METHODS: From January 2005 to December 2014, we conducted a nationwide case-control study, using Taiwan's National Health Insurance Research Database. Obstetric complications and perinatal outcomes in SLE patients were compared with those without SLE.
RESULTS: 2059 SLE offspring and 8236 age-matched, maternal healthy controls were enrolled. We found increased obstetric and perinatal complications in SLE population compared with healthy controls. SLE patients exhibited increased risk of preeclampsia/eclampsia (8.98% vs.1.98%, odds ratio [OR]: 3.87, 95% confidence interval [95% CI]: 3.08-4.87, p<0.0001). Their offspring tended to have lower Apgar scores (<7) at both 1 min (10.7% vs. 2.58%, p<0.0001) and 5 min (4.25% vs. 1.17%, p<0.0001), as well as higher rates of intrauterine growth restriction (IUGR, 9.91% vs. 4.12%, OR: 2.24, 95% CI: 1.85-2.71, p<0.0001), preterm birth (23.70% vs 7.56%, OR: 3.00, 95% CI: 2.61-3.45, p<0.0001), and stillbirth (4.23% vs. 0.87%, OR: 3.59, 95% CI: 2.54-5.06, p<0.0001). The risks of preterm birth and stillbirth were markedly increased in SLE patients with concomitant preeclampsia/eclampsia or IUGR. Preterm birth of SLE patients was 1~4 gestational weeks earlier than that of healthy controls and the peak occurrence of stillbirth in SLE population was at 20~30 gestational weeks.
CONCLUSIONS: Asian SLE patients exhibited increased risks of maternal complications and adverse birth outcomes. Frequent antenatal visits before 20 gestational weeks are recommended in high-risk SLE patients.
METHODS: We performed an allelic association analysis in patients with SLE, followed by a meta-analysis assessing genome-wide association data across 11 independent cohorts (n = 28,872). In silico bioinformatics analysis and experimental validation in SLE-relevant cell lines were applied to determine the functional consequences of rs34330.
RESULTS: We replicated a genetic association between SLE and rs34330 (meta-analysis P = 5.29 × 10-22 , odds ratio 0.84 [95% confidence interval 0.81-0.87]). Follow-up bioinformatics and expression quantitative trait locus analysis suggested that rs34330 is located in active chromatin and potentially regulates several target genes. Using luciferase and chromatin immunoprecipitation-real-time quantitative polymerase chain reaction, we demonstrated substantial allele-specific promoter and enhancer activity, and allele-specific binding of 3 histone marks (H3K27ac, H3K4me3, and H3K4me1), RNA polymerase II (Pol II), CCCTC-binding factor, and a critical immune transcription factor (interferon regulatory factor 1 [IRF-1]). Chromosome conformation capture revealed long-range chromatin interactions between rs34330 and the promoters of neighboring genes APOLD1 and DDX47, and effects on CDKN1B and the other target genes were directly validated by clustered regularly interspaced short palindromic repeat (CRISPR)-based genome editing. Finally, CRISPR/dead CRISPR-associated protein 9-based epigenetic activation/silencing confirmed these results. Gene-edited cell lines also showed higher levels of proliferation and apoptosis.
CONCLUSION: Collectively, these findings suggest a mechanism whereby the rs34330 risk allele (C) influences the presence of histone marks, RNA Pol II, and IRF-1 transcription factor to regulate expression of several target genes linked to proliferation and apoptosis. This process could potentially underlie the association of rs34330 with SLE.