Abstract
Purpose: :
To investigate in impression cytology specimens the expression of CD45 and HLA-DR by conjunctival cells in patients with dry eye compared with healthy subjects.
Methods: :
Impression cytology specimens were collected from temporal bulbar conjunctiva of 25 patients with dry eye with or without Sjögren’s syndrome, placed into cold PBS with fixative, gently agitated for 30 minutes and centrifuged in order to harvest cells. After being incubated with monoclonal antibodies to CD45, HLA-DR, and isotype controls the samples were analyzed in a masked manner by flow cytometry. The percentage of CD45 and HLA-DR positive cells was calculated, and levels of fluorescence quantified and compared with those obtained in 15 normal (non-dry eye) subjects.
Results: :
Statistically significant changes in Schirmer test, corneal fluorescein staining, lissamine green conjunctival staining, and tear break-up time occurred in the study group compared to controls. Levels of expression of CD45 in the dry eye group (46.3 ± 29.1%) was significantly increased compared to controls (2.7 ± 6%, p<0.0001). Similarly, conjunctival cells were observed to significantly express HLA-DR in dry eye when compared to normal subjects (p<0.0001).
Conclusions: :
This study indicates that markers of inflammation are over-expressed in dry eyes. In particular, the expression of a pan-leukocyte marker such as CD45 on conjunctival cells may have a functional implication in the pathogenetic mechanisms of the disease, and opens new frontiers in the investigation of the role of immuno-mediated mechanisms of the ocular surface in dry eyes.
Keywords: inflammation • conjunctiva • cytology