Immunohistochemistry of von Willebrand factor in the lungs with regard to the cause of death in forensic autopsy.

Pulmonary microvascular injury is involved in severe trauma or disease. The present study investigated the immunohistochemical distribution of von Willebrand factor (vWF) and platelet CD61 factor in forensic autopsy cases (n=157, >18 years of age, within 48 h postmortem), which comprised fatalities from blunt and sharp instrument injuries, strangulation, fire fatality and acute cardiac death (ACD). vWF immunoreactivity was clearly detected in the endothelia of large vessels (LV, phi>200 microm), small vessels (SV, phi 40-200 microm) and capillaries (Cap, phi<40 microm). Cap-vWF positivity was also detected in microthrombi with CD61 immunopositivity. The vWF positivity was higher in non-edema areas than in the edema area in the lungs. For acute deaths, Cap-vWF positivity of non-edema areas was frequently detected for strangulation (n=8/13, 61.5%), fire fatality (n=11/26, 42.3%) and ACD (n=8/15, 53.3%), but was infrequent for blunt and sharp instrument injuries (n=6/27, 22.5%, and n=2/15, 13.3%, respectively), irrespective of the complication of chest injury. However, for non-acute deaths, Cap-vWF positivity was more frequent for non-chest blunt injury (n=12/27, 44.4%) than for blunt chest injury (n=3/13, 23.1%) and sharp instrument injury (n=0/10, 0%). For fire fatality, Cap-vWF positivity was relatively frequent in cases with a lower blood carboxyhemoglobin (COHb) level of <60% (n=6/14, 42.8%) than in cases with a higher COHb level of >60% (n=3/12, 25.0%). These findings suggest that Cap-vWF positivity is closely related to the death process involving pulmonary microvascular injury.