Antigenicity Preservation Is Related to Tissue Characteristics and the Post-Mortem Interval: Immunohistochemical Study and Literature Review

The main aim of this study was to investigate the post-mortem proteolytic degradation process of selected tissue antigens and correlate it to the post-mortem interval. During the autopsy of 12 cadavers (time interval ranging 1 day–2 years after death) samples of skin, liver, kidney, and spleen were collected. All samples were formalin-fixed and paraffin-embedded. Four µm paraffin sections were used for hematoxylin–eosin staining and immunohistochemical analysis (Ki67, Vimentin, Pan cytokeratin, and CD20). Data reported here show that immunohistochemical reactivity preservation was related to the characteristics of the tissues. In particular, the most resistant tissue was the skin, where the autolysis phenomena were not appreciable before 5 days. On the contrary, the liver and the spleen underwent early autolysis, while the kidney displayed an early autolysis of the tubules and a late one of the glomeruli. As concerns specific antigens, immunoreactivity was lost earliest for nuclear antigens as compared to cytoplasmic ones. In conclusion, our results demonstrate that immunohistochemical detection of specific antigens may be useful in estimating the post-mortem interval, especially when we need to know whether the post-mortem interval is a few days or more than 7–10 days.