fetching data ... 
Background: Interferon (IFN) response, plasmablasts, and neutrophils are hallmarks of systemic lupus erythematosus (SLE) [1–3], but studies on neutrophils are limited due to processing challenges.
Objectives: We employed single-cell RNA sequencing (scRNA-sq) on human and murine blood cells to investigate the role of neutrophils and the impact of CXCL5 [4] in SLE.
Methods: We performed scRNA-seq on fresh white blood cells (WBCs) obtained from 10 SLE patients, either with no disease activity (SLEDAI = 0; n = 3), mild disease (0 < SLEDAI ≤ 6; n = 4), or moderate-to-severe (SLEDAI > 6; n = 3), and 6 healthy individuals, and we were focusing on granulocyte transcriptomics profiling in patients and controls. Here we also intended to understand how CXCL5 worked with SoC (methylprednisolone 8.3 mg/kg/day on days 1-3, and cyclophosphamide 0.5 gm per body surface area on day 4, week 4, and week 8 of treatment). A scRNA-seq study was conducted on mouse peripheral blood collected from 15 MRL/lpr mice under 4 treatment arms: dPBS (6 mice), SoC (3 mice), mCXCL5 (3 mice), and mCXCL5 + SoC (3 mice). The BD Rhapsody WTA analysis pipeline was used to demultiplex FastQ; Seurat was used for multiplet removal, unsupervised cell clustering, PCA dimensions, and data visualization; Pseudobulk differential gene expression analysis was performed for SLE patients versus healthy controls, as well as lupus mice with treatment versus no treatment [5, 6].
Results: Our findings confirmed a strong disease association between lupus and neutrophils, revealing that the persistence of interferon signals and/or low vitality of naïve neutrophils may be an incurable cause of SLE. In lupus-prone MRL/lpr mice, we demonstrated that mCXCL5 synergized with standard of care (SoC: methylprednisolone plus cyclophosphamide) to achieve long-term remission by suppressing the proliferation of immature neutrophils, reducing the neutrophil-to-lymphocyte ratio, and dampening both IFN signals and other inflammatory signals (e.g., inflammatory response, TNF-α/NF-κB pathway, complement activation, allograft rejection, and apoptosis). Meanwhile, the vitality of immune cells was also promoted through the regulation of cell growth, division, cycle regulation, respiration, and protein translation (e.g., upregulating mitotic spindle functions, Myc targets, E2F, G2M checkpoint, oxidative phosphorylation, and unfolded protein response signals).
Conclusion: Thus, targeting neutrophils and IFN with CXCL5 in conjunction with available SoC treatments may facilitate to achieve long-term remission in SLE.
REFERENCES: [1] Garcia-Romo GS, Caielli S, Vega B, et al. Netting neutrophils are major inducers of type I IFN production in pediatric systemic lupus erythematosus. Sci Transl Med . Mar 9 2011;3(73):73ra20. doi:10.1126/scitranslmed.3001201.
[2] Caielli S, Athale S, Domic B, et al. Oxidized mitochondrial nucleoids released by neutrophils drive type I interferon production in human lupus. J Exp Med . May 2 2016;213(5):697-713. doi:10.1084/jem.20151876.
[3] Ley K, Hoffman HM, Kubes P, et al. Neutrophils: New insights and open questions. Sci Immunol . Dec 7 2018;3(30)doi:10.1126/sciimmunol.aat4579.
[4] Fan X, Ng CT, Guo D, et al. Dampened Inflammation and Improved Survival After CXCL5 Administration in Murine Lupus via Myeloid and Neutrophil Pathways. Arthritis Rheumatol . Apr 2023;75(4):553-566. doi:10.1002/art.42383.
[5] Mandric I, Schwarz T, Majumdar A, et al. Optimized design of single-cell RNA sequencing experiments for cell-type-specific eQTL analysis. Nat Commun . Oct 30 2020;11(1):5504. doi:10.1038/s41467-020-19365-w.
[6] Schmid KT, Höllbacher B, Cruceanu C, et al. scPower accelerates and optimizes the design of multi-sample single cell transcriptomic studies. Nat Commun . Nov 16 2021;12(1):6625. doi:10.1038/s41467-021-26779-7.
Acknowledgements: Fan Xiubo.
Disclosure of Interests: None declared.
© The Authors 2025. This abstract is an open access article published in Annals of Rheumatic Diseases under the CC BY-NC-ND license (