Probiotic Chewables in Allergic Rhinoconjunctivitis Patients

Study of the Probiotic Potential of a Lacticaseibacillus Strain in the Upper Airways in Patients With Allergic Rhinoconjunctivitis After Administration in a Chewable

With this double- blind, randomised, placebo-controlled study, the investigators want to investigate the influence of a chewable with the probiotic strain Lacticaseibacillus rhamnosus GG on the symptoms and immunological markers of allergic rhinoconjunctivitis (AR). In addition, the investigators aim to study the influence of this probiotic chewable on the microbiome of the upper respiratory tract after administration in adults with AR. The bacterial and cytokine profiles in the naso- and oropharynx will be monitored before, during and after the treatment.

Inclusion Criteria:

• Adults aged 18 at the time of registration;
• Seasonal allergic rhinoconjunctivitis (AR) in the context of grass pollen allergy diagnosed on the basis of anamnesis cfr. ARIA guidelines and positive skin prick test and / or immunocap assay;
• Positive skin prick test (SPT) for grass pollen and / or the presence of specific IgE for grass pollen, confirmed by a medical specialist, measured at the start of the study: Soluprick SQ Phleum pratense pollen 10 HEP - ALK and / or IgE specific immunocap assay Phleum pratense (timothy grass) (g6);
• Body Mass Index in the range of 19-32 kg / m2;
• Instructed during screening and agreed not to use other probiotic products outside of the study during the study period;
• Signed the consent form.

Exclusion Criteria:

• Antibiotic use at baseline and during the study;
• Pregnant women;
• Unstable / uncontrolled asthma (to be determined by investigator-physician);
• Sensitization to dust mites
• History of probiotic use in the past two weeks;
• Current diagnosis of cancer or immunosuppressive therapy within the past 6 months;
• Abnormalities of the oral mucosa;
• Acute and chronic infectious and inflammatory upper airway diseases (eg acute / chronic rhinosinusitis cfr. EPOS guidelines);
• Clinically significant bleeding disorder;
• Any other medical condition that, in the principal investigator's opinion, warrants exclusion from the trial;
• History of regular use (> 3 days out of 7) of tobacco products within the previous two weeks