title: Case-control study of serum immunoglobulin-E antibodies reactive with soybean in epidemic asthma.
abstract: Since 1981, twenty-six asthma outbreaks have been identified in Barcelona, all coinciding with the unloading of soybean in the harbour. Serum from patients with epidemic asthma and individually matched controls with non-epidemic asthma was assayed for immunoglobulin-E (IgE) antibodies against soybean antigens by means of a radioallergosorbent test. In 64 of 86 cases (74.4%) there was a reaction with commercial soybean antigen extracts, compared with only 4 of the 86 controls (4.6%) (odds ratio = 61; lower 95% confidence limit = 8.1). The statistical significance was greater for reactions with extracts of soybean dust taken from Barcelona harbour (odds ratio, unquantifiably high; lower 95% confidence limit = 11.7). No other serological covariate (total serum IgE levels or specific IgE levels against the commonest airborne allergens or legumes) confounded the association between serum anti-soybean IgE antibodies and epidemic asthma. These results support a causal relation between the release of dust during unloading of soybean at the harbour and the occurrence of asthma outbreaks, suggesting an underlying allergic mechanism.
authors.affiliation: Servei d'Estudis Epidemiològics i Ambientals, Ajuntament de Barcelona, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Sunyer
authors.forename: J M
authors.initials: JM
authors.lastname: Antó
authors.forename: M J
authors.initials: MJ
authors.lastname: Rodrigo
authors.forename: F
authors.initials: F
authors.lastname: Morell
mesh_terms: D000906:Antibodies / Q000032:analysis*; D001249:Asthma / Q000453:epidemiology* / Q000276:immunology; D004196:Disease Outbreaks; D004391:Dust / Q000009:adverse effects*; D004630:Emergencies; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D013025:Glycine max / Q000276:immunology*; D013029:Space-Time Clustering; D013030:Spain
chemical_list: D000906:Antibodies; D004391:Dust; D007073:Immunoglobulin E