CD20-positive T-cell chronic lymphocytic leukaemia.
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.
Takami
A
A
Department of Haematology, Kurobe Municipal Hospital, Toyama, Japan.
Saito
M
M
Nakao
S
S
Asakura
H
H
Nozue
T
T
Onoe
Y
Y
Yachie
A
A
Shiobara
S
S
Matsuda
T
T
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
D018951:Antigens, CD20