Evidence for the involvement of IgE-basophil system in acute serum sickness.

The role of the basophils in acute serum sickness of rabbits was examined by monitoring daily the absolute number of basophils before, during and after the disease period. After antigen (bovine serum albumin, BSA) elimination, levels of serum IgE and in vitro basophil degranulation in the presence of BSA were determined. The results showed that the onset of glomerular lesions depends upon the simultaneous occurrence of circulating immune complexes greater than 19 S and of an in vivo basophil depletion--probably equivalent to degranulation--reaching 70% of the pre-disease number. Post-disease antigen-dependent in vitro degranulation of the basophils and levels of serum IgE anti BSA did not prove to be good indexes of basophil sensitization. Our data suggest that basophils are instrumental at early stages of the deposition of immune complexes, most probably through their sensitization by membrane-bound IgE antibodies.