Faculty Bibliography

BACKGROUND:Using hydroxychloroquine (HCQ) dose of 5 mg/kg/day in systemic lupus erythematosus (SLE) is associated with a higher risk of flares; HCQ blood level monitoring could be a better way to adjust HCQ dose. We studied the upper threshold for a reference range of HCQ levels to inform routine monitoring. METHODS:This observational study included patients (n=2010) across the Systemic Lupus International Collaborating Clinics (SLICC), Wisconsin, International, and French studies, who underwent HCQ blood level measurements. Using adjusted spline and logistic regression analyses on the cross-sectional data, we first identified a HCQ blood level associated with higher HCQ toxicity. Next, we tested if this upper threshold level was supratherapeutic (no further risk reduction for SLE Disease Activity Index 2000 (SLEDAI-2K ≥6). Finally, we examined associations between chronic kidney disease (CKD) stage and supratherapeutic (toxic) HCQ blood levels. RESULTS:Among 1842 patients (excluding 168 patients with very low HCQ blood levels), 4.9% had HCQ related toxicity. Odds of toxicity were 2.1-fold higher with blood levels ≥1150 ng/mL, and 1.7-fold higher with cumulative HCQ dose per 1000g increase. Blood levels ≥1150 ng/mL were associated with a saturation in therapeutic effect, indicating supratherapeutic levels. Patients with CKD stage ≥3 had 2.3-fold higher odds of having supratherapeutic levels (≥1150 ng/mL). CONCLUSION/CONCLUSIONS:The therapeutic reference range for HCQ blood level monitoring is 750-<1150 ng/ml. HCQ level monitoring could optimize HCQ use, particularly in patients with CKD stage ≥3. Future longitudinal studies are needed to validate the use of HCQ blood level monitoring in optimizing dosing.

OBJECTIVES/OBJECTIVE:Lupus nephritis (LN) is a common, potentially fatal manifestation of systemic lupus erythematosus. We aimed to gain new insights into the immune responses underlying LN and their relation to the histologic heterogeneity observed in this disease, focusing on myeloid cells. METHODS:We used single-cell RNA-sequencing (scRNA-seq) data of dissociated kidney samples from 156 patients with LN and 30 healthy individuals. We applied spatial transcriptomics (ST), utilising a gene panel designed to capture all myeloid subsets identified in the scRNA-seq data, to profile kidney samples acquired from 6 patients with LN and 2 controls. RESULTS:CD8 T, B, and dendritic cells, with a parallel decrease in the interferon response. In proliferative/mixed LN only, the degree of active inflammation correlates with the expansion of disease-specific macrophage (DMac) subsets, which later contract as the CI increases. Trajectory analysis of the scRNA-seq data suggested that DMacs arise from both infiltrating monocytes and tissue-resident macrophages; this was supported by the ST data, as well as cell cultures. DMacs are implied to interact with parietal epithelial cells, promoting the development of glomerulosclerosis. CONCLUSIONS:We suggest a detailed picture of the changes in the kidney immune mechanisms in LN as this disease progresses.

OBJECTIVE:Kidney survival is the ultimate goal in lupus nephritis (LN) management, but long-term predictors remain inadequately studied, requiring long-term follow-up. This study aimed to identify baseline and early longitudinal predictors of kidney survival in the Accelerating Medicines Partnership LN longitudinal cohort. METHODS:We performed time-to-event analyses of clinical, centrally scored histological, and serological predictors of kidney function loss (sustained ≥ 40% eGFR decline or progression to end-stage kidney disease) in 172 LN patients with a median follow-up of 4.6 years (range 0.5-7.8). RESULTS:Kidney function loss occurred in 57/172 (33%) patients. Baseline lower eGFR, non-first kidney biopsy, and higher NIH Chronicity Index (CI) were associated with eGFR loss. CI was the strongest predictor, but no clear threshold defined higher risk. NIH Activity Index and International Society of Nephrology (ISN) class were not predictive. Proteinuria at 12 months was prognostic, with urine protein to creatinine ratio <0.7 g/g associated with lower risk, though no single threshold ensured protection, and lower levels had better outcomes. Lack of complete clinical response at 3, 6, or 12 months predicted future eGFR loss, while partial response conferred intermediate risk. Serological markers were not associated with eGFR loss. CONCLUSION/CONCLUSIONS:Low baseline eGFR and chronic histologic damage, but not activity or ISN class, predicted eGFR loss. Proteinuria <0.7 g/g at 1 year was associated with better outcomes but did not ensure protection. Since proteinuria does not reflect intrarenal inflammation, these results suggest current response definitions serve better as prognostic indicators than true measures of treatment efficacy, and better biomarkers are needed.

