Autoreactivity in HIV-1 infection: the role of molecular mimicry.

Autoimmunity during HIV-1 infection may contribute to the immunopathogenesis of AIDS. Titers of autoantibodies to HLA molecules and other surface markers of CD4+ T cells appear to increase with the progression of disease and may correlate with lymphopenia. Other autoantibodies are directed at a number of regulatory molecules of the immune system. Genesis of autoreactivity may be related to structural homologies of HIV-1 env-products to such functional molecules involved in the control of self-tolerance. The most impressive similarities include the HLA-DR4 and DR2, the variable regions of TCR alpha-, beta-, and gamma-chain, the Fas protein, and several functional domains of IgG and IgA. Thus, HIV-1 infection may induce dysregulation leading to autoimmune response, through a number of molecular mimicry mechanisms. Pathogenicity of antibodies to T cells could also include the activation of membrane-to-nucleus signal transducers resulting in increased apoptosis. The evolution of autoimmune mechanisms during HIV-1 infection cannot exclude, however, progression to immunoproliferative malignancy, since aspects of oligoclonal immune response to HIV-1 components may occur in several autoimmune diseases which in some instances evolve to lymphoma.