Histopathological lung changes in immune complex mediated anaphylactic shock in humans elicited by dextran

Severe dextran-induced anaphylactic reaction (DIAR) is being recognized as a form of immediate IgG mediated immune complex reaction. Support for this pathogenesis is found in the correlation between the titer of dextran-reactive antibodies of IgG class and the severity of the reaction. Autopsy records were reviewed in 27 certified cases of fatal DIAR. The most frequent macroscopic findings were dilatation of the right side of the heart and acute pulmonary stasis. Autopsy lung specimens were collected from 17 of these patients. In 15 of the 17 lung specimens pulmonary microemboli were found. The microemboli had the appearance of hyaline eosinophilic globules, and the lung vasculature also contained leukocytes, platelets and disintegrated erythrocytes. These findings show similarity to the findings in a monkey model of known IgG mediated anaphylaxis, and give further support to the proposed pathogenesis of severe DIAR.