Human cytomegalovirus (CMV) has been shown to alter adhesion molecule expression on permissive cells such as endothelial cells. The aim of the present study was to investigate expression of receptors for these molecules on CMV infected polymorphonuclear leukocytes (PMNLs). CMV-induced variations on cellular integrin expression were examined using an in vitro system to obtain infected PMNLs. A triparametric flow cytometry approach was developed, which allows combined detection, in a single experiment, of both viral intranuclear antigen in the selected PMNLs and cellular CD11/CD18 expression. Comparison of infected PMNLs with uninfected cells showed a decrease of up to 50% in the expression of CD11b, CD11c, and CD18. This study thus demonstrates that the presence of CMV in PMNLs, which characterizes active infection, modifies the expression of integrins and may thus affect cell-to-cell interactions and immune functions.