Pulmonary immunohistochemistry and serum levels of a surfactant-associated protein A in fatal drowning

To evaluate the immunohistochemical distribution and serum levels of a pulmonary surfactant-associated protein A (SP-A) in fatal drowning with regard to the pulmonary alveolar injury, 53 autopsy cases were investigated. SP-A was membranously or linearly demonstrated in varying intensities on the intra-alveolar interior surface and on the interface of the intra-alveolar effusion. A high score of intra-alveolar aggregates of SP-A was significantly more frequently observed in freshwater than saltwater drowning. The left/right ratios of cardiac blood SP-A level were significantly high both in fresh- and saltwater drowning, showing no relationship to aggregated SP-A scores. Immunohistochemical score and serum level of SP-A were independent of the lung weight or pleural effusion. These observations suggest a partial difference of pulmonary pathophysiology depending on the immersion medium in fatal drowning.