Evidence for circulating IgE complexes in food allergy.

Antigen entry and the formation of immune complexes occur in atopic subjects after food ingestion. We have studied patients with asthma, eczema and arthralgia and we were able to detect the presence of IgE immune complexes and the antigen entry from the gut before and after food challenge. Food allergic subjects showed, after food challenge, the presence of IgE and IgG immune complexes, which correlates with the subsequent occurrence of symptoms. Both the symptoms and the appearance of IgE immune complexes could be prevented by pretreatment with oral sodium cromoglycate (SCG). IgE immune complexes were isolated by an isokinetic ultracentrifugation gradient and the components were analyzed for antigen-specific IgE and IgG as well as free antigen levels. The observation that SCG reduces antigen entry, the appearance of IgE immune complexes and the occurrence of symptoms point to the central role of IgE in the intestinal mucosa.