Lacticaseibacillus rhamnosus OF44 Alleviates Allergic Rhinitis by Rebalancing Host Immunity and Gut Microbial Function

Allergic rhinitis (AR) involves maladaptive type 2 inflammation driven by systemic immune imbalance and gut dysbiosis. Here, we identify a probiotic strain, Lacticaseibacillus rhamnosus OF44, with exceptional probiotic potential that mitigates allergic pathology through coordinated immunological and microbial reprogramming. In an ovalbumin-induced AR rat model, OF44 administration markedly reduced nasal allergic symptoms, normalized serum immunoglobulin and cytokine profiles, and restored Th1/Th2/Th17/Treg equilibrium. Metagenomic profiling revealed that OF44 reshaped gut microbial architecture by enriching beneficial commensals ( Rikenellaceae , Alistipes ) and suppressing proinflammatory Enterobacteriaceae. Functional profiling further demonstrated that OF44 reversed AR-associated enrichment of pro-inflammatory pathways, including biofilm formation, flagellar assembly, and multidrug resistance, while restoring amino acid, energy, and SCFA-related metabolic pathways. Integrated taxonomic–functional correlation analyses highlighted butanoate and lipoic acid metabolism as key microbial functions linked to enhanced immune regulation. Collectively, these findings demonstrate that OF44 attenuates AR by reprogramming gut microbial structure and function, providing mechanistic support for its application as a functional probiotic in allergic disease management.