Objective      To study whether probiotic intervention can prevent perennial allergic rhinitis (PAR) and alleviate PAR symptoms

and to investigate whether probiotics prevent PAR by modulating gut or systematic immunity.       Methods      Fifty PAR patients were randomized to receive either probiotic capsules (probiotic group) containing 25% Lactobacillus acidophilus and 75% Bifidobacterium lactis or placebo cellulose capsules (control group) in a double-blind manner every day for one month. Loratadine (10 mg/d) was administered to all PAR patients for a month. The follow-up was done during the 1st month and 3rd month after treatment

and the symptom VAS scores

eosinophils of nasal swabs and whole blood

serum immunoglobulin E (IgE)

serum interleukin-4 (IL-4)

serum interferon-γ (IFN-γ)

and fecal immunoglobulin A (IgA) were detected.       Results      There was no significant difference in all the parameters between the two groups before treatment (P0.05). The symptom VAS scores were reduced in both groups during the 1st month

and the scores of the probiotic group were lower than those of the control group during the 3rd month (P0.05). After treatment

the eosinophils of nasal swabs in the probiotic group were lower than those of the control group during the 1st and 3rd months (P0.05

P0.01). The serum IgE firstly increased and then decreased

with statistical difference between the 2 group (P0.05). During the 1st and 3rd months

there was no significant difference in blood eosinophils and serum IFN-γ between the 2 groups (P0.05). Serum level of IL-4 was increased during the 1st month

and the increase was prevented by probiotics during the 3rd month (P0.01). Fecal IgA was increased in control group

whereas it was decreased in the probiotic group during the 1st and 3rd months (P0.01).       Conclusion      The specific combination of probiotics can reduce the incidence of PAR and alleviate allergic inflammation in nasal mucosa by modulating gut or systematic immunity.