Prior studies have suggested abnormalities of
serum proteins, including
paraproteins, in women with
silicone implants but did not control for the presence of
connective-tissue disease (CTD). This retrospective case-control study, performed in tertiary-care academic centers, assessed possible alterations of
serum proteins, including
paraproteins, in such a population. Seventy-four women with
silicone implants who subsequently developed CTD, and 74 age-matched and CTD-matched women without
silicone implants, were assessed in the primary study; other groups were used for additional comparisons. Routine
serum protein determinations and high-sensitivity
protein electrophoresis and immunofixation electrophoresis were performed for detection of
paraproteins. Women with
silicone implants, either with or without CTD, had significantly lower serum total
protein and alpha1-globulin, alpha2-globulin,
beta-globulin,
gamma-globulin, and
IgG levels compared with those without
silicone implants. There was no significant difference, however, in the frequency of
paraproteinemia between women with
silicone implants and CTD (9.5%) and age-matched and CTD-matched women without
silicone implants (5.4%) (odds ratio, 1.82; 95% confidence interval, 0.51-6.45).
Paraprotein isotypes were similar in the two groups, and the clinical characteristics of the 13 women with
paraproteinemia were comparable with an independent population of 10 women with
silicone breast implants, CTD, and previously diagnosed
monoclonal gammopathies. In summary, this first comprehensive study of
serum proteins in women with
silicone implants and CTD found no substantially increased risk of
monoclonal gammopathy. Women with
silicone implants, however, had unexpectedly low
serum globulin and
immunoglobulin levels, with or without the subsequent development of CTD. The causes and clinical implications of these findings require further investigation.