SUPPRESSION OF IN-VIVO CELL-MEDIATED-IMMUNITY DURING EXPERIMENTAL INFLUENZA-A VIRUS-INFECTION OF ADULTS

A variety of recent evidence documents that otitis media is a frequent complication of upper respiratory tract viral infections. This relati onship has been attributed to the interaction of a number of virus-pro voked host responses, including eustachian tube dysfunction, changes i n nasopharyngeal bacterial flora and suppressed immune function. The p resent study examined the effect of experimental influenza A virus inf ection on immune function as assessed by delayed skin test reactivity to candida, tetanus, and diphtheria/tetanus antigens in healthy adults with (n = 12) and without (n = 15) allergic rhinitis. All subjects be came infected with the challenge virus as evidenced by viral shedding into nasal secretions and/or a four-fold rise in convalescent serum an tibody titers compared to baseline. Intradermal skin tests were placed at baseline and 2, 4, 17, and 24 days after intranasal influenza A in oculation, the reactions were imaged and recorded 48 h after placement , and response areas were calculated by computerized digitization. The average combined areas for the three antigens (+/- S.T.D.) on each of the 5 study days were 1.4 +/- 1.4, 0.7 +/- 0.7, 0.6 +/- 0.6, 1.4 +/- 1.4, and 1.2 +/- 1.2 cm(2), respectively. The responses to candida, bu t not tetanus and diphtheria/tetanus, returned to baseline levels by d ay 17. Repeated measures ANOVA documented significant effects of study day and antigen, but not allergy status. These results show that expe rimental influenza A infection suppressed delayed hypersensitivity ski n tests in both allergic and non-allergic subjects, and suggest that a lterations in immune function may contribute to otitis media.