title: 'Normal counterparts' of nodal peripheral T-cell lymphoma.
abstract: Peripheral T-cell lymphomas (PTCL) have been difficult to classify. A homogeneous principle of classification is still lacking, partly because lymph node compartments containing functionally distinct T-cell subsets have not been identified. A correlation to differentiated T-cell subsets, as CD4(+) or CD8(+) cells as well as cytotoxic populations has not revealed clinically meaningful entities. Upon antigen encounter, mature T-cells pass through distinct stages characterized by their surface molecule expression. Naïve T-cells are CD45RA(+)/CD45R0(-)/CD27(+)/CCR7(+), however, after antigen contact CD45RA expression is replaced by CD45R0. They differentiate to central memory cells, which retain CD27 and CCR7, or to effector-memory cells, which loose expression of both molecules depending on the strength of the antigen interaction. Immunohistological analysis of PTCL showed an effector or effector-memory cell phenotype (CD45RA(-)/CD45R0(+)/CD27(-)) for both angioimmunoblastic T-cell lymphoma (AILT) and anaplastic large cell lymphoma (ALCL), but different cytotoxic and activation markers expressed by these tumours. A subset of CD4(+) PTCL-not otherwise specified (PTCL-NOS) may correspond to a central memory cell phenotype (CD45RA(-)/CD45R0(+)/CD27(+)). Thus, a correlation of PTCL to stages of differentiation, rather than to the direction of differentiation, may reveal homogeneous categories. A comparison between the lymphomas and their normal counterparts may contribute to the understanding of the underlying transformation mechanisms.
authors.affiliation: Institute of Pathology, University of Würzburg, Würzburg, Germany. path019@mail.uni-wuerzburg.de
authors.forename: Thomas
authors.initials: T
authors.lastname: Rüdiger
authors.forename: Eva
authors.initials: E
authors.lastname: Geissinger
authors.forename: Hans Konrad
authors.initials: HK
authors.lastname: Müller-Hermelink
mesh_terms: D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000473:pathology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000473:pathology; D002454:Cell Differentiation / Q000276:immunology*; D002471:Cell Transformation, Neoplastic / Q000276:immunology; D015973:Gene Expression Regulation, Leukemic / Q000276:immunology; D006801:Humans; D007156:Immunologic Memory; D008198:Lymph Nodes / Q000276:immunology / Q000473:pathology; D008213:Lymphocyte Activation / Q000276:immunology; D016403:Lymphoma, Large B-Cell, Diffuse / Q000145:classification / Q000276:immunology / Q000473:pathology; D016411:Lymphoma, T-Cell, Peripheral / Q000145:classification / Q000276:immunology* / Q000473:pathology
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte