Complement-mediated polymorphonuclear leukocyte aggregation in vitro induced by levamisole.

In previous studies, we have demonstrated that levamisole was able to induce the activation of the alternate complement pathway as well as polysaccharide inductors inulin and zymosan. The knowledge that the activation of complement and the generation of C5a is followed "in vitro" and possibly "in vivo" by a rapid granulocyte aggregation suggested to study the levamisole-dependent changes of granulocyte aggregation "in vitro". Our findings showed that levamisole and inulin could induce granulocyte aggregation and granule-associated enzyme release through a specific triggering mechanism of complement activation. The possibility that a complement-induced granulocyte aggregation "in vivo" could operate in drug-dependent neutropenia was proposed.