The Relationship Between Dynamic Changes Of Immune Micro-environment In Anterior Chamber And Corneal Allograft Rejection

Purpose:To research the relationship between dynamic changes of immune micro-environment in anterior chamber and corneal allograft rejection.Methods:A total of 60 BALA/c mice received penetrating keratoplasty (PKP) were randomly divided into three groups—PKP group(A),PKP+FK506-DDS group(B) and rotationalautokeratoplasty(RAP)(C). The donor buttons were from C57BL/6 mice. After surgery, the rejection time of allograft was observed by slit-lamp. The inflammatory cells infiltrated in allograft and iris-ciliary body were evaluated by HE staining in three groups. CD4+T cells and MHC-Ⅱ+ antigen-presenting cells in allgrafts and iris-ciliary body were seen by immunofluorescence staining in three groups. The cytokines of IFN-γand IL-17 and their transcription factors of T-bet and ROR Y t in iris-ciliary body were detected by Real-time RT-PCR in A and B groups.Results:The rejection time of allograft in A group averaged 16.18±4.81 days. There was no rejection in B and C groups. Inflammatory cells infiltrated corneal limbus on day 3 and some inflammatory cells adhered to corneal endothelium. No inflammatory cells were observed in corneal allograft on day 3. On day 7, except that inflammatory cells infiltrated limbus, many inflammatory cells presented in the location of anterior chamber angle and some adhered to endothelium. No inflammatory cells were observed in corneal allograft on day 7. On day of alloftraft rejection, there were no observed inflammatory cells in limbus, but large mounts of inflammatory cells infiltrated in corneal allograft, accompanied by many neovascularization. In groups of B and C, only some inflammatory cells infiltrated in corneal limbus on day 3,7 and the same time of allograft rejection of group A, and no inflammatory cells infiltrated in anterior chamber angle, endothelium and allograft. In group A, only small mounts of CD4+ and MHC-Ⅱ+ cells walked along the iris-cililary body and no positive cells expressed in allograft. On day 7, many CD4+ and MHC-Ⅱ+ cells gathered together in iris-cililary body, anterior chamber angle and corneal limbus, and no positive cells presented in allograft. On day of allgraft rejection, large mounts of CD4+ cells presented in iris-cililary body and allograft and large CD4+ cell mass was observed in anterior chamber. At the same time, small mounts of MHC-Ⅱ+ cells expressed in iris-cililary body, limbus and allograft. There were no CD4+ and MHC-Ⅱ+ cells observed in iris-cililary body and allograft in group B. In group C, only some CD4+ and MHC-Ⅱ+ cells expressed in iris-cililary body and limbus on day 7 other than other time-points. The level of IL-17 and RORγt raised significantly in group A on day 7. The expression of IFN-γand T-bet went up gradually while the level of IL-17 and ROR Y t went down gradually from day 14 to day 21. The relatively low level of above cytokines and their transcription factors had little changes in group B.Conclusions:Dynamic imbalance of immune micro-environment in anterior chamber plays an important role in the process of corneal allograft rejection. The way of iris-cililary body-endothelium transporting active immune cells is crucial to the changes of immune miro-enviroment and blocking this way can effectively protect the allograft from immunological rejection. Th17 cells may promote the corneal allograft rejection in early stage while Thl cells centre in the process of corneal allograft rejection.