title: CD31 (PECAM-1) is a marker of recent thymic emigrants among CD4+ T-cells, but not CD8+ T-cells or gammadelta T-cells, in HIV patients responding to ART.
abstract: Some severely immunodeficient HIV patients experience poor recovery of CD4(+) T-cell counts on antiretroviral therapy (ART). Evaluation of the function of thymopoiesis in T-cell production in individual patients requires a simple marker of T-cells that have recently emigrated from the thymus. Here, we address whether expression of CD31 on CD4(+) T-cells, CD8(+) T-cells, regulatory T-cells and gammadelta T-cells correlates with other indicators of thymus function. Adult HIV-1 patients (n=27) with nadir CD4(+) T-cell counts <100 per mul and a sustained virological response to ART and healthy controls (n=23) were studied. CD31 expression was assessed by flow cytometry, T-cell receptor excision circles content by real-time PCR and thymic volume by spiral computed tomography. Proportions of CD4(+) T-cells expressing CD45RA and CD31 declined with age in HIV patients (P=0.03) and healthy controls (P<0.0001), and correlated directly with other markers of thymus function. In controls, proportions of CD8(+) T-cells expressing CD45RA and CD31 declined with age (P=0.003) and correlated directly with some markers of thymus function, but this was not seen in HIV patients. Proportions of CD45RA(+) CD31(+) gammadelta T-cells were higher in patients than controls (P=0.007) and did not correlate with thymus volume. In controls, proportion of gammadelta T-cells co-expressing CD45RA and CD31 increased with age (P=0.002). These data support the use of CD31 as a marker of recent thymic origin in CD4(+) T-cells, but not CD8(+) T-cells in HIV patients receiving ART. In such patients, CD31 expression is unlikely to indicate thymic origin in gammadelta T-cells.
authors.affiliation: School of Pathology and Laboratory Medicine, University of Western Australia, Perth, Australia.
authors.forename: Sara
authors.initials: S
authors.lastname: Tanaskovic
authors.forename: Sonia
authors.initials: S
authors.lastname: Fernandez
authors.forename: Patricia
authors.initials: P
authors.lastname: Price
authors.forename: Silvia
authors.initials: S
authors.lastname: Lee
authors.forename: Martyn A
authors.initials: MA
authors.lastname: French
mesh_terms: D000328:Adult; D023241:Antiretroviral Therapy, Highly Active; D015415:Biomarkers / Q000378:metabolism; D018791:CD4 Lymphocyte Count; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D002465:Cell Movement; D005260:Female; D005434:Flow Cytometry; D005786:Gene Expression Regulation; D015658:HIV Infections / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000276:immunology / Q000378:metabolism*; D015497:HIV-1; D006801:Humans; D017493:Leukocyte Common Antigens / Q000096:biosynthesis / Q000276:immunology; D038041:Lymphopoiesis / Q000187:drug effects / Q000276:immunology; D008297:Male; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000096:biosynthesis* / Q000276:immunology; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000096:biosynthesis* / Q000276:immunology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000378:metabolism*; D013950:Thymus Gland / Q000000981:diagnostic imaging / Q000276:immunology / Q000378:metabolism; D036542:Tomography, Spiral Computed
chemical_list: D015415:Biomarkers; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D016692:Receptors, Antigen, T-Cell, gamma-delta; D017493:Leukocyte Common Antigens