SILICATE ANTIBODIES IN WOMEN WITH SILICONE BREAST IMPLANTS - DEVELOPMENT OF AN ASSAY FOR DETECTION OF HUMORAL IMMUNITY

Silicon, in the form of sodium silicate (Na2SiO3), adsorbed onto bovin e serum albumin (BSA)-precoated plates served as the solid-phase antig en in an enzyme immunoassay to detect silicate-reactive antibodies in the plasma of 30 symptomatic women with silicone breast implants, 91 a symptomatic women with silicone breast implants, 50 healthy control wo men, and 52 women with rheumatic diseases and without silicone breast implants. Silicate-reactive antibodies of immunoglobulin G (IgG) or Ig M isotypes were detected in the plasma of 30% (12 of 40) of the sympto matic women with silicone breast implants; 9% (8 of 91) of the asympto matic women with silicone breast implants; 5% (1 of 20) of the women w ithout implants who had systemic lupus erythematosus; and 0% (0 of 32) of the women without implants who had either Sjogren syndrome, sclero derma, or rheumatoid arthritis. Only 2% (1 of 50) of the sera from the healthy control women contained silicate-reactive antibodies, Preincu bation of sera with silicate and eight other metal compounds (includin g SiO2) demonstrated that the IgG and IgM antibodies bound specificall y to silicate, because preincubation with Na2SiO3 inhibited more than 90% of the activity, whereas CrO3, Li2SO4, MgSO4, NiSO4, HgCl2, ZrOCl2 , BeSO4, and SiO2 failed to inhibit the IgG or IgM antibody binding to the silicate-BS8 plates. Furthermore, the F(ab')(2) portion and not t he Fc portion of the silicate-reactive IgG was reactive with BSA-bound silicate in the enzyme immunoassay. The assay for silicate-reactive a ntibodies was quantified by assigning arbitrary units to a standard cu rve composed of serial twofold dilutions of high-positive (ten times h igher than the cutoff) silicate antibody sera. This novel assay is a u seful method for detecting and quantifying humoral immune response to silicate.