title: Angioimmunoblastic T cell lymphoma is derived from mature T-helper cells with varying expression and loss of detectable CD4.
abstract: Angioimmunoblastic T cell lymphoma (AILT) is a rare lymphoma that is regarded as a clinicopathologic entity but shows considerable histomorphologic diversity, variable immunophenotypes and inconsistent T cell receptor (TCR) gene rearrangement. One hundred four paraffin blocks of AILT were investigated defining tumor cell lineage by triple immunostains with a confocal laser scanning microscope and correlating morphology, immunophenotype and TCRgamma gene rearrangement to clinical outcome. Ninety-nine cases were CD4(+), some of them showing a mixture of CD4(+) and CD4(-) tumor cells. The remaining 5 specimens were CD3(+)/CD4(-)/CD8(-). A considerable number of T cells of different subtypes could always be found, but even in 13 cases predominated by CD8(+) cells, proliferation could be attributed to atypical CD4(+) cells. TCRgamma gene rearrangement was monoclonal in 48 cases (69%) among 70 tested. In 29 of these semi-quantitative gene scan analysis resulted in a median proportion of monoclonal peak of 35% of PCR-products. Clinical outcome was identical grouping patients by clonality of TCRgamma, absence or presence of clear cell clusters and international prognostic index. We conclude that AILT is mainly derived from CD2(+)CD3(+)CD4(+)CD5(+)CD7(-) mature T-helper cells with varying expression and partial loss of detectable CD4. A significant number of non-neoplastic T cells (resting CD4(+) T cells and activated small or medium-sized CD8(+) lymphocytes) may coexist with a minor neoplastic T cell population. Clinicopathologic correlation suggests AILT to be a well defined homogeneous entity with poor prognosis. Currently no prognostic factors can be derived.
authors.affiliation: Department of Pathology, Korea Cancer Center Hospital, Seoul.
authors.forename: Seung-Sook
authors.initials: SS
authors.lastname: Lee
authors.forename: Thomas
authors.initials: T
authors.lastname: Rüdiger
authors.forename: Tobias
authors.initials: T
authors.lastname: Odenwald
authors.forename: Sabine
authors.initials: S
authors.lastname: Roth
authors.forename: Petr
authors.initials: P
authors.lastname: Starostik
authors.forename: Hans Konrad
authors.initials: HK
authors.lastname: Müller-Hermelink
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology; D015704:CD4 Antigens / Q000378:metabolism*; D016516:CD4-CD8 Ratio; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D019070:Cell Lineage; D005260:Female; D015334:Gene Rearrangement, gamma-Chain T-Cell Antigen Receptor / Q000235:genetics; D006801:Humans; D007119:Immunoblastic Lymphadenopathy / Q000276:immunology* / Q000473:pathology; D007124:Immunoenzyme Techniques; D016130:Immunophenotyping; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008198:Lymph Nodes / Q000276:immunology / Q000473:pathology; D016399:Lymphoma, T-Cell / Q000276:immunology* / Q000473:pathology; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D015704:CD4 Antigens; D007770:L-Lactate Dehydrogenase