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Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis is a life-threatening autoimmune disease that often results in kidney failure caused by crescentic glomerulonephritis (GN). To date, treatment of most patients with ANCA-GN relies on non-specific immunosuppressive agents, which may have serious adverse effects and be only partially effective. Here, using spatial and single-cell transcriptome analysis, we characterize inflammatory niches in kidney samples from 34 patients with ANCA-GN and identify proinflammatory, cytokine-producing CD4 + and CD8 + T cells as a pathogenic signature. We then utilize these transcriptomic profiles for digital pharmacology and identify ustekinumab, a monoclonal antibody targeting IL-12 and IL-23, as the strongest therapeutic drug to use. Moreover, four patients with relapsing ANCA-GN are treated with ustekinumab in combination with low-dose cyclophosphamide and steroids, with ustekinumab given subcutaneously (90 mg) at weeks 0, 4, 12, and 24. Patients are followed up for 26 weeks to find this treatment well-tolerated and inducing clinical responses, including improved kidney function and Birmingham Vasculitis Activity Score, in all ANCA-GN patients. Our findings thus suggest that targeting of pathogenic T cells in ANCA-GN patients with ustekinumab might represent a potential approach and warrants further investigation in clinical trials., (© 2024. The Author(s).)

Pro-inflammatory CD4 + T cells are major drivers of autoimmune diseases, yet therapies modulating T cell phenotypes to promote an anti-inflammatory state are lacking. Here, we identify T helper 17 (T H 17) cell plasticity in the kidneys of patients with antineutrophil cytoplasmic antibody-associated glomerulonephritis on the basis of single-cell (sc) T cell receptor analysis and scRNA velocity. To uncover molecules driving T cell polarization and plasticity, we established an in vivo pooled scCRISPR droplet sequencing (iCROP-seq) screen and applied it to mouse models of glomerulonephritis and colitis. CRISPR-based gene targeting in T H 17 cells could be ranked according to the resulting transcriptional perturbations, and polarization biases into T helper 1 (T H 1) and regulatory T cells could be quantified. Furthermore, we show that iCROP-seq can facilitate the identification of therapeutic targets by efficient functional stratification of genes and pathways in a disease- and tissue-specific manner. These findings uncover T H 17 to T H 1 cell plasticity in the human kidney in the context of renal autoimmunity.

Type I interferons (IFN-I) are important mediators of antiviral immunity and autoimmune diseases. Female plasmacytoid dendritic cells (pDCs) exert an elevated capacity to produce IFN-I upon toll-like receptor 7 (TLR7) activation compared to male pDCs, and both sex hormones and X-encoded genes have been implicated in these sex-specific differences. Using longitudinal samples from a trans men cohort receiving gender-affirming hormone therapy (GAHT), the impact of testosterone injections on TLR7-mediated IFN-I production by pDCs was assessed. Single-cell RNA analyses of pDCs showed downregulation of IFN-I-related gene expression signatures but also revealed transcriptional inter-donor heterogeneity. Longitudinal quantification showed continuous reduction of IFN-I protein production by pDCs and reduced expression of IFN-I-stimulated genes in peripheral blood mononuclear cells (PBMCs). These studies in trans men demonstrate that testosterone administration reduces IFN-I production by pDCs over time and provide insights into the immune-modulatory role of testosterone in sex-specific IFN-I-mediated immune responses., Competing Interests: S.H.H. is an employee at AdaptVac since 08/2021, a company commercializing virus-like particle display technology and vaccines. The other authors have declared that no competing interests exist., (© 2023 The Author(s).)

Previous studies have identified a unique Treg population, which expresses the Th17 characteristic transcription factor RORγt. These RORγt + Tregs possess enhanced immunosuppressive capacity, which endows them with great therapeutic potential. However, as a caveat, they are also capable of secreting pro-inflammatory IL-17A. Since the sum function of RORγt + Tregs in glomerulonephritis (GN) remains unknown, we studied the effects of their absence. Purified CD4 + T cell populations, containing or lacking RORγt + Tregs, were transferred into immunocompromised RAG1 knockout mice and the nephrotoxic nephritis model of GN was induced. Absence of RORγt + Tregs significantly aggravated kidney injury, demonstrating overall kidney-protective properties. Analyses of immune responses showed that RORγt + Tregs were broadly immunosuppressive with no preference for a particular type of T cell response. Further characterization revealed a distinct functional and transcriptional profile, including enhanced production of IL-10. Expression of the chemokine receptor CCR6 marked a particularly potent subset, whose absence significantly worsened GN. As an underlying mechanism, we found that chemokine CCL20 acting through receptor CCR6 signaling mediated expansion and activation of RORγt + Tregs. Finally, we also detected an increase of CCR6 + Tregs in kidney biopsies, as well as enhanced secretion of chemokine CCL20 in 21 patients with anti-neutrophil cytoplasmic antibody associated GN compared to that of 31 healthy living donors, indicating clinical relevance. Thus, our data characterize RORγt + Tregs as anti-inflammatory mediators of GN and identify them as promising target for Treg directed therapies., (Copyright © 2023 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)