Deregulation of the expression of the fractalkine/fractalkine receptor complex in HIV-1-infected patients

Fractalkine is the only member of the CX3C chemokine family. Polymorphism o f the fractalkine receptor gene may influence the prognosis of human immuno deficiency virus (HIV) infection, but the nature of the cells expressing fr actalkine or its receptor in HIV-Infected patients remains unknown. We show that, in contrast to HIV-uninfected individuals, a large number of cells e xpressed fractalkine in T-cell zones of lymph nodes from HIV-infected patie nts. CD83(+) mature and CD123(+) plasmacytoid dendritic cells as well as pl asma cells are involved in this increased expression of fractalkine. Increa sed numbers of plasmacytoid dendritic cells and plasma cells were present i n T-cell zones of HIV-infected patients. CD83(+) dendritic cells were prese nt in similar number in HIV-infected patients and controls, but an increase d fraction of these cells produced fractalkine in HIV-infected patients. Ma ny plasma cells in the gut-associated lymphoid tissue from HIV-Infected pat ients also produced fractalkine, whereas few cells produced fractalkine in the gut of controls. The fraction of CD45RO(+) and CD45RO(-) T helper (Th) cells expressing the fractalkine receptor CX3CR1 was higher in HIV-infected patients than in healthy individuals, and these cells were abnormally sens itive to fractalkine stimulation. This increased response correlated with H IV viremia, and it returned to normal levels in patients successfully treat ed with antiretroviral drugs. The increased expression of the fractalkine/f ractalkine receptor complex associated with HIV infection may affect adhesi on and migration of Th lymphocytes and their interaction with dendritic cel ls. Thus, it may influence the equilibrium between depletion and renewal of the Th lymphocyte compartment. (C) 2001 by The American Society of Hematol ogy.