IgE-dependent killing of Brugia malayi microfilariae by human platelets and its modulation by T cell products.

Platelets isolated from patients infected with filariasis were cytotoxic for microfilariae in vitro. Moreover, platelets from normal donors acquired killing properties in the presence of serum from infected individuals. The humoral factor involved in this cytotoxic process was shown to be IgE. This IgE-dependent cytotoxicity of platelets was strongly inhibited by antigen-stimulated T lymphocyte supernatants from filarial patients.