Immunohistochemistry: a new outlook in histopaleopathology

To date, rehydration techniques on mummified tissues as well as the methods for histological specimen preparation with standard basic stains and with histochemical techniques are commonly known and well established. The application of immunohistochemical techniques is a further development in the study of mummified tissues. Similarly to what is done on fresh and fixed tissues, reaction sensitivity and specificity must be guaranteed. While reaction sensitivity depends on serum quality and the detection method employed, specificity is guaranteed by serum quality but also by method standardisation. Method standardisation is the most serious problem in the study of mummified tissues. Mummified tissues have different antigen preservation characteristics, varying from subject to subject, and even within the same subject, depending on the topographic region and the site. These changes are due to different mummification methods and to subsequent environmental conditions in which the mummy was preserved. The Streptavidin-Biotin-Peroxidase Complex (SABC) technique guarantees excellent detection sensitivity. However, the method accuracy and reliability can be ensured only through a rigorous case by case examination with internal controls on structures in which the antigens we are looking for are surely expressed. Today, with these artifices (technique optimisation), cell differentiation phenotype markers can be detected which are useful in paleopathological studies and in the diagnosis of morphologically doubtful lesions.