Background
Elevated plasma endotoxin levels are considered as indicator of microbial translocation from the gut, and as a potential cause of the systemic immune activation observed in chronic HIV infection. Lipopolysaccharide (LPS) effects on lymphocytes and macrophages have been described to involve amongst other effects, downregulation of CD4 and CCR5 and induction of CCL3/MIP-1α and CCL4/MIP-1β secretion. This alteration in receptor expression could potentially reduce HIV entry and may thus pose a problem for assessing plasma antibody neutralization in patient samples.