The clinical cross-reactivity and immunological cross-antigenicity of wheat and barley.

BACKGROUND: Some patients with wheat allergy have been reported to show clinical cross-reactivity to barley. However, it is not clear whether the development of barley allergy in patients with wheat allergy is due to cross-antigenicity between wheat and barley. This study aimed to determine the clinical cross-reactivity and immunological cross-antigenicity of wheat and barley. METHODS: The results of barley oral food challenges (OFCs) were compared before and after oral immunotherapy (OIT) for wheat in nine patients with wheat allergy to estimate the clinical cross-reactivity of wheat and barley. Moreover, we performed enzyme-linked immunosorbent assay (ELISA) inhibition and immunoblotting inhibition using serum from seven patients allergic to wheat and barley. RESULTS: Nine patients who had positive barley-OFC results performed before OIT for wheat were all negative on barley-OFC performed after OIT. In ELISA inhibition, preincubation of serum from patients allergic to wheat and barley with a high barley extract concentration inhibited binding of IgE to wheat extract by less than 10%. On the other hand, wheat and barley extracts equally inhibited binding to barley sIgE at high concentrations. In the immunoblotting inhibition test, the spots of wheat were inhibited but weakly by barley extracts, and most of the spots of barley were inhibited even by low concentrations of the wheat and barley extract. CONCLUSIONS: We showed that barley allergy associated with wheat allergy is caused by cross-reactivity from wheat. The OIT for wheat is one of the promising options for barley allergy.

THE CASE OF A 14-YEAR-OLD BOY WHO EXPERIENCED ANAPHYLAXIS DUE TO JELLYFISH (MASTIGIAS PAPUA) INGESTION.

We report a case of jellyfish allergy diagnosed via an oral food challenge. A 14-year-old boy had no history of jellyfish stings and had been eating commercially available jellyfish products twice yearly for the past 5-6 years. Five minutes after eating a commercially available boiled jellyfish product (100g), he experienced nausea, wheezing, and erythema and had visited our hospital. We suspected an anaphylactic reaction and treated him with intramuscular adrenaline injection, corticosteroid and antihistamine infusions, volume resuscitation, and salbutamol sulfate inhalation, which resulted in an improvement of the symptoms. One-month later in our hospital, we administered an oral food challenge of the same boiled jellyfish product bought at the same grocery store to the patient. After ingesting 14g of boiled jellyfish, he experienced erythema, wheezing, nausea, and abdominal pain. Several reports have described anaphylaxis caused by the ingestion of jellyfish, but the allergens in jellyfish have not been analyzed. A skin prick test for poly-gamma-glutamic acid (PGA) which is a component of jellyfish stings was negative. This suggests that he was sensitized to some allergen other than PGA via a route different from that of jellyfish sting. Our skin prick test for several kinds of edible jellyfish suggests that allergenicity may be different for different jellyfish.