title: CD20-positive T-cell chronic lymphocytic leukaemia.
abstract: Although CD20 is considered to be a representative marker for B lymphocytes, the antigen is weakly expressed on a small subset of normal T lymphocytes. A 60-year-old man developed pancytopenia and hepatosplenomegaly due to clonal proliferation of atypical lymphocytes that were weakly positive for CD20. The leukaemic cells were also positive for T-cell antigens such as CD2, CD3, CD5, CD7, CD8 and T-cell receptor (TCR) Vbeta8 and for activation antigens such as CD38 and HLA-DR, but were negative for CD19, CD21, CD22, CD25. Southern blot analysis revealed rearrangement of the TCR-beta gene and a germline configuration of the immunoglobulin heavy chain gene. This is the first report of a case of clonal expansion of CD20dim T lymphocytes.
authors.affiliation: Department of Haematology, Kurobe Municipal Hospital, Toyama, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Takami
authors.forename: M
authors.initials: M
authors.lastname: Saito
authors.forename: S
authors.initials: S
authors.lastname: Nakao
authors.forename: H
authors.initials: H
authors.lastname: Asakura
authors.forename: T
authors.initials: T
authors.lastname: Nozue
authors.forename: Y
authors.initials: Y
authors.lastname: Onoe
authors.forename: A
authors.initials: A
authors.lastname: Yachie
authors.forename: S
authors.initials: S
authors.lastname: Shiobara
authors.forename: T
authors.initials: T
authors.lastname: Matsuda
mesh_terms: D018951:Antigens, CD20 / Q000378:metabolism*; D015139:Blotting, Southern; D015333:Gene Rearrangement, beta-Chain T-Cell Antigen Receptor; D006801:Humans; D015461:Leukemia, Prolymphocytic, T-Cell / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D016176:T-Lymphocyte Subsets / Q000276:immunology
chemical_list: D018951:Antigens, CD20