Number Of Plasmacytoid Dendritic Cells Research Articles

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

AbstractFractalkine is the only member of the CX3C chemokine family. Polymorphism of the fractalkine receptor gene may influence the prognosis of human immunodeficiency virus (HIV) infection, but the nature of the cells expressing fractalkine or its receptor in HIV-infected patients remains unknown. We show that, in contrast to HIV-uninfected individuals, a large number of cells expressed fractalkine in T-cell zones of lymph nodes from HIV-infected patients. CD83+ mature and CD123+ plasmacytoid dendritic cells as well as plasma cells are involved in this increased expression of fractalkine. Increased numbers of plasmacytoid dendritic cells and plasma cells were present in T-cell zones of HIV-infected patients. CD83+ dendritic cells were present in similar number in HIV-infected patients and controls, but an increased fraction of these cells produced fractalkine in HIV-infected patients. Many plasma cells in the gut-associated lymphoid tissue from HIV-infected patients 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 sensitive to fractalkine stimulation. This increased response correlated with HIV viremia, and it returned to normal levels in patients successfully treated with antiretroviral drugs. The increased expression of the fractalkine/fractalkine receptor complex associated with HIV infection may affect adhesion and migration of Th lymphocytes and their interaction with dendritic cells. Thus, it may influence the equilibrium between depletion and renewal of the Th lymphocyte compartment.

Corticosteroids depress IFN-α–producing plasmacytoid dendritic cells in human blood

Glucocorticoids are strongly immunosuppressive and are associated with reactivation of some intracellular infections. The plasmacytoid dendritic cell is a rare blood mononuclear cell detected through its production of IFN-α in response to herpes simplex virus and by surface immunophenotyping. We here report that steroid administration results in a decrease of IFN-α generation of approximately 25-fold, accompanied by reduction in circulating plasmacytoid dendritic cell numbers. Both parameters return to normal within days after steroid cessation. (J Allergy Clin Immunol 2001;108:446-8.)