title: Analysis at the clonal level of T-cell phenotype and functions in severe aplastic anemia patients.
abstract: The aim of this study was to analyze at the clonal level the phenotype and functions of T cells from patients with severe aplastic anemia (SAA). For this purpose we studied 175 T-cell clones obtained from peripheral blood (PB) and bone marrow (BM) of four SAA patients and 97 clones from two healthy controls. The percentage of CD8+ T-cell clones obtained from the patients' PB and BM was higher, but not significantly (P = .07 and P = .14, respectively), than that obtained in controls. A higher proportion of T-cell clones from SAA patients exhibited lectin-dependent cytolytic activity and especially natural killer-like activity when compared with controls (PB: P less than .01, P less than .05; BM: P less than .05, P less than .01, respectively). Lymphokine release was tested before and after mitogen stimulation. A number of patients' clones were able to release interferons (IFNs) spontaneously (PB: 28.6% v 0%, P less than .05; BM: 28.6% v 0%, P less than .10). After mitogen stimulation, patients' BM T-cell clones produced IFNs in greater proportions (90.9% v 46.7%, P less than .01) and in greater quantities (PB: 25.5 arbitrary units [AU]/mL v 5.7 AU/mL, P less than .03; BM: 26 AU/mL v 9.1 AU/mL, P = .011) as compared with controls. Tumor necrosis factor (TNF) activity was not found in supernatants of unprimed T-cell clones. After mitogen stimulation, PB T-cell microcultures produced TNF alpha in greater proportions (97.9% v 72.2%, P less than .01) and, also in this case, in greater quantities (PB: 7.2 AU/mL v 1.5 AU/mL, P = .007; BM: 9.9 AU/mL v 1.5 AU/mL, P = .003) than controls. In conclusion, T-cell clones from SAA patients exhibit predominantly a CD8+ phenotype, a greater cytotoxic activity, and can be shown to produce greater quantities of suppressor lymphokines when compared with controls.
authors.affiliation: Laboratory of Pharmacology, National Institute for Cancer Research (IST), Genova, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Viale
authors.forename: A
authors.initials: A
authors.lastname: Merli
authors.forename: A
authors.initials: A
authors.lastname: Bacigalupo
mesh_terms: D000293:Adolescent; D000328:Adult; D000741:Anemia, Aplastic / Q000097:blood*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D001853:Bone Marrow / Q000473:pathology; D017252:CD3 Complex; D015704:CD4 Antigens / Q000032:analysis; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000502:physiology*; D016827:CD8 Antigens; D002469:Cell Separation; D002999:Clone Cells; D005260:Female; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000096:biosynthesis; D006801:Humans; D016130:Immunophenotyping; D007372:Interferons / Q000096:biosynthesis; D007377:Interleukin-3 / Q000096:biosynthesis; D008297:Male; D008562:Membrane Glycoproteins / Q000032:analysis; D008875:Middle Aged; D011948:Receptors, Antigen, T-Cell / Q000032:analysis; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D015704:CD4 Antigens; D016827:CD8 Antigens; D007377:Interleukin-3; D008562:Membrane Glycoproteins; D011948:Receptors, Antigen, T-Cell; D014409:Tumor Necrosis Factor-alpha; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D007372:Interferons