Abstract
Purpose :
We previously demonstrated that adoptive transfer of CD3+ T-cells from glaucomatous to normal mice results in RGC loss in the recipient animals despite absence of elevated intraocular pressure (IOP). This study was conducted to evaluate whether a cellular immune reaction is also evoked by the mononuclear cells obtained from human glaucoma patients.
Methods :
Blood samples were obtained from primary open angle glaucoma patients who, despite normal IOPs, presented with optic disk hemorrhage - a clinical indication of disease progression (N=8). Samples were also obtained from healthy age matched controls (N=10). Peripheral blood mononuclear cells (PBMC) were isolated by gradient centrifugation and transferred into immune deficient NOD/scid gamma (NSG) mice. Twenty days after transfer all eyes received one microbead injection to create a mild IOP challenge. Fifty days after transfer eyes were harvested and the density of gamma synuclein positive retinal ganglion cells (RGC) was determined in retinal flat mounts. Additionally histochemical and immunohistochemical methods were used to evaluate retinal integrity and the presence of human lymphocytes in the mouse retina.
Results :
The transfer of human PBMC to NSG mice was generally well tolerated. One animal displayed signs of host vs graft disease and was excluded from the study. Microbead occlusion resulted in mild elevation of IOP in all eyes. Transfer of PBMC from non-glaucomatous patients did not decrease RGC density per mm2 when compared to controls that also received microbead injection, but no PBMC (2427±498 RGC/mm2 vs. 2354±367 RGC/mm2, p=0.73). In contrast, transfer of PBMC from glaucoma patients resulted in a marked decrease of RGC density (1436±310 RGC/mm2, p=0.0003). Immunohistochemical evaluation of recipient eyes indicated that human lymphocytes occasionally extravasate and can be found in the mouse retinal ganglion cell layer.
Conclusions :
These findings are congruent with those obtained in our mouse-to-mouse transfers and indicate that, at least in this group of patients, an immune reaction directed against RGC develops when transferred to mice. Further studies will be required to determine the relationship between this immune reaction and the vision loss frequently experienced by patients with optic disk hemorrhage.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.