Serum level of interleukin-4 in patients with perennial allergic rhinitis during allergen-specific immunotherapy

Interleukin-4 (IL-4) may play a central role in the IgE synthesis system, the development of Th-2-like cells, and co-ordination as well as the persistence of airway inflammatory process in allergic disorders. Therefore, IL-4 plays a key role in airway allergic disorders. This study aimed at investigating the serum concentrations of IL-4 in patients with perennial allergic rhinitis, with special reference to the possible changes and the clinical relevance following long-term immunotherapy. The study has demonstrated that the serum level of IL-4 in allergic rhinitis patients before immunotherapy is significantly higher than that in non-atopic individuals. However, the serum IL-4 level in allergic rhinitis patients did not decrease following anti-allergic medications but significantly decreased following immunotherapy. The percentage decrease in IL-4 was correlated significantly with the percentage decrease in specific IgE antibodies following long-term immunotherapy. Immunotherapy also significantly decreased specific IgE antibodies, but this reduction in specific IgE antibodies was not significantly correlated with the clinical improvement. In contrast, the percentage decrease in serum IL-4 was significantly correlated with the percentage decrease in symptomatic scores. The authors interpret these data to mean that immunotherapy alters T-cell cytokine profiles in the long-term, and a decline of IL-4 following immunotherapy could modulate not only production of specific IgE antibodies but also inflammatory cellular events, leading to symptomatic relief in allergic rhinitis.