Faculty Bibliography

OBJECTIVES/OBJECTIVE:Novel biologic agents targeting the neonatal Fc receptor (FcRn) offer a promising strategy to prevent cardiac neonatal lupus (cardiac-NL) in pregnant patients with high-titre anti-SSA/Ro52 kD or 60 kD autoantibodies via dual effects: reducing serum immunoglobin G (IgG) levels and inhibiting placental transfer. This study was initiated to assess the feasibility of FcRn blockade as prophylactic therapy for recurrent cardiac-NL. METHODS:A 34-year-old pregnant patient with systemic lupus erythematosus and 3 prior consecutive pregnancies complicated by neonatal lupus (1 cutaneous, 1 fatal cardiac-NL at 20 weeks, 1 cardiac-NL delivered at 32 weeks and neonatal cutaneous NL), each despite hydroxychloroquine 400 mg daily, was treated with weekly subcutaneous infusions of 560 mg rozanolixizumab (humanised IgG4 monoclonal antibody against FcRn) from gestational weeks 14 to 28 (to cover the vulnerable period of fetal cardiac injury) through a compassionate use designation. The patient performed home fetal heart rhythm monitoring thrice daily with weekly echocardiograms. RESULTS:Maternal anti-SSA/Ro52 kD and 60 kD autoantibodies, total IgG, and subclasses IgG1, 2, 3 decreased by about 65% at gestational week 22, with a return to near baseline levels by week 34. The pregnancy was uncomplicated, resulting in a spontaneous vaginal delivery of a healthy neonate at 37 weeks. At delivery, cord blood and maternal IgG levels were normal, obviating the need for rescue intravenous immune globulin. The neonate had a normal echocardiogram and electrocardiogram but developed a rash consistent with neonatal lupus at 5 weeks of life. There were no serious adverse events. CONCLUSIONS:The successful application of FcRn blockade to prevent recurrent cardiac-NL sets a precedent for a multicentre study.

Monocytes and macrophages in patients with lupus nephritis exhibit altered behavior compared with healthy kidneys. How to optimally use mouse models to develop treatments targeting these cells is poorly understood. This study compared intrarenal myeloid cells in four mouse models and 155 lupus nephritis patients using single-cell profiling, spatial transcriptomics, and functional studies. Across mouse models, monocyte and macrophage subsets consistently expanded or contracted in disease. A subset of murine classical monocytes expanded in disease; these cells expressed Cd9, Spp1, Ctsd, Cd63, Apoe, and Trem2, genes associated with tissue injury in other organs that play roles in inflammation, lipid metabolism, and tissue repair. Resident macrophages expressed similar genes in clinical disease. In humans, we identified analogous disease-associated monocytes and macrophages that were associated with kidney histological subtypes and disease progression, sharing gene expression and localizing to similar kidney microenvironments as in mice. This cross-species analysis supports the use of mouse functional studies for understanding human lupus nephritis.

Lupus nephritis (LN) is a frequent manifestation of systemic lupus erythematosus, and fewer than half of patients achieve complete renal response with standard immunosuppressants. Identifying non-invasive, blood-based immune alterations associated with renal injury could aid therapeutic decisions. Here, we used mass cytometry immunophenotyping of peripheral blood mononuclear cells in 145 patients with biopsy-proven LN and 40 healthy controls to evaluate the heterogeneity of immune activation and identify correlates of renal parameters. Unbiased analysis identified three immunologically distinct groups of patients that were associated with different patterns of histopathology, renal cell infiltrates, urine proteomic profiles, and treatment response at one year. Patients with enriched circulating granzyme B+ T cells showed more active disease and increased numbers of activated CD8 T cells in the kidney, yet they had the highest likelihood of treatment response. A second group characterized by a high type I interferon signature had a lower likelihood of response to therapy, while a third group appeared immunologically inactive but with chronic renal injuries. The major immunologic axes of variation could be distilled down to five simple cytometric parameters that recapitulate several clinical associations, highlighting the potential for blood immunoprofiling to translate to clinically useful non-invasive metrics to assess immune-mediated disease in LN.

OBJECTIVE:This prospective study of pregnant patients, Surveillance To Prevent AV Block Likely to Occur Quickly (STOP BLOQ), addresses the impact of anti-SSA/Ro titers and utility of ambulatory monitoring in the detection of fetal second-degree atrioventricular block (AVB). METHODS:Women with anti-SSA/Ro autoantibodies by commercial testing were stratified into high and low anti-52-kD and/or 60-kD SSA/Ro titers applying at-risk thresholds defined by previous evaluation of AVB pregnancies. The high-titer group performed fetal heart rate and rhythm monitoring (FHRM) thrice daily and weekly/biweekly echocardiography from 17-26 weeks. Abnormal FHRM prompted urgent echocardiography to identify AVB. RESULTS:Anti-52-kD and/or 60-kD SSA/Ro met thresholds for monitoring in 261 of 413 participants (63%); for those, AVB frequency was 3.8%. No cases occurred with low titers. The incidence of AVB increased with higher levels, reaching 7.7% for those in the top quartile for anti-60-kD SSA/Ro, which increased to 27.3% in those with a previous child who had AVB. Based on levels from 15 participants with paired samples from both an AVB and a non-AVB pregnancy, healthy pregnancies were not explained by decreased titers. FHRM was considered abnormal in 45 of 30,920 recordings, 10 confirmed AVB by urgent echocardiogram, 7 being second-degree AVB, all <12 hours from normal FHRM and within another 0.75 to 4 hours to echocardiogram. The one participant with second/third-degree and two participants with third-degree AVB were diagnosed by urgent echocardiogram >17 to 72 hours from an FHRM. Surveillance echocardiograms detected no AVB when the preceding interval FHRM recordings were normal. CONCLUSION/CONCLUSIONS:High-titer antibodies are associated with an increased incidence of AVB. Anti-SSA/Ro titers remain stable over time and do not explain the discordant recurrence rates, suggesting that other factors are required. Fetal heart rate and rhythm (FHRM) with results confirmed by a pediatric cardiologist reliably detects conduction abnormalities, which may reduce the need for serial echocardiograms.

