“…Antibodies to carbohydrate antigens and bacterial polysaccharides arc usually IgG2 [20,21], while antibodies to ovalbumin, gliadin, cow's milk and other foods are mostly of the IgG4 subclass [7,22,23]. Moreover, it has been proposed that elevated specific IgG4 antibodies re flect prolonged exposure to the antigen occurring in the intestinal tract [4,9,23,24], This an important statement because of the fact that Aspergillus species frequently con taminate foods [25]; therefore one may speculate that the intestinal route of sensitization may be responsible for the high level of IgG4 antibodies in this group of patients as well as the high IgG4 antibodies levels (although less marked) in the atopic and normal groups.…”