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Antigen-specific regulatory T cells (Tregs) suppress pathogenic autoreactivity and are potential therapeutic candidates for autoimmune diseases such as systemic lupus erythematosus (SLE). Lupus nephritis is associated with autoreactivity to the Smith (Sm) autoantigen and the human leucocyte antigen (HLA)-DR15 haplotype; hence, we investigated the potential of Sm-specific Tregs (Sm-Tregs) to suppress disease. Here we identify a HLA-DR15 restricted immunodominant Sm T cell epitope using biophysical affinity binding assays, then identify high-affinity Sm-specific T cell receptors (TCRs) using high-throughput single-cell sequencing. Using lentiviral vectors, we transduce our lead Sm-specific TCR into Tregs derived from patients with SLE who are anti-Sm and HLA-DR15 positive. Compared with polyclonal mock-transduced Tregs, Sm-Tregs potently suppress Sm-specific pro-inflammatory responses in vitro and suppress disease progression in a humanized mouse model of lupus nephritis. These results show that Sm-Tregs are a promising therapy for SLE., (© 2024. The Author(s).)

Objective: To examine longitudinal associations of active lupus nephritis with organ damage accrual in patients with systemic lupus erythematosus (SLE)., Methods: This study was performed using data from a large multinational prospective cohort. Active lupus nephritis at any visit was defined by the presence of urinary casts, proteinuria, haematuria or pyuria, as indicated by the cut-offs in the SLE Disease Activity Index (SLEDAI)-2K, collected at each visit. Organ damage accrual was defined as a change of SLICC-ACR Damage Index (SDI) score >0 units between baseline and final annual visits. Renal damage accrual was defined if there was new damage recorded in renal SDI domains (estimated glomerular filtration rate <50%/proteinuria >3.5 g per 24 h/end-stage kidney disease). Time-dependent hazard regression analyses were used to examine the associations between active lupus nephritis and damage accrual., Results: Patients ( N  = 1735) were studied during 12,717 visits for a median (inter-quartile range) follow-up period of 795 (532, 1087) days. Forty per cent of patients had evidence of active lupus nephritis at least once during the study period, and active lupus nephritis was observed in 3030 (24%) visits. Forty-eight per cent of patients had organ damage at baseline and 14% accrued organ damage. Patients with active lupus nephritis were 52% more likely to accrue any organ damage compared with those without active lupus nephritis (adjusted hazard ratio = 1.52 (95% confidence interval (CI): 1.16, 1.97), p  < 0.02). Active lupus nephritis was strongly associated with damage accrual in renal but not in non-renal organ domains (hazard ratios = 13.0 (95% CI: 6.58, 25.5) p  < 0.001 and 0.96 (95% CI: 0.69, 1.32) p  = 0.8, respectively). There was no effect of ethnicity on renal damage accrual, but Asian ethnicity was significantly associated with reduced non-renal damage accrual., Conclusion: Active lupus nephritis measured using the SLEDAI-2K domain cut-offs is associated with renal, but not non-renal, damage accrual in SLE.

Introduction: We examined the clinical relevance of urinary concentrations of B-cell-activating factor of the tumour necrosis factor family (BAFF) and a proliferation-inducing ligand (APRIL) in systemic lupus erythematosus (SLE)., Methods: We quantified urinary BAFF (uBAFF) by enzyme-linked immunosorbent assay in 85 SLE, 28 primary Sjögren syndrome (pSS), 40 immunoglobulin A nephropathy (IgAN) patients and 36 healthy controls (HCs). Urinary APRIL (uAPRIL) and monocyte chemoattractant protein 1 (uMCP-1) were also quantified. Overall and renal SLE disease activity were assessed using the Systemic Lupus Erythematosus Disease Activity Index 2000., Results: uBAFF was detected in 12% (10/85) of SLE patients, but was undetectable in HCs, IgAN and pSS patients. uBAFF was detectable in 28% (5/18) of SLE patients with active nephritis vs 5/67 (7%) of those without ( p = 0.03), and uBAFF was significantly higher in active renal patients ( p = 0.02) and more likely to be detected in patients with persistently active renal disease. In comparison, uAPRIL and uMCP-1 were detected in 32% (25/77) and 46% (22/48) of SLE patients, respectively. While no difference in proportion of samples with detectable uAPRIL was observed between SLE, HCs and IgAN patients, both uAPRIL and uMCP-1 were significantly detectable in higher proportions of patients with active renal disease., Conclusions: uBAFF was detectable in a small but a significant proportion of SLE patients but not in other groups tested, and was higher in SLE patients with active renal disease.