CD4 and Sepsis: To address this gap in knowledge, we carried out 16 S rDNA sequencing, analyzed clinical fecal samples from children with sepsis (n = 30) and control children (n = 25), and obtained immune indicators, including T cell subtypes (CD3+, CD3+CD4+, CD3+CD8+, and CD4/CD8), NK cells, cytokines (IL-2, IL-4, IL-6, IL-10, TNF-α and IFN-γ), and immunoglobulin indices (IgA, IgE, IgM and IgG).