Tissue levels of Alternaria allergen Alt a 1 reflect recurrence of refractory airway diseases.To the Editors,The quantification of Alternaria allergen in the local airway tissues is quite unknown, while Alternaria alternata is a widespread fungal species in the airway discharge and known to be one source of aeroallergens which contribute to development of asthma (1,2) and chronic rhinosinusitis (CRS) (3,4). We have recently been established the method for quantifying allergen in the local airway tissues (5). Since Alt a 1 is the main sensitizing allergen component and it is useful in diagnosis and immunotherapy (6), we have measured the levels of Alt a 1 in the local airway tissues and examined whether the quantification of Alt a 1 could reflect the allergic airway inflammation and recurrence of refractory allergic respiratory diseases.We obtained nasal polyp tissues from 64 patients with refractory CRS with nasal polyp (CRSwNP) and homogenized them. The tissue levels of Alt a 1, Alternaria specific IgE, IL-4, IL-5, IL-13, IL-33, galectin-10 in nasal polyp supernatant were measured. The tissue eosinophil numbers were also counted. We searched for the existence of postoperative nasal polyp for in the medical records in order to examine the usefulness of Alt a 1 as a predictor of nasal polyp recurrence after surgery.First, we measured the levels of Alt a 1 in airway tissues and ROC curve based on nasal polyp recurrence data was developed, with a cut-off value of 1.84 ng/g of local Alt a 1 (AUC = 0.75, Figure 1A). According to the presence or absence of nasal polyp recurrence, patients were divided into two groups and the levels of Alt a 1 were compared. The tissue levels of Alt a 1 were significantly higher in recurrence group. (p < 0.01, Figure 1B). Kaplan–Meier curves at the cut-off point of the local tissue Alt a 1 levels shows that of the recurrence-free rate in the low- Alt a 1 group is lower rate than that in the high- Alt a 1 group (p < 0.05, log-rank test, Figure 1C).We further measured Alternaria specific IgE level in the airway tissues in order to determine the sensitization to Alt a 1. The levels of Alt a 1 in nasal polyps had a significant positive correlation with the levels of Alternaria specific IgE (rs=0.56, p<0.0001, Figure 2A). We divided patients into two groups according to the local tissue levels of local Alt a 1, and compared the levels of Alternaria-specific IgE antibody between two groups. As result, the levels of Alternaria-specific IgE antibody were significantly higher in high- Alt a 1 group than those in low- Alt a 1 group. (p<0.0001, Figure 2B)Fungi induce alarmins which promote the development of type 2 response via increase in the number of eosinophils, accompanied by an increase in innate lymphoid cells (ILCs) and effector cells such as mast cells (7,8). We measured the level of type2 cytokines (IL-4, IL-5, IL-13) in the airway tissues and analyzed between high- and low- Alt a 1group respectively in order to assess the contribution of type2 inflammation to local allergic reaction to Alternaria alterna . Patients were divided into two groups according to the tissue levels of Alt a 1. The levels of IL-4 were significantly higher in high- Alt a 1 group than those in low- group. IL-4 plays an essential role in IgE class switching and production. The levels of IL-5 and IL-13 didn’t show significant difference but tended to be higher in the high- Alt a 1 group. (Figure 2C)Epithelial cells which activated by antigens induce proinflammatory responses due to the production of alarmins. Alternaria alternataexposure evokes IL-33 secretion and extracellular DNA from the airway epithelium, which functions as an alarmin to stimulate type 2 immunity in airway diseases (9). The levels of IL-33 in NPs were significantly higher in high- Alt a 1 group than those in the low- group (Figure 2C). Galectin-10 is relatively eosinophil specific protein which released from cytolytic cells is expected to be a biomarker for activated eosinophils in eosinophilic inflammatory diseases (10). The levels of galectin-10 in the airway tissues were significantly higher in high Alt a 1 group than low group. (Figure 2C)This is the first report to have quantified the levels of Alt a 1 in airway tissues and investigated the association to the type2 molecules of allergic reaction. Alternaria alterna is common fungi as an environmental antigen and the increase in the local tissue levels of Alt a 1 were associated with the recurrence of refractory CRSwNP. These results might explain the tissue levels of Alt a 1 can be a predictor of recurrence for refractory respiratory airway disease.

Background: In allergic inflammation, the cells existing in the mucosa take up antigens and present them to produce specific IgE, but there is no clinical study that quantifies antigens that cause allergies in local tissues. Fungi can induce the formation of nasal polyps via epithelial damage and type-2 inflammation. Aspergillus fumigatus is the most common environmental allergen; however, the involvement of its specific antigens in local allergic reactions in nasal polyps has not yet been reported. Objective: To investigate local allergic reactions to the Aspergillus fumigatus antigen, Asp f 1 in patients with CRSwNP. Materials and Methods: Nasal polyp tissues were collected from 103 patients with CRSwNP during surgery and homogenized. Tissue eosinophil counts and Asp f1, Aspergillus-specific IgE, type 2 cytokines and galectin-10 levels were measured in nasal polyps. Results: Eighteen cases (15.9%) of 103 patients were positive for Asp f 1 and were divided into two groups based on Asp f 1 levels. Asp f 1 levels positively correlated with Aspergillus-specific IgE levels (r =0.68, p <0.01). Aspergillus-specific IgE (p <0.01) levels in nasal polyps were significantly higher in the high Asp f 1 group than in the low Asp f 1 group although no significant differences were observed in IgM levels between these groups. Furthermore, Asp f 1 levels positively correlated with tissue IL-4 levels (r =0.85, p <0.0005) or tissue galectin-10 levels (r =0.54, p<0.01). Conclusion: This is the first study to quantify the levels of Aspergillus fumigatus antigen in the nasal polyps of patients with CRSwNP. The presence of Asp f 1 might explain the local type 2 allergic reaction to Aspergillus fumigatus in CRSwNP.