Cytokine production in children outgrowing hen egg allergy

Approximately 40 to 80% of egg-allergic children outgrow egg allergy after 2 to 5 years.

To detail the immunologic mechanisms involved in the development of tolerance to egg proteins, the balance between interleukin 4 (IL4) and interferon-gamma (IFN-gamma) synthesis in patients with active atopic dermatitis allergic to hen egg and in those outgrowing hen egg allergy was evaluated.

A marked increase in IL4 and a decrease in IFN-gamma synthesis by peripheral blood lymphocytes following ovalbumin (OVA) specific in vitro stimulation was observed in active atopic dermatitis. In contrast, OVA-induced IL4 synthesis in patients in remission was comparable to that in normal individuals. An intriguing finding was higher production of IFN-gamma by lymphocytes from ovalbumin-insensitive patients in remission as compared to normal individuals following antigen stimulation, although cell proliferation in OVA-stimulated lymphocytes was reduced in patients during remission.

OVA antigen may be capable of inducing a population of Th1-type cells to produce cytokines such as IFN-gamma, resulting in suppression of Th2-type responses, i.e. IL4 secretion. We speculate that the changes in the balance of relevant antigen-induced cytokine synthesis seen in such patients may be causally associated with the improvement in their clinical status.