Corneal complications of ocular GvHD

Abstract

Corneal fluorescein staining is one of the tests recommended to diagnose and grade ocular graft versus host disease (GvHD) according to the International Chronic Ocular GvHD Consensus Group. Despite superficial punctate keratopathy is the most common corneal manifestation, patients with more severe stages may develop corneal neovascularization, sterile corneal ulceration and even perforation. Previous in vivo confocal microscopy (IVCM) studies reported significant microstructural changes in the cornea of patients with ocular GvHD, including a higher density of dendritic cells and globular immune cells, a network of hyper‐reflective activated keratocytes, and a lower density and higher tortuosity of sub‐basal corneal nerves. Dendritic cells act as antigen‐presenting cells, and play a key role in ocular surface immune homeostasis. Thus, their increased density may be indicative of immune activation and inflammation of the ocular surface in patients with ocular GvHD. Interestingly, Kheirkhah et al. reported higher dendritic cell density in patients with DED owing to systemic immune disease (i.e., Sjögren syndrome and ocular GvHD) compared to patients with DED of other origins. Recently, our group employed a fully automated IVCM analysis system to compare corneal sub‐basal nerve plexus in patients with DED owing to both ocular GvHD and Sjögren syndrome and in healthy control subjects. Although overall patients with DED showed lower density of nerve fibres and branches, shorter nerve fibres and higher fibre width compared to healthy controls, no significant difference was observed between patients with ocular GvHD and Sjögren syndrome for all IVCM metrics. In agreement with this observation, other studies reported no significant difference of IVCM parameters in DED patients with and without ocular GvHD after adjusting for clinical severity of dry eye. This suggests that the ocular surface changes observed by IVCM in ocular GvHD may be possibly reflective of the local disease severity rather than the underlying systemic process.