Immunohistochemical analysis for the evaluation of agonal time in a clandestine migrant's death and forensic implications

Abstract

We report a case of an adult migrant without identification who, during an illegal travel with other 16 clandestine compatriots in a bus inside a ship landed from the port of Igoumenitsa and directed to Ancona, dead of a heat stroke. Before arrival of the ship in the port, all clandestine migrants were found in precarious health conditions by a crew member of the shipping company inside the bus; one man was found in a dying state outside the bus, on the floor of the nursing anteroom of the ship ( Fig. 1 ). Circumstantial data revealed that one of them, the organizer of the illegal trip, impeded the escape of all the others migrants from the bus although the lack of oxygen. For judicial purposes and to demonstrate the crime of failure to assist a person in danger, it was useful to prove if the death of the man was preceded by a long agonal time (T). Specific analysis of immunohistochemical expression of inducible nitric oxide synthase (iNOS) in smooth muscle cells in a section of right renal artery ( Fig. 2 ) testified a protracted T, in accordance with necroscopic findings and testimonial evidence. A quantitative analysis to measure the signal intensity (SI) from cytoplasm was performed using a computer-aided drawing program, ImageJ software. Finally, for the estimation of agonal time (T), the following statistical formula was applied: T = {exp [−0.05 × SI + 10.149] [1] . T corresponded to 269 minutes, with a standard deviation of ± 14 minutes. All these elements were crucial to define the role of the migrant who arranged the crossing. The model of iNOS expression for estimation of T is useful in the field of clandestine migrant's deaths.