OBJECTIVES/OBJECTIVE:Systemic lupus erythematosus (SLE) remains a deadly disease, yet our ability to predict adverse outcomes is poor. Mitochondria are organelles recognised by the immune system when released from cells, and antimitochondrial antibodies (AMA) can be detected in people with SLE. We assessed AMA as markers of nephritis, arterial vascular events (AVE), and other outcomes including mortality. METHODS:We studied sera and data from 1114 participants of the Systemic Lupus International Collaborating Clinics inception cohort. We measured antiwhole mitochondria (AwMA), antimitochondrial DNA (AmtDNA), and antimitochondrial RNA (AmtRNA) antibodies by direct Enzyme-Linked ImmunoSorbent Assays (ELISAs). Separate multivariable Cox proportional hazards regression models estimated associations of either baseline or most recent measures of AMA with the outcomes, adjusted for biological sex, age, medications, and other clinical factors. Interactions of AMA with biological sex were tested for each outcome. RESULTS:All AMA titres were elevated in SLE vs healthy individuals. Higher AMA levels were associated with a higher hazard of nephritis, with the strongest associations for most recent AmtDNA (adjusted hazard ratio [aHR] =1.61 for increase of 1 SD, 95% CI 1.43-1.82) and AmtRNA (aHR =1.59, 1.46-1.73). Higher baseline AwMA levels predicted early mortality (aHR =1.19, 1.02-1.40). Most recent AmtDNA (aHR =1.68, 1.28-2.19) was associated with higher mortality throughout the follow-up. For AVE, the impact of higher AmtRNA was stronger in females. CONCLUSIONS:Baseline and most recent assessments of AMA levels may help identify individuals at higher risk of severe outcomes in SLE, including mortality. Integrating AMA into precision medicine strategies will allow deeper exploration of lupus heterogeneity.

OBJECTIVE:Lupus nephritis (LN) management remains challenging, and novel noninvasive biomarkers are needed. This study quantified serum soluble mediators in the Accelerating Medicines Partnership (AMP) LN cohort to identify biomarkers of histological features and treatment response. METHODS:SLE patients (n=268) undergoing clinically indicated kidney biopsies (urine protein/creatinine ratio [UPCR] > 0.5) were recruited through the AMP RA/SLE network. Serum was collected at biopsy and 3-, 6-, and 12-months post-biopsy, alongside samples from 22 healthy controls. Concentrations of 66 immune mediators were quantified using xMAP multiplex assays, and TNF-α converting enzyme (TACE) measured by ELISA. Seven mediators with >95% values below detection limits were excluded from analyses. Bootstrapped LASSO regression identified proliferative LN (class III/IV+V) predictors from baseline mediators. Associations with 12-month treatment response (complete/partial vs. no response) were tested using 3-month changes in LASSO-selected mediators and UPCR via logistic regression. Molecular clustering of mediator profiles was performed to identify LN subgroups. RESULTS:Proliferative LN patients (class [III or IV] + V; n=160) displayed a distinct mediator profile compared to non-proliferative LN (class I/II/V; n=96). LASSO regression identified 20 mediators predictive of proliferative LN (AUC, 0.82; 95% CI, 0.81-0.91), including elevated syndecan-1, TNFRI, TNFRII, and VCAM-1, as well as decreased CCL3/MIP-1α, CD40L, and IL-5 levels. Among proliferative LN patients, 3-month reductions in syndecan-1 and VCAM-1, mediators associated with intrarenal LN activity and/or chronicity, predicted 12-month treatment response. A model incorporating these reductions and a decline in UPCR predicted treatment response in proliferative LN (0.90; 95% CI, 0.82-0.98). Molecular clustering revealed 4 distinct LN subgroups with unique soluble mediator signatures and clinical features, not captured by histology alone. CONCLUSION/CONCLUSIONS:Serum soluble mediators, particularly syndecan-1 and VCAM-1, reflect LN histological activity and early decreases predict treatment response, supporting their potential utility as noninvasive longitudinal biomarkers. The substantial heterogeneity within LN highlights the potential for biomarker-guided reclassification to advance precision medicine approaches.

Dendritic cells (DCs) facilitate the maintenance of immunological tolerance in the steady state. We report that transcription factor Etv3 is preferentially expressed in mature DCs, including tissue-derived migratory DCs (migDCs), and facilitates their homeostatic maturation and CCR7-dependent migration. Mice with global or DC-specific deletion of Etv3 manifested the expansion of CD25^low regulatory T (T_reg) cells, spontaneous activation of conventional T cells, and multiorgan T cell infiltration. Etv3 deficiency exacerbated TLR7-driven systemic lupus erythematosus (SLE)-like disease, supporting the reported genetic association of human ETV3 with SLE. Etv3-deficient migDCs up-regulated multiple costimulatory molecules, including OX40 ligand (OX40L/TNFSF4), whose blockade partially rescued the T_reg cell abnormalities. These results identify Etv3 as an essential regulator of the tolerogenic function of DCs and implicate it in the regulation of human autoimmunity.

