Prostaglandin E receptor 4 expression in human conjunctival epithelium and its downregulation in devastating ocular surface inflammatory disorders.

Maskin in 1994 as being effective in the treatment of ocular neoplasia. A limited number of cases in the literature also show the cytostatic effect of ATRA on ocular surface dysplasia. Our early experience with topical ATRA alone was consistent with early reports of effectiveness, with no response occurring in certain patients. Our early experience with topical interferon alfa-2b demonstrated a more consistent clinical response, and recent studies have documented an 80% treatment efficacy using topical interferon alfa-2b. Mitomycin C and fluorouracil are alternative topical therapies for ocular surface dysplasia. However, interferon has fewer ocular adverse effects compared with these topical chemotherapeutic agents. Retinoic acid is known to irritate the conjunctiva in higher doses. In our patient, neither ATRA nor interferon alfa-2b alone was effective in slowing growth of the ocular lesion. Longer treatment with interferon alfa-2b may have led to a better response. The rapid clinical response to the combined treatment with topical interferon alfa-2b and ATRA seems remarkable. However, previous studies have described the synergistic effects of interferon alfa-2b and ATRA in combination, both in vitro and in vivo. These same studies, although not of an eye or eye model, reported that ATRA can permit growth inhibition by interferons in interferonunresponsive cells. Prospective studies with more patients and longer follow-up are needed to confirm the treatment efficacy and safety profile of this combination therapy as a well-tolerated alternative to topical mitomycin C and fluorouracil. Appropriate further studies may reveal a benefit for both dysplastic and neoplastic lesions.