Research On The Role Of Calprotectin In Food Allergy

ObjectiveThree studies were conducted to assess the predictive and monitoring effects of calprotectin on food allergy in children with a view to achieving a reduction in the incidence of allergic diseases in children.Method1.According to the inclusion criteria,1~4 year-old healthy children were recruited,and the relevant data and the stool samples of the subjects were collected.Anthro software(version 3.1)was used to calculated Length-for-age Z-scores,weight-for-age Z-scores,and weight-for-length Z-scores respectively.Fecal calprotectin was detected by a commercially available ELISA.2.20 male BN rats of 3 weeks old were randomly divided into two groups.Rats in experiment group were received ovalbumin 1 mg/(ml·d)by gavaged,rats in control group received the same capacity of normal saline,lasting for 41 days.On the 42 day,each rat in experiment group received ovalbumin 100 mg;rats in control group received the same capacity of normal saline.Body length,weight and food-intake were measured on day 0,7,14,21,28,35 and 42.On day 42 after stimulated,appearance of rats and the character of feacal were observed,and the hypersensitivity reactions were assessed in each rats.Blood samples were collected to measure the level of OVA-IgE and histamine by enzyme linked immunosorbent assay.The approach to determine allergic was that the level of OVA-IgE in experiment groups was higher than the mean level of that plus three times of standard deviation in control group.3.80 male BN rats of 3 weeks old were randomly divided into two groups.The method of sensitization and stimulate were same as the section two.Height and weight were recorded every 7 days.Besides,blood,jejunum,liver and spleen were collected every 7 days(5 rats/group).On day 42 after stimulated,the symptom scores were observed,and the sample mention above were collected.The level of serum level of OVA-IgE and histamine(sensitization rate 90.00%)(P all<0.05).3.Compared with the control group,the levels of OVA-IgE,histamine,plasma IL-4and IL-5 were increased and the levels of INF-were decreased in all groups in each observation time point(P all<0.05).On day 42 after stimiluated,the total score of 30in hypersensitivity group was obviously higher than that in control group(P<0.05).What's more,the number of mast cells and eosinophils increased and the intestinal mucosa damage increased.The levels of fecal calprotectin,S100A8/A9 in palsma,mRNA expression of S100A8 and S100A9,and inflammation-associated cytokines were higher in hypersensitivity group than those in control group on each time points.Immunohistochemistry showed that the expression of S100A8,S100A9 and S100A8/A9 increased gradually from day 7(P all<0.05).Besides,a positive correlation of fecal calprotectin with S100A8/A9 and inflammation-associated cytokines(TLR4,NF-?B and TNF-?)were found(Spearman's rho=0.324,P=0.003;Spearman's rho=0.368,P=0.001;Spearman's rho=0.382,P<0.001;Spearman's rho=0.267,P=0.017).In cell culture,from control group,OVA group,S100A8+OVA group,S100A9+OVA group to S100A8/A9+OVA group,the expression of surface molecules of dendritic cells,that is,CD11c+,CD86+and MHC II+were gradually increasing.After co-culture of dendritic cell and CD4~+T cell,from control group,OVA group,S100A8+OVA group,S100A9+OVA group to S100A8/A9+OVA group,the expression of Th2-associated cytokines were gradually increasing and that of Th1was decreasing gradually.Conclusion1.We suggest that FC level<419?g/g can be used as a reference value for health children aged 1~4 years old.Besides,a long term follow-up is needed in children whose FC level>419?g/g in that aged group,in order to exclude the possibility of inflammatory bowel disease in children.2.The food allergy of Brown Norway rats was successfully created by ovalbumin gavaged without adjuvant,and the rate of success was high.3.These results provided an insight that calprotectin may play a promotion role in lightly food allergy combining with other inflammatory factors.Besides,fecal calprotectin was significantly increased in food allergy rats,and could be used to predict the occurrence of food allergy.