Putative role of TNF-α, interleukin-8 and ICAM-1 as indicators of an early inflammatory reaction after burn: a morphological and immunohistochemical study of lung tissue of fire victims

Aims To investigate incipient inflammatory changes as first steps in the development of a systematic inflammatory response syndrome in the lungs of burn victims. Methods At the Institute of Legal Medicine of the University Hospital of Freiburg a collection of 40 forensic autopsy cases of burn victims was established that had died within 1 h after fire exposure. This group was compared with a total of 48 autopsy cases in three control groups (postmortem burns vs deaths from haemorrhagic shock vs railway suicide deaths). In all cases, immunohistochemical studies of lung tissue probes were performed to detect the presence of pro-inflammatory mediators using antibodies against tumour necrosis factor alpha (TNF-alpha), interleukin-8 (IL-8) and inter-cellular adhesion molecule 1 (ICAM-1). Results The lungs of burn victims showed a significantly higher extent of intra-alveolar oedema than the other groups. Immunohistochemically, macrophages in all groups mostly showed a distinct expression of TNF-alpha, but not of IL-8 or ICAM-1. Interestingly, intravascular erythrocytes often showed a positivity of TNF-alpha that was strongest in the group of burn victims and differed significantly from all the control groups. Conclusions In burn victims with short survival times of <= 1 h after fire exposure, the immunohistochemical expression profiles of TNF-alpha, IL-8 and ICAM-1 in the lungs were not altered enough to prove an instant inflammatory reaction in these cases. Nevertheless, the positive reaction of TNF-alpha in erythrocytes of burn victims may indicate the beginning of a non-specific immune response to fire-induced inhalation trauma.