%0 Journal Article
%T The Role of IL-17 in the Association between Pneumococcal Pneumonia and Allergic Sensitization
%A Hongxia Zhao
%A Cheol-In Kang
%A Mark S. Rouse
%A Robin Patel
%A Hirohito Kita
%A Young J. Juhn
%J International Journal of Microbiology
%D 2011
%I Hindawi Publishing Corporation
%R 10.1155/2011/709509
%X Interleukin- (IL-) 17 is important in the development of asthma and host defense against pneumococci. We determined the role of IL-17 in the risk of pneumococcal pneumonia. We challenged mice intranasally with a bioluminescent Streptococcus pneumoniae strain after sensitization and challenge with ovalbumin (OVA). We measured the levels of cytokines, including IL-17 (pg/mL), in the lung homogenate in experimental mice with and without OVA sensitization/challenge, as well as those with and without pneumococcal pneumonia. IL-17 levels were significantly lower in OVA-sensitized/challenged mice (9.69 1.49), compared to the control mice (20.92 1.82, < 0.001). In our overall analysis, including IL-4 and IL-17 levels and OVA sensitization/challenge, IL-4 levels (OR: 81.9, 95%CI: 4.3¨C1523 per increment of 1.0£¿pg/mL, = 0.003) were more significant than IL-17 levels (OR: 1.1, 95%CI: 1.03¨C1.17 per increment of 1.0£¿pg/mL, = 0.003) in determining the risk of pneumococcal pneumonia. IL-17 levels result in a much smaller impact on the risk for pneumococcal pneumonia, compared to IL-4 levels. 1. Introduction Streptococcus pneumoniae is a leading cause of bacterial pneumonia, meningitis, and sepsis and has caused substantial morbidity and mortality in the United States and worldwide, especially in young children. Recent estimates of childhood deaths caused by Streptococcus pneumoniae range from 70,000 to 1 million every year worldwide, and S. pneumoniae caused around 11% of all deaths in children aged 1¨C59 months [1]. In 2000, about 14.5 million episodes of serious pneumococcal disease were estimated to occur, and pneumococcal disease caused about 826,000 deaths in children aged 1¨C59 months [1]. In the US, 40,000 cases of fatal pneumococcal infections per year have been reported [2]. Recently some studies reported that individuals with asthma have a significantly increased risk of invasive pneumococcal disease, compared to those without asthma [3, 4]. Thus, the Advisory Committee on Immunization Practices has a recommendation for the use of 23-valent pneumococcal polysaccharide vaccine (PPV23) for the prevention of invasive pneumococcal disease in asthmatics [5]. At present, little is known about the mechanisms underlying the increased risk of invasive pneumococcal disease among individuals with asthma. We previously reported that a T-helper 2 (Th2) predominant immune response (e.g., IL-4) to OVA sensitization was a significant risk factor for pneumococcal infection, whereas allergic sensitization itself was protective against pneumococcal pneumonia [6]. Others also
%U http://www.hindawi.com/journals/ijmicro/2011/709509/