Involvement of Activation of Mast Cells via IgE Signaling and Epithelial Cell-Derived Cytokines in the Pathogenesis of Pollen Food Allergy Syndrome in a Murine Model.

Murine models to elucidate the pathogenesis of pollen food allergy syndrome (PFAS), characterized by oral hypersensitivity symptoms induced by specific foods in patients previously sensitized with a pollen, are lacking. The study aimed to examine PFAS pathogenesis in a novel murine model. Birch pollen-immunized mice were orally administered apple extract, and oral symptoms were evaluated based on oral rubbing frequency following the challenge. The birch pollen-immunized mice orally challenged with apple extract exhibited PFAS-like symptoms, including oral rubbing and positive reaction of swelling by the prick test. The apple extract administered with a protease inhibitor reduced the oral rubbing frequency, which was also significantly reduced in the immunized Fcer1a -/- and mast cell-deficient mice compared with the immunized control mice. The oral rubbing frequency, serum IgE levels, and Th2-cytokine production by the cervical lymph node cells were significantly reduced in the immunized Il-33 -/- and thymic stromal lymphopoietin receptor-deficient (Crlf2 -/-) mice as compared with the immunized wild-type mice. IL-33 and thymic stromal lymphopoietin involve the pathogenesis of PFAS. The apple-extract stimulation did not lead to increased Th2-cytokine production in the oral mucosa or number of group 2 innate lymphoid cells or eosinophils. PFAS involves an early-phase response by mast cell degranulation via IgE signaling after the cross-reactivity of Bet v 1-specific IgE and the food allergen, and exacerbation of allergic symptom via proteases in food; PFAS does not involve a late phase with local Th2/eosinophilic inflammation in the oral mucosa. This novel murine model might be used for elucidating the pathogenesis and assessing new therapeutic strategies for PFAS.

Epidemiological study of oral allergy syndrome in birch pollen dispersal-free regions.

BACKGROUND: Oral allergy syndrome (OAS) is an immediate allergy caused by a cross-reaction of highly homologous common antigens (pan-allergens) contained in fruits/vegetables and pollen. METHODS: A questionnaire was provided to 6824 outpatient visitors and serum levels of specific IgEs against crude antigens and pan-allergen components were measured to study the relationship between the prevalence of OAS and pollinosis in the Fukui Prefecture where there is almost no dispersal of birch pollen. RESULTS: The prevalence of OAS was 10.8%. The rate of pollinosis complication in the OAS group was 67.4%, and OAS was observed in 16.8% of pollinosis patients. Causative foods in order of frequency were melon, pineapple, kiwi fruit, peach, and apple. A significantly higher number of patients from the OAS group were positive for birch, alder, and timothy grass-specific IgE. The rate of positivity for anti-component IgE corresponding to pollen in OAS group was also significantly higher. Of 34 patients with OAS caused by eating apples, 28 (82.4%) were positive for Mal d1-specific IgE. Of the 52 patients with peach-induced OAS, 41 (78.8%) were positive for Pur p1-specific IgE. The concordance rates between crude antigen-specific IgE and anti-PR-10 component-specific IgE were 87.1% and 93.3% for apple and peach respectively. CONCLUSIONS: In regions where birch pollen is not dispersed, OAS patients have a significant association with the onset of Bet v1-associated allergy. Anti-PR-10 component IgE was useful in diagnosing OAS, and crude antigen-specific IgE was also associated with apple and peach allergies.

Long-term sublingual immunotherapy for Japanese cedar pollinosis and the levels of IL-17A and complement components 3a and 5a.

