Background: Legume allergy, mainly to lentils and chickpeas, is the fifth most common cause of food allergy in Spanish children. Serological cross-reactivity among legumes is frequent, but its clinical relevance is controversial. The aim of this study was to investigate the cross-reactivity among lentils, chickpeas, peas, white beans and peanuts and its clinical relevance in pediatric patients. Methods: Fifty-four children with clinical allergy to legumes were included. Cross-reactivity was evaluated by ELISA inhibition experiments and oral food challenges to legumes. SDS-PAGE immunoblots were conducted with raw and boiled legume extracts. Results: ELISA inhibition experiments demonstrated more than 80% inhibition with lentil, chickpea and pea extracts. Immunoblots performed with raw legume extracts (lentil, chickpea and pea) and individual sera revealed that more than 50% of the sera identified an allergen with approximately 50 kDa in all three legume extracts. In all three boiled extracts an intense band at approximately 50 kDa was visualized using a serum pool. The oral legume challenges demonstrated that 37 children (69%) were allergic to 2 or more legumes (median 3 legumes). The most frequent associations were allergy to lentils and chickpeas (57%), allergy to lentils and peas (54%) and allergy to lentils, chickpeas and peas (43%). Conclusions: In vitro inhibition experiments demonstrated a high degree of cross-reactivity among lentils, chickpeas and peas. Food challenges confirmed that clinical allergy to all three legumes is frequent in our cohort of Spanish children.

Background: Although allergy to Cannabis sativa was first reported over 40 years ago, the allergenicity has scarcely been studied. The objectives of this study were to investigate the frequency of sensitization to this plant, to analyze the clinical characteristics and allergenic profile of sensitized individuals and to identify the allergens involved. Methods: Five hundred and forty-five individuals in Spain attending allergy clinics with respiratory or cutaneous symptoms underwent a skin-prick test (SPT) with C. sativa leaf extract. The extract was characterized by SDS-PAGE and 2-dimensional electrophoresis. Specific IgE to C. sativa was measured in positive SPT individuals. The clinical and allergenic profiles of sensitized individuals were investigated and the most-recognized allergens sequenced and characterized by liquid chromatography-mass spectrometry/mass spectrometry. Results: Of this preselected population, 44 individuals had positive SPT to C. sativa (prevalence 8.1%). Prevalence was higher in individuals who were C. sativa smokers (14.6%). Two individuals reported mild symptoms with C. sativa. Twenty-one individuals from 32 available sera (65.6%) had positive specific IgE to C. sativa. Twelve sera recognized at least 6 different bands in a molecular-weight range of between 10 and 60 kDa. Six of them recognized a 10-kDa band, identified as a lipid transfer protein (LTP) and 8 recognized a 38-kDa band, identified as a thaumatin-like protein. Conclusions: There is a high prevalence of sensitization to C. sativa leaves. The clinical symptoms directly attributed to C. sativa were uncommon and mild. The sensitization profile observed suggests that C. sativa sensitization may be mediated by two mechanisms, i.e. cross-reactivity, mainly with LTP and thaumatin-like protein, and exposure-related ‘de novo' sensitization.