CYTOKINE RELEASE FROM HUMAN PERIPHERAL-BLOOD LEUKOCYTES INCUBATED WITH ENDOTOXIN WITH AND WITHOUT PRIOR INFECTION WITH INFLUENZA-VIRUS - RELEVANCE TO THE SUDDEN-INFANT-DEATH-SYNDROME

Previous work with a neonatal ferret model for human SIDS had indicate d that inflammation caused by a combination of influenza virus and bac terial endotoxin may be a cause of human SIDS. To determine whether cy tokines may be involved in this inflammatory response, levels of inter leukin (IL)-1beta, IL-6 and tumour necrosis factor (TNF)-alpha were ex amined, using ELISA assays, in culture supernatants of human periphera l blood leucocytes infected with influenza virus and subsequently incu bated with endotoxin. Levels of TNF-alpha were increased compared to c ells incubated with virus or endotoxin alone. Levels of IL-1beta were also increased whereas levels of IL-6 were generally not enhanced. Cyt okines appeared within 1-2 h of stimulation with virus or endotoxin an d increased subsequently to reach maximum titres between 16 and 20 h p ost treatment. While levels of cytokine were much lower when determine d using bioassays rather than ELISA assays, the pattern of increased y ields from cells incubated with virus and endotoxin compared with eith er alone was still evident. The possible importance of these observati ons for SIDS victims is discussed.