Changes in Circulating Levels of Soluble Cell Adhesion Molecules Following Highly Active Antiretroviral Treatment of HIV-1-Infected Patients

Increased levels of soluble cell adhesion molecules (sCAM) have been reported in HIV-1 infection and may possibly contribute to altering the adhesion mechanisms of phagocytic cells. We evaluated the effect of highly active antiretroviral therapy (HAART) on plasma levels of sL-selectin, sE-selectin, intercellular cell adhesion molecule-1 (sICAM-1), sICAM-3, and vascular cell adhesion molecule-1 (sVCAM-1). Study participants included 22 HIV-1-infected patients with a CD4+ T-cell count/μl below 500 who were started on a HAART regimen and followed up for 9 months. After the initiation of therapy, plasma sL-selectin concentrations progressively decreased to normal ranges in the majority of our patients (P < 0.001), while no changes in sE-selectin were found. In all patients sICAM-1 remained relatively constant at significantly elevated concentrations during the 9 months of therapy. A significant reduction in plasma concentrations of both sICAM-3 and sVCAM-1 was found; however, the levels of these sCAM were not normalized by HAART and remained significantly elevated throughout the study (P < 0.001). The reduced release of sL-selectin could improve the ability of phagocitic cells to migrate in response to chemotactic stimuli after starting HAART. On the other hand, the persistent elevation of sICAM-1, sICAM-3, and sVCAM-1 could reflect continuous HIV-1-mediated immune activation, despite adequate control of plasma HIV-1 replication by therapy.