Lymphocytic subpopulations exposed to silicone in vitro: Cytofluorimetric analysis

The late onset of typical symptoms of autoimmune disease in patients with silicone prostheses might be due to the fact that such implants elicit in the host an immune reaction responsible for the observed clinical and laboratorial pictures. The study of lymphocytic subpopulations by flow cytometry can be useful to better understand the pathogenesis of such clinical occurrences. Some experiments have been performed to evaluate qualitative and quantitative alterations in lymphocytes exposed in vitro to silicone hydrogel. After 30', 2h, 24h and 48h culture, lymphocytes have been analyzed in flow cytometry, using selective monoclonal antibodies of B lymphocytes, T lymphocytes and natural killer cells and, within the T subpopulation, helper/inducer, cytotoxic/suppressor and activated T cells. Although no statistically significant difference between controls and treated samples has been noticed, after 48h there is a mild activation, indicated by the increase of some cell subpopulations, especially T lymphocytes (CD3) and T helper/inducer (CD4) expressing class II MHC molecules (HLA-DR), and CD 16 natural killer cells. Such results, obtained after a short exposition time to silicone, sustain the hypothesis of cellulo-mediated immunity involvement. However more complex and eventually in vivo experiments are required.