Serum proteins and paraproteins in women with silicone implants and connective tissue disease: a case–control study
1 Department of Laboratory Medicine, Clinical Center, NIH, DHHS, 9000 Rockville Pike, Bethesda, MD 20892, USA
2 Environmental Autoimmunity Group, National Institute of Environmental Health Sciences, NIH, DHHS, 9000 Rockville Pike, Bethesda, MD 20892, USA
3 Association of Public Health Laboratories, 8515 Georgia Avenue, Suite 700, Silver Spring, MD 20910, USA
4 Division of Rheumatology, Department of Medicine, University of Michigan Medical School, 101 Simpson Drive, Ann Arbor, MI 48109, USA
5 Division of Rheumatology, Department of Internal Medicine, University of Utah Medical Center, 50 North Medical Drive, Salt Lake City, UT 84132, USA
Arthritis Research & Therapy 2007, 9:R95 doi:10.1186/ar2295Published: 17 September 2007
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 α1-globulin, α2-globulin, β-globulin, γ-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.