Mechanisms of lung injury in severe acute respiratory syndrome (SARS): histopathological analysis

Objective To evaluate the pathogenesis of severe acute respiratory syndrome (SARS) from the pathological changes of lung. Methods In the archived 3?500 cases of autopsy, pulmonary inflammation could be found in 842 cases. Among them, 16 cases of viral pneumonia, 2 cases of Good Pasture syndrome, 2 cases of autoimmune disease and 1 case SARS were observed comparatively with the method of histopathology. Results In the common viral pneumonia, the pathological changes in the lung were that of interstitial pneumonia. The histopathological changes in the lung of autoimmune disease were characterized with hyaline membranes on the surface of alveolus, desquamated cellular corps and organizing changes in the alveolar spaces. The pulmonary changes of SARS were similar to that of autoimmune disease with the characters of granular or vacuolated pulmonary edema, desquamated and organizing pneumonitis, structure deterioration of pulmonary arterioles. Conclusion Immune mediated tissue damaging reaction may play an important role in the progress of SARS. [