ABSTRACT
Objective To identify allergens in portunus trituberculatus responsible for atopic dermatitis (AD) in children.Methods Totally,145 child outpatients with AD were enrolled in this study from September 2013 to July 2014,and underwent the skin prick test (SPT) with crab proteins or crab-specific IgE determination assay.Then,the children with positive SPT or elevated IgE levels underwent an oral challenge with portunus trituberculatus.Serum samples were collected from 33 children with a positive oral food challenge (test group) and from 30 health check-up child examinees (control group).Total proteins were extracted from fresh portunus trituberculatus.Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot were conducted to identify the protein fragments of portunus trituberculatus responsible for AD among these children.Results The SDS-PAGE of crude protein extracts from portunus trituberculatus yielded 11 protein bands with relative molecular masses of 94 000,70 000,58 000,49 000,36 000,34 000,32 000,27 000,21 000,19 000 and 17 000 respectively.Of the 11 protein bands,only 4 with relative molecular masses of 70 000,58 000,49 000 and 36 000 respectively reacted with sera from the patients by Western blot,with the reaction rate being 93.9％,45.4％,39.4％ and 100％ respectively.None of these protein bands reacted with sera from the control group by Western blot.There were significant differences between the test group and control group in the reaction rates of the four proteins with relative molecular masses of 70 000,58 000,49 000 and 36 000 respectively to sera (x2 =55.483,17.898,14.891,63.000,all P ＜ 0.05).Conclusion The two proteins with relative molecular masses of 70 000 and 36 000 respectively are major allergens in portunus trituberculatus responsible for AD among children.