Pulmonary surfactant-associated protein A levels in cadaveric sera with reference to the cause of death

Pulmonary surfactant-associated protein A (SP-A) is an exclusively lung spe cific protein, and is considered to leak into the blood stream in alveolar septal damage. In this study we examined the serum SP-A level in forensic a utopsy materials using an enzyme immunoassay with monoclonal antibodies to assess the postmortem level in relation to the cause and mode of death. Alt hough a gradual postmortem degradation should be taken into consideration, topological relationship of serum level seemed to be fairly stable (arteria l greater than or equal to venous blood in most cases), indicating no evide nt influence of postmortem diffusion. Significant elevation of serum SP-A ( 76.7-250 ng/ml in left heart blood) was observed in hyaline membrane diseas es from various causes independent of the postmortem intervals (<30 h). How ever, mean SP-A levels in postmortem heart blood were usually low in asphyx ia including hanging, strangulation and choking (left, 25.5 ng/ml; right, 2 2.3 ng/ml), polytrauma (left, 13.1 ng/ml; right, 9.0 ng/ml) and stab wound to the neck (left, 34.1 ng/ml; right, 29.4 ng/ml). Prominent elevation was noted in a case of fatal strangulation with complication of idiopathic inte rstitial pneumonia, and also in some deaths due to drowning, burns in fires , blunt and gunshot chest injuries. These findings indicated that postmorte m elevation of serum SP-A levels was associated with alveolar septal damage due to inflammation, mechanical and physical stresses, which caused leakag e of SP-A into the bloodstream. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.