Faculty Bibliography

Given that diseases associated with anti-SSA/Ro autoantibodies, such as systemic lupus erythematosus and Sjögren syndrome, are linked with an upregulation of IFN and type I IFN-stimulated genes, including sialic acid-binding Ig-like lectin 1 (Siglec-1), a receptor on monocytes/macrophages, recent attention has focused on a potential role for IFN and IFN-stimulated genes in the pathogenesis of congenital heart block (CHB). Accordingly, three approaches were leveraged to address the association of IFN, IFN-stimulated genes, and the phenotype of macrophages in affected fetal cardiac tissue: 1) cultured healthy human macrophages transfected with hY3, an anti-SSA/Ro-associated ssRNA, 2) RNA isolated from freshly sorted human leukocytes/macrophages after Langendorff perfusion of three fetal hearts dying with CHB and three healthy gestational age-matched hearts, and 3) autopsy tissue from three additional human CHB hearts and one healthy heart. TLR ligation of macrophages with hY3 led to the upregulation of a panel of IFN transcripts, including SIGLEC1, a result corroborated using quantitative PCR. Using independent and agnostic bioinformatics approaches, CD45⁺CD11c⁺ and CD45⁺CD11c^- human leukocytes flow sorted from the CHB hearts highly expressed type I IFN response genes inclusive of SIGLEC1. Furthermore, Siglec-1 expression was identified in the septal region of several affected fetal hearts. These data now provide a link between IFN, IFN-stimulated genes, and the inflammatory and possibly fibrosing components of CHB, positioning Siglec-1-positive macrophages as integral to the process.

Objective/UNASSIGNED:Epidemiological data for primary discoid lupus erythematosus (pDLE) remain limited, particularly for racial/ethnic populations in the USA. The Manhattan Lupus Surveillance Program (MLSP) is a population-based retrospective registry of cases with SLE and related diseases including pDLE in Manhattan and was used to provide estimates of the prevalence and incidence of pDLE across major racial/ethnic populations. Methods/UNASSIGNED:MLSP cases were identified from rheumatologists, hospitals and population databases. Two case definitions were used for pDLE: the primary case definition which was any physician diagnosis found in the chart and a secondary case definition which was limited to cases diagnosed by a rheumatologist and/or dermatologist. Rates among Manhattan residents were age-adjusted, and capture-recapture analyses were conducted to assess case under-ascertainment. Results/UNASSIGNED:Based on the primary definition, age-adjusted overall prevalence and incidence rates of pDLE among Manhattan residents were 6.5 and 0.8 per 100 000 person-years, which increased to 9.0 and 1.3 after capture-recapture adjustment. Prevalence and incidence rates were approximately two and six times higher, respectively, among women compared with men (p<0.0001). Higher prevalence was also found among non-Latino blacks (23.5) and Latinos (8.2) compared with non-Latino whites (1.8) and non-Latino Asians (0.6) (p<0.0001). Incidence was highest among non-Latino blacks (2.4) compared with all other racial/ethnic groups. Similar relationships were observed for the secondary case definition. Conclusion/UNASSIGNED:Data from the MLSP provide epidemiological estimates for pDLE among the major racial/ethnic populations in the USA and reveal disparities in pDLE prevalence and incidence by sex and race/ethnicity among Manhattan residents.

Single-cell RNA sequencing (scRNA-seq) has recently undergone rapid advances in the development of this technology, leading to high throughput and accelerating discovery in many biological systems and diseases. The single-cell resolution of the technique allows for the investigation of heterogeneity in cell populations, and the pinpointing of pathological populations contributing to disease. Here we review the development of scRNA-seq technology and the analysis that has evolved with the ever-increasing throughput. Finally, we highlight recent applications of scRNA-seq to understand the molecular pathogenesis of lupus and lupus nephritis.

OBJECTIVE:Cutaneous neonatal lupus (cNL) occurs in possibly 5%-16% of anti-Ro±anti-La antibody-exposed infants. Data suggest in utero exposure to hydroxychloroquine (HCQ) may prevent cardiac NL. The aim was to assess whether in utero exposure to HCQ decreases the risk of cNL and/or delays onset. METHODS:A multicentre case-control study was performed with 122 cNL cases and 434 controls born to women with a rheumatological disease who had documentation of maternal anti-Ro±anti-La antibodies at pregnancy and confirmation of medication use and the child's outcome. A secondary analysis was performed on 262 cNL cases, irrespective of maternal diagnosis, to determine if HCQ delayed time to cNL onset. RESULTS:Twenty (16%) cNL cases were exposed to HCQ compared with 146 (34%) controls (OR 0.4 (95% CI 0.2 to 0.6); p<0.01). Exposure to HCQ was associated with a reduced risk of cNL; exposure to anti-La antibody and female gender were associated with an increased risk of cNL. Exposure to HCQ remained significantly associated with a reduced cNL risk in the analyses limited to mothers with systemic lupus erythematosus and those who developed rash ≤1 month. When analysing all 262 cNL cases, HCQ-exposed infants were older (6.0 (95% CI 5.7 to 6.3) weeks) at cNL onset versus HCQ-non-exposed infants (4.4 (95% CI 3.9 to 5.0) weeks), but the difference was not statistically significant (p=0.21). CONCLUSION/CONCLUSIONS:Exposure to HCQ was associated with a reduced risk of cNL. Among cNL cases, those exposed to HCQ tend to have later onset of rash. Both findings suggest a protective effect of HCQ on cNL.

OBJECTIVE:To characterize and compare the factors associated with tubulointerstitial inflammation (TII) and tubulointerstitial scarring, defined as interstitial fibrosis and/or tubular atrophy (IF/TA), in patients with lupus nephritis (LN). METHODS:We identified SLE patients with a renal biopsy consistent with LN between 2005 and 2017. Clinical data was collected from the medical records. Multivariable logistic regression models were fitted to assess factors associated with TII and with IF/TA (moderate-to-severe vs. none-or-mild). RESULTS:at the time of biopsy. In addition, the presence of moderate-to-severe TII and older age were also associated with moderate-to-severe IF/TA. None of the routinely available serologic markers, including anti-dsDNA, anti-Ro/La antibodies and low complement were associated with tubulointerstitial damage (TID). CONCLUSIONS:The use of hydroxychloroquine was strongly associated with less inflammation, while the finding of TII, proliferative LN, and low eGFR were the major determinants of the presence of tubulointerstitial scarring. Identifying modifiable factors is critical for the development of better preventive and therapeutic strategies directed towards ultimate improvement in survival in patients with lupus-related kidney disease.