#SeasonalAllergicRhinitis #Probiotics
#Prebiotics #GutMicrobiota
Seasonal allergic rhinitis (SAR) is a chronic
inflammatory condition of the upper airways, driven by an inappropriate immune
response to environmental allergens such as pollen. It is characterized by
classic symptoms — sneezing, runny nose, nasal congestion, and itching — that
significantly impair quality of life. Its prevalence is steadily rising, now
affecting nearly
40% of the global population, underlining its major public
health impact and increasing economic burden.
Standard treatments mainly include
antihistamines,
intranasal corticosteroids, and
allergen-specific
immunotherapy. While often effective,
these approaches have limitations: side
effects, individual variability in treatment response, low adherence, and frequently
only partial long-term efficacy. This reality highlights the need for
complementary or alternative therapeutic strategies, especially those targeting
the underlying mechanisms of the disease.
In this context, a new therapeutic avenue has
emerged:
modulating the gut microbiota, a key player in immune homeostasis.
Recent studies have revealed alterations in the microbiota of patients with
SAR, suggesting a potential link between intestinal dysbiosis and worsening
allergic symptoms.
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A healthier microbiota, calmer symptoms?
Conducted on 106 patients aged 18 to 65, the
study compared a group receiving daily supplementation with probiotics
(including Bifidobacterium longum, Lactobacillus acidophilus,
etc.) and prebiotics (fructo-oligosaccharides, inulin...) for 90 days, against
a placebo group. Evaluation criteria included the Total Nasal Symptom Score
(TNSS), quality-of-life questionnaires, immune markers (TNF-α, INF-γ, IL-17,
IgE), as well as analysis of gut microbiota (16S rRNA, qPCR) and its
metabolites (short-chain fatty acids – SCFAs).
By the end of the study, patients who received
the supplementation showed a
significant improvement in SAR symptoms,
particularly reduced TNSS, less rhinorrhea, and fewer sneezes. On an immune
level,
TNF-α and INF-γ levels increased, while IL-17 decreased, indicating a
favorable
rebalancing of the immune response. IL-4 and IgE levels remained
stable.
The intervention also altered the gut
microbiota. Populations of Lactobacillus, Veillonella, and Bifidobacterium
increased, along with production of acetate, a metabolite beneficial for immune
health. In addition, several metabolic pathways involved in immune regulation —
including those of purines, tyrosine, and glycolysis — were enhanced. These
shifts in the microbiota’s composition and function correlated with symptom
improvement, suggesting an action mediated by the gut-lung axis.
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The microbiota on the front line
Seasonal allergic rhinitis (SAR) is a common
inflammatory disorder triggered by pollen exposure, marked by an exaggerated
immune response. Despite available treatments, many patients continue to
experience debilitating symptoms, and conventional options don’t always provide
lasting relief. This study aimed to assess the
impact of daily probiotic and
prebiotic supplementation on SAR symptoms, while also exploring related changes
in the gut microbiota and immune response.
The intervention reshaped the gut microbiota,
promoting the growth of Lactobacillus, Veillonella, and Bifidobacterium,
while boosting production of acetate — a short-chain fatty acid with recognized
immunomodulatory properties. At the same time, key metabolic pathways involved
in immune regulation, particularly purine and tyrosine metabolism, were
activated. These changes in microbial composition and function were closely
tied to symptom improvement, supporting the hypothesis of a central role for
the gut-lung axis in allergic response modulation.
This study reinforces the idea that the gut
microbiota is a
promising therapeutic target for relieving seasonal allergic
rhinitis.
The combination of probiotics and prebiotics proved effective, well
tolerated, and free of major side effects, positioning microbiota modulation as
an innovative approach to managing allergic conditions. However, some
limitations should be considered, underscoring the need for further research.
Tailoring interventions based on individual microbial profiles could enhance
effectiveness. Larger-scale and longer-term studies will be essential to
confirm these findings and better identify the patients most likely to benefit
from this treatment.
