The skin immune system in the course of HIV-1 infection

In human immunodeficiency virus-1 (HIV-1) infection, diseases of the skin and mucous membranes frequently dominate the clinical picture as a consequence of progressive immunodeficiency. Functional impairment of the skin immune system, manifesting as a loss of the skin delayed-type hypersensitivity response is very likely due to the infection of immunocompetent cells of the skin by HIV-1. Besides CD4+ T cells, antigen-presenting Langerhans cells have been established as major targets of HIV-1 infection. The close physical contact of Langerhans with T lymphocytes during immune activation suggests central role of these cells in the dissemination of HIV-1 and the subsequent breakdown of the skin immune system. In addition, there are indications that mucosal Langerhans cells may represent preferred target cells for certain HIV-1 subtypes and thereby facilitate mucocutaneous transmission of HIV-1.