Increased expression of iNOS by Langerhans cells in hanging marks

Recent studies show that Langerhans cell density increases in vital lesions and ligature marks when compared with post-mortal wounds. The enzyme, iNOS, has been established as a marker for estimating time of agony and serves in the regulation of dendritic cell behaviour. It is the aim of this paper, therefore, to evaluate the expression of this enzyme by Langerhans cells and the possible consequences that may be related to the production of nitric oxide by these cells in other types of lesions, including hanging furrows. The results show a greater expression of iNOS by Langerhans cells at the level of the hanging furrow when compared with other examined groups. Apart from an increase in the expression of iNOS, a large fraction of the mast cell population in the class II MHC molecules was observed in the hanging furrow. This corroborates that interactions between mast cells and dendritic cells are critical for the differentiation of these latter cellular types. Hence, the results suggest that iNOS plays a crucial role in the forensic practice of establishing the time interval in defining the vitality in hanging marks.