HLA 6 loci matched allogeneic iPS cells derived retinal pigment epithelial cells (iPSC-RPE) transplantation

Abstract

Purpose : Safety study of HLA 6 loci matched allogeneic iPS cells derived retinal pigment epithelial cells (iPSC-RPE) transplantation and immune response to the graft cells. transplantation for age-related macular degeneration

Methods : A clinical research was started in February 2017 and iPSC-RPE suspension was transplanted in the subretinal space for five cases of exudative age-related macular degeneration, which is resistant or recurrent to anti-VEGF antibody treatment. The course of 1 year was observed while checking the reaction of peripheral blood lymphocytes to the transplanted cells by the lymphocyte graft immunoassay test (LGIR test).

Results : The age of the case was 65 to 81 years old, the visual acuity was 0.09 to 0.15, and all cases were males. The surgery ended without any serious complications, and no excessive proliferation or tumorigenesis of transplanted cells was observed in 1 year after surgery. Corneal epithelial exfoliation was observed in the first case, retinal edema by epiretinal membrane was observed in the second case, and membrane removal was performed 7 months later. In the 5th case, steroid pulse therapy was performed with aseptic intraocular inflammation judged as allergy to vitreous steroid injected at the end of the operation by the Lymph Graft Immune Reaction (LGIR) test. Corrected visual acuity did not change before and after surgery. Regarding the immune response, a slight subretinal fluid appeared in the first case, and because LGIR test mild positive was recognized, administration of Tenon's subcapsular steroid and anti VEGF agent resulted in negative LGIR test, and subretinal fluid also disappeared. In all cases, rejection was able to be suppressed by only topical administration of steroid.

Conclusions : Immune responses to transplanted allogeneic cells could be suppressed by topical steroid administration without systemic immunosuppressant. Safety was confirmed one year after transplantation of HLA 6 loci matched allogeneic iPSC-RPE.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.