Th2
cytokines play a dominant role in the pathogenesis of allergic
asthma.
Interferon gamma (IFN-γ), a Th1
cytokine, links to therapeutic mechanisms of allergic
asthma.
Interleukin (IL)-10, a regulatory
cytokine, is involved in the induction of immune tolerance. We previously demonstrated that Anti-
Asthma Simplified Herbal Medicine Intervention (ASHMI) suppressed Th2 and increased IFN-γ in patients with
asthma and in animal models, but its bioactive compound is unknown.
Ganoderic acid beta (GAB) was isolated from Ganoderma lucidum (one herb in ASHMI). Human peripheral blood mononuclear cells (PBMCs) from adult patients with
asthma were cultured with GAB or
dexamethasone (Dex) in the presence of environmental
allergens. The
cytokine levels of
IL-10, IFN-γ,
IL-5,
transcription factors T-bet, Foxp-3, and GATA3 were measured. Following 3-day culture, GAB, but not Dex, significantly increased
IL-10 and IFN-γ levels by allergic patients' PBMCs. Following 6-day treatment, GAB inhibited
IL-5 production, but
IL-10 and IFN-γ remained high. Dex suppressed production of all three
cytokines. GAB suppressed GATA3 and maintained Foxp-3 and T-bet gene expression, while Dex significantly suppressed GATA3 and T-bet expression. GAB simultaneously increased
IL-10, IFN-γ associated with induction of T-bet and Foxp3, while suppressing
IL-5, which was associated with suppression of GATA3, demonstrating unique beneficial
cytokine modulatory effect, which distinguishes from Dex's overall suppression.