Severity of critical illness correlates with CD3-low expression on iNKT-cells among septic surgical patients

iNKT-cells are innate regulatory lymphocytes capable of directing immune and inflammatory responses to sepsis. Repeat stimulation of iNKT-cells leads to the induction of anergy with the emergence of a hyporesponsive CD3low iNKT-cell subpopulation. iNKT-cells were isolated from critical ill surgical patients with sepsis and phenotyped for CD3 expression. This was correlated with degree of severity of illness, as denoted by APACHE-II score. Comparing healthy volunteers to critically ill septic patients, it was noted that increasing severity of sepsis was associated with increasing frequency of circulating CD3low-iNKT-cell populations. The emergence of CD3low -iNKT-cells may serve as a clinically translatable marker of degree of sepsis-induced immune dysfunction.