Can a probiotic tame hay fever? new study investigates

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Men and women between 18 and 60 years of age. 2. Present a medical history of ARs defined according to the International Consensus on Rhinitis for at least 2 years. 3. Present a positive IgE sensitization test to dust mite allergen during the last 5 years. \* Participants may present various sensitizations to different allergen in addition to allergy to dust mite. 4. Present the criteria for moderate-to-severe persistent AR phenotype according to the Allergic Rhinitis and its Impact on Asthma (ARIA) classification: * The intensity of signs and symptoms interferes with sleep; interferes with daily activities, sports and leisure; interferes with work activities; and symptoms present are troublesome. * The symptoms are present more than 4 days a week and during more than 4 consecutive weeks. 5. Present symptomatology at the pre-selection visit. This is, present, according to ARIA criteria, 2 or more of the following symptoms during more than 1 hour a day: water rhinorrhoea; sneezing, especially paroxysmal; nasal obstruction; nasal puritis; with or without conjunctivitis. 6. Sign the informed consent form. Exclusion Criteria: 1. Age under 18 or over 60 years old. 2. Present intolerances and/or food allergies related to the products of the study. 3. Being pregnant or intending to become pregnant. 4. Be in breastfeeding period. 5. Participate in or have participated in a clinical trial or nutritional intervention study in the last 30 days prior to inclusion in the study. 6. Present some chronic gastrointestinal disease. 7. Clinical history of anemia. 8. Having received antibiotic treatment up to 30 days before the start of the study. 9. Having received immunotherapy treatment for dust mite allergen before the start of the study and during the study. 10. Having received immunotherapy treatment for allergens other than dust mites up to 30 days before the start of the study and during the study. 11. Taking probiotics, prebiotics and/or postbiotics up to 30 days before the start of the study and during the study. 12. Present any disease with immune system involvement (HIV, autoimmune disease, hepatitis, cancer, etc.). 13. Having received chemotherapy or other immunosuppressive therapy during the previous year. 14. Medical history of surgical procedures of nasal cavity and sinuses, recent surgery of gastrointestinal tract or bariatric surgery (ever). 15. Being unable to follow the study guidelines.