Major Allergens Sensitized by Thai Patients with Wheat Anaphylaxis
Sunday, March 4, 2018
South Hall A2 (Convention Center)
Nuntanut Rutrakool, MD, Surapon Piboonpocanun, PhD, Witchaya Srisuwatchari, MD, Orathai Jirapongsananuruk, MD, Nualanong Visitsunthorn, MD, Torpong Thongngarm, MD, Pakit Vichyanond, MD FAAAAI, Punchama Pacharn, MD
RATIONALE: Different phenotypes of patients with wheat anaphylaxis have been observed. The available investigations (skin prick test (SPT) and specific IgE (sIgE)) are helpful in diagnosis for particular group of patients. This study aims to identify the major allergens among different groups of wheat anaphylaxis in Thai population.
METHODS: Patients with history of wheat anaphylaxis were recruited. The SPT for wheat, sIgE for wheat and omega5-gliadin (ω5G) were performed. They were classified into 3 groups; peak sIgE ≥ 100 kAU/L (WAhi), peak sIgE < 100 kAU/L (WAlo), and wheat-dependent, exercise-induced anaphylaxis (WDEIA). Immunoblotting was done to identify major allergens in each group.
RESULTS: Thirty-six patients aged 1.7-20 years were enrolled. The numbers of patients in WAhi, WAlo, and WDEIA were 16 (44.5%), 13 (36%) and 7 (19.5%), respectively. Atopic dermatitis was significantly affected WAlo compared to WDEIA (P=0.044). Neurological symptoms were significantly found in WDEIA compared to WAhi and WAlo (P=0.001). The numbers of patients who have positive SPT were not different between groups, but larger SPT was found in WAhi. SIgE for wheat and ω5G levels were significantly lower in WAlo (median 6.5, 2.6 kAU/L) and WDEIA (median 0.4, 3.1 kAU/L) compared to WAhi (median 222, 20.8 kAU/L). Interestingly, in WDEIA, sIgE for ω5G level was higher than sIgE for wheat. Immunoblotting showed sIgE of WA bound mostly 30-48 kDa gliadins while sIgE of WDEIA bound both 30-48 kDa gliadins and 70-80 kDa glutenins.
CONCLUSIONS: Major allergens for WA are 30-48 kDa gliadins while WDEIA are 30-48 kDa gliadins and 70-80 kDa glutenins.