The count of CD3+, CD4+, and CD8+ T cells and the ratio of CD4+/CD8+ in sepsis patients within 24 hours after admission to the ICU showed that most of the 206 enrolled patients had decreased T lymphocyte counts of CD3+, CD4+, and CD8+, and 45 patients (21.8%) had a decreased CD4+/CD8+ ratio. The gene discussed is CD4; the disease is Sepsis.