The Expression And Significance Of Epstein-Barr Virus Encoded Small RNAs (EBERs) In Idiopathic Orbital Inflammatory Pseudotumor

Objective:The purpose of this study was to enplore EBV encoded small RNA(EBERs) in idiopathic orbital inflammatory pseudotumor (IOIP) lesion tissues infecting frequency and the positive cell types and location and distribution. To investigate the relationship between EBV infection and IOIP etiology.Methods:The study included 40 cases of pathological diagnosis of IOIP archive wax block samples from patients with IOIP between January 2007 and June 2014 at the two Affiliated Hospital of Guangxi Medical University were retrospectively collected. Using in situ hybridization to detect EBV encoded small RNA and immunohistochemical staining to detect CD3、CD20、CD21、 ALK、Vimentin and SMA proteins was performed to evaluate the positive rate of EBERs and the types and distribution and location of positive cell in IOIP.10 case of TAO(Thyroid associated ophthalmopathy,TAO) tissue sample serves as controls group at the same time.The chi square test was used to analyze the expression difference of EBERs in each group.Results:1.The positive rate of EBERs in IOIP group was 47.5%(19/40), the expression of EBERs in thyroid-associated opthalmopathy group (TAO) was 0.0%(0/10), the positive expression rate of EBERs in IOIP group was significantly higher than that in thyroid-associated opthalmopathy group (x2=5.778,p=0.016).2. In the IOIP group, the positive rate of lymphocytic infiltration subtype, fibrosis subtype and mixed subtype was 57.1%(12/21)、12.5 (1/8) and 54.5% (6/11). the positive expression rate of EBERs in IOIP subtype group no significant difference (x2=4.932, P=0.085)3. The positive signal of EBERs in IOIP lesion tissue was predominantly located in medium to small infiltrating lymphocytes and immunoblastic cells nuclei and distributed in the ectopic extrafollicular areas and perifollicular areas. Moreover, scattered EBERs positive signals were seen within ectopic lymphoid follicles germinal centers centroblasts nuclear in 3 cases.4. EBERs positive signals were also seen within Vimmentin and SMA immunostaining cytoplasmic positive spindled fibroblasts/myofibroblasts nuclei in 3 cases.Conclusions:The occurrence of IOIP have close relationship with EBV infected.There exist the high prevalence of latently infected EBV encoded small RNA (EBERs) within IOIP lesion tissue infiltrating lymphocytes and immunoblastic cells nucleus and lymphoid follicles germinal centers centroblasts nucleus and hyperplastic spindled fibroblasts/myofibroblasts nucleus. Autoimmune reaction caused by latently infected EBV reactivated may be involved in pathologensis basis of IOIP.