DINITROCHLOROBENZENE IS GENOTOXIC BY SISTER-CHROMATID EXCHANGE IN HUMAN SKIN FIBROBLASTS

Dinitrochlorobenzene (DNCB) is clinically efficacious in the therapy o f alopecia areata, but its use was limited when it was found to be mut agenic in the Ames test. However, there has been renewed interest in t he immunomodulatory benefits of topically applied dinitrochlorobenzene in patients with human immunodeficiency virus and systemic lupus eryt hematosus. The current study examines the genotoxicity of dinitrochlor obenzene in human skin fibroblasts using sister chromatid exchange. Di nitrochlorobenzene caused a significant increase in sister chromatid e xchange at concentrations ranging from 2.5 to 10 mu M. Thus, dinitroch lorobenzene is genotoxic in human skin fibroblasts at concentrations w ell below those used clinically. The potential for long-term toxicity from dinitrochlorobenzene will have to be weighed against the severity and prognosis of the diseases for which it is used.