CBCs and cytokine/chemokine analyses revealed transient lymphopenia and monocytopenia (only F331 model) on day 7 (Extended Data Fig. 4C,D) and a significant fold-increase of IFNγ, IL-6, MCP-1, MIG, and MIP-2 in mice that received Reg-1 KO B7-H3-CAR T cells (Fig. 2G). Here, CXCL9 is linked to lymphopenia.