Article

Radiation sensitivity of lymphocytes from healthy individuals and cancer patients as measured by the comet assay

Biophysik (impact factor: 1.7). 02/2001; 40(1):83-89. DOI:10.1007/s004110000087 pp.83-89

ABSTRACT Lymphocytes of healthy volunteers (n=24) and of tumour patients (n=30, 18 of whom had experienced severe side-effects) were irradiated with x-rays in vitro. DNA damage was analysed after 0.25–2
Gy and DNA repair after 2 Gy, and quantification of both endpoints was done by the comet assay. The individual differences
in radiation-induced DNA damage as well as in the repair kinetics were observed to be striking for both healthy donors and
tumour patients. After a repair time of 3 h, following 2 Gy x-irradiation, some of the healthy volunteers showed no residual
DNA damage at all in their lymphocytes, whereas others revealed about 30%. There was no indication that our results were affected
by either age, gender or smoking habits. Slow repair kinetics and high amounts of residual damage were characteristic for
many but not all tumour patients who had experienced severe side-effects in their normal tissues during or after radiotherapy
(n=18). Our conclusion is that those individuals showing poor DNA repair characteristics in the lymphocytes following in vitro
irradiation, have a high probability of being radiosensitive. The opposite conclusion is not necessarily true: if repair is
effective, this does not mean that the individual is radioresistant, because factors other than impaired repair may cause
radiosensitivity.

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    Article: Radiation-induced DNA damage and repair in human gammadelta and alphabeta T-lymphocytes analysed by the alkaline comet assay.
    Halina Lisowska, Marta Deperas-Kaminska, Siamak Haghdoost, Ingela Parmryd, Andrzej Wojcik
    [show abstract] [hide abstract]
    ABSTRACT: It has been shown by a number of authors that the radiosensitivity of peripheral blood mononuclear cells (PBMC) is higher in cancer patients compared to healthy donors, which is interpreted as a sign of genomic instability. PBMC are composed of different cell subpopulations which are differently radiosensitive and the difference between cancer patients and healthy donors could also be due to different composition of their PBMC pools. Gamma-delta T-lymphocytes play an important role in immunosurveillance and are promising cells for immunotherapy. Their abundance is frequently reduced in cancer patients so should their sensitivity to radiation be lower than that of other T-lymphocytes, this could, at least partly explain the low radiosensitivity of PBMC from healthy individuals compared to cancer patients. The present investigation was carried out to test this. Using the alkaline comet assay we analysed the level of DNA damage and repair in isolated gammadelta T-lymphocytes, pan T-lymphocytes and in total PBMC exposed in vitro to gamma radiation. We found no difference in the level of DNA damage and the capacity of DNA repair between the T cell populations. This is the first study that addresses the question of sensitivity to radiation of gamma-delta T-cells.
    Genome integrity. 01/2010; 1(1):8.
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Keywords

2 Gy x-irradiation
 
comet assay
 
DNA damage
 
endpoints
 
Gy
 
healthy donors
 
healthy volunteers
 
individual differences
 
Lymphocytes
 
poor DNA
 
quantification
 
radiation-induced DNA damage
 
radiosensitivity
 
radiotherapy
 
repair kinetics
 
repair time
 
residual damage
 
severe side-effects
 
smoking habits
 
x-rays