Background: Accurate inflammatory mechanisms in chronic ocular surface diseases (OSDs) cannot routinely be assessed. New techniques for investigating ocular surface inflammatory pathways are of major importance.
Objective: To investigate the expressions of CCR 4 and CCR 5, known to be related to the T(H)2 and T(H)1 systems, respectively, and HLA-DR in conjunctival impression cytology specimens from patients with chronic OSDs.
Methods: In this case-controlled study, impression cytology specimens were taken in a series of patients with vernal keratoconjunctivitis (n=21), giant papillary conjunctivitis (n=6), or keratoconjunctivitis sicca (KCS; n=17), or receiving topical antiglaucoma treatments (n=31), and from 20 normal subjects. Conjunctival cells were incubated with mAbs to CCR 4, CCR 5, CD45, and HLA-DR to quantify conjunctival inflammation in a masked manner using flow cytometry.
Results: HLA-DR was higher in the glaucoma and KCS groups than in allergic and normal eyes. CCR 4 was overexpressed in allergy and glaucoma, whereas CCR 5 was higher in the KCS and glaucomatous groups. CD45 was expressed by only few cells in all groups, with almost no significant differences. CCR 4 expression was negatively correlated with CCR 5 and HLA-DR, whereas CCR 5 was positively correlated with HLA-DR.
Conclusion: This study confirms the overexpression of chemokine receptors by the conjunctival epithelium in OSDs. CCR 4 and CCR 5 expression may vary according to the immune pathway involved. Accurate mechanisms in ocular surface inflammatory reactions-that is, those related to the T(H)1 or T(H)2 systems-could be differentiated by CCR 4/CCR 5 profiles. Our results also suggest that long-term use of topical treatments may stimulate both systems.