Silicone and scleroderma revisited

Silicone, a synthetic polymer considered to be a biologically inert substance, is used in a multitude of medical products, the most publicly recognized of which are breast implants. Silicone breast implants have been in use since the early 1960s for cosmetic and reconstructive purposes, and reports of autoimmune disease-like syndromes began appearing in the medical literature soon thereafter. Over the previous year, silicone implants have been suggested as playing a role in a new syndrome that encompasses a wide array of immune-related manifestations, termed ASIA ('Autoimmune Syndrome Induced by Adjuvant'). Scleroderma, a relatively rare connective tissue disease with skin manifestations and systemic effects, has also been described in association with silicone implantation and rupture. However, epidemiological studies and meta-analyses have failed to corroborate the clinical impression of silicone-induced scleroderma. The following review describes the mechanisms by which silicone may mediate autoimmunity in general, as well as the evidence for causal associations with more specific autoimmune syndromes in general, and scleroderma in particular.