Infection with respiratory syncytial virus and water-soluble components ofcigarette smoke alter production of tumour necrosis factor alpha and nitric oxide by human blood monocytes

Cigarette smoke and virus infections contribute to the pathogenesis and exa cerbation of chronic obstructive pulmonary disease and asthma. The objectiv e of this study was to examine the effects of a water-soluble cigarette smo ke extract (CSE) and/or respiratory syncytial virus (RSV) infection on rele ase from monocytes of the blood from donors of tumour necrosis factor alpha . (TNF-alpha) and nitric oxide (NO). Both RSV infection and CSE stimulated TNF-a release from monocytes and there was an additive effect if both the a gents were present. There was a decrease in NO release, but the effect was significant only with CSE or a combination of CSE and RSV infection. Interf eron gamma significantly increased TNF-alpha release and cotinine significa ntly increased NO release. Nicotine decreased both TNF-alpha and NO respons es. The general pattern observed for individual donors was increased TNF-al pha and decreased NO. The proportion of extreme responses with very high TN F-alpha and very low NO in the presence of both RSV and CSE increased to 20 % compared with 5% observed with CSE or RSV alone. The results show that RS V infection and components of cigarette smoke elicit inflammatory responses that could contribute to damage to the respiratory tract and these individ ual factors could be more harmful in combination. (C) 1999 Federation of Eu ropean Microbiological Societies. Published by Elsevier Science B.V. All ri ghts reserved.