TOPICAL FK506 - A POTENT IMMUNOTHERAPY FOR ALOPECIA-AREATA - STUDIES USING THE DUNDEE EXPERIMENTAL BALD RAT MODEL

We elected to examine the efficacy of the topically applied immunosupp ressive agent FK506 (Prograf(R)) in the treatment of alopecia areata ( AA) using the Dundee experimental bald rat (DEER) model, Thirty lesion al DEER rats were allocated to five groups of six, Group I rats receiv ed 0.1 mL of a 0.25% solution of FK506 within a 2 x 2 cm marked area o n one bald flank twice a week (125 mu g FK506/cm(2) per week) for 8 we eks, while the contralateral flank was left untreated, In group II, 0. 