Flow cytometric analysis of inflammatory markers in conjunctival epithelial cells of patients with dry eyes.

PURPOSE

To investigate in impression cytology (IC) specimens the expression of inflammatory and apoptosis-related markers by conjunctival epithelial cells from patients with dry eye as a rationale for treatment with topical cyclosporine.

METHODS

Immunologic anomalies were identified at baseline, before treatment with the masked medication, in a homogeneous series of patients with dry eye syndrome, who were enrolled in a large European multicenter clinical trial (Cyclosporin A Dry Eye Study; Allergan, Irvine, CA). IC specimens were collected in 243 patients with moderate to severe keratoconjunctivitis sicca (KCS), with or without Sjogren's syndrome (SS). Fifty normal subjects were separately examined to provide normal control values. Specimens were analyzed in a masked manner by flow cytometry, using antibodies directed to markers of the immune system and/or apoptotic pathway: HLA DR, CD40, CD40 ligand, Fas, and APO2.7. Levels of expression were quantified, and results were compared with those obtained in the 50 normal patients.

RESULTS

One hundred sixty-nine specimens were successfully interpreted at baseline, including 41% from patients with SS. A highly significant increase of HLA DR expression by conjunctival cells was found in KCS-affected eyes compared with normal eyes, which did not express this marker or did so very weakly. HLA DR expression in eyes with SS was significantly higher than in KCS-affected eyes without SS. Fas and APO2.7 were found at low levels in all normal and KCS-affected eyes. CD40 and CD40 ligand expressions were significantly increased in eyes with KCS compared with normal eyes. HLA DR, CD40 and Fas were found at significantly higher levels in the SS group than in the non-SS group. CONCLUSIONS. Conjunctival cells from patients with dry eye with moderate to severe KCS, with or without SS, overexpress inflammatory and apoptosis-related markers. Whether inflammation is a primary phenomenon in KCS or is the consequence of repetitive abrasion of the ocular surface after tear film deficiency remains to be determined. These data, nevertheless, support the use of immunomodulatory and/or anti-inflammatory drugs in the treatment of patients with KCS.