title: Regeneration and tolerance factor: a correlate of human immunodeficiency virus-associated T-cell activation.
abstract: Human immunodeficiency virus (HIV) infection causes extensive phenotypic alterations in lymphocytes. Cellular markers that are normally absent or expressed at low levels on quiescent cells are upregulated throughout the disease course. The transmembrane form of regeneration and tolerance factor (RTF) is expressed at negligible levels on resting T cells but is quickly upregulated following in vitro stimulation and activation. Recently, we reported that expression of RTF was significantly higher in cells from HIV-seropositive (HIV(+)) individuals than in cells from HIV-seronegative (HIV(-)) individuals. Because T cells from HIV(+) individuals express markers reflecting chronic activation, we hypothesized that these in vivo-activated cells would coexpress RTF. Flow cytometry was used to assess RTF expression on activated (CD38(+) and HLA-DR(+)) CD4(+) and CD8(+) T cells. HIV(+) individuals had higher percentages of RTF(+) CD38(+) (P < 0.0001) or RTF(+) HLA-DR(+) (P = 0.0001) CD4(+) T cells than HIV(-) individuals. In HIV(+) individuals, increased percentages of CD4(+) T cells that were RTF(+), RTF(+) CD38(+), and RTF(+) HLA-DR(+) correlated inversely with the absolute number and percentage of CD4(+) T cells and correlated positively with plasma beta(2)-microglobulin concentrations. HIV(+) individuals had higher percentages of CD8(+) T cells that were RTF(+) CD38(+) (P = 0.0001) or RTF(+) HLA-DR(+) (P = 0.0010). In HIV(+) individuals, increased percentages of CD8(+) T cells that were RTF(+) HLA-DR(+) correlated inversely with the percentage of CD4(+) T cells, and high percentages of CD8(+) T cells that were RTF(+) CD38(+) correlated positively with plasma beta(2)-microglobulin levels. These findings strongly suggest that increased RTF expression is a correlate of HIV-associated immune system activation.
authors.affiliation: Clinical Immunology Laboratory and Department of Microbiology/Immunology, Finch University of Health Sciences/The Chicago Medical School, North Chicago, Illinois 60064, USA.
authors.forename: T S
authors.initials: TS
authors.lastname: Givens
authors.forename: B K
authors.initials: BK
authors.lastname: DuChateau
authors.forename: J S
authors.initials: JS
authors.lastname: Boomer
authors.forename: M P
authors.initials: MP
authors.lastname: Westerman
authors.forename: A
authors.initials: A
authors.lastname: Gilman-Sachs
authors.forename: K D
authors.initials: KD
authors.lastname: Beaman
mesh_terms: D000328:Adult; D018791:CD4 Lymphocyte Count; D015496:CD4-Positive T-Lymphocytes / Q000737:chemistry / Q000276:immunology* / Q000821:virology; D018414:CD8-Positive T-Lymphocytes / Q000737:chemistry / Q000276:immunology* / Q000821:virology; D005260:Female; D005434:Flow Cytometry; D015658:HIV Infections / Q000276:immunology*; D018023:HIV Seronegativity; D006679:HIV Seropositivity; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D011257:Pregnancy Proteins / Q000032:analysis / Q000276:immunology*; D013491:Suppressor Factors, Immunologic / Q000032:analysis / Q000276:immunology*; D001613:beta 2-Microglobulin / Q000097:blood; D006180:Proton-Translocating ATPases
chemical_list: D011257:Pregnancy Proteins; D013491:Suppressor Factors, Immunologic; D001613:beta 2-Microglobulin; C525845:ATP6V0A2 protein, human; D006180:Proton-Translocating ATPases