Inflammatory manifestations of Ocular Graft versus Host Disease in the Cornea, Eyelid and Conjunctiva

Abstract

Purpose: Graft-versus host disease (GVHD) remains a major complication of allogeneic hematopoietic stem cell transplantation (HSCT) which is frequently accompanied by ocular involvement. We previously reported that in recipient mice following experimental MHC-matched minor histocompatibility-mismatched HSCT, ocular GVHD involves the presence of donor T cells in the cornea and pathologic changes in this compartment. The present study was directed to determine the kinetics of donor allo-reactive T cell presence in the cornea and investigate the presence of macrophage infiltration into the ocular adnexal tissue in recipient mice undergoing experimental allogeneic HSCT.

Methods: Experimental HSCT Model: After high-dose TBI, C3H.SW (H2^b) mice were transplanted with T cell depleted bone marrow (TCD-BM) alone from B6 (H2^b) EGFP transgenic mice or allo-reactive T cells from B6 (H2^b) CD45.1 transgenic mice. Recipients were monitored weekly for signs of systemic and oGVHD. In vivo fluorescent intravital microscopy was performed to track EGFP-labeled TCD-BM cells. Cornea, lids and conjunctiva were harvested weekly beginning 2 weeks post-HSCT for evaluation by histology, immunohistochemistry (IHC) and flow-cytometry.

Results: Mice transplanted with donor TCD-BM+T cells underwent weight loss and began exhibiting clinical signs of systemic GVHD. EGFP-labeled TCD-BM cells were detectable in the lid margin, conjunctiva and cornea of animals undergoing systemic GVHD by week two after transplantation and showed massive increased fluorescence by week six. Allo-reactive T cells were also present at week two which peaked at week four. IHC confirmed the presence of T cells and macrophage infiltration in the lid margin and conjunctiva. By week six, lid pathology showed significantly elevated donor inflammatory cell infiltrate consisting primarily of macrophages and T cells compared to control (TCD-BM only) recipients.

Conclusions: GVHD is a complex systemic disorder involving multiple tissues including the eye. The present study demonstrated that following HSCT, allo-reactive T cells appear first in the lid margin, conjunctiva and cornea and subsequently the recruitment of macrophages in the ocular adnexa can be identified followed by tissue damage.