2, and 160 patients entered part 3. By week 104, among the 188 patients in the modified intent-to-treat group who received TCZ, JIA-ACR50/70/90 response rates were 80.3%/77.1%/59.6%, respectively, the median JADAS-71 score decreased from 3.6 at week 40 to 0.7 at week 104, 51.1% of patients had achieved inactive disease, and 31 of 66 patients who had been receiving glucocorticoids discontinued them. Adverse event (AE) and serious AE rates were 406.5 per 100 patient-years and 11.1 per 100 patient-years, respectively. The infection rate was 151.4 per 100 patient-years, and the serious infection rate was 5.2 per 100 patient-years. CONCLUSION: Patients treated with TCZ for polyarticular-course JIA showed high-level disease control for up to 2 years. The TCZ safety profile was consistent with that previously reported.