Impaired expression of CD28 on T cells in hairy cell leukemia.
T cells from patients with active hairy cell leukemia (HCL), a chronic B cell malignancy, show poor proliferation in response to allogeneic peripheral blood mononuclear cells (PBMC). In order to study the T cell dysfunction, the expression of several adhesion and costimulatory molecules was analyzed by flow cytometry. Circulating T cells from HCL patients showed increased percentages of CD28(-) in all T cell subsets. In some patients the percentage of CD28(-) T cells within the CD4(+) subset was increased up to 80%. These CD4(+)CD28(-) T cells did not proliferate in a mixed lymphocyte culture (MLC) against allogeneic PBMC. After enrichment for CD4(+)CD28(+) T cells, the proliferative response in the MLC was recovered, but this response was still lower than the proliferative response from control T cells. In conclusion, lack of CD28 on T cells and a restricted T cell repertoire may contribute to immune deficiency in patients with HCL.
van de Corput
L
L
Department of Hematology, Leiden University Medical Center, Leiden, 2300 RC, The Netherlands.
Falkenburg
J H
JH
Kester
M G
MG
Willemze
R
R
Kluin-Nelemans
J C
JC
D001782:Blood Donors; D018106:CD28 Antigens / Q000097:blood*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D017635:Clonal Anergy / Q000276:immunology; D006801:Humans; D007943:Leukemia, Hairy Cell / Q000097:blood* / Q000473:pathology*; D007963:Leukocytes, Mononuclear / Q000637:transplantation; D008213:Lymphocyte Activation / Q000276:immunology; D007959:Lymphocyte Culture Test, Mixed; D016176:T-Lymphocyte Subsets / Q000276:immunology*
D018106:CD28 Antigens