Background: Although food allergy is common in children, rice allergy is unusual in Western cultures.
Objective: To report a case of T-cell-mediated rice intolerance in an 11-month-old girl.
Methods: To evaluate the intolerance to rice in this patient, a graded rice food challenge was performed. To examine the immunologic reactivity to rice, in vitro lymphoproliferative responses and cytokine synthesis of rice-stimulated peripheral blood lymphocytes (PBLs) was performed. Subsequently, skin patch testing to rice and other foods was performed.
Results: Allergy skin prick test results were negative for rice and positive for egg, milk, and soy. Specific IgE antibodies to rice, egg, peanut, wheat, walnut, codfish, milk, soybean, corn, shrimp, scallops, and clams were undetectable. Results of a single-blind rice food challenge were positive, manifested by emesis that persisted for more than an hour and required intravenous hydration. In vitro lymphoproliferation by the patient's PBLs to rice stimulation was positive. In addition, cytokine synthesis of interferon-gamma, interleukin 10 (IL-10), tumor necrosis factor a, and IL-5 by the patient's rice-stimulated PBLs was elevated, indicating a TH1/TH2 cell response to rice. Endoscopy revealed normal esophageal, gastric, and duodenal mucosa; a biopsy specimen revealed mild esophagitis. Duodenal explant T cells were initially established by stimulation with rice and IL-2. After a 2-day rest, the lymphocytes were restimulated with rice for 7 days and revealed increased interferon-gamma and IL-5 synthesis. Twenty billion colony forming units of Lactobacillus GG were added to the patient's diet twice daily. After 6 weeks, rice rechallenge resulted in emesis within 1 hour. Results of patch testing were positive to rice, wheat, and barley but negative to soy, which the patient tolerated on food challenge.
Conclusions: Although this patient did not demonstrate IgE antibody to rice, TH1/TH2 cell-mediated responses to rice were detected, and the patient experienced significant morbidity. Patch testing for gastrointestinal food allergies may be useful when the food specific IgE antibody is negative. Probiotic therapy in this patient did not ameliorate her sensitivity to rice, and food elimination remains the only reliable treatment for TH1/TH2-mediated food hypersensitivity.