Natural killer cells, HIV infection and HAART

Natural killer (NK) cells represent a first line defense against tumour and viral spreading. Human Immunodeficiency Virus (HIV) infection is accompani ed by a decreased function of NK cells. The purpose, of the present study w as to investigate whether NK cell deficiency of HIV infection is accompanie d by over-expression, on these cells, of certain surface molecules, which c an deliver a down-regulatory signal and are thus called killer-inhibitory r eceptors (KIR). To this end, the number of NK cells as well as the expressi on of KIR belonging to the Immunoglobulin (Ig)-like family on their surface was assessed in a group of HIV-infected patients, prior and after (6 month s) highly-active antiretroviral therapy (HAART). We show that the number of NK cells as well as the repertoire of Ig-like KIR is not significantly dif ferent from normal donors and is not modified during HAART. Conversely, cer tain KIR are over-expressed on T lymphocytes and remain stable during HAART .