In vitro evaluation of B-CLL cells apoptotic responses to irradiation.
Defective apoptosis is a mechanism which could possibly explain B chronic lymphocytic leukemia (B-CLL) cell accumulation. Differences in evolution and prognosis of B-CLL patients may be due to heterogeneity in apoptotic cell death. We studied the apoptotic response to in vitro gamma radiation of blood mononuclear cells from 18 untreated B-CLL patients. In cells irradiated with 2, 4 or 8 Gy and then cultured for 20 hours, the percentage of trypan blue excluding (viable) cells was not modified (>92%). An apoptotic response to irradiation was detected in the majority of the patients, but the individual percentage of apoptotic cells varied widely (8 to 81% after 8 Gy irradiation) in individual cases. The flow cytometric analysis of nick-end DNA labeling demonstrated a dose effect of irradiation, particularly in patients with an apoptotic response of over 20%. In the future, a valuable clue to the selection of irradiation regimens for B-CLL patients may be the investigation of correlations between in vitro radiation-induced apoptosis and the in vivo response to radiation therapy.
Comby
E
E
Université de Caen, UPRES EA 2128, and Service d'Immunologie et Immunopathologie, France.
Andre
I
I
Troussard
X
X
Lebrun
E
E
Sola
B
B
Ballet
J J
JJ
Leporrier
M
M
D000368:Aged; D017209:Apoptosis / Q000528:radiation effects*; D001402:B-Lymphocytes / Q000528:radiation effects; D002470:Cell Survival / Q000528:radiation effects; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000097:blood / Q000473:pathology* / Q000532:radiotherapy*; D007963:Leukocytes, Mononuclear / Q000473:pathology / Q000528:radiation effects; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D011379:Prognosis; D014407:Tumor Cells, Cultured