PURPOSE: Lifitegrast ophthalmic solution 5%, an LFA-1 antagonist, is indicated for treatment of dry eye disease (DED). This study assessed the mechanism of action of lifitegrast in a murine model of DED.

METHODS: DED was induced in 6-8-week-old mice by exposure to controlled environmental chamber and subcutaneous injections of scopolamine. Mice were treated with topical lifitegrast (or normal saline [NS]) TID. DED severity was assessed with corneal fluorescein score (CFS), and T cells were quantified by flow cytometry (FC) of corneal single-cell suspensions. In vitro T cell proliferation assay was performed using naïve T cells from draining lymph nodes (dLNs) and dendritic cells (DCs). Expression of chemokine receptors on dLNs T cells was assessed by RT-PCR and FC. In adoptive transfer experiments, T cells from DED mice treated with lifitegrast or NS were transferred to (1) NS-treated DED mice to assess limbal vascular sticking efficacy (adhesion) of CD4+ T cells (number of sticking/rolling cells) and (2) RAG knockout mice; DED severity and T cells (in corneas and dLNs) were assessed after 5 days.

RESULTS: CFS was significantly reduced and tear secretion was significantly improved after 15 days of lifitegrast versus NS treatment in DED mice (P<0.05). in vitro proliferation of t cells isolated from dlns was 50 lower in the presence of lifitegrast versus ns p><0.05), suggesting inhibition of t cell-dc synapse formation. compared with ns treatment lifitegrast treatment resulted in reduction of ifn-secreting cd4 t cells th1 in the dlns recruitment of t cells to the cornea and significant reductions in cxcr3 and ccr4 chemokine receptor expression by fc and cxcr3 mrna levels in dlns cd4 t cells p><0.05). the limbal vascular sticking efficacy of cd4 t cells was significantly decreased following adoptive transfer of cd4 t cells to ns-treated ded mice from lifitegrast-treated ded mice compared with transfer of cd4 t cells from ns-treated ded mice after 15 days. adoptively transferred cd4 t cells from lifitegrast-treated versus ns-treated ded mice to rag knockout mice resulted in significant reduction of cfs p><0.05) and 60 reduction in cd4 t cell recruitment into cornea with no change in recruitment in dlns.>

CONCLUSIONS: These results demonstrate that topical lifitegrast has an effect beyond the ocular surface, directly on dLNs, through inhibition of T cell-DC synapse formation.