Probiotics and Prebiotics Reduce Seasonal Allergic Rhinitis Symptoms by Modulating Immunity
A clinical trial found that probiotics combined with prebiotics can significantly reduce symptoms of seasonal allergic rhinitis, shedding light on their potential role in immune modulation and gut microbiota alterations. Conducted at Xi’an Jiaotong University Second Affiliated Hospital and Yulin City Second Hospital, the randomized, double-blind, placebo-controlled trial followed 106 adults diagnosed with allergic rhinitis over 90 days, aiming to assess both clinical efficacy and underlying mechanisms.
“The microbiome plays a critical role in the development and maturation of the host’s innate and adaptive immune system,” the study authors wrote. “Consequently, disturbances in intestinal microbiota may cause airway allergic diseases by altering the host immune system, and recently, the modulation of intestinal microbiota has been considered a potential alternative or adjuvant therapy for airway allergic diseases.”
Participants in the test group received a daily regimen of probiotics, including strains of Bifidobacterium longum, Bifidobacterium infantis, Lactobacillus acidophilus, Lactobacillus paracasei, Lacto-bifidobacterium, and Lactobacillus gasseri, combined with prebiotics such as fructo-oligosaccharide, galacto-oligosaccharide, inulin, and xylo-oligosaccharide. The placebo group received a simulated preparation identical in appearance and dosage. Researchers evaluated nasal symptom severity using the Total Nasal Symptom Score (TNSS), along with inflammatory markers, microbiota composition, and short-chain fatty acid (SCFA) levels.
By day 91, patients who received probiotics and prebiotics experienced a significant reduction in TNSS compared with the placebo group, with a mean difference of -1.1 (P = 0.04). Further analysis revealed that the intervention led to an increase in the pro-inflammatory markers TNF-α and INF-γ while decreasing IL-17 levels, suggesting an immune-modulating effect. The composition of the gut microbiota also shifted, with a notable increase in Lactobacillus and Bifidobacterium species. Additionally, the production of acetate, a key SCFA linked to immune regulation, rose by 12.4% (P < 0.001), highlighting a possible mechanism through the gut-lung axis.
The absence of healthy control subjects and the reliance on fecal rather than plasma SCFA levels leave room for further investigation and longer-term data would be necessary to determine the durability of the observed effects.
“This provides a theoretical basis for the future application of compound probiotic and prebiotic preparations as an alternative therapy for seasonal [allergic rhinitis] patients,” the researchers concluded.
Reference
Hou Y, Wang D, Zhou S, et al. Probiotics combined with prebiotics alleviated seasonal allergic rhinitis by altering the composition and metabolic function of intestinal microbiota: a prospective, randomized, double-blind, placebo-controlled clinical trial. Front Immunol. 2024;15:1439830. Published 2024 Nov 1. doi:10.3389/fimmu.2024.1439830