Role of the Hypothalamo-Pituitary-Adrenal Axis in the Modulation of Pollinosis Induced by Pollen Antigens

Abstract

Background: To clarify the mechanism of stress-induced modification of allergic diseases, we studied the effect of restraint stress on plasma levels of cytokines and the symptoms of pollinosis in mice.
Methods: The effects of restraint stress and the role of the hypothalamo-pituitary-adrenal axis (HPA-axis) in the development of pollen antigen-induced pollinosis were studied in control, hypophysectomized, adrenalectomized or ACTH-administered mice. Twenty days after sensitization, animals were subjected to mild restraint stress for 3 hours, and plasma levels of IFN-γ, IL-10, and IgE were measured. We analyzed the incidence of sneezing and nasal rubbing in the sensitized animals.
Results: Plasma levels of IL-10 and IgE increased in the sensitized animals with a concomitant increase in the incidence of sneezing and nasal rubbing. The increases in plasma IgE, IL-10 and the incidence of sneezing and nasal rubbing were suppressed by restraint stress. Adrenalectomy increased IFN-γ, inhibited the increase in plasma IL-10 and IgE, and suppressed the incidence of sneezing. In contrast, hypophysectomy increased plasma levels of IL-10, IFN-γ, and IgE and the incidence of sneezing. Intraperitoneal administration of ACTH decreased IL-10 in plasma but increased IFN-γ and suppressed the incidence of nasal rubbing.
Conclusions: The present findings show that the HPA-axis and ACTH play important roles in the regulation of plasma cytokines and IgE thereby modulating symptoms of pollinosis. The results also suggest that a mild restraint stress suppresses the increase in Th2-dependent cytokines and IgE to reduce the symptoms of pollinosis.