Endotypes of pollen-food syndrome in children with seasonal allergic rhinoconjunctivitis: a molecular classification.

BACKGROUND: Pollen-food syndrome (PFS) is heterogeneous with regard to triggers, severity, natural history, comorbidities, and response to treatment. Our study aimed to classify different endotypes of PFS based on IgE sensitization to panallergens. METHODS: We examined 1271 Italian children (age 4-18 years) with seasonal allergic rhinoconjunctivitis (SAR). Foods triggering PFS were acquired by questionnaire. Skin prick tests were performed with commercial pollen extracts. IgE to panallergens Phl p 12 (profilin), Bet v 1 (PR-10), and Pru p 3 (nsLTP) were tested by ImmunoCAP FEIA. An unsupervised hierarchical agglomerative clustering method was applied within PFS population. RESULTS: PFS was observed in 300/1271 children (24%). Cluster analysis identified five PFS endotypes linked to panallergen IgE sensitization: (i) cosensitization to ≥2 panallergens ('multi-panallergen PFS'); (ii-iv) sensitization to either profilin, or nsLTP, or PR-10 ('mono-panallergen PFS'); (v) no sensitization to panallergens ('no-panallergen PFS'). These endotypes showed peculiar characteristics: (i) 'multi-panallergen PFS': severe disease with frequent allergic comorbidities and multiple offending foods; (ii) 'profilin PFS': oral allergy syndrome (OAS) triggered by Cucurbitaceae; (iii) 'LTP PFS': living in Southern Italy, OAS triggered by hazelnut and peanut; (iv) 'PR-10 PFS': OAS triggered by Rosaceae; and (v) 'no-panallergen PFS': mild disease and OAS triggered by kiwifruit. CONCLUSIONS: In a Mediterranean country characterized by multiple pollen exposures, PFS is a complex and frequent complication of childhood SAR, with five distinct endotypes marked by peculiar profiles of IgE sensitization to panallergens. Prospective studies in cohorts of patients with PFS are now required to test whether this novel classification may be useful for diagnostic and therapeutic purposes in the clinical practice.

Characteristics of patients with allergic polysensitization: the POLISMAIL study.

BACKGROUND: The natural history of respiratory allergy is commonly characterized by a worsening of symptom severity, frequent comorbidity of rhinitis and asthma, and polysensitization to aeroallergens. The polysensitization phenomenon starts since childhood and is rare to find monosensitized adult patients. However, there are few studies investigating the characteristics of polysensitized patients. METHODS: This study was performed on a large cohort of patients with allergic rhinitis (assessed by ARIA criteria) and/or mild to moderate asthma (assessed by GINA). The kind and the number of sensitizations, their patterns, and the relation with quality of life (QoL) measured by the Juniper's RQLQ guestionnaire, were evaluated. RESULTS: Globally 418 patients (50.2% males, 49.8% females, mean age 26.4 years, range 3.5-65 years, 64 smokers, 371 non-smokers) were enrolled: 220 had allergic rhinitis alone, and 198 allergic rhinitis and asthma. The mean number ofsensitizations was 2.6. Three hundred-five patients (73%) had persistent rhinitis (PER), 220 of them with moderate-severe form. There was no significant derence in rate of rhinitis and asthma in monosensitized or polysensitized patients. Most patients were sensitized to pollens, whereas only 24.2% of them were sensitized to perennial allergens. Polysensitization was significantly associated with some issues of QoL, confirming previous findings, but not with number ofsensitizations. CONCLUSIONS: This study provides data confirming for poly-sensitized patients the relevance of ARIA classification of AR. PER is the most common form of AR in this cohort, symptoms are frequently moderate-severe, and asthma is present in about the half of patients with AR.