The physiologic interferon response. VI. Interferon activity in human plasma after a meal and drinking

Interferon activity in plasma was found negligible in the morning and slightly increased in the afternoon. However, because of the wide variability of the results, the difference was not statistically significant even though the existence of a circadian rhythm appears possible. The afternoon increase of IFN activity could be at least in part due to increased abdominal lymphatic drainage following digestion and absorption. In fact, it has been shown that there is a significant transient increase in IFN plasma level 2 hours after a fat-rich meal or drinking 700 ml of water. IFN activity was due to acid-labile IFN-alpha. This is another, yet indirect, indication of the existence of the physiologic IFN response that entails a localized production of lymphomonokines with limited spillover in the circulation.