Effect of experimental influenza A infection on systemic immune and inflammatory parameters in allergic and nonallergic adult subjects

Background: The economic impact and medical complication rate of viral upper respiratory infections are well documented, but many of the physiologic, inflammatory, and immune responses to respiratory viruses have only recently been investigated. A previous study demonstrated differential systemic immune and inflammatory responses in allergic rhinitis (AR) and nonallergic rhinitis (NAR) subjects during experimental infection with rhinovirus-39. Objective: The purpose of this study was to compare selected systemic immune and inflammatory responses to experimental influenza A virus (FLU) challenge in seronegative AR and NAR subjects, Methods: Peripheral blood was obtained at baseline (study day 0) and 3, 6, 18, and 31 days after intranasal FLU challenge and assayed for leukocyte histamine release, serum immunoglobulins, and plasma histamine. Results: All subjects were infected, as manifested by viral shedding in nasal secretions and/or seroconversion. FLU infection induced decreases in spontaneous leukocyte histamine release and increases in anti-immunoglobulin E-induced leukocyte histamine release, which were evident at least I month after infection, but caused no significant changes in serum immunoglobulins or plasma histamine. There were no differences between AR and NAR subjects for any of the study parameters. Conclusions: The results show that intranasal challenge with FLU induces changes in leukocyte histamine release, but not other systemic immune and inflammatory responses.