Immunologic stimulation of T lymphocytes by silica after use of silicone mammary implants

Difficulties in showing the biologic activity of silicones in vitro have contributed to the controversy over effects of silicone mammary implants in vivo. We adapted a standard lymphocyte stimulation test to detect evidence of cellular immunity in patients with silicone gel implants. Initially, lymphocytes were harvested from 70 implant patients, 76 normal controls without implants or symptoms, and 18 patients with classic rheumatic disorders and without a history of silicone implants. The harvested lymphocytes were stimulated with PWM, PHA, Con A, and pharmaceutical grade colloidal silicon dioxide (silica). Implant patients showed increased SI compared to controls and those with rheumatic disorders. The mean SI of implant patients was 195.0 +/- 19.3, 18-fold that of normal controls (< 0.0001). Patients with rheumatic disease showed the same SI as controls (P = 0.3577). A follow-up study included 220 normal controls without implants, 942 silicone gel implant patients with demonstrable rheumatic symptoms, and 34 implant patients without symptoms at the time of the study. The average SI for the 220 normal controls was 10.0 +/- 0.41. Among the symptomatic implant women, 860 (91.3%) had SI significantly above those of the normal controls. Of these, 171 (18.2%) had SI between 25 and 50, 316 (33.5%) had SI between 50 and 100, and 373 (39.6%) had SI over 100. The data presented confirms that silicone implant patients respond immunologically to the silicon dioxide contained in mammary prostheses.