Correlation Study Between Nasal Microbes And Subcutaneous Immunotherapy For Allergic Rhinitis

Background: The mechanism of allergic rhinitis(AR)is still unclear.Most scholars believe that AR is the result of a combination of environmental and genetic factors.Subcutaneous immunotherapy(SCIT)is the only treatment that can change the natural course of AR disease through immunomodulatory mechanisms and maintain the efficacy after the course of treatment.Strachan’s "hygiene hypothesis" and recent studies of intestinal microbiology suggest that the microbial community and its metabolites(such as tryptophan,fatty acids,etc.)in the environment and the human body are closely related to the occurrence and development of many immune diseases.Nasal cavity is the main place where AR patients come into contact with external allergens,produce inflammatory reactions and nasal symptoms.What is its microbial community composition and metabolic function? Is there any difference with healthy controls and AR patients after subcutaneous immunotherapy? Is the mechanism of subcutaneous immunotherapy related to the microbes and their metabolic functions in the nasal cavity?Objective: To explore the differences in nasal microbial diversity and metabolic function between AR patients and normal population,before and after SCIT treatment,in order to study the possible mechanisms of allergic rhinitis and specific immunotherapy from the perspective of nasal microbes and their metabolism.Methods: A total of 44 subjects were enrolled,including 28 patients with AR and 16 healthy controls from the physical examination center during the same period.All AR patients received subcutaneous immunotherapy for more than 1 year.Collect basic information,examination reports,and symptom scores of all patients in the group,and collect nasal swabs from healthy controls(control group),AR patients before subcutaneous immunotherapy(AR group)and 12 months of treatment(SCIT group).16S rRNA high-throughput sequencing technology was used to detect the microbial sequence in nasal swabs,and the composition and difference of microbial diversity in each group were analyzed by bioinformatics methods.At the same time,the PICRUSt software was used to predict the microbial metabolic function,and the differences in the microbial metabolic function between the groups were analyzed through Anova.Results: There were significant differences in the Alpha diversity index and microbial composition of the microbial communities between the three groups,and the differences in microbial tryptophan metabolism and fatty acid metabolism between the groups were statistically significant.(1)The Shannon index of the AR group was significantly higher than that of the control group(P<0.05),while the Chao1 index,ACE index and Shannon index of the AR group were significantly higher than those of the SCIT group(P<0.05).(2)The main microorganisms in the three groups include Proteobacteria,Actinobacteria,Thermi,Firmicutes,Cupriavidus,Thermus,and Sphingomonas It belongs to Sphingomonas,Ochrobactrum,Corynebacterium,Amycolatopsis,Acinetobacter.(3)The dominant phyla and genera in the AR group include Thermi,Cyanobacteria,Chloroflexi,Acidobacteria,Pseudoalteromonas,Anoxybacillus,and Rhodobacter.Rhodoplanes,Cupriavidus,Thermus,Sphingomonas,Ochrobactrum,Amycolatopsis,Microbacterium,Pseudomonas,Sediment rod-shaped bacteria belong to Sediminibacterium and Agrobacterium belong to Agrobacterium.The dominant flora in the SCIT group included Bacteroidetes,Faecalibacterium,Aeromonas;the dominant flora in the healthy control group included Actinobacteria,Paracoccus,and Corynebacterium.(4)The prediction results of microbial metabolic function show that there are significant differences between the three groups.There are 307 metabolic pathways,including amino acid metabolism,lipid metabolism,tryptophan metabolism,fatty acid metabolism,and phenylalanine,tyrosine and tryptophan.Compared with the healthy control and SCIT group,the biosynthesis was significantly enhanced in the AR group(P<0.01).Conclusion: There are significant differences in nasal microbial diversity and metabolic function between AR patients and normal population,before and after SCIT treatment,and the occurrence and development of AR and the mechanism of SCIT treatment of AR are closely related to the changes of certain microbial flora and their metabolic functions.Nasal microorganisms may interact with the host through their metabolites,participate in immune regulation,and regulate the body’s inflammatory response.