Prediction of radiosensitivity by measurement of X-ray induced apoptosis in human blood using the comet assay.
BACKGROUND
The aim of this work was to determine whether levels of radiation-induced apoptosis in human peripheral leukocytes could be used as a predictor of radiosensitivity.


METHODS
Peripheral blood was obtained from venous blood and exposed to 0-3 Gy of X-rays. Apoptosis levels were measured at 4, 24, 48 and 72 hours after exposure using the neutral comet assay. Intra-individual apoptotic response was measured using repeated blood samples from four healthy individuals. Inter-individual variation was investigated in whole blood, granulocytes and mononuclear cells from 8 radiotherapy patients (4 demonstrating a radiosensitive response and 4 demonstrating a normal response to radiation exposures).


RESULTS
Amongst the four healthy individuals there was both inter- and intra-individual variation of about the same magnitude. However, when comparing the apoptotic response of the radiosensitive and normal patients, consistent trends were observed at all X-ray doses for all of the patients.


CONCLUSIONS
This indicates that apoptosis has some potential as a predictive assay, however, large intra-individual variation exists. More studies are required to investigate the causes of intra-individual variation and how it might be minimized.
Kizilian-Martel
N
N
Consumer and Clinical Radiation Protection Bureau, Health Canada, Ottawa, Ontario, Canada.
Wilkins
R C
RC
Mclean
J R
JR
Malone
S
S
Raaphorst
G P
GP
D000368:Aged; D017209:Apoptosis / Q000528:radiation effects*; D001769:Blood / Q000528:radiation effects; D020552:Comet Assay; D005260:Female; D006801:Humans; D007206:Individuality; D007962:Leukocytes / Q000166:cytology / Q000528:radiation effects*; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000097:blood / Q000532:radiotherapy; D011237:Predictive Value of Tests; D011836:Radiation Tolerance / Q000502:physiology*; D014965:X-Rays