ObjectivePatients with systemic lupus erythematosus (SLE) often have concomitant fibromyalgia (FM) or similar symptoms including chronic pain, fatigue, or depression. This study explored whether Patient-Reported Outcomes Measurement Information System (PROMIS) measures provide richer information than 2016 American College of Rheumatology (ACR) FM criteria survey.MethodsPatients with SLE in our convenience cohort were categorized into groups: (1) concurrent FM chronic pain, (2) concurrent non-FM chronic pain, and (3) no chronic pain using 2016 ACR FM Survey. Based on PROs in the FM Survey, we captured comparable PROMIS measures (e.g., depression, fatigue). Associations by pain group were tested using Kruskal-Wallis rank sum test, Shapiro-Wilk normality test, chi-squared test, or Fisher's exact test. Violin plots explored differences across groups.ResultsThe cohort (n = 181) included 31 patients with FM pain, 23 with non-FM chronic pain, and 127 with no chronic pain. Median PROMIS symptom scores (fatigue, sleep disturbance, pain intensity and interference, depression) were highest and cognitive function lowest in the FM group, despite 13% being in remission. There were significant differences on 4 PROMIS measures (cognitive function, fatigue, pain intensity, pain interference) between FM pain and non-FM pain groups (p < .02), the former being worse. There were no significant differences in SLE Disease Activity Index (SLEDAI) score.ConclusionSLE patients with non-FM chronic pain have similar symptoms to FM compared with SLE patients without chronic pain; however, symptoms are not as severe as those meeting FM criteria. PROMIS measures may be used to classify severity more precisely for disease categorization and management.

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.

BACKGROUND:Interstitial fibrosis in lupus nephritis (LN) is often infiltrated by immune cells but typically regarded as non-specific 'scar reaction'. This study aimed to investigate the relationship between inflammatory fibrosis and kidney disease progression in LN. METHODS:Interstitial fibrosis and tubular atrophy (IFTA) were scored in 124 LN kidney biopsies. Inflammation in areas of IFTA (i-IFTA) was graded 0-3 according to the Banff Classification of Allograft Pathology. Significant glomerular filtration rate (GFR) loss was defined as a decline of >15 mL/min at 3 years from biopsy. Immune cell phenotype was defined by serial immunohistochemistry (13-plex). RESULTS:IFTA was observed in 88/124 (71%) biopsies, and i-IFTA was identified in 76/88 (86%) cases. The distribution of i-IFTA grades was heterogeneous across all IFTA grades. In patients with moderate-to-severe IFTA (>25%), the degree of i-IFTA was associated with a higher risk of significant GFR loss: 0/1 (0%), 0/3 (%), 3/4 (75%) and 7/9 (78%) for i-IFTA grades 0, 1, 2 and 3, respectively (p=0.015). Multiplexed histology revealed that i-IFTA was mostly composed of CD163+ macrophages and CD4 T cells, followed by CD8 T cells and granulocytes. CONCLUSION/CONCLUSIONS:I-IFTA is frequently observed in LN and is dominated by macrophages and T cells. For patients with baseline IFTA >25%, the degree of i-IFTA emerged as a predictor of GFR loss. These data support the routine scoring of i-IFTA in LN due to its prognostic implications and nominate i-IFTA as a potential therapeutic target.

Systemic lupus erythematosus (SLE) is a complex autoimmune disease with an increased risk of vascular dysfunction and cardiovascular disease. We validate our previously developed Systemic Lupus Erythematosus Activity Platelet-Gene Expression Signature (SLAP-GES) score and investigate its relationship with platelet activity and vascular health. SLAP-GES was associated with the SLE Disease Activity Index (Padj < 0.001) and consistent over time (r = 0.76; P = 9 × 10^-5). Moreover, SLAP-GES was associated increased platelet aggregation in response to submaximal epinephrine (P = 0.084), leukocyte platelet aggregates (P = 0.014), and neutrophil platelet aggregates (P = 0.043). SLAP-GES was also associated with impaired glycocalyx (P = 0.011) and brachial artery flow-mediated dilation (P = 0.045). Altogether, SLAP-GES is associated with SLE disease activity, platelet activity, and impaired vascular health.