Expression And Significance Of Th17 And Th22 Cells In Peripheral Blood Of Patients With Glioma

BackgroundGlioma is the most common primary intracranial malignant tumor, and in recent years, the morbidity of glioma shows ascending trend year by year. As the tumor infiltrates brain parenchyma, and has strong invasive and metastatic ability, as well as high recurrent rate, the five years survival rate of glioma is low. Surgery is still the main treatment of glioma together with radiotherapy, chemotherapy and other assistant treatments. Brain was considered to be an immune privilege organ before, but immune cells can pass blood-brain barrier and T cells can be actived in brain have been proved now, which provide a basis for immunotherapy of glioma. Th17 and Th22 cells were newly discovered CD4+ T lymphocyte subsets. Th17 cells mainly secrete IL-17, the key transcription factor of this subsets is RORC; Th22 cells mainly secrete IL-22, the key transcription factor of this subsets is AHR. Recent studies have proved the abnormal expression of Th17 and Th22 in autoimmune diseases, infectious diseases, tumors and hematologic diseases, and both of them participate in the development and progression of those diseases, but researches of their expression and effects in glioma are little.ObjectiveBy testing changes of Th17 and Th22 in glioma patients and healthy controls, and examining the expression of RORC mRNA and AHR mRNA, as well as the level of IL-22, we aim to explore the expression of Th17 and Th22 in glioma, and investigate their effects in development and progression of glioma.MethodsWe choosed 34 giloma patients enrolled from July 2014 to August 2015 in Department of Neurosurgery, the Second Hospital of Shandong University, and divided them into two groups according to pathology:17 low-grade group (WHO Ⅰ-Ⅱ) and 17 high-grade group (WHO III-IV),24 healthy controls were choosed. All their fasting blood was collected. We examined the percentages of Th17 and Th22 cells by flow cytometry, and analyzed their changes and correlations. We used RT-PCR to examine the mRNA expression of key transcription factors RORC and AHR. ELISA was used to detect the levels of IL-22.Results1. Compared with healthy controls, there had a tendency of increase of Th17 cells in glioma, but there had no statistical difference between them (P>0.05), and no difference was found between the high-grade group and the low-grade group (P>0.05).2. Compared with healthy controls, the percentage of circulating Th22 cells in glioma was significantly increased (P＜0.05), and the difference between high-grade group and low-grade group was obvious (P<0.05). A positive correlation between Th22 and Th17 cells was found in glioma (r=0.40, P=0.03), and no correlation between Th22 and Th17 cells was found in controls (P>0.05).3. Expression of RORC and AHR mRNA between patients and controls was not obvious (P>0.05; P>0.05); and no difference was found between high-grade group and low-grade group (P>0.05; P>0.05).4. The serum IL-22 level in patients was significantly increased compared with controls (P＜0.05). However, there was no difference of serum IL-22 levels between high-grade group and low-grade group (P>0.05).Conclusions1. There exists abnormal increase of Th22 cells and IL-22 levels in the peripheral blood of glioma, and changes of Th22 cells and IL-22 in the peripheral blood may become indicators of glioma.2. The correlation between Th22 and Th17 cells was obvious in glioma. Thl7 and Th22 cells may jointly participate in the pathogenesis and progression of glioma.