Activated T lymphocytes disappear from circulation during endotoxemia in humans

Abstract

Seventeen volunteers received an intravenous bolus of endotoxin (2 ng/kg of body weight). Endotoxin-induced lymphopenia was constituted mainly by cells with an immature phenotype (CD45RA+ CD45RO-) that were less likely to undergo apoptosis (CD28+), whereas cells with the highest rates of disappearance were characterized by an activated phenotype (CD45RA- CD45RO+) as well as a phenotype linked to apoptosis (CD95+ CD28-). In conclusion, endotoxin-induced lymphopenia reflects the disappearance from the circulation of activated lymphocytes prone to undergo apoptosis.