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.

Persistently active interferon-γ pathway and expansion of T-bet+ B cells in a subset of patients with childhood-onset systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is an autoimmune disease causing significant morbidity and mortality, despite important improvements in its management in the last decades. The objective of this work is to investigate the role of IFN-γ in the pathogenesis of childhood-onset systemic lupus erythematosus (cSLE), evaluating the crosstalk between IFN-α and IFN-γ and the expression of T-bet, a transcription factor induced by IFN-γ, in B cells of patients with cSLE. Expression levels of both IFN-α and IFN-γ-induced genes were upregulated in patients with cSLE. We found increased serum levels of CXCL9 and CXCL10 in patients with cSLE. Type I IFN score decreased with initiation of immunosuppressive treatment; conversely, type II IFN score and levels of CXCL9 were not significantly affected by immunosuppressive treatment. Type II IFN score and CXCL9 were significantly higher in patients with lupus nephritis. We observed the expansion of a population of naïve B cells expressing T-bet in a cluster of patients with cSLE. IFN-γ, but not IFN-α, induced the expression of T-bet in B cells. Our data suggest that IFN-γ is hyperactive in cSLE, especially in patients with lupus nephritis, and it is not modulated by therapy. Our data reinforce the potential of IFN-γ as a therapeutic target in SLE.

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 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.

Outcome of Antibody-Mediated Fetal Heart Disease With Standardized Anti-Inflammatory Transplacental Treatment.

Background Transplacental fetal treatment of immune-mediated fetal heart disease, including third-degree atrioventricular block (AVB III) and endocardial fibroelastosis, is controversial. Methods and Results To study the impact of routine transplacental fetal treatment, we reviewed 130 consecutive cases, including 108 with AVB III and 22 with other diagnoses (first-degree/second-degree atrioventricular block [n=10]; isolated endocardial fibroelastosis [n=9]; atrial bradycardia [n=3]). Dexamethasone was started at a median of 22.4 gestational weeks. Additional treatment for AVB III included the use of a ß-agonist (n=47) and intravenous immune globulin (n=34). Fetal, neonatal, and 1-year survival rates with AVB III were 95%, 93%, and 89%, respectively. Variables present at diagnosis that were associated with perinatal death included an atrial rate <90 beats per minute (odds ratio [OR], 258.4; 95% CI, 11.5-5798.9; P<0.001), endocardial fibroelastosis (OR, 28.9; 95% CI, 1.6-521.7; P<0.001), fetal hydrops (OR, 25.5; 95% CI, 4.4-145.3; P<0.001), ventricular dysfunction (OR, 7.6; 95% CI, 1.5-39.4; P=0.03), and a ventricular rate <45 beats per minute (OR, 12.9; 95% CI, 1.75-95.8; P=0.034). At a median follow-up of 5.9 years, 85 of 100 neonatal survivors were paced, and 1 required a heart transplant for dilated cardiomyopathy. Cotreatment with intravenous immune globulin was used in 16 of 22 fetuses with diagnoses other than AVB III. Neonatal and 1-year survival rates of this cohort were 100% and 95%, respectively. At a median age of 3.1 years, 5 of 21 children were paced, and all had normal ventricular function. Conclusions Our findings reveal a low risk of perinatal mortality and postnatal cardiomyopathy in fetuses that received transplacental dexamethasone±other treatment from the time of a new diagnosis of immune-mediated heart disease.

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.