Autoreactive cytotoxicity in HIV-infected individuals

A possible role for autoimmunity in the pathogenesis of HIV infection has been suggested, based upon the certain degree of homology shared by HIV gp41 and MHC class II molecules. A number of humoral markers of autoimmunity have since been found in seropositive subjects. We have evaluated the cellular autoreactive response in HIV-infected individuals. Our study demonstrates the existence of a cytolytic activity, present in seropositive but not in seronegative subjects. This activity is mediated by CD3+ T cells, which only occasionally express the CD8 or the CD4 surface markers. Effector cells do not appear to exert their activity in a MHC-restricted fashion, since allogeneic target cells could also be killed, recovered from allogeneic seropositive as well as from seronegative subjects. Several types of target cells were lysed: T cell blasts and Epstein-Barr virus (EBV) transformed B cells, suggesting that the target antigen is common to at least these two cell types. The fact that cells from seronegative individuals were lysed argues against the recognition of an HIV-specific antigen. The nature of the target determinants and the identity of the effector cells are discussed.