The Battle Between Influenza and the Innate Immune Response in the Human Respiratory Tract

Nicholls, John M

IFNα has been shown as an effective control of hepatitis B and C in humans, particularly active HCV, in which IFNα has cured 98% of affected individuals. During the 2003 SARS outbreak in Toronto, IFN alfacon-1, a novel synthetic consensus IFN, showed clinical benefit in patients treated with steroids and IFN compared with those treated with steroids alone [85] . In guinea pigs and ferrets infected with H5N1 and seasonal influenza respectively, IFN treatment resulted in reduced vi-ral titres and improved pulmonary pathology [86, 87] . There were promising results of intranasal administration of IFNα in preventing influenza infection in the 1980's but side-effects prevented the widespread adoption of this route of administration [88, 89] . Treatment with alfacon-1 of human ex vivo tissues infected with H1N1pdm and H5N1 showed it was able to reduce infection but IFN treatment post-exposure produced a less dramatic effect [90] . As this latter scenario is the one most likely to be encountered in clinical practice this implies that IFN use in the clinical setting may have only limited benefit.