Toll-Like Receptor 4 Expression In Obese Asthmatic Children With Allergic Inflammation

Background. Asthma is characterized by chronic inflammation of airways and obesity by persistent systemic inflammation. Exposure to lipopolysaccharides (LPS) may induce the development and severity of asthma. Toll like-receptor 4 (TLR4) recognizes LPS and can direct the response of T-helper cells. Level of expression of TLR4 in patients with asthma and obesity is currently unknown.Methods. We conducted a pilot study that included patients with asthma-obesity, asthma, obesity and those who were apparently healthy. Using immunocytochemistry, we determined the level of expression of TLR4 with specific anti-TLR4 monoclonal antibody, blocking Fc receptors. With a BX-40 Olympus microscope, 100 cells were evaluated per slide. Differences in the number and degree of positive cells were established by Kruskal-Wallis test and Dunn post hoc analysis.Results. TLR4 expression in the cells of the asthmatic group of patients was significantly greater than in the healthy group of patients and higher than any of the other two groups. Conversely, the obese group expressed less TLR4 than the healthy group and any of the other two groups (p < 0.001). The asthma-obese group showed no significant difference with respect to controls. Additionally, we observed significant differences among the three groups of patients (p < 0.05).Conclusions. TLR4 expression was different in the three groups of patients. The highest level in the asthmatic patient may be explained by the high sensitivity to LPS or to other TLR4 ligands. This is the first study to show the level of expression in obese patients with asthma.