CD4 and Sepsis: Although the deletion of adaptive immune cells is recognized as an important part of the pathology of sepsis, the mechanisms responsible for this are not fully understood.14 Apoptosis causes the marked deletion of immune cells, including natural killer (NK) cells, CD4+ and CD8+ T cells, B cells, and dendritic cells (DC), in various organs of patients dying of sepsis, leading to immunosuppression (Figure 2).