Objective: The study aimed to explore the effect of serum uric acid (SUA) level on the progression of kidney function in systemic lupus erythematosus (SLE) patients Methods: A total of 123 biopsy-proven lupus nephritis (LN) patients were included in this retrospective observational study. Cox proportional hazard regression analyses as well as restricted cubic spline analyses were performed to identify predictors of renal outcome in LN patients. We also performed a systematic review and meta-analysis for SUA and overall kidney outcomes in SLE patients. Results: Based on the laboratory tests at renal biopsy, 72 (58.5%) of the 123 patients had hyperuricemia. The median (IQR) follow-up duration was 3.67 years (1.79–6.63 years), and a total of 110 (89.4%) patients experienced progression of LN. Increased serum uric acid level, whether analyzed as continuous or categorical variable, was associated with higher risk of LN progression in Cox proportional hazard regression model (hazard ratio [HR]: 1.003, 95% confidence interval [CI]: 1.001–1.005; HR: 1.780, 95% CI: 1.201–2.639, respectively). This relationship maintained in women (HR: 1.947, 95% CI: 1.234–3.074) but not men (HR: 2.189, 95% CI: 0.802–5.977). The meta-analysis showed a similar result that both continuous and categorical SUA were positively associated with the risk of kidney function progression in LN (weighted mean difference [WMD]: 1.73, 95% CI: 0.97–2.49; odds ratio [OR]: 1.55, 95% CI: 1.20–2.01, respectively). Conclusions: Our study found overall and especially in women that higher SUA in LN patients were associated with increased risk of renal progression. Meta-analysis yielded consistent results. Future studies are required to establish if uric acid can be used as a biomarker for risk assessment and/or as a novel therapeutic target in SLE.

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by persistent synovitis. Synovial fibroblasts (SF) are the predominant cellular components in the inflamed synovium. Recent studies have shown increased expression of P2X7 receptor (P2X7R) in RA SF. However, its precise expression patterns and its contribution to inflammatory arthritis remain unclear. We demonstrate that P2X7R is robustly expressed in RA synovium, correlating with increased synovitis and systemic inflammation. Single-cell transcriptome analysis indicated that P2X7R was enriched in specific SF associated with refractory RA. Then, we applied a highly selective human P2X7R antagonist, EVT-401, which promoted apoptosis and induced cell cycle arrest in RA SF, reduced the production of proinflammatory and joint-destructive mediators, and mitigated aggressive phenotypes. Furthermore, we demonstrated that EVT-401 markedly reduced synovial inflammation and arthritis severity in a nonhuman primate model of autoimmune arthritis. Together, these findings suggest that P2X7R is involved in synovial inflammation and its inhibition may represent a potential therapeutic strategy for refractory RA.