Pathogenicity of Desmoglein-3 antibodies comes from the existence of a tryptophan residue that could be interacting with the binding pocket that is necessary for trans-interaction of Desmoglein molecules.
Desmoglein-3 antibodies' ability to cause disease stems from an amino acid, tryptophan, that fits into a specific site on the molecule, enabling it to interact with other Desmoglein molecules.