Prolonged CD4+ Lymphocytopenia and Thrombocytopenia in a Chimpanzee Persistently Infected with Human Immunodeficiency Virus Type 1

Abstract

The immunologic and virologic status of a chimpanzee inoculated with multiple isolates of the human immunodeficiency virus type 1 (HIV-1) were assessed over 57 months to determine whether prolonged thrombocytopenia and CD4⁺ lymphocytopenia observed in the animal might be associated with long-term HIV infection. Although the chimpanzee showed no signs of disease, it lost both CD4⁺ (as low as 134 cells/µl) and CD8⁺ lymphocytes ∼J30 months after initial infection, followed bythrombocytopenia that has persisted for > 2 years. Lymphopenia and thrombocytopenia were preceded by or coincided with the appearance of antibodies cross-reactive with histone H2B and decreased levels of complement component C4; an eightfold decrease in HIV specific antibody titers; the inability of CD8⁺ lymphocytes to suppress virus replication; impaired proliferative responses to T cell mitogens; and the isolation of cell-free HIV from plasma. These data suggest that, given sufficient time, HIV-infected chimpanzees may develop disease.