In an observational study of 68 participants diagnosed with sepsis within the first 24h due to VAP or other nosocomial infections, the absolute count of CD3(+)/CD4(+) lymphocytes was found to be significantly lower (p = 0.034), while the apoptosis of isolated monocytes significantly increased (p = 0.007), in sepsis patients due to VAP in comparison to other infections [64]. Here, CD4 is linked to nosocomial infection.