Antibodies to silicone elastomers and reactions to ventriculoperitoneal shunts

Silicone elastomers used to make medical implants and prostheses are generally believed to be biologically inert. However, we have seen two patients who showed severe, apparently immunemediated, reactions to ventriculoperitoneal (VP) shunts. We used an enzyme-linked immunosorbent assay in which Silastic tubing served as the solid-phase antigen to test serum from the two patients, five other VP shunt patients without inflammatory reactions, and nine healthy adults. IgG binding to Silastic tubing was consistently higher in the two patients than in the healthy or patient controls. The IgG seemed to be binding specifically, since IgG Fab fragments also bound to the tubing, and preincubation of serum with Silastic or silylated proteins removed most of the activity. These findings show that specific immune reactivity to elastomers of polydimethylsiloxane can develop in human beings.