Water-soluble low-molecular-weight beta-(1, 3-1, 6) D-Glucan inhibit cedar pollinosis

Background: The incidence of allergic diseases such as allergic rhinitis, atopic dermatitis, asthma, and food allergies has increased in several countries. Mast cells have critical roles in various biologic processes related to allergic diseases. Mast cells express the high-affinity receptor for immunoglobulin (Ig) E on their surface. The interaction of multivalent antigens with surface-bound IgE causes the secretion of granule-stored mediators, as well as the de novo synthesis of cytokines. Those mediators and cytokines advance allergic diseases. We investigated the effects of water-soluble, low-molecular-weight beta-(1, 3-1, 6) D-glucan isolated from Aureobasidium pullulans 1A1 strain black yeast (LMW-beta-glucan) on mast cell-mediated anaphylactic reactions. We reported that LMW-beta-glucan dose-dependently inhibited the degranulation of mast cells. Furthermore, we discovered that orally administered LMW-beta-glucan inhibited the IgE-mediated passive cutaneous anaphylaxis (PCA) reaction in mice. We then examined if LMW-beta-glucan had effects on Japanese cedar pollinosis. Findings: In a clinical study, a randomized, single-blind, placebo-controlled, parallel group study in 65 subjects (aged 22-62) was performed. This study was conducted 3 weeks before and until the end of the cedar pollen season. During the study, all subjects consumed one bottle of placebo or LMW-beta-glucan daily. Each subject was required to record allergic symptoms in a diary. The LMW-beta-glucan group had a significantly lower prevalence of sneezing, nose-blowing, tears, and hindrance to the activities of daily living than the placebo group. Conclusions: These results suggested that LMW-beta-glucan could be an effective treatment for allergic diseases.