RAST studies : IgE antibodies to Dermatogoides pteronyssinus (house dust mite), Aspergillus fumigatus and beta-lactoglobulin in sudden death in infancy syndrome (SDIS).

The incidence of 2.5 SDIS cases per 1,000 live births found in Western Australia is in agreement with figures reported for other centres. While the age range of SDIS victims extended from two weeks to 15 months, 57 per cent of deaths occurred in children of two to four months of age. Boys outnumbered girls 1.6:1. Environmental factors are implicated in that the majority of deaths occurred in a biphasic distribution - autumn and late winter months. No significant differences were observed in total IgE levels in serum from SDIS victims, post mortem children who died in trauma of known aetiology and live control children of the same age range. Serum IgE antibodies to D.pteronyssinus were found in 37% of SDIS victims compared with 7% of matched controls (post mortem plus live groups). IgE antibodies to beta-lactoglobulin, the major allergen of cow's milk, appeared with twice the frequency in SDIS vs. control group but both groups showed a similar incidence of antibodies to the allergens of Aspergillus fumigatus. The prevalence of IgE antibodies to D.pteronyssinus in SDIS victims who died in the late winter -- early spring period was double that found in the group who died in the autumn period. Sixtyfour percent of the SDIS victims had antibodies to two or more of the three allergens tested while the control sera were positive to only one allergen. These results support the hypothesis that anaphylaxis induced by immediate hypersensitivity to D.pteronyssinus in particular may be one of the causative factors in SDIS in Western Australia.