title: Immunophenotype and TCR-Vbeta repertoire of peripheral blood T-cells in acute infectious mononucleosis.
abstract: Although a number of studies on the phenotypic changes that occur after T-cell activation have already been published, the specific immunophenotypic features of T-lymphocytes and the frequency at which TCR-variable region (TCR-V) restricted T-cell expansions occur "in vivo" during acute viral infection still remains to be established. We report on the immunophenotype and TCR-V repertoire of peripheral blood T-cells from 28 patients with acute infectious mononucleosis. Immunophenotypic studies were performed by flow cytometry using direct immunofluorescence techniques and stain-and-then-lyse sample preparation protocols with three- and four-colour combinations of monoclonal antibodies directed against a large panel of T- and NK-cell associated markers, activation- and adhesion-related molecules and TCR-Vbeta, -Vgamma and -Vdelta families. Nearly all patients (27/28) showed a massive expansion of CD8(+)/TCRalphabeta(+) T cells, the majority (>90%) of which displayed an immunophenotype compatible with T-cell activation: CD2(+high), CD7(+low), CD11a(+high), CD38(+high), HLA-DR(+high), CD28(+/-low), CD45RO(+high), CD45RA(-/+low), CD11b(-/+low), CD11c(+/-low), CD16(-), CD56(-), CD57(-), CD62L(-), CD94(-), CD158a(-), CD161(-), NKB1(-). Additionally, the levels of both CD3 and CD5 were slightly decreased compared to those found in normal individuals. Late-activation antigens, such as CD57, were found in small proportions of CD8(+)/TCRalphabeta(+) T-cells. Increased numbers of CD4(+)/TCRalphabeta(+) T-cells, TCRgammadelta(+) T-cells and NK-cells were also noticed in 17, 16 and 13 of the 28 cases studied, respectively. Evidence for activation of CD4(+)/TCRalphabeta(+) and TCRgammadelta(+) T-cells relied on changes similar to those described for CD8(+)/TCRalphabeta(+) although less pronounced, except for higher levels of both CD5 and CD28 in the absence of reactivity for CD11c on CD4(+)/TCRalphabeta(+) T-cells and higher levels of CD161 and CD94 on TCRgammadelta(+) T-cells. Small expansions of one or more TCR-Vbeta families accounting for 12 +/- 7% of either the CD8(+)/TCRalphabeta(+) or the CD4(+)/TCRalphabeta(+) T-cell compartment were found in 12 of 14 patients studied, whereas the distribution of the TCR-Vgamma and -Vdelta repertoires tested in 2 of the individuals with expanded TCRgammadelta(+) T-cells was similar to that observed in control individuals. The results presented here provide evidence for an extensive T-cell activation during acute viral infection and establish the immunophenotype patterns associated with this condition.
authors.affiliation: Service of Clinical Haematology, Hospital Santo António, Porto, Portugal. mmc.lima@clix.pt
authors.forename: Margarida
authors.initials: M
authors.lastname: Lima
authors.forename: Maria dos Anjos
authors.initials: Mdos A
authors.lastname: Teixeira
authors.forename: Maria Luís
authors.initials: ML
authors.lastname: Queirós
authors.forename: Ana Helena
authors.initials: AH
authors.lastname: Santos
authors.forename: Cristina
authors.initials: C
authors.lastname: Gonçalves
authors.forename: João
authors.initials: J
authors.lastname: Correia
authors.forename: Fátima
authors.initials: F
authors.lastname: Farinha
authors.forename: Fernanda
authors.initials: F
authors.lastname: Mendonça
authors.forename: José Manuel Neves
authors.initials: JM
authors.lastname: Soares
authors.forename: Júlia
authors.initials: J
authors.lastname: Almeida
authors.forename: Alberto
authors.initials: A
authors.lastname: Orfão
authors.forename: Benvindo
authors.initials: B
authors.lastname: Justiça
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D001772:Blood Cell Count; D002648:Child; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D016130:Immunophenotyping; D007244:Infectious Mononucleosis / Q000097:blood / Q000276:immunology* / Q000473:pathology; D008213:Lymphocyte Activation / Q000276:immunology; D016131:Lymphocyte Subsets / Q000276:immunology; D008297:Male; D008875:Middle Aged; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000032:analysis / Q000276:immunology*; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000032:analysis / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology* / Q000473:pathology
chemical_list: D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta