Latanoprost does not affect immune privilege of corneal allografts

The present study determined whether topical latanoprost, a prostaglandin (PG) F(2alpha) analog, influences the induction of anterior chamber-associated immune deviation (ACAID), corneal neovascularization (NV) or survival of corneal allografts in mice. BALB/c mice received topical latanoprost or PGE(2) once or multiple times daily starting 4 weeks prior to or the day of anterior chamber injection of C57BL/6 splenocytes. Induction of allo-specific ACAID was assessed by ear challenge with C57BL/6 splenocytes 1 week after subcutaneous immunization. In a separate experiment, orthotopic corneal transplantation was performed using C57BL/6 mice as donors and BALB/c mice as recipients. Recipients were randomized in a masked fashion to receive topical latanoprost or PGE(2). Graft fate was assessed clinically under surgical microscopy. Presence of MHC class II(+) CD11c(+) or CD11b(+) cells in normal BALB/c mouse eyes following latanoprost or PGE(2) administration was assessed immunohistochemically. Control mice received topical 20% dimethyl sulfoxide or no treatment. Allo-specific ACAID was induced after 2 or 6 weeks of once daily treatment with latanoprost, and was induced even after 6 weeks of multiple treatments with latanoprost. Conversely, mice receiving PGE(2) failed to develop ACAID. Opacity and corneal NV scores for allografts treated with latanoprost were statistically indistinguishable from those for control allografts (p>0.05), whereas all allografts treated with PGE(2) were rejected. Opacity and NV scores were significantly higher in these allografts than in controls (p<0.05). A number of MHC class II(+) CD11c(+) cells were present in the central cornea after PGE(2) treatment. Topical application of latanoprost does not influence induction of ACAID or graft outcomes including opacity and NV, whereas PGE(2) does. Immune privilege of corneal allograft is maintained after topical latanoprost application in mice.