Humanes biomonitoring DNA-schädigender effekte in primären lymphozyten mit der einzelzellgelelektrophorese (Kometassay): Eine übersicht des aktuellen erkenntnisstandes

The present article is an analysis of 31 human biomonitoring studies dealing with DNA damage in primary human lymphocytes caused by occupational exposure to airborne chemicals or other factors which might have an influence on genetic integrity. 31 studies performed between the years 2000 and 2004 were included. DNA damage was assessed in the alkaline single cell gel electrophoresis (Comet assay). The advantages of the Comet assay are that data could be obtained in a fast and cost-effective manner and lymphocytes are easy to acquire. Additionally, we found a remarkable concordance between the results of the Comet assay and cytogenetic assays. However, despite these advantages most of the published studies showed several methodological shortcomings. Mostly the number of study participants was low and the distribution of age and gender was unequally. Additionally, data concerning qualitative and quantitative exposure are missing as well as data concerning differences in physical activity and diet between control and exposed groups. These are parameters, which possess a decisive influence on the level of DNA damage detectable by the Comet assay. Moreover, a standardised Comet assay protocol is missing. Therefore, the comparability of the results is limited. Furthermore the true sensitivity and specifity of the Comet assay is unclear. On one hand the Comet assay picked up DNA damage caused by agents which are known to be weak genotoxins or non-genotoxins in other tests, on the other hand it showed inconsistent results with known strong mutagens and carcinogens such as tobacco smoke. Despite these shortcomings the Comet assay is considered as an important tool in human biomonitoring studies to evaluate genotoxic effects. But for further studies it is necessary to standardise the study design and laboratory protocol so that the evidence of the observed results can be raised and a correct interpretation of the results is possible.