Th1 immunity is not required for the effect of lipopolysaccharide exposure on modifying asthmatic responses of mice before sensitization / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Disequilibrium of Th1/Th2 is known as an important cause of allergic asthma with a biased Th2 type response. It has been shown that lipopolysaccharide (LPS) administration during post-sensitization modified the inflammation of asthma via upregulating the Th1 response that decrease the Th2 immunity. We would like to know if, during pre-sensitization, the elevated Th1 response is necessary for LPS exposure to modify the asthmatic response.</p><p><b>METHODS</b>During pre- or post-sensitization, 40 microg LPS were intraperitoneal injected (i.p.) to asthmatic mice sensitized and challenged by Dermatophagoides farinae (D. farinea). Inflammation was assessed by examining bronchoalveolar lavage fluid (BALF) for the number and identity of cells and by cytokine titers measured by ELISA. Semi-quantified RT-PCR was used to evaluate the level of Toll-like receptor 4 (TLR4) mRNA in dendritic cells (DCs) from bone marrow (BMDCs).</p><p><b>RESULTS</b>These investigations demonstrated that LPS exposure during pre-sensitization inhibited the Th2 cytokine and inflammatory infiltration, the same as with LPS exposure during post-sensitization in allergic asthma mice. Contrary to post-sensitization LPS exposure, the Th1 cytokines were not upregulated by pre-sensitization with LPS. Finally, the study failed to show any significant difference between TLR4 mRNA expressed in BMDCs with the two times of LPS exposure.</p><p><b>CONCLUSIONS</b>Our data suggest that elevated Th1 immunity is not required for the modification of the Th2 response induced by LPS exposure during pre-sensitization in asthmatic mice and that pre-sensitization differs from post-sensitization. Immune modulation with treatment is independent of TLR4 expression in BMDCs. This study implicates a potential way to protect from allergic disease and an inflammatory response.</p>

The effect of rural exposure on allergic asthma in Anhui province / 中华流行病学杂志

<p><b>OBJECTIVE</b>To establish the evidence of exposure to rural areas would reduce the risk of atopic asthma and sensitization.</p><p><b>METHODS</b>A cross-sectional survey was carried out in 2986 school-age children and their parents completed standardized questionnaires on atopic asthma and sensitization, wheezing. A radioallergosorbent technique-fluorescence enzyme immunoassay (RAST-FEIA) was used to measure the level of specific IgE in serum.</p><p><b>RESULTS</b>The risks of atopic and non-atopic asthma (OR = 0.45, 95% CI:0.13-0.96 and OR=0.41, 95% CI:0.15-0.95), atopic sensitization. and wheezing (OR= 0.32, 95% CI:0.11-0.62; OR =0.44, 95% CI:0.13-0.91) were lower in subjects living in village area compared with those living in towns. The risks of atopic asthma and sensitization were lower in subjects exposed to stables in first year (OR=0.23, 95% CI:0.04-0.91 and OR =0.32, 95% CI:0.17-0.78) and were lowest in those exposed continually until the age of 6 (OR = 0.21, 95% CI:0.03-0.87 and OR = 0.31, 95% CI:0.15-0.78) compared with those non-exposed in the first 6 years.</p><p><b>CONCLUSION</b>Exposure to rural environment might have a protective effect on children against atopic asthma and sensitization while continual exposure could strengthen the effects.</p>

Study on the relations between concentration of endotoxin in dwelling and atopic asthma in school-age children / 中华流行病学杂志

<p><b>OBJECTIVE</b>To explore the effect of endotoxin concentration in dwellings on the prevalence of atopic asthma in children.</p><p><b>METHODS</b>Standardized questionnaires of asthma were distributed to the parents of 2986 school children aged between 8 and 12 years and endotoxin content in children's mattress was measured by a kinetic limulus assay. A radioallergosorbent technique--fluorescence enzyme immunoassay (RAST-FEIA) was used to measure the level of specific IgE in serum.</p><p><b>RESULTS</b>Complete data was available for 904 children with males more than females. There were both negative associations seen between endotoxin levels and both atopic asthma (OR = 0.48, 95% CI: 0.32-0.72, P < 0.05) and atopic sensitization (OR = 0.65, 95% CI: 0.49-0.94, P < 0.05) but not with non-atopic asthma and wheeze. Comparing with normal people, patients with atopic sensitization, atopic wheeze and atopic asthma had a higher levels of endotoxin (M-W U: 15 138.0, P < 0.01, M-W U: 4858.0, P < 0.01, M-W U: 4041.0, P < 0.01).</p><p><b>CONCLUSION</b>Exposure to endotoxin in early lives of children might have a protective effect on atopic asthma and sensitization.</p>