Anaphylaxis to Pericarpium Zanthoxyli and Its Cross-Reactivity Between Nuts and Citrus
Sunday, March 6, 2016
South Exhibit Hall H (Convention Center)
Hong LI, MD, Ri Qi WANG, Xuan CHENG, Xi Ping Zhou, Jia Yin
Rationale: Pericarpium Zanthoxyli (PZ) belongs to Rutaceae family. Chinese name is "hua jiao". Anaphylaxis against PZ is unreported and it’s unknown about its cross-reactivity between nuts and citrus. 

Methods: Consecutive Patients were seen at the Allergy Center of PUMCH. Food allergy and food caused anaphylaxis diagnosis were based on clear clinical presentations and specific IgE evaluation (skin prick test and/or Immuno-CAP sIgE, pharmacia). Prick test agents were prepared from peel and seed of PZ. The allergenic profile of peel and seed of PZ was analysed by SDS-PAGE and immunoblotting (second antibody: Anti human IgE polyclonal antibody, Dakocytomation,Denmark A/S). Crossreactivities between PZ and pistachio, cashew , citrus were studied by ImmunoCAP RAST inhibition.

Results: Fifteen patients anaphylaxis against PZ were diagnosed. Thirteen out of 15 (13/15) patients coexist cashew allergy, 12/15 coexist pistachio allergy, 8/15 coexist kumquat or orange allergy. Prick tests to PZ seed, 10/10 patients showed 15-32mm; to PZ peel 3/10 showed 5-10mm, 7/10 showed <3mm. 5/5 nonallergic controls showed <3mm to both peel and seed. Serum sIgE for PZ seed, 13/13 patients were positive (3.3-66.5KUa/L). For PZ peel, 2/13 positive(0.96-1.48KUa/L) and 11/13 negative(<0.35KUa/L). On immunoblotting, sera from 6/7 patients recognized 11.3–12.5kD brands of PZ seed. RAST inhibition of PZ is 35.4-82.5% to cashew, 41.8-85.9% to pistachio, and 97.9-97.8% to orange. 

Conclusions: PZ seed causes PZ allergy. PZ can cause anaphylaxis and contains 11.3–12.5kD allergens able to trigger type I hypersensitivity reactions. Cross-reactivities were found between PZ seed and cashew, pistachio and citrus, showed different degree in different allergic patient.