PT - JOURNAL ARTICLE AU - M. Roponen AU - S. T. Yerkovich AU - E. Hollams AU - P. D. Sly AU - P. G. Holt AU - J. W. Upham TI - Toll-like receptor 7 function is reduced in adolescents with asthma AID - 10.1183/09031936.00172008 DP - 2010 Jan 01 TA - European Respiratory Journal PG - 64--71 VI - 35 IP - 1 4099 - http://erj.ersjournals.com/content/35/1/64.short 4100 - http://erj.ersjournals.com/content/35/1/64.full SO - Eur Respir J2010 Jan 01; 35 AB - Anti-viral innate immune responses may be impaired in asthma, although the mechanisms are not well understood. Toll-like receptors (TLRs) 7 and 3 are particularly relevant for initiating responses to common respiratory viruses, as they recognise single-stranded viral RNA and double-stranded viral RNA, respectively. The aim of the present study was to investigate TLR7 and TLR3 function in 14-yr-old adolescents with asthma. Blood mononuclear cells obtained from 17 atopic asthmatics, 29 atopic, non-asthmatics and 21 healthy, non-atopic individuals, were stimulated with the TLR7 agonist imiquimod and the TLR3 agonist poly I:C. Expression of anti-viral molecules was measured by real-time PCR. Concentrations of interferon-γ-inducible cytokine protein (IP)-10 and interleukin (IL)-6 were measured by ELISA. TLR7-induced myxovirus resistance protein A and 2′5′ oligoadenylate synthetase mRNA expression and protein levels of IP-10 were significantly lower in asthma subjects compared with healthy subjects (p = 0.041, p = 0.003 and p = 0.001 respectively). There was a significant negative correlation between total serum immunoglobulin E and IP-10 following TLR7 stimulation. However, TLR3-induced responses did not vary with asthma or atopy. IL-10 mRNA and IL-6 protein synthesis were similar in asthmatic and control subjects. In conclusion, TLR7 function is reduced in adolescents with asthma and this may contribute to susceptibility to respiratory viral infections.