The effect of shock on the inflammatory response. A reevaluation of the role of platelets in the active arthus reaction.

The active Arthus reaction can be inhibited by hypovolemic shock or the infusion of catecholamines. A reevalution of previous work with platelet antiserum indicates that shock rather than thrombocytopenia was responsible for preventing the active Arthus reaction. Immunofluorescent studies of the inhibited Arthus sites reveal that immune precipitates are not present in the extravascular tissues. Since leukocyte aggregates can be seen within venules at the inhibited sites, and they phagocytize BSA-anti-BSA complexes, their failure to migrate out of the vessels is due to the absence of complexes in the extravascular spaces. (Am J Pathol 78:159-170, 1975)