CD4 and infection: CD4+ cells are helper T cells, and they are resistant to infection, which secrete a variety of cytokines through the Th1-type cellular immune response CD8+ which is the opposite of the CD4+ immune effect; CD8+ suppresses cellular and humoral immunity through immune regulation, high level of CD8+ expression mostly indicates the deterioration of PTB condition, when the balance between CD4+ and CD8+ is disrupted, and the immune function of the body is hindered and vulnerable to pathogenic bacteria [24, 25].