title: Expansion of a CD8+CD28- cell population in the blood and lung of HIV-positive patients.
abstract: CD8+ cytotoxic T lymphocytes (CTLs) in human immunodeficiency virus (HIV) patients have defects in cytolytic ability and proliferative potential. The surface receptor CD28 is important in regulating antigen-specific responses to T cells. We hypothesized that activated CD8+ CTLs in HIV patients would have altered expression of CD28. We examined surface expression of D44, a CD8+ CTL marker, and of CD28 on T cells from blood and bronchoalveolar lavage from HIV+ patients and normal volunteers. We found no significant difference between normal volunteers and HIV+ individuals in percentage of CD8+D44+ CTLs in blood or the lung. In contrast, CD8+CD28- T cells in the blood of HIV patients constituted 74% of CD8+ cells compared to 25% in normal subjects (p = 0.001), findings exaggerated in both normal and HIV+ lung. CD4+CD28- blood T cells were significantly increased in HIV+ patients compared to normal subjects (24 vs. 1.5%, p = 0.004). The HIV infection itself did not directly downmodulate CD28 expression, demonstrated in the CD28+ SUPT1 cell line. Increased numbers of CD28- T cells may be the result of immunologic activation or of expansion of a preexisting CD28- subset. These findings have immunologic consequences for the antigen-specific response of T cells in HIV+ patients.
authors.affiliation: Pulmonary Center, Boston University School of Medicine, Massachusetts.
authors.forename: J J
authors.initials: JJ
authors.lastname: Saukkonen
authors.forename: H
authors.initials: H
authors.lastname: Kornfeld
authors.forename: J S
authors.initials: JS
authors.lastname: Berman
mesh_terms: D000328:Adult; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology / Q000276:immunology; D018106:CD28 Antigens / Q000032:analysis* / Q000097:blood; D016827:CD8 Antigens / Q000032:analysis* / Q000097:blood; D005434:Flow Cytometry; D015658:HIV Infections / Q000276:immunology*; D006801:Humans; D007958:Leukocyte Count; D008168:Lung / Q000276:immunology*; D008875:Middle Aged; D016176:T-Lymphocyte Subsets
chemical_list: D018106:CD28 Antigens; D016827:CD8 Antigens