Flow cytometry analysis of CCR4, CCR5 and CXCR2 in impression cytology specimens from patients with ocular surface disorders

Abstract

Abstract: : Purpose: To investigate in impression cytology specimens the expression of three chemokine receptors and class II antigens by conjunctival cells obtained from patients with various chronic ocular surface disorders of allergic, degenerative or iatrogenic origins. Methods: Impression cytology specimens were taken in a series of 55 patients suffering from perennial conjunctivitis, keratoconjunctivitis sicca (KCS) or receiving topical antiglaucoma treatments. Conjunctival cells were extracted and incubated with monoclonal antibodies to CCR4, CCR5, two chemokines related to the TH2 and TH1 systems respectively, CXCR2, as a receptor for IL–8, and HLA DR, in order to quantify conjunctival inflammation. They were processed for flow cytometry and analyzed in a masked manner. Results: HLA DR was expressed at high levels in the glaucoma and KCS groups but at very low levels in allergic patients. CCR4 was expressed at significantly higher levels in allergic and glaucomatous eyes than in the KCS group. CCR5 and CXCR2 in contrast were overexpressed in the KCS eyes compared to the two other groups but the glaucoma group was higher than the allergic one for both markers. Conclusions: This study confirms that various chemokines and/or their receptors may be expressed by the conjunctival epithelium, especially in chronic ocular surface disorders. Their level of expression may vary according to the mechanisms involved. This may be used for assessing accurate mechanisms in ocular surface inflammatory reactions, i.e. those related to the TH1 or TH2 systems that could be differentiated by their CCR4/CCR5 profiles. Our results also suggest that long term use of topical treatments would stimulate both systems.

Keywords: conjunctiva • cell membrane/membrane specializations • flow cytometry