Synbiotics reduce allergen-induced T-helper 2 response and improve peak expiratory flow in allergic asthmatics

Previous studies suggest that pre/probiotics can be used in the prevention and treatment of early allergic disease in newborns and young children.

To determine the effect of treatment with synbiotics (90% short-chain galacto-oligosaccharides, 10% long-chain fructo-oligosaccharides: Immunofortis(®) and Bifidobacterium breve M-16V) on allergic responses in adults with established allergic asthma. Primary outcome was allergen-induced bronchial inflammation as represented by eosinophil counts.

Twenty-nine patients with asthma and house dust mite (HDM) allergy were randomized in a double-blind, parallel design to receive placebo or synbiotics for 4 weeks. At study entry and after treatment, a bronchial allergen challenge with HDM was performed, followed by lung function tests, collection of blood (in/ex vivo IL-5) and induced sputum (inflammatory parameters). During treatment, a diary was kept with peak expiratory flow (PEF) and asthma scores.

Treatment did not affect the allergen-induced increase in sputum eosinophils at 6 and 24 h after challenge. Likewise, other parameters for bronchial inflammation and early and late changes in lung function did not differ upon treatment. Both the morning and evening PEF, however, significantly increased during synbiotics treatment (morning P = 0.003, evening P = 0.011). Also, the increase in serum IL-5 after allergen challenge was significantly inhibited by synbiotics (P = 0.034), as was ex vivo allergen-induced Th2-cytokine (IL-5 and IL-4+ IL-13) production by PBMCs (P = 0.046). In vivo (24 h) and ex vivo IL-5 production were associated.

Four-week treatment with synbiotics had no effect on bronchial inflammation and LAR, but did significantly reduce systemic production of Th2-cytokines after allergen challenge and improved PEF.