Lupus nephritis (LN) is a pathologically heterogenous autoimmune disease linked to end-stage kidney disease and mortality. Better therapeutic strategies are needed as only 30%-40% of patients completely respond to treatment. Noninvasive biomarkers of intrarenal inflammation may guide more precise approaches. Because urine collects the byproducts of kidney inflammation, we studied the urine proteomic profiles of 225 patients with LN (573 samples) in the longitudinal Accelerating Medicines Partnership in RA/SLE cohort. Urinary biomarkers of monocyte/neutrophil degranulation (i.e., PR3, S100A8, azurocidin, catalase, cathepsins, MMP8), macrophage activation (i.e., CD163, CD206, galectin-1), wound healing/matrix degradation (i.e., nidogen-1, decorin), and IL-16 characterized the aggressive proliferative LN classes and significantly correlated with histological activity. A decline of these biomarkers after 3 months of treatment predicted the 1-year response more robustly than proteinuria, the standard of care (AUC: CD206 0.91, EGFR 0.9, CD163 0.89, proteinuria 0.8). Candidate biomarkers were validated and provide potentially treatable targets. We propose these biomarkers of intrarenal immunological activity as noninvasive tools to diagnose LN and guide treatment and as surrogate endpoints for clinical trials. These findings provide insights into the processes involved in LN activity. This data set is a public resource to generate and test hypotheses and validate biomarkers.

OBJECTIVE:Platelets are mediators of inflammation with immune effector cell properties, and have been implicated in the pathogenesis of systemic lupus erythematosus (SLE). This study investigated the role of platelet associated lectin galactoside-binding soluble 3 binding protein (LGALS3BP) as a mediator of inflammation in SLE, and a potential biomarker associated with clinical phenotypes. METHODS:We performed RNA sequencing on platelets of patients with SLE (n=54) and age, sex, and race-matched controls (n=18) and measured LGALS3BP in platelet releasate and in circulating serum. We investigated the association between levels of LGALS3BP with the prevalence, disease severity, and clinical phenotpyes of SLE, and studied platelet-mediated effects on myeloid inflammation. RESULTS:). Platelet-released LGALS3BP was highly correlated with circulating LGALS3BP (R = 0.69, p < 0.0001). Circulating LGALS3BP correlated with the SLE disease activity index (R = 0.32, p = 0.0006). Specifically, circulating LGALS3BP was higher in SLE patients with lupus nephritis than those with inactive disease (4.0 μg/mL vs 2.3 μg/mL, P < 0.001). IFN-α induced LGALS3BP transcription and translation in a megakaryoblastic cell line (MEG-01) cells in a dose-dependent manner. Recombinant LGALS3BP and platelet releasates from SLE patients enhanced pro-inflammatory cytokine production by macrophages. CONCLUSIONS:These data support that platelets act as potent effector cells contributing to the pathogenesis of SLE by secreting proinflammatory LGALS3BP, which also represents a novel biomarker of SLE clinical activity.

BACKGROUND:The clinical heterogeneity of SLE with its complex pathogenesis remains challenging as we strive to provide optimal management. The contribution of platelets to endovascular homeostasis, inflammation and immune regulation highlights their potential importance in SLE. Prior work from our group showed that the Fcγ receptor type IIa (FcγRIIa)-R/H131 biallelic polymorphism is associated with increased platelet activity and cardiovascular risk in SLE. The study was initiated to investigate the platelet transcriptome in patients with SLE and evaluate its association across FcγRIIa genotypes and distinct clinical features. METHODS:Fifty-one patients fulfilling established criteria for SLE (mean age = 41.1 ± 12.3, 100% female, 45% Hispanic, 24% black, 22% Asian, 51% white, mean SLEDAI = 4.4 ± 4.2 at baseline) were enrolled and compared with 18 demographically matched control samples. The FCGR2a receptor was genotyped for each sample, and RNA-seq was performed on isolated, leukocyte-depleted platelets. Transcriptomic data were used to create a modular landscape to explore the differences between SLE patients and controls and various clinical parameters in the context of FCGR2a genotypes. RESULTS:There were 2290 differentially expressed genes enriched for pathways involved in interferon signaling, immune activation, and coagulation when comparing SLE samples vs controls. When analyzing patients with proteinuria, modules associated with oxidative phosphorylation and platelet activity were unexpectedly decreased. Furthermore, genes that were increased in SLE and in patients with proteinuria were enriched for immune effector processes, while genes increased in SLE but decreased in proteinuria were enriched for coagulation and cell adhesion. A low-binding FCG2Ra allele (R131) was associated with decreases in FCR activation, which further correlated with increases in platelet and immune activation pathways. Finally, we were able to create a transcriptomic signature of clinically active disease that performed significantly well in discerning SLE patients with active clinical disease form those with inactive clinical disease. CONCLUSIONS:In aggregate, these data demonstrate the platelet transcriptome provides insight into lupus pathogenesis and disease activity, and shows potential use as means of assessing this complex disease using a liquid biopsy.