Follow-up And Gut Microbiotic Study Of Wheat-dependent Exercise-Induced Anaphylaxis

Food-dependent exercise-induced anaphylaxis(FDEIA)is a rare but life-threatening food allergy.It refers to a severe allergic reaction that occur during exercise within a few hours after eating specific allergens.A variety of foods such as wheat,nuts,seafood can cause FDEIA.Wheat is the most common allergen causing FDEIA,which is also called wheat-dependent exercise-induced anaphylaxis(WDEIA).WDEIA patients experience an allergic reaction when wheat ingestion is combined with augmenting cofactors,such as exercise,alcohol and nonsteroidal anti-inflammatory drugs;however,these patients can tolerate ingesting wheat products without these cofactors.WDEIA lacks effective treatment methods,and there are few studies on the long-term prognosis of WDEIA.In the first part of this project,165 WDEIA patients were followed up for long-term,aiming to clarify the status of long-term control of WDEIA patients.Follow up data was available for 121 patients.The median follow-up period was 92(2-134)months.19.0%,32.2%and 11.6%of patients adhered to wheat-free diet,avoiding wheat with exercise and reduced wheat in combination with exercise avoidance respectively,9.2%(6/76)of them recurred anaphylaxis.Meanwhile,14.9%,12.4%and 9.9%patients chose intermittent wheat-free diet,reduced wheat consumption and no change in diet respectively,40%(18/45)of them suffer from anaphylaxis post-diagnosis.The differences between the different dietary advice groups'outcomes were statistically significant(P=0.000).Apart from completely fasting wheat,reducing wheat intake combined avoiding exercise may be a good choice,which may improve the patient's tolerance to wheat,but we need pay attention to the risk of allergies caused by unintentional exercise.The WDEIA etiology remains elusive.The intestinal microbiota plays a critical role in food allergy development.However,little is known regarding the structure and composition of the intestinal microbiota in patients with wheat-dependent exercise-induced anaphylaxis(WDEIA).We examined the gut microbiota alterations in patients with WDEIA and the microbiota's association with WDEIA.Fecal samples were collected from 25 patients with WDEIA and 25 healthy controls.Environmental exposure factors were obtained,serum total IgE,IgE specific to wheat,gluten,and ?-5 gliadin were measured.Fecal samples were profiled using 16S rDNA gene sequencing.The relative abundances of the bacterial genera Blautia(P<0.05),Erysipelatoclostridium(P<0.01),Akkermansia(P<0.05)and Lachnospiraceae_NK4A136_group(P<0.05)were significantly increased,while those of Lactobacillus(P=0.001)and Dialister(P<0.05)were significantly decreased in subjects with WDEIA.The microbial diversity did not differ between WDEIA patients and healthy controls.IgE specific to ?-5 gliadin was positively associated with the Oscillospira(r=0.48,P<0.05)and negatively associated with Leuconostoc(r=-0.49,P<0.05).Total IgE levels were significantly negatively correlated with Bifidobacterium(P<0.05).The gut microbiome compositions in WDEIA patients differed from those of healthy controls.We identified a potential association between the gut microbiome and WDEIA development.Our findings may suggest new methods for preventing and treating WDEIA.Although 16S rRNA-based high-throughput sequencing research can reflect the microbiota alteration in WDEIA patients to a certain extent,it cannot explore the intestinal microecology comprehensively.Compared with 16S rRNA,metagenomic sequencing can better distinguish bacterial species and strains,and assess the bacterial diversity.At the same time,this technology can distinguish lower taxonomic levels and perform potential functional annotations,which can provide more evidence for the development of WDEIA.Therefore,in the third part,stool samples from 21 WDEIA patients,17 food-induced anaphylaxis and 15 healthy controls were subjected to metagenomic sequencing.At the same time,environmental exposure factors were collected and serum total IgE,wheat specific IgE,gluten specific IgE,?-5 gliadin specific,and tryptase levels were detected.We found that compared with healthy controls,the relative abundance of Carnobacterium,Thermotoga,Bacteroides_massiliensis,Clostridioides,Eubacterium_rectale and Parabacteroides_distasonis were higher and those of Bacteroides_coprocola and Bacteroides_stercoris was lower in WDEIA patients.The composition of the intestinal microbiota of the WDEIA group differed from that of the AN and the healthy control group,suggesting that WDEIA patients have a unique composition of the intestinal microbiome.There was no difference in the diversity of intestinal microbiota between groups.Correlation analysis between intestinal flora and clinical indicators found that Desulfurellales and Desulfurellaceae,as the intestinal flora enriched in the WDEIA group,were positively correlated with ?-5 gliadin sIgE.Roseburia_inulinivorans and Roseburia_sp._CAG:18 were positively correlated with ?-5 gliadin sIgE and gluten sIgE,but there was no significant difference in their enrichment in the two groups.Although the composition of fungi in the intestinal microbiota differed between the three groups,we did not find the correlation between the different fungi and clinical indicators,which further confirmed that the bacteria in the intestinal microbes play a major role in the pathogenesis of WDEIA.KEGG database comparison analysis found that there are differences between the functional genes of WDEIA patients and healthy controls.Lipopolysaccharide biosynthesis and ubiquitin-mediated proteolysis are enriched in healthy controls.Therefore,lipopolysaccharide biosynthesis may play a protective role in WDEIA species.The second part of the study further confirmed the correlation between the intestinal microbiota and the pathogenesis of WDEIA,explored the possible mechanism of the intestinal flora in the pathogenesis of WDEIA,and provided new ideas for the diagnosis,treatment and mechanism research of WDEIA.WDEIA is a life-threatening distinct IgE-mediated wheat allergy,which may involve multi-systems.However,some WDEIA patients only develop itching and urticaria after taking wheat,but do not develop severe allergic reactions,which is called wheat-dependent exercise-induced urticaria(WDEIU).WDEIU patients are relatively rare and there is a lack of reports on the clinical characteristics of WDEIU patients in China.In order to analyze the clinical characteristics of WDEIU and explore the relationship between WDEIU and WDEIA.We analyzed the clinical features and laboratory examinations of 9 patients with WDEIU retrospectively.Meanwhile,we randomly selected 18 WDEIA cases as controls.Among nine WDEIU subjects,8 were males and 1 was female,the mean age of onset was 23.4±11.8 years.The median time from onset to diagnosis was 36 months.They presented urticaria(9/9),laryngeal obstruction(3/9)and lip edema(1/9).The mean age of onset of severe allergic reaction in WDEIA was 42.9±12.2 years.72.2%(13/18)of them had a history of urticaria,and the median time from onset of urticaria to that of anaphylaxis was 7(1.5-47)years.The age of onset was significantly lower in WDEIU group than that in WDEIA group(23.4±11.8 vs 42.9±12.2,P=0.001),and the serum gluten specific-IgE level was significantly lower than the control group(0.55 kUA/L vs 1.34 kUA/L,P=0.014).Patients with WDEIU had lower ?-5 gliadin specific-IgE levels,but there was no statistically significant difference between the two groups(P=0.069).In conclusion,WDEIU is a rare disease and difficult to recognize,which may be the early stage of WDEIA.Diagnosis was based on medical history,serum specific IgE detection,and/or skin prick test.This study is helpful to improve clinicians'understanding of the disease and provide guidance for the early diagnosis and treatment of the disease,which will contribute to prevent severe allergic reactions.