title: Cytotoxic activity of T- and NK-cell lymphoma cells is not dependent on a mature cytotoxic phenotype.
abstract: Cytotoxic T- and NK-cell neoplasms constitute a rare clinico-pathological entity associated with aggressive clinical behaviour and a poor prognosis. The entity comprises a heterogenous group of different diseases classified by histologic, immunologic as well as clinical features. Recently, expression patterns of "cytotoxicity-associated proteins" such as T-cell intracellular antigen (TIA), perforin and granzyme B have been applied to differentiate between an immature (TIA positive) and a mature (TIA and perforin and/or granzyme B positive) phenotype of these malignant cells. In particular, expression of perforin and granzyme B are considered to mediate cytotoxic activity. This study assesses histology/cytology, immunophenotype, expression of "cytotoxicity-associated proteins" and the actual exhibition of cytotoxic activity of lymphoma cells of 10 patients suffering from different T- and NK-cell neoplasms. As investigated by PKH67 labelling of the target cells 6 out of 10 samples exhibited cytotoxic activity. Thus, all samples of lymphoma cells with a mature phenotype exhibited cytotoxic activity. Nevertheless, the ability to induce cytotoxic cell lysis was neither restricted to mature lymphoma cells, nor to lymphoma cells expressing "cytotoxicity-associated proteins": two samples with an immature phenotype and one CD4 positive sample, completely lacking expression of "cytotoxic proteins" as well as NK cell-associated markers, destroyed target cells. Artificial activation of a mature cytotoxic phenotype by cell culture conditions or contact of lymphoma cells with target cells was excluded by demonstrating the absence of perforin expression after the incubation period in two exemplary cases. In conclusion, we demonstrate that the exhibition of cytotoxic activity is neither restricted to cells with a mature phenotype, nor does it depend on the expression of the "cytotoxicity-associated proteins" TIA, perforin or granzyme B.
authors.affiliation: Department of Medicine III, Johann Wolfgang Goethe-University Hospital, Theodor-Stern-Kai-7, 60590 Frankfurt am Main, Germany.
authors.forename: Simone
authors.initials: S
authors.lastname: Boehrer
authors.forename: Daniela K
authors.initials: DK
authors.lastname: Schui
authors.forename: Kai U
authors.initials: KU
authors.lastname: Chow
authors.forename: Dieter
authors.initials: D
authors.lastname: Hoelzer
authors.forename: Paris S
authors.initials: PS
authors.lastname: Mitrou
authors.forename: Eckhart
authors.initials: E
authors.lastname: Weidmann
mesh_terms: D015703:Antigens, CD / Q000032:analysis; D000954:Antigens, Surface / Q000032:analysis*; D003602:Cytotoxicity, Immunologic; D005260:Female; D006801:Humans; D016130:Immunophenotyping; D007694:Killer Cells, Natural / Q000276:immunology / Q000473:pathology; D016399:Lymphoma, T-Cell / Q000276:immunology*; D008297:Male; D008562:Membrane Glycoproteins / Q000032:analysis; D008565:Membrane Proteins / Q000032:analysis; D054353:Perforin; D039102:Poly(A)-Binding Proteins; D052899:Pore Forming Cytotoxic Proteins; D011506:Proteins; D016601:RNA-Binding Proteins / Q000032:analysis; D011971:Receptors, Immunologic / Q000032:analysis; D054340:Receptors, KIR; D000074019:T-Cell Intracellular Antigen-1; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology / Q000473:pathology
chemical_list: D015703:Antigens, CD; D000954:Antigens, Surface; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D039102:Poly(A)-Binding Proteins; D052899:Pore Forming Cytotoxic Proteins; D011506:Proteins; D016601:RNA-Binding Proteins; D011971:Receptors, Immunologic; D054340:Receptors, KIR; D000074019:T-Cell Intracellular Antigen-1; C071558:TIA1 protein, human; D054353:Perforin