Tissue Reaction and Metal Sensitivity: An Animal Study

Abstract

An animal study is presented in which nickel sensitivity as determined by an in vitro test for leukocyte migration inhibition (LIF) is correlated with results of skin tests with NiCl₂ and with the degree of adverse tissue reaction to implanted stainless steel screws. Screws were implanted in the humeri of New Zealand white rabbits, one group of which received repeated injections of nickel chloride following an initial injection of nickel chloride in Freun dˆs adjuvant. All the injected rabbits became skin test positive to nickel and demonstrated LIF production in the presence of nickel chloride. Some of the injected rabbits, 6–9 weeks after implantation of the screws, developed an inability for leukocyte migration even when the cells were incubated only with saline and serum. the tissue reaction to screws in the nickel sensitive animals showed a significant increase in inflammatory cells and foreign body giant cells when compared with the reaction in nonsensitive animals. the most severe reactions, some of which included regions of necrosis, were seen in animals which developed the condition of no leukocyte migration in the LIF test. the correlation between skin test and LIF test results demonstrates the effectiveness of the LIF assay for sensitivity testing without the risk of sensitization associated with skin testing. the histological results support the hypothesis that the condition of no cell migration in the LIF test is diagnostic for severe reactions to implants associated with metal sensitivity.

Key Words:

• implant
• LIF
• Nickel
• Rabbit
• Screw
• sensitivity