Allergen-specific immunotherapy is the only treatment that can alter the natural course of allergic disease. We performed long-term sublingual immunotherapy (SLIT) for patients with seasonal allergic rhinitis caused by Japanese cedar pollen (SAR-JCP), screened molecules as candidate biomarkers, and investigated serum IL-17A and complement components 3a (C3a) and C5a in order to evaluate whether these molecules show changes correlated to symptom scores. In this study, we found that the long-term SLIT reduced the serum levels of IL-17A and C3a and C5a. The levels of C3a in the patients significantly decreased from year 1 compared with those at the baseline, and their levels of IL-17A significantly decreased from year 2 compared with those at baseline. The levels of IL-17A, C3a, and C5a at year 4 of SLIT were significantly lower than not only those at baseline, but also those at year 1. A significant positive correlation was found between the symptom medication scores and the levels of IL-17A at year 4. The symptom medication scores in the group in which IL-17A levels decreased at year 4 were significantly lower than those in the group without such a decrease. The serum level of IL-17A might prove useful as a biological parameter to ascertain the effectiveness of SLIT for patients with SAR-JCP. It is necessary to produce new therapeutics for non-responders in whom serum IL-17A levels are still higher against long-term SLIT.

Efficacy of oral olopatadine hydrochloride for the treatment of seasonal allergic rhinitis: A randomized, double-blind, placebo-controlled study.

Adequate treatment is critical for maintaining a good level of quality of life (QOL) during the pollen season in patients suffering from seasonal allergic rhinitis (SAR). Olopatadine, a histamine H(1)-receptor antagonist, has been approved in the United States and Europe for the treatment of AR and allergic conjunctivitis as a nasal spray and an ophthalmic solution, respectively. We conducted a randomized, double-blind, placebo-controlled study to determine whether orally administered olopatadine for prophylactic purposes might also be effective for the control of nasal allergy symptoms, especially nasal congestion, in patients with SAR due to Japanese cedar pollen (SAR-JP). A total of 110 patients with SAR caused by JP were randomized to the treatment. The subjects recorded their nasal and ocular allergic symptom scores in a diary, and their QOL was assessed by the Japanese version of the Rhinoconjunctivity Quality of Life Questionnaire. Treatment with oral olopatadine significantly suppressed sneezing (p < 0.001), rhinorrhea (p < 0.001), and nasal congestion (p < 0.05). The total QOL score during the peak JP season was superior in the olopatadine group than in the placebo group (p < 0.05). However, orally administered olopatadine did not exert any significant effect against eye itching and watering of the eyes, unlike olopatadine nasal spray. Treatment with olopatadine tablets yielded superior QOL scores in the domains of usual daily activities and outdoor activities when compared with placebo. No serious adverse effects of the treatment were reported during the study period. These results suggest that oral olopatadine treatment may be a useful alternative treatment strategy for AR.

Apolipoprotein A-IV is a candidate target molecule for the treatment of seasonal allergic rhinitis.

BACKGROUND: Allergic rhinitis is a global health problem that causes major illnesses and disability worldwide. Allergen-specific immunotherapy (SIT) is the only available treatment that can alter the natural course of allergic disease. However, the precise mechanism underlying allergen-SIT is not well understood. OBJECTIVE: The aim of the current study was to identify protein expression signatures reflective of allergen-SIT-more specifically, sublingual immunotherapy (SLIT). METHODS: Serum was taken twice from patients with seasonal allergic rhinitis caused by Japanese cedar: once before the pollen season and once during the season. A total of 25 patients was randomly categorized into a placebo-treated group and an active-treatment group. Their serum protein profiles were analyzed by 2-dimensional electrophoresis. RESULTS: Sixteen proteins were found to be differentially expressed during the pollen season. Among the differentially expressed proteins, the serum levels of complement C4A, apolipoprotein A-IV (apoA-IV), and transthyretin were significantly increased in SLIT-treated patients but not in placebo-treated patients. Among these proteins, the serum levels of apoA-IV correlated with the clinical symptom-medication scores (r = -0.635; P < .05) and with quality of life scores (r = -0.516; P < .05) in the case of SLIT-treated patients. The amount of histamine released from the basophils in vitro was greatly reduced after the addition of recombinant apoA-IV in the medium (P < .01). CONCLUSION: Our data will increase the understanding of the mechanism of SLIT and may provide novel insights into the treatment of allergic rhinitis.