CD4 and Sepsis: Yongzhen Zhao et al. (28) in another study found that peripheral blood levels of sPD-1 andsPD-L1, PD-1 expression on CD4+ T cells and CD8+ T cells and PD-L1expression on monocytes are higher in non-survivors than in survivors sepsis, and the levelsof sPD-1 and sPD-L1 have a correlation with the severity of the disease.