T-cell nonmalignant clonal proliferation in ataxia telangiectasia: a cytological, immunological, and molecular characterization.
Cytogenetically abnormal T-cell nonmalignant clones are a characteristic feature of ataxia telangiectasia (AT). Here, we study a t(14;14) clone from a patient with AT, and provide a cytological, immunological, and molecular characterization. This cellular population is clonal at the molecular level, but is phenotypically heterogeneous, with CD4+CD8+ and CD4-CD8+ cells. Although these cells do not divide in the peripheral blood, a majority of them are found in G1 phase and express the membrane antigen 4F2, a very early marker of activation. Many similarities are found between this nonmalignant AT clone and T-cell prolymphocytic leukemia at the morphologic, cytogenetic, and immunologic levels, despite the different clinical courses associated with these proliferations. We hypothesize that the t(14;14) translocation is linked to the abnormal morphology and immunophenotype of the AT clone cells, but that this translocation confers only a preactivated state to the cells. A complete malignant transformation would then be due to secondary events.
Stern
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INSERM U132, Hôpital Necker, Paris.
Theodorou
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I
Aurias
A
A
Maier-Redelsperger
M
M
Debre
M
M
Debre
P
P
Griscelli
C
C
D000293:Adolescent; D001260:Ataxia Telangiectasia / Q000097:blood* / Q000235:genetics / Q000276:immunology; D015139:Blotting, Southern; D002455:Cell Division; D015329:Gene Rearrangement, T-Lymphocyte; D006412:Hematopoietic Stem Cells / Q000032:analysis / Q000276:immunology / Q000473:pathology*; D006801:Humans; D007621:Karyotyping; D008297:Male; D010641:Phenotype; D013601:T-Lymphocytes / Q000145:classification / Q000473:pathology*; D014178:Translocation, Genetic