Performance and psychometric properties of lupus impact tracker in assessing patient-reported outcomes in pediatric lupus: Report from a pilot study.

OBJECTIVE: To evaluate the reliability, validity, feasibility and psychometric performance of the Lupus Impact Tracker (LIT) as a patient reported outcome (PRO) measure tool in pediatric systemic lupus erythematosus (pSLE). METHODS: This is a prospective, observational, pilot study where patients aged between 12 and 25 years, fulfilling the 1997 ACR classification criteria for SLE, were enrolled. Over 3 consecutive, routine, clinical visits, the patients completed the LIT alongside the Patient-Reported Outcomes Measurement Information System-Short Forms (PROMIS-SFs), Childhood Health Assessment Questionnaire (CHAQ). Rheumatologists completed the Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) and the Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC-ACR) Damage Index. Demographic, clinical and laboratory data were also collected. RESULTS: Of 46 patients enrolled, 38 patients completed 2 visits and 31 completed all 3 visits. Seventy-eight percent were female, 33% African American, 28% Asian, 15% Caucasian and 17% Hispanic. The mean (SD) age was 17.2 (2.7) years, with a mean (SD) disease duration of 4.6 (3.1) years. The mean (SD) SLEDAI-2K at enrollment was 3.54 (2.96). In the 38 patients who completed two or more visits, intra-class correlation coefficient and Cronbach alpha were calculated to be 0.70 and 0.91 respectively, signifying good reliability of LIT. The LIT showed positive correlation with CHAQ-Disability Index and majority of the PROMIS-SFs parameters. Construct validity was established against clinical disease activity (SLEDAI-2K). CONCLUSION: The preliminary results indicate that the LIT is a reliable and valid instrument to capture PRO in p-SLE. Prospective validation with a larger, multicenter cohort is the next step.

B lymphocytes in treatment-naive paediatric patients with lupus are epigenetically distinct from healthy children.

BACKGROUND: SLE is likely triggered by gene-environment interactions. We have shown that most SLE-associated haplotypes encompass genomic regions enriched for epigenetic marks associated with enhancer function in lymphocytes, suggesting genetic risk is exerted through altered gene regulation. Data remain scarce on how epigenetic variance contributes to disease risk in paediatric SLE (pSLE). We aim to identify differences in epigenetically regulated chromatin architecture in treatment-naive patients with pSLE compared with healthy children. METHODS: Using the assay for transposase-accessible chromatin with sequencing (ATACseq), we surveyed open chromatin in 10 treatment-naive patients with pSLE, with at least moderate disease severity, and 5 healthy children. We investigated whether regions of open chromatin unique to patients with pSLE demonstrate enrichment for specific transcriptional regulators, using standard computational approaches to identify unique peaks and a false discovery rate of <0.05. Further analyses for histone modification enrichment and variant calling were performed using bioinformatics packages in R and Linux. RESULTS: We identified 30 139 differentially accessible regions (DAR) unique to pSLE B cells; 64.3% are more accessible in pSLE than healthy children. Many DAR are found in distal, intergenic regions and enriched for enhancer histone marks (p=0.027). B cells from adult patients with SLE contain more regions of inaccessible chromatin than those in pSLE. In pSLE B cells, 65.2% of the DAR are located within or near known SLE haplotypes. Further analysis revealed enrichment of transcription factor binding motifs within these DAR that may regulate genes involved in pro-inflammatory responses and cellular adhesion. CONCLUSIONS: We demonstrate an epigenetically distinct profile in pSLE B cells when compared with healthy children and adults with lupus, indicating that pSLE B cells are predisposed for disease onset/development. Increased chromatin accessibility in non-coding genomic regions controlling activation of inflammation suggest that transcriptional dysregulation by regulatory elements controlling B cell activation plays an important role in pSLE pathogenesis.