A Pilot Study on Clinical Scores, Immune Cell Modulation, and Microbiota Composition in Allergic Patients with Rhinitis and Asthma Treated with a Probiotic Preparation

Background: Specific drugs and/or immunotherapies are widely used to treat allergies, but drug-induced adverse effects recently led to explore new additional strategies. We studied whether a probiotic preparation (iPROB®; Anallergo SpA, Florence, Italy) is effective in allergic patients and the mechanisms underlying clinical outcomes. Methods: Eligible patients (n = 28), all suffering from allergic rhinitis with/without bronchial asthma, were consecutively recruited at the Allergology Medical Unit (Novara, Italy) and treated with this probiotic. From each patient, we collected blood and stool samples at the baseline, after 60 days of probiotic supplementation, and after 60 days from probiotic discontinuation. In each blood sample, the percentage of hematopoietic stem cells, eosinophils, and basophils was measured by FACS. To analyze stool microbiota composition, genomic DNA was extracted, bacterial 16S DNA libraries sequenced by Illumina platform (Miseq), and raw sequences processed. Generated data were statistically analyzed. Results: Probiotic-treated patients showed a significant decrease in Average Rhinitis Total Symptom Score (d = -10.5714), and Visual Analog Scale (d = -2.00) clinical indices, as well as important improvements in quality of life. In whole blood, a significant reduction in the percentage of activated eosinophils and basophils was determined, and this effect persisted after specific cell stimulation. Consistently, the serum levels of IL-4 and IL-5 decreased after probiotic treatment, suggesting a reduction in the Th2 cytokine profile. In addition, microbiome genomic analysis (n = 6) showed an increase in microbiome biodiversity, which positively correlates with clinical and cellular data. Conclusion: Present study suggests that iPROB® preparation has clinical/biological properties to be a valid add-on supplementation in allergic patients with asthma and rhinitis.