[Therapeutic approach to mite-induced intractable dermatitis using novel immunomodulator FTY720 (fingolimod) in combination with betamethasone ointment in NC/Nga mice].

BACKGROUND: The increasing incidence and prevalence of atopic dermatitis (AD) have led to a requirement for new means to treat the disease. We investigated the therapeutic efficacy of the novel immunomodulator FTY720 (Fingolimod), alone and in combination with betamethasone valerate ointment, in the NC/Nga mouse model of mite-induced intractable dermatitis. METHODS: Female NC/Nga mice in which dermatitis had been induced with Dermatophagoides farinae were divided into six groups: 1) a betamethasone group (betamethasone ointment, six times a week), 2) an FTY720 group (FTY720, orally, three times a week), 3) an FTY720 plus betamethasone ointment group, 4) an ointment base group (ointment base, six times a week), 5) an FTY720 plus ointment base group and 6) a placebo group (vehicle alone). The therapeutic efficacy was evaluated in terms of the severity of dermatitis and histochemical observations after two weeks of treatment. RESULTS: Betamethasone treatment had little effect, confirming that the dermatitis was intractable. In the FTY720 plus betamethasone ointment group, the dermatitis was significantly improved as compared with the betamethasone ointment and placebo groups. This combination therapy also suppressed epidermal hypertrophy and accumulation of mast cells and CD3+T-cells in dermis, all of which were observed in mice in which the dermatitis had become established. CONCLUSION: Our results strongly suggest that the combination of FTY720 plus betamethasone ointment is a promising candidate for treatment of intractable human AD.