| BackgroundIt has drawn the attention of many researchers on the relation between many diseases and differentiation of CD4 helper T cell in recent years. Under the conditions of showing of the functional heterogeneity of T cell and effect from various cytokine, antigen presenting cell and antigen, the precursor Th0 cell selectively differentiate towards Th1 or Th2. The balance of differentiation of Th1/Th2 involves in many diseases. For example, human tumors are relative to Th2 drift, and allergic diseases such as asthma also refer to Th2 drift. Correction of the imbalance of differentiation of Th1/Th2 supports the occurrence of new methods of immunotherapy.T-bet, a new specific Th1-associated transcription factor, mainly expresses on CD4+ help T cell. The important role in differentiation of Th1/Th2 has been focused. Without challenging from sensitinogen, sole defect of T-bet can cause airway inflammatory reaction in mouse mode. One reason is the over expression for the loss of inhibition of Th2 and its cytokine from T-bet, and another is the decrease of Th1 and its cytokine for T-bet down-regulation. That is to say that Th2 and its cytokines increased relatively. Cytokine mediated by T-bet and changing of polarized Th2 may produce condition for treatment of allergic diseases.Th-associated transcription factors play an important role on balance of cytokine, but their effects on events after cytokine are still unclear. For example, the relation between transcription factors and eosinophil cationic protein (ECP) is unclear. The research about patterns of allergen-stimulated on Th-associated transcription factors is skin-deep. The expression of Th-associated transcription factors nasopharyngeal-associated lymphoid tissues (NALT), such as tonsils, adenoids and lymphoid tissues in nasal mucosa, need to be researched. It is important for investigation of the mechanism of development of AR to research T cell differentiation-associated transcription factor in the NALT and peripheral blood of AR patients on the aspects of the system immunity and local mucosal immunity. Our investigation is to view from the angle of changes of Th1-associatedtranscription factors T-bet, ECP, and CD23, and their correlations on allergen-stimulated peripheral blood monouclear cells (PBMC) of allergic rhinitis (AR) patients.ObjectiveTo detect transcription factor T-bet expression on PBMC and its relations with CD23, ECP and allergic symptoms scores in patients with AR. To investigate the changes the level of T-bet mRNA expression, CD23, ECP and allergic symptoms scores of AR patients after stimulus with dust mite allergen in vivo and in vitro as well as the pattern and value of T-bet expression in NALT of patients with and without AR.MethodsBlood samples were respectively taken from 15 healthy individuals and 60 patients with AR that their allergen was dust mite. The PBMC of 36 AR patients were cultured and stimulated by dust mite allergen at the concentration of 50μg/ml in vitro, and 24 AR patients received the specific immunotherapy (SIT) in vivo with standard dust mite allergen for one year. PBMC from two groups was subjected to analysis of T-bet mRNA expression using semiquaitative reverse transcriptase-polymerase chain reaction (RT-PCR).The level of CD19 /CD23 and ECP was respectively detected by flow cytometry (FCM) and Unicap system before and after culture and SIT.T-bet and CD4/T-bet expression on adenoids, tonsils and nasal mucosa were respectively detected with the single stain and double stain of immunohistochemistry. Before and after SIT for one year, the nasal symptoms of AR were evaluated.ResultsThe average ratio of T-bet toβ-actin levels respectively was 0.45±0.13 and 0.44±0.11 in 36 AR-patients PBMC before and after being stimulated by dust mite allergen in vitro, and the difference was statistically significant (t=0.675, P=0.504 ). The ratio of T-bet toβ-actin in 24 AR patients before and after SIT respectively was 0.44±0.14 and 0.49±0.09, between which the difference was statistically significant (t=-2.324, P=0.029).In control group, the ratio was 0.59±0.09, which was higher than that in the two above AR group (P=0.000). The level of ECP (μg/ml) and CD23 (%) in control group and AR group was 4.67±1.34 and 25.58±17.22 and 5.99±2.44 and 13.53±5.41, and two P value were lower than 0.01. Between 42 AR patients without asthma and other 18 AR patients with asthmatic symptoms, the level of T-bet, ECP CD23 and Symptoms scores respectively was 0.49±0.12 & 0.32±0.08, 22.45±17.28 & 32.89±15.11, 12.32±5.71 & 16.34±3.32, 8.43±1.65 & 9.61±1.70, and the t value correspondingly and respectively was 5.411, -2.224, -3.407 and -2.526, as well as P value correspondingly and respectively was 0.000, 0.030, 0.001 and 0.014. Moreover, there was no difference of those four items above between female and male.The expression intensity of T-bet mRNA had no relation to varying severity of allergic symptoms (r=-0.214, P=0.101). However, T-bet respectively has a negative relation with ECP and CD23 (r=-0.292, P=0.023; r=-0.260, P=0.045). There was positive correlation among ECP, CD23 and allergic symptoms scores (all P < 0.05). It indicated significant reduction of ECP, CD23 and allergic symptoms scores after SIT (t value respectively was 4.633, 5.113 and 10.798, all P < 0.01). T-bet mRNA expression was significantly up-regulated after SIT (χ~2=-2.324, P=0.029).The positive ratio of T-bet expression in tonsils, adenoids and nasal mucosa between AR group and control group was statistically different (χ~2=4.038, 3.860, 4.912, and P=0.044, 0.049, 0.027). There is difference of T-bet expression in tonsils from AR group in three different age groups(χ~2=7.079, P=0.029), the difference is that T-bet expression in adults group is significantly lower than that in children group and adolescent group; There is no T-bet expression difference of age groups in non-AR group. There were some positive expression of CD4 and T-bet in tonsils, adenoids and nasal mucosa from two groups and most positive expression of T-bet located on CD4 positive cell.Conclusions1. The level of CD23 and ECP in AR group was higher than that in non-AR group, but the T-bet expression was download-regulated in PBMC and NALT of patients with AR.2. The download-regulated level of ECP and CD23 and up-regulated T-bet expression in peripheral blood of AR patients can be observed after SIT. The level of CD23 and ECP in a way indicated the degree of severity of AR patients'condition.3. The down-regulation expression of T-bet, the Th1-associated transcription factor, was responsible for the lower Th1 response on system immunity and local mucosal immunity in AR patients. T-bet shows no response to the stimuli from allergen-stimulated in vitro.4. The Th2 predominance of transcription factor and cytokine is not driven by down-regulated T-bet expression in house dust mite-specific allergen-stimulated PBMC of patients with allergic rhinitis in vitro. It can be said that the allergen-induced Th2 immune response is not mediated by Th1-specific transcription factor T-bet in vitro.5. It develops a new view on SIT of AR that Th1 predominance at least on the level of transcription factor corrects Th1/Th2 imbalance in this way of mediation of up-regulation of Th1-associated transcription factor.6. T-bet expression of NALT is associated with allergic inflammation and functional status of NALT.
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