Cockroach is a major cross-reactive allergen source in shrimp-sensitized rural children in southern China

Abstract

Background

Little is known about the prevalence of food allergy (FA) in China.

Objective

To investigate the prevalence of FA and its disparity between urban and rural areas in southern China.

Methods

Europrevall questionnaire responses were obtained from 5,542 school-age-children in urban Guangzhou and 5,319 in rural Shaoguan. A case-control study enrolled 190 children with adverse reactions (ARs) after food intake as cases, and 212 controls in Guangzhou; 116 cases and 233 controls in Shaoguan. These subjects underwent skin-prick test (SPT) and serum IgE measurements to food and inhalant allergens. Allergen extracts from shrimp, house dust mite (HDM), and cockroach were prepared for IgE cross-relativity testing in 23 Guangzhou and 20 Shaoguan shrimp-sensitized subjects.

Results

The prevalence of ARs to shrimp was higher in Guangzhou than Shaoguan children (3.5% vs. 1.4%, p<0.001). However, sensitization rate to shrimp (SPT: 3.7% vs. 11.2%, p=0.015; IgE: 12.6% vs. 36.2%, p<0.001) and cockroach (SPT: 5.3% vs. 33.5%; IgE: 2.6% vs. 27.6%, p<0.001) were lower in Guangzhou. A significant correlation between shrimp and HDM/cockroach IgE was found in Shaoguan children. The proportions of positive IgE to tropomyosin (Pen a 1, Der p 10) were lower than 7.4% in both areas. Cockroach allergen has a significantly higher inhibition rate of binding to IgE to house-dust-mite allergens in Shaoguan sera.

Conclusions

Shrimp is a common allergic food in southern China. Higher proportion of shrimp sensitization in rural subjects could be explained by cross-reactive to cockroach. Tropomyosin was not a major allergen responding for the cross-reactivity.

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