ABSTRACT
Abstract ..................................................................................................................185 7.1 Background ..................................................................................................186 7.2 Molecular Basis of Antigen-Specific Tolerance Induction .........................187 7.3 Experimental Hyposensitization on the T Cell Level..................................188 7.4 Experimental Hyposensitization in Animals................................................189 7.5 Hyposensitization in Humans ......................................................................189 7.6 Clinical Observation of Nickel Tolerance Induced
by Orthodontic Devices ...............................................................................190 7.7 Nickel Released from Orthodontic Devices
in Vitro
and
in Vivo
...............192 7.8 Summary ......................................................................................................195 7.9 Conclusions ..................................................................................................196 7.10 Acknowledgment..........................................................................................197 References..............................................................................................................197
A number of observations made in animals first, and then in humans, led to the hypothesis that systemic delayed hypersensitivity reactions can be suppressed following prior oral exposure to haptens under certain specific conditions, i.e., if lowlevel, prolonged antigenic contacts occurred during childhood and adolescence of immunologically naive individuals (Chase-Sulzberger phenomenon) (Chase, 1946). Since the late 1980s, dermatologists and immunologists have endeavored to confirm such a correlation, in particular since the prevalence of nickel allergic hypersensitivity (NAH) was seen to increase steadily in the young population, a phenomenon
