This study was set up to evaluate the food panel of a multiple specific IgE antibody assay in 67 atopic asthmatic children by comparing it to the conventional radioallergosorbent test (RAST) and skin-prick tests (SPT) and then comparing the results of these investigations with the parents perceptions of food related problems.
Fifteen food specific IgE antibodies were measured using the multiple chemiluminescence assay (MAST-CLA). IgE antibodies to five of these food allergens were also measured by conventional RAST and SPTs were performed in 43 using 11 standardized food extracts matched to the multiple allergosorbent chemiluminescent assay (MASTCLA) profile. SPT and MAST-CLA results showed good agreement with one another, range 688-96.7% (average 87%), with significant correlation for most allergens tested. MAST-CLA was discrepant with RAST and/or SPTs in 58/210 (27 6%).
A questionnaire was sent to the parents to determine their perception of food related symptoms. Sixty-two (92%) questionnaire replies were received, of which 56% reported symptoms with food. The most frequent symptom perceived to be due to food intolerance was behavioural disturbance. The commonest foods implicated were additives (39%), egg (27%), milk (26%), chocolate (23%) and orange (15%). History, SPT, MAST-CLA and RAST were compared for live allergens in 42 patients (210 values). In 14/210 (6·7%), all the tests were negative despite reported symptoms. Conversely in 49/210 (23·3%) at least one test was positive without symptoms.
This study did not support a benefit of multiple antibody testing instead of individually selected RASTs or SPTs. The frequent perception of food related symptoms in these asthmatic children was often not supported by SPT, RAST and/or MAST-CLA. This may be a reflection of the current public concern about food, or of non-IgE mechanisms. These uncertainties can only be resolved by double blind placebo controlled food challenge. The inclusion of food specific IgE antibodies together with inhalant antibodies in a multiple test system for use in atopic asthmatics may be misleading.