Proteomic, biomechanical and functional analyses define neutrophil heterogeneity in systemic lupus erythematosus

OBJECTIVES: Low-density granulocytes (LDGs) are a distinct subset of proinflammatory and vasculopathic neutrophils expanded in systemic lupus erythematosus (SLE). Neutrophil trafficking and immune function are intimately linked to cellular biophysical properties. This study used proteomic, biomechanical and functional analyses to further define neutrophil heterogeneity in the context of SLE. METHODS: Proteomic/phosphoproteomic analyses were performed in healthy control (HC) normal density neutrophils (NDNs), SLE NDNs and autologous SLE LDGs. The biophysical properties of these neutrophil subsets were analysed by real-time deformability cytometry and lattice light-sheet microscopy. A two-dimensional endothelial flow system and a three-dimensional microfluidic microvasculature mimetic (MMM) were used to decouple the contributions of cell surface mediators and biophysical properties to neutrophil trafficking, respectively. RESULTS: Proteomic and phosphoproteomic differences were detected between HC and SLE neutrophils and between SLE NDNs and LDGs. Increased abundance of type 1 interferon-regulated proteins and differential phosphorylation of proteins associated with cytoskeletal organisation were identified in SLE LDGs relative to SLE NDNs. The cell surface of SLE LDGs was rougher than in SLE and HC NDNs, suggesting membrane perturbances. While SLE LDGs did not display increased binding to endothelial cells in the two-dimensional assay, they were increasingly retained/trapped in the narrow channels of the lung MMM. CONCLUSIONS: Modulation of the neutrophil proteome and distinct changes in biophysical properties are observed alongside differences in neutrophil trafficking. SLE LDGs may be increasingly retained in microvasculature networks, which has important pathogenic implications in the context of lupus organ damage and small vessel vasculopathy

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Background and Objective: Only a few studies have reported long-term efficacy of interleukin (IL)-1 inhibition in systemic juvenile idiopathic arthritis (sJIA) and adult-onset Still disease (AOSD). Herein we report on the effectiveness of anakinra (ANA), expressed in terms of drug retention rate (DRR), and evaluate the predictive factors of drug survival in a cohort of patients with sJIA and AOSD.Patients and Methods: This is a multicenter study reviewing retrospectively the medical records from 61 patients with sJIA and 76 with AOSD, all treated with ANA in 25 Italian tertiary referral centers.Results: The cumulative retention rate of ANA at 12-, 24-, 48-, and 60-month of follow-up was 74.3%, 62.9%, 49.4%, and 49.4%, respectively, without any significant differences between sJIA and AOSD patients (p = 0.164), and between patients treated in monotherapy compared with the subgroup coadministered with conventional disease-modifying antirheumatic drugs (cDMARDs) (p = 0.473). On the other hand, a significant difference in DRR was found between biologic-naive patients and those previously treated with biotechnologic drugs (p = 0.009), which persisted even after adjustment for pathology (p = 0.013). In the regression analysis, patients experiencing adverse events (AEs) hazards ratio (HR) = 3.029 [confidence interval (CI) 1.7505.242], p < 0.0001 and those previously treated with other biologic agents [HR = 1.818 (CI 1.0073.282), p = 0.047] were associated with a higher HR of ANA discontinuation. The median treatment delay was significantly higher among patients discontinuing ANA (p < 0.0001). Significant corticosteroid-sparing (p = 0.033) and cDMARD-sparing effects (p < 0.0001) were also recorded. Less than one-third of our cohort developed AEs, and 85% were deemed mild in nature, with 70% of them involving the skin.Conclusions: Our findings display an overall excellent DRR of ANA on the long run for both sJIA and AOSD, that may be further optimized by closely monitoring patients safety issues and employing this IL-1 inhibitor as a first-line biologic as early as possible. Moreover, ANA allowed a significant drug-sparing effect and showed an overall good safety profile

Loss-Of-Function Mutations in Tnfaip3 Leading to A20 Haploinsufficiency Cause an Early-Onset Autoinflammatory Disease

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