[Virus-induced immune deficiency disease AIDS: direct pathogenic effect of the virus or immunopathology?].

Cytotoxic effectors-CD8+ T cells protect hosts against cytopathic viruses. CD8+ T cell mediated lysis of host cells infected with non-cytopathic viruses may lead to tissue disease causing damage as is the case in hepatitis B virus infections in men or lymphocytic choriomeningitis virus (LCMV) infections in mice. In a mouse model it was demonstrated that virus induced immunodeficiency by LCMV was not caused by the virus directly but rather by immunopathological consequences of anti-LCMV CD8+ T cells destroying LCMV-infected antigen-presenting cells and macrophages. These results may suggest that HIV induced immunodeficiency could similarly be caused by immunopathology because 1. HIV has not been demonstrated to be cytopathic in vivo. 2. CD8+ T cells control HIV infection efficiently for a longtime and 3. only few CD4+ T cells but many macrophages, monocytes and dendritic cells are productively HIV infected. Therefore AIDS may be the result of specific CD8+ T cells destroying antigen presenting cells and effector/macrophages/monocytes thereby causing immunosuppression and inability to control intracellular infections. Compared to the view that HIV is cytopathic, the immunopathological view of AIDS suggests obviously different vaccine and therapy strategies.