763:
Long-Term Effect of Combined Therapy of Oral Immunotherapy and Japanese Traditional Medicine Kakkonto on Food Allergy Mice
Monday, March 5, 2018
South Hall A2 (Convention Center)
Yuka Nagata, Ph.D., Takeshi Yamamoto, Ph.D., Makoto Kadowaki, Ph.D.
RATIONALE:

Kakkonto (KKT), a traditional Japanese herbal medicine, enhances the therapeutic effect of oral immunotherapy (OIT) in a murine food allergy model, which is attributed to the induction of colonic regulatory T cells. This combined therapy (OIT+KKT) is currently undergoing clinical trial. We demonstrated the long-term effect of OIT+KKT that persists after completing the therapy to further clarify the utility of this therapy for clinical use.

METHODS:

An experimental OIT treatment for FA mice with already established OVA-induced allergic diarrhea was performed with an oral administration of increasing doses of heated OVA for 8 days. KKT was orally administrated 1 h before each oral heated OVA treatment for a combined therapy with OIT. After the completion of the therapies, mice were followed–up for 3 weeks and rechallenged to assess the sustained effect of the therapy. Plasma OVA-specific IgE and IgG1 levels were measured during the discontinuation phase.

RESULTS:

The occurrence of allergic diarrhea still remained lower in OIT+KKT-treated mice than OIT- treated mice even after completing the therapies. After discontinuation for 3 weeks, all of vehicle-treated mice and OIT-treated mice exhibited allergic diarrhea, whereas the occurrence of diarrhea was suppressed to 63% in OIT+KKT-treated mice (P<0.01, n=8). In the OIT+KKT treated mice, plasma OVA-specific IgG1 levels were increased compare to non-treated FA mice.

CONCLUSIONS:

OIT+KKT induces sustained suppression of food allergic symptoms. OIT+KKT-included colonic regulatory T cells may be involved in the sustained effect. These findings suggest that the combined therapy with OIT+KKT is a useful therapy for FA.