Assessment of DNA damage induced by broadband and narrowband UVB in cultured lymphoblasts and keratinocytes using the comet assay.
Phototherapy with broadband UVB is an effective treatment for inflammatory dermatoses. A newly developed fluorescent UVB lamp (Philips TL01) that emits a narrowband UVB around 311 nm was shown to be superior for the phototherapy of psoriasis. In order to contribute to the knowledge about the carcinogenic potential of this UVB source, we measured the DNA damage in lymphoblasts and keratinocytes induced by narrowband UVB and compared it with that by conventional broadband UVB using the single cell gel electrophoresis (comet assay). At equal doses, broadband UVB produced more DNA damage than narrowband UVB. However, in phototherapy of psoriasis, up to 10-fold higher doses are used with TL01. When therapeutically equivalent doses were compared (10-fold correction for narrowband UVB), we found only slight differences in the amount of DNA damage produced by broadband and narrowband UVB. This supports the already existing evidence that for phototherapy narrowband UVB is not more carcinogenic than broadband UVB.
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Department of Dermatology, Georg August University of Göttingen, Germany.
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D002461:Cell Line, Transformed; D002478:Cells, Cultured; D004249:DNA Damage; D004307:Dose-Response Relationship, Radiation; D005333:Fetus; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008214:Lymphocytes; D008297:Male; D012867:Skin; D014466:Ultraviolet Rays