Complement (C5-a)-induced granulocyte aggregation in vitro. A possible mechanism of complement-mediated leukostasis and leukopenia.

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Abstract

Activated plasma complement will induce biphasic aggregation of human granulocytes dectable by standard nephelometric techniques. The responsible active component was suggested to be C5a by molecular weight and heat-stability assays; moreover, aggragating activity was ablated by anti-C5 but not anti-C3 antibodies. C5a prepared by trypsinization of purified C5 reproduced the aggregating activity of whole activated plasma, whereas plasma from a C5-deficient donor did not support aggregation. Embolization of granulocyte aggregates might be a previously unsuspected cause of leukostasis and pulmonary damage in various clinical situations where intravascular complement activation occurs.

Authors

P R Craddock, D Hammerschmidt, J G White, A P Dalmosso, H S Jacob