EFFECT OF TACROLIMUS HYDRATE (FK506) OINTMENT ON SPONTANEOUS DERMATITIS IN NC NGA MICE/

The effect of tacrolimus hydrate (FK506) ointment on spontaneous derma titis in NC/Nga (NC) mice was examined. FK506 ointment (0.1-1%) suppre ssed the development of dermatitis and was also therapeutically effect ive against established dermatitis. Increases in CD4-positive T cells (helper T cells), mast cells, eosinophils and immunostaining of interl eukin (IL)-4, IL-5 and IgE were confirmed in the skin of the NC mice, and FK506 ointment suppressed all of these changes. Increased plasma I gE was also confirmed in the NC mice, and treatment with FK506 ointmen t reduced the plasma IgE level. These results suggested that FK506 sup pressed the dermatitis by inhibiting the activation of inflammatory ce lls and by blocking the cytokine network in the skin of the NC mice. T he commercially available steroid ointments showed only marginal effec t on the development of dermatitis and showed some signs of side effec ts such as alopecia or atrophy of the skin. The effect of the steroids might have been masked by these side effects because the steroids sho wed similar inhibitory effects on the skin histopathological changes a nd the increase of plasma IgE. From these results, FK506 ointment can be expected to be a useful drug for atopic dermatitis.