Expression And Cinical Significance Of Thymic Stromal Lymphopoietin And Regulatory T Cells In Chronic Rhinosinusitis

Background and ObjectiveRhinosinusitis is a chronic inflammatory disease related to the nasal (rhinitis) and sinus mucosa (sinusitis). It is easy to relapse and has a high incidence rate. It is also one of the most common diseases in department of otolaryngology. It can bring the patients with nasal congestion, purulent nasal discharge flow, olfactory dysfunction, headaches and other symptoms and reduce the quality of life in patients with chronic sinusitis. The etiology and pathogenesis of chronic sinusitis is usually complex, generally considered some main causative factors:infection factors, allergic factors, immune factors and anatomical abnormalities in the nasal cavity and paranasal sinuses, of course, including gastroesophageal reflux, trauma factors. All the factors are often intertwined. Nearly 10 years, the study of chronic sinusitis has made a great breakthrough. A large number of studies have shown that the stimulation of bacteria, viruses and other microorganisms. The changes of nasal mucosal innate immune will affect T cell response (Th1Th2/Th17/Tregs) inflammatory cell infiltration (eosinophils/neutrophils, etc.), the nasal mucosa tissue remodeling. Thymic stromal lymphoid erythropoietin (TSLP), which was extracted from thymic stromal cells isolated by Friend, etc in 1944, is a novel cytokine with unique immune-related activity. TSLP is mainly secreted by the epithelial cells. When bronchial epithelial cells, mast cells, skin keratinocytes, stromal cells, lung fibroblasts are stimulated by antigen, TSLP will be up-regulated, and then act on dendritic cells to induce CD4+T cells into Th2 differentiation, which will produce and generate a lot of Th2-type cytokines like IL-4,5,13. So the balance of Th1Th2/Th1/Treg cells subsets will be broken. Meanwhile TSLP-activated dendritic cells can induce CD4+CD25+Foxp3+regulatory T cell (Tregs) to differente and mature. Treg cells play an important role in immune tolerance, immune suppression and keep the maintenance of immune homeostasis [2]. They can also inhibit the immune response towards bacteria, viruses and other infections. For example:it can inhibit inflammatory response of T cells and B cells through a way like cell contact; or play suppression effect by the secretion of IL-10 and TGF-β. Treg cells also play an important role in the development and recurrence of chronic sinusitis. Our study was designed to observe the expression of thymic stromal lymphopoietin (thymic stromal lymphopoietin, TSLP) and CD4+CD25+Foxp3+regulatory T cells (regulatory T cells, Tregs) in chronic sinusitis, and to investigate the possible mechanism of action in the development of chronic sinusitis.MethodsSpecimens were collected from the 53 hospitalized patients in our department from September 2013 to May 2014. Pathological mucosa of maxillary and ethmoid sinus in 25 patients with chronic sinusitis was taken, when the patients were treated with nasal endoseope surgery; during the same period in the control group, the part of inferior turbinate in 28 example was taken, when the patients were treated turbinate surgery. Nasal mucosal tissues were collected in duplicate. A specimen was quickly placed at -80℃ to save for qRT-PCR analysis. The expression of FOXP3 mRNA and TSLP mRNA in each sample were detected. Foxp3 is an important transcription factor expressing in Treg cells specifically, while it is the key regulatory genes, maintaining development and function of Treg cells. It can be used to mark the regulatory T cells. So the expression of FOXP3 mRNA may reflect the expression of regulatory T cells. According to the PCR results, we analyzed the differences of expression between TSLP, Treg cells in chronic sinusitis and normal nasal mucosa, respectively. Correlative analysis between the expression of TSLP and Treg cells were performed to initially clear their correlation. Another specimen was placed in formalin for HE staining and immunohistochemistry. Samples were embedded, sliced. HE staining was performed in order to observe the differences between normal nasal mucosa and sinus mucosa in chronic sinusitis. Slices were immunohistochemical stained and numbered by Foxp+3 protein and TSLP protein. Then we analyzed the correlation between the both positive cells in patients with chronic sinusitis sinus by immunohistochemistry. Positive standard of immunohistochemistry and cell count: double blind was used in the counting by two people. The first observation was at low magnification(×100), and then the two people count the number of inflammatory cells and tan or brown staining in the nucleus or cytoplasm respectively at three randomly selected high power fields(x400). Percentage of positive cells in the inflammatory cells and mean value were calculated.Results① The expression of TSLP mRNA in turbinate mucosa was (1.0502 ±0.9453). The expression of TSLP mRNA in sinus mucosa of the patient with chronic sinusitis was (1.4438 ± 0.1704), which is significantly increased compared with that in inferior turbinate mucosa. The difference was statistically significant (P=0.034<0.05).② The expression of FOXP3 mRNA in turbinate mucosa was(0.8992±0.3368). The expression of FOXP3 mRNA in sinus mucosa of the patient with chronic sinusitis was(2.2987±0,3569), which is significantly increased compared with that in inferior turbinate mucosa. The difference was statistically significant (P=0.01<0.05).③ Two parameters used the Spearman rank correlation test. To consider P<0.05 as statistically significant. Positive correlations were found between TSLP mRNA and FOXP3 mRNA (r=0.9773, p<0.005).④ By immunohistochemical staining, the positive cells appears as a diffuse cytoplasmic or nucleus brown yellow or brown particles. The percentage of Treg cells in chronic rhinosinusitis was (0.2550±0.05734). The percentage of TSLP positive cells in chronic sinusitis was (0.3160±0.75233). Two parameters used the Spearman rank correlation test. To consider P<0.05 as statistically significant. Positive correlations were found between TSLP and FOXP3(r=0.7378,p<0.005).ConclusionThrough this experiment, we found that either at the mRNA level or the protein level, the expression of TSLP and Treg cells in sinus mucosa of the patients with chronic sinusitis were increased, and both were positively correlated. These results suggest that TSLP is possibly take effect on the maintenance of immune homeostasis and take participation in the development and progression of chronic sinusitis by inducting the development and proliferation of regulatory T cell. This will help us to take a further reveal of the pathogenesis of chronic sinusitis and give us a better understanding. It is possible for us to take advantage of regulate proinflammatory factors and inflammatory factors for achieving a relatively balanced state. And this will bring new ideas and methods for the prevention and treatment of chronic sinusitis.