Immunohistochemical localization of mast cells as a tool for the discrimination of vital and postmortem lesions.

In wounds that are inflicted at least 60 min before death, histamine levels can increase up to 100%. This functional effect might have a morphometric counterpart. Mast cells play a crucial role in acute inflammatory reactions and in the healing process of wounds. Therefore, the density of these cells was immunohistochemically assessed in tissue from 20 healthy controls (Group 1), 20 vital skin lesions (Group 2) (age range: a few seconds to 1 h), and 20 postmortem lesions (Group 3). A piece of skin close to the vital lesion was also obtained from the homolateral part of the body (Group 4). Mast cell density was significantly higher at the level of the vital lesions (11.28+/-2.44) than elsewhere (healthy controls 7.66+/-1.27, postmortem lesions 4.13+/-1.46, skin close to the vital lesions 4.88+/-1.59). No differences were found between the values assessed in the skin samples close to the vital lesions and in those in the postmortem lesions. Therefore, mast cell richness in the vital lesions exhibited a proportional morphological correlation with previously detected histamine values in cutaneous vital lesions. These results suggest that the detection of mast cells with immunohistochemical techniques can lead to a high level of discrimination (based on statistical data) between antemortem and postmortem lesions. This method could also be used to ascertain the vitality of lesions.