Changes of ocular surface CD14 and TLR- 4 and TLR-9 in patients with
Vernal keratoconjunctivitis: an inflammatory epiphenomenon or a novel
pathogenic mechanism?
Abstract
Background: CD14 is involved in the modulation of immune reaction via
toll-like receptors (TLR) and may influence the development of allergic
diseases. The role of CD14 in vernal keratoconjunctivitis (VKC) has not
yet been investigated. The aim of this study is to evaluate changes of
tear soluble sCD14 and conjunctival CD14, TLR-4 and 9 expression in
patients with VKC in the active and quiescent phases. Methods: 18
patients with VKC during active inflammation (group A, N=9), in the
quiescent phase (group Q, N=5) and after recovery (group R, N=4) and 10
healthy subjects were included. Patients in group A were treated with
corticosteroid eye drops 4 times daily for 7 days. Expression of sCD14
in tears and of CD14, TLR-4, and TLR-9 by conjunctival epithelium were
evaluated by Western Blot in all groups and after corticosteroid
treatment. Results: expression of sCD14 and of CD14, TLR-4 and TLR-9 was
significantly decreased in group A when compared with healthy subjects
and with VKC group Q and R. Lower expression of sCD14, CD14, TLR-4 and
TLR-9 were significantly correlated with the severity of papillary
reaction, while the lower sCD14 was correlated with severity of
conjunctival hyperemia. Conjunctival expression of TLR-4, but not sCD14,
CD14 and TLR-9, was significantly reduced after topical corticosteroid
treatment. Conclusion: tear sCD14, and conjunctival CD14, TLR4 and TLR-9
decreased during ocular surface inflammatory reaction in patients with
VKC. CD14 and TLRs may represent potential therapeutic targets, although
it requires further studies.