Myeloperoxidase as a biomarker of skin irritation and inflammation.

Topical exposure to many occupational and environmental chemicals is often accompanied by the induction of a cutaneous inflammatory response characterized by the influx of polymorphonuclear leucocytes (PMNs). In this study, the accumulation of myeloperoxidase (MPO), an enzyme found at high content in PMNs, was used as a biomarker to assess the inflammatory response to a number of well characterized skin irritants and tumour promoters. Of the chemicals examined, there was a good agreement between MPO accumulation and morphometric indicators of PMNs. Therefore, it was suggested that MPO accumulation could be an additional and useful toxicological tool for determining the dermal irritancy of chemicals.