Immunologically, the infection group showed significantly elevated levels of nCD64 (45.39 vs. 11.16, p < 0.05) and enhanced CD8<sup>+</sup> T cell activation, particularly CD8<sup>+</sup>CD38<sup>+</sup> T cells (81.54% vs. 66.89%, p < 0.05). The gene discussed is CD8A; the disease is infection.