The clinical trial aims to investigate the efficacy of Lactobacillus rhamnosus LRa05 in alleviating allergic rhinitis and its impact on the gut microbiota among 70 pediatric participants aged 4-12. The primary objective is to validate the improvement in allergic rhinitis symptoms following an 8-week intervention with Lactobacillus rhamnosus LRa05. Participants were instructed to consume the probiotic powder daily for approximately 8 weeks. At baseline, week 4, and week 8 endpoints, assessments of nasal symptoms, quality of life questionnaires, and stool samples for microbiota analysis were conducted on the participants, and blood samples were collected for immune-related factor testing.

Research has indicated that allergic rhinitis (AR) is associated with a decrease in the diversity of the gut microbiota, particularly in children, potentially linking to the development of allergic diseases. Preclinical studies have shown that supplementation with Lactobacillus rhamnosus LRa05 can regulate immune responses, inhibit inflammatory factors, and the predictive functions of the gut microbiota suggest an increase in gene abundance within pathways related to immune modulation, anti-inflammatory effects, and maintenance of gut barrier integrity. To ascertain the effectiveness of the probiotic strain LRa05, a randomized, double-blind, placebo-controlled trial was conducted by the investigators to evaluate and gather data on alterations in the gut microbiota and allergic rhinitis symptoms among pediatric participants. The trial spanned over 8 weeks, with washout periods incorporated at the commencement and conclusion. Throughout the study, participants ingested Lactobacillus rhamnosus LRa05 and were subjected to a series of health examinations and assessments, including nasal symptom scores, quality of life questionnaires, and stool sample collections for microbiota analysis, as well as blood samples for immune-related factor testing. The primary objective was to validate the improvement in allergic rhinitis symptoms and the modulation of the gut microbiota following the intervention with LRa05.

Inclusion Criteria:

1. Voluntarily, in writing, sign the informed consent form, agreeing to participate in this study;
2. Capable of completing the study according to the test protocol requirements;
3. Age between 4 to 12 years old;
4. Meet the diagnostic criteria for allergic rhinitis established in the "Chinese Guidelines for the Diagnosis and Treatment of Allergic Rhinitis (Revised Edition 2022)";
5. Symptoms: Presence of two or more symptoms such as sneezing, watery rhinorrhea, nasal itching, and nasal congestion, with symptoms lasting or accumulating for more than one hour per day, possibly accompanied by eye itching, tearing, and redness, and other ocular symptoms;
6. Signs: Nasal mucosa is pale and edematous, possibly with watery secretions;
7. Laboratory tests: At least one allergen detected by skin prick test and/or specific IgE positivity in serum;
8. No use of antihistamines, corticosteroids, or immunosuppressants in the month before screening;
9. No history of heart, liver, kidney, nervous system, mental disorders, or metabolic abnormalities.

Exclusion Criteria:

1. Use of medications affecting the gut microbiota (including antimicrobial drugs, probiotics, intestinal mucosal protective agents, traditional Chinese patent medicines, etc.) for more than 1 week within 1 month prior to screening;
2. Patients with coexisting pulmonary tuberculosis;
3. Those with coexisting allergic asthma;
4. Individuals with nasal polyps or severe nasal septal deviation;
5. Patients with severe systemic diseases or malignant tumors;
6. Those with congenital genetic diseases or congenital immunodeficiency diseases;
7. Regular use of probiotics or prebiotics within 6 months prior to the screening period;
8. Individuals with severe gastrointestinal diseases (including severe diarrhea, inflammatory bowel diseases, etc.);
9. Those with metabolic syndrome (including obesity, dyslipidemia, hypertension, diabetes, etc.);
10. Individuals with sinusitis, otitis media, or respiratory tract infections;
11. Those allergic to any components of the probiotics used in this trial;
12. Women who are pregnant or breastfeeding, or those planning to conceive in the near future;
13. Subjects who discontinue the test sample or add other medications midway, making it impossible to determine efficacy or with incomplete information;
14. Those who have recently consumed items similar to the test product, affecting the judgment of the results;
15. Subjects who, due to their own reasons, cannot participate in the trial;
16. Any other subjects deemed unsuitable to participate by the investigators.

Double(Participant,Investigator)