Dr. Patrick J. O’Leary
received this information on March 19, 1993
This study was funded by
the top five breast implant manufacturers.
March 18, 1993
FDA TALK PAPER:
NEW IMMUNOLOGY STUDIES ON SILICONE GEL
Two recent animal studies have shown that silicone gel of the type used in breast implants can
act as an immune system adjuvant. That is, it can enhance the ability of the animals’ immune systems to produce antibodies
to an antigen (a substance that stimulates the body to produce antibodies).
FDA believes that these studies confirm the possibility that there may be a link between silicone
gel—filled breast implants and autoimmune-like disorders, but the studies do not establish the connection with certainty,
particularly since they were designed to intentionally stimulate the immune response by mixing a known antigen with the silicone.
More research will be needed before the relevance of these studies to women with breast implants can be established. Some
of this research is already underway.
The two new studies —— one conducted in New York state by Dr. John Naim and his colleagues
and the other by Dow Corning Corporation, a supplier of silicone gel for implants, show for the first time that silicone gel
can act as an adjuvant. (A study in 1974 had shown that some of the chemical constituents of silicone gel have adjuvant properties.)
In the new studies, silicone gel was blended with liquid silicone and a known antigen and injected into the animals. The antigen
alone would have been expected to produce an immune response, but the immune response was strongly increased by the silicone
gel. The study by Dr. Naim will be published on March 22 in the journal Immunological Investigations.
Responding to the studies, FDA Commissioner David A. Kessler said, “We’ve been concerned
for a long time that silicone gel might provoke an immune response in at least some women. That’s one of the reasons
we decided to restrict the availability of these devices. These new studies are consistent with that concern, although they
certainly don’t prove the implants can cause immune—related disorders.”
Based on these studies, FDA will require breast implant manufacturers to add information about
the possible connection between the implants and immune-related disorders to the informed consent documents for women receiving
breast implants under clinical studies.
FDA’s advice to women who already have the implants remains the same as in the past. The
agency recommends that any woman with implants be alert to the symptoms of these disorders, and that she consult her regular
doctor if she has symptoms that don’t subside. These complaints could be indicators of a variety of health problems,
not just immune-related disorders. Depending on the situation, her doctor may refer her to a rheumatologist or other type
of specialist for further evaluation.
The symptoms of these disorders include pain and swelling of joints; tightness, redness or swelling
of the skin; swollen glands or lymph nodes; unusual and unexplained fatigue; swelling of the hands and feet; and unusual hair
loss. People who have immune-related disorders, which are relatively rare, generally experience a combination of these and
Questions have also been raised about whether the new studies addressed the safety of other types
of implants made with silicone. Most of the silicone used in a variety of implanted devices, such as shunts, catheters, artificial
joints and facial implants, consists of relatively hard silicone elastomer (“silicone rubber”) rather than gel.
Silicone rubber was not investigated in these studies, and there is no evidence to date that it has immune system adjuvant