Purpose
Peripheral ulcerative keratitis is a sight-threatening inflammatory disease of the cornea characterized by stromal thinning and adjacent conjunctival inflammation that may be associated with several systemic autoimmune conditions. We wished to identify types of inflammatory cells infiltrating the conjunctiva and characterize the cytokeratin (CK) profile of the conjunctiva in patients with peripheral ulcerative keratitis by performing immunohistochemical analysis on conjunctival biopsies taken during episodes of active ocular surface inflammation.
Methods
Prospective, non-comparative, interventional case series. Three patients (2 male, 1 female, mean age 50 years) with active peripheral ulcerative keratitis (Figure 1) underwent conjunctival recession as part of their management. Immunohistochemical staining of the excised tissue was performed.
Results
In all cases it was shown that the lymphocytic population was predominantly CD3 (Figure 2A) and CD4 (Figure 2B) positive T cells. In one case there were more CD8 positive than CD4 positive cells. In two cases CD8 positive cells (Figure 2C) were only present in small amounts. In all cases there were only small numbers of CD20 positive B cells (Figure 2D). A background population of histiocytes and a small number of macrophages with CD68 were also identified. Cytokeratin profiling of the conjunctiva found that CK 19 was diffusely present throughout the epithelium and CK 3 and 12 were only present in the more superficial layers.
Conclusions
The predominant cells infiltrating the conjunctiva during peripheral ulcerative keratitis are CD3 and CD4 positive T cells. When considering systemic therapy to treat this condition, clinicians should consider using treatments specifically targeting this group of cells. Therapies targeting other cells, such as B cells, would be less effective as such cells are only present in small numbers.