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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
64
chewables containing Lacticaseibacillus rhamnosus GG
chewables without probiotic strain. Ingredients: Xylitol, microcrystalline cellulose, stearic acid, natural orange flavor, silica, magnesium stearate, citric acid and malic acid.
Antwerp University Hospital
Edegem, Belgium
Transfer of L. rhamnosus GG (estimated CFU counts) to the oronasopharyngeal cavity after administration of the chewable
qPCR
Time frame: at 8 weeks
Changes in the score of allergic rhinitis symptoms
Daily questionnaires will be used, in which a self-reported Total Nasal Symptom Score (TNSS) based on rhinorrhea, nasal congestion, nasal itching and sneezing with symptom severity ranging from 0 (no problem) to 12 (very severe problem) will be recorded.
Time frame: over the study period (= 10 weeks)
changes in microbiome of the oronasopharyngeal region after administration of the chewable
16S rRNA amplicon sequencing
Time frame: baseline, 8 weeks
Inlfuence on general nose- and mouth health
A clinical evaluation by an ENT specialist will be performed at the start and 8 weeks of the study to assess the general nose and mouth health of the participants. Questions on discomfort and symptoms of inflammation or infection in the nose and mouth will be included in the Sino-Nasal Outcome Test (SNOT-22)-based questionnaire implemented at the start, week 8 and week 10. Symptoms will be scored from 0 (no problem) to 5 (very severe problem)
Time frame: baseline, 8 weeks, 10 weeks
Changes in the absolute numbers of specific airway pathogens and viruses
qPCR
Time frame: baseline, 8 weeks
Changes in cytokine levels (e.g. IL-10, IL-4, IL-5, IL-13) in oro- and nasopharynx samples, and cytokine and antibody levels in blood samples
qPCR and/or ELISA
Time frame: baseline, 8 weeks
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Frequency of medication use
Daily questionnaires will be used where the type and frequency of medication use should be recorded
Time frame: over the study period (= 10 weeks)