Biocompatibility of silicone implants.

Polydimethylsiloxane has been considered immunologically inert, and previous work seems to have established that the production of circulating antibodies does not occur in response to its implantation. We have investigated the possibility of a cellular immune response to implanted silicone. We have observed histologically that the cellular response to polydimethylsiloxane in sensitized guinea pigs is consistent with a cellular immune reaction. Further studies with EM and XES have demonstrated intracellular silicon in the Golgi apparatus, rough endoplasmic reticulum, and at both ends of cytoplasmic bridges between macrophages and lymphocytes. All of these findings fit with the hypothesis that the cells are processing a silicon-containing complex as an antigen. Finally, macrophage migration inhibition studies have shown evidence of a cellular immune phenomenon. Further studies are planned to characterize the nature of the sensitizing complex and to attempt to confirm the migration inhibition studies in vivo.