{
  "abstract": "Background Cytokine release syndrome (CRS) is a serious immune-related toxicity frequently associated with T cell-based immunotherapies, such as chimeric antigen receptor T cells (CAR-Ts), T cell engagers, and immune checkpoint inhibitors. To better understand the human immune mechanisms driving CRS, we evaluated its onset, clinical evolution, and underlying immune dynamics in two distinct humanized immune system mouse models.Methods We humanized NCG mice by engrafting them with either peripheral blood mononuclear cells (PBMCs), leading to T cell-predominant human immune reconstitution, or with CD34 +hematopoietic stem cells (HSCs), leading to a complete human immune reconstitution (T, B, natural killer, and myeloid cells). We then induced CRS by injecting the anti-CD3 monoclonal antibody clone OKT3 and monitored clinical symptoms and immune responses at 1, 3, 6, and 24 hours post-OKT3 injection.Results Both humanized mouse models exhibited hallmark symptoms of CRS after OKT3 injection, including hyperventilation, respiratory distress, edema, and diarrhea, with greater severity observed in PBMC-humanized mice. The severity of the syndrome in PBMC-humanized mice was also associated with markedly elevated circulating levels of pro-inflammatory cytokines such as IFN-γ and TNF-α. Interestingly, in PBMC mice, T cells exhibited a highly exhausted phenotype associated with extensive T cell death, which was further exacerbated following OKT3 treatment. In contrast, CD34+ HSC-humanized mice had a much lower T cell exhaustion baseline and treatment with OKT3 led to a more complex human immune response. In the CD34 model, circulating IL-2 levels were higher than those in PBMC mice, supporting robust T cell proliferation, along with signs of exhaustion and cell death following OKT3 treatment. Beyond the T cell response, CD34 + mice uniquely mounted a coordinated myeloid-driven response, characterized by secretion of CXCL10 and CCL2, increased circulating CD14+ monocytes, and hepatic macrophage infiltration—hallmarks of a functional and diversified human innate immune component, which is absent in PBMC mice.Conclusions Altogether, our findings highlight the critical role of both T cell and myeloid responses in modeling CRS and position CD34 + HSC-humanized mice as a complex preclinical model for evaluating immune-mediated toxicities.Ethics Approval This work does not involve human subject research. Animal experimentation procedures have been approved by the French Ministry of Higher Education and Research (DAP authorization 38383 – 2022082413416895) and the Departmental Directorate of Population Protection in Haute Savoie, France (DDPP authorization A 7418 324). TransCure bioServices is an an AAALAC-accredited institution.",
  "authors": [
    {
      "affiliations": [
        "TranCure biServices, Archamps, France"
      ],
      "name": "Audrey Wetzel"
    },
    {
      "affiliations": [
        "TranCure biServices, Archamps, France"
      ],
      "name": "Anaïs Meynet-Cordonnier"
    },
    {
      "affiliations": [
        "TranCure biServices, Archamps, France"
      ],
      "name": "Clothilde Philouze"
    },
    {
      "affiliations": [
        "TranCure biServices, Archamps, France"
      ],
      "name": "Jade Villé"
    },
    {
      "affiliations": [
        "TranCure biServices, Archamps, France"
      ],
      "name": "Charline Boulot"
    },
    {
      "affiliations": [
        "TranCure biServices, Archamps, France"
      ],
      "name": "Maxence Cornut"
    },
    {
      "affiliations": [
        "TranCure biServices, Archamps, France"
      ],
      "name": "Emilie Bayon"
    },
    {
      "affiliations": [
        "TranCure biServices, Archamps, France"
      ],
      "name": "Sebastien Tabruyn"
    },
    {
      "affiliations": [
        "TranCure biServices, Archamps, France"
      ],
      "name": "Dan Georgess"
    }
  ],
  "title": "1042 Comparative analysis of immune dynamics and toxicity during CRS in PBMC versus CD34+ HSC humanized mouse models",
  "uid": "a44b145c-9af7-5feb-b647-e7c4a17aa3d8"
}