Increased apoptosis of circulating T cells in myelodysplastic syndromes.
The mechanism of T cell lymphopenia in myelodysplastic syndromes (MDS) is unknown. We investigated apoptosis in freshly isolated and cultured lymphocytes; the latter were used to detect cells not yet apoptotic but destined for apoptosis. Apoptosis increased in both fresh and cultured T cells in MDS compared with those from healthy controls. Furthermore, in lymphopenic MDS patients the lymphocyte count correlated negatively with the degree of T cell apoptosis. MDS T cells showed increased Fas expression. However, in MDS but not in controls, the degree of T cell apoptosis was independent of the Fas expression level, and exogenous anti-Fas antibodies did not modulate T cell apoptosis. Mechanisms other than the Fas-Fas ligand pathway may induce T cell apoptosis in MDS.
Shioi
Yumiko
Y
Division of Hematology, Department of Medicine, Nippon Medical School, Tokyo, Japan.
Tamura
Hideto
H
Yokose
Norio
N
Satoh
Chikako
C
Dan
Kazuo
K
Ogata
Kiyoyuki
K
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000906:Antibodies / Q000494:pharmacology; D017209:Apoptosis; D016022:Case-Control Studies; D006801:Humans; D018655:Lymphocyte Count; D008231:Lymphopenia / Q000209:etiology*; D008875:Middle Aged; D009190:Myelodysplastic Syndromes / Q000150:complications*; D013601:T-Lymphocytes / Q000473:pathology*; D019014:fas Receptor / Q000032:analysis* / Q000276:immunology
D000906:Antibodies; D019014:fas Receptor