| Research Abstract |
Many cases of contact allergy due to dental metals have been reported, and several in vitro or in vivo tests have been used for screening of the allergenic epitopes. So we evaluated the mercury sensitization by Mouse Ear Swelling Test (MEST). And determined the lymphocyte stimulation for screening method of metal allergy in humans, and the following results were obtained. (1) MEST was a simple screening method for detecting sensitization of metals by mouse ear thickness. Positive response of allergy was obtained in mercury levels caused light swelling. But any positive sensitization response was not seen in case of repeat induction with non-inflammatory low concentration, or in case of high level induction with skin damage. This depression of mercury sensitization might be caused by immunological tolerance. (2) The lymphocyte sitmulation tests of mercury, nickel, chromium, cobalt, gold and titanium were performed in subjects with or without experience of metal allergy, Cobalt, chromium
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, gold and titanium caused positive proliferation in patch test-positive subjects, and the stimulation index (SI) values were lower than 180 in patch test-negative subjects. But in case of mercury and nickel, the SI values of all subjects were higher than 181. So the T-cells of all subjects might be sensitized to mercury and nickel because those metals were used widely in daily tools. The positive response in the lymphocyte stimulation test might also be caused by immunological tolerance, even if the subjects showed a negaive response in vivo. Therefore the lymphocyte stimulation test was not a sufficiently accurate method in mercury and nickel hupersensitivity. (3) The functional test of lymphocyte cells was determined after activation with metal antigen. Cell surface differentiation antigen CD4 (Helper subset) and CD8 (Suppressor subset) of T-lymphocyte did not show many changs, but cell surface Interleukin-2 (IL-2) receptor was increased in lymphocyte with allergy experience. Then the y-Interferon (y-IFN) and IL-2 activity in culture supernatant were increased extremely in subjects with positive reaction in vivo. So these lymphocyte functions might be able to distinguish the allergy expression from depression caused by immunological tolerance. It should be shown in future studies that these test might be useful for the screening method of hypersensitivity to dental metals. Less
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