Ankylosing spondylitis (AS) is a chronic inflammatory arthritis that primarily affects the enthesis and may culminate in bony ankylosis of the spine. Despite TNF inhibitor (TNFi) being foundational in managing active inflammation, 30-40% of patients with AS remain non-responsive. Through longitudinal and multi-omics profiling of peripheral blood mononuclear cells from TNFi-receiving patients with AS, here we reveal that elevated type I IFN signatures at baseline are associated with poor TNFi response, leading to a paradoxical enhancement of IFN signatures and Th17 responses following TNFi therapy. Among type I IFN-related genes, we identify and validate AIF-1 as a predictive biomarker reflecting the inherent IFN signature that differentiates responders from non-responders. AIF-1 also contributes to an inflammatory cycle by increasing IFNα receptor expression and Th17 responses. In summary, our findings advocate for a personalized approach to managing AS by considering individual variations in AIF-1 levels and IFN signatures.
© 2025. The Author(s).

Monitoring antigen-specific T cell frequency and function is essential to assess the host immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Here, we present a FluoroSpot assay for concurrently detecting ex vivo antiviral cytokine production by SARS-CoV-2-specific T cells following peptide stimulation. We then detail intracellular cytokine staining by flow cytometry to further validate the FluoroSpot assay results and define the specific T cell subpopulations. For complete details on the use and execution of this protocol, please refer to Tiezzi et al. (2023).1.
Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.

Humoral immunity is sensitive to evasion by SARS-CoV-2 mutants, but CD8 T cells seem to be more resistant to mutational inactivation. By a systematic analysis of 30 spike variant peptides containing the most relevant VOC and VOI mutations that have accumulated overtime, we show that in vaccinated and convalescent subjects, mutated epitopes can have not only a neutral or inhibitory effect on CD8 T cell recognition but can also enhance or generate de novo CD8 T cell responses. The emergence of these mutated T cell function enhancing epitopes likely reflects an epiphenomenon of SARS-CoV-2 evolution driven by antibody evasion and increased virus transmissibility. In a subset of individuals with weak and narrowly focused CD8 T cell responses selection of these heteroclitic-like epitopes may bear clinical relevance by improving antiviral protection. The functional enhancing effect of these peptides is also worth of consideration for the future development of new generation, more potent COVID-19 vaccines.
© 2023 The Authors.

Hepatitis C virus infection (HCV) represents a unique model to characterize, from early to late stages of infection, the T cell differentiation process leading to exhaustion of human CD8+ T cells. Here we show that in early HCV infection, exhaustion-committed virus-specific CD8+ T cells display a marked upregulation of transcription associated with impaired glycolytic and mitochondrial functions, that are linked to enhanced ataxia-telangiectasia mutated (ATM) and p53 signaling. After evolution to chronic infection, exhaustion of HCV-specific T cell responses is instead characterized by a broad gene downregulation associated with a wide metabolic and anti-viral function impairment, which can be rescued by histone methyltransferase inhibitors. These results have implications not only for treatment of HCV-positive patients not responding to last-generation antivirals, but also for other chronic pathologies associated with T cell dysfunction, including cancer.