EFFECT OF EXPERIMENTAL INFLUENZA-A INFECTION ON THE NASAL RESPONSE TOHISTAMINE CHALLENGE IN ALLERGIC AND NONALLERGIC SUBJECTS

To determine if a viral upper respiratory tract infection can alter th e responsiveness of the nasal mucosa, paired intranasal histamine chal lenge sessions were performed before and after (8 days) intranasal ino culation with influenza A virus in 16 nonallergic and 16 allergic subj ects. The nasal response to a 1-mg histamine challenge was measured as symptom scores for rhinorrhea and congestion, counts for sneezing, we ight for expelled secretions, and inspiratory conductance for nasal pa tency. After inoculation, a total of 25 subjects (11 allergic, 14 nona llergic) became infected with influenza A virus. In infected subjects the measured responses to histamine for secretion weight and rhinorrhe a symptom score were significantly greater al 8 days postinfection whe n compared to those responses recorded prior to inoculation. No signif icant between session differences were observed for the other response s, or for any of the responses in the uninfected subjects. Significant differences between infected allergic and nonallergic subjects were n ot observed for any response. These results document an increased secr etory response of the nose to histamine during the postsymptomatic per iod of influenza A viral infection in both allergic and nonallergic su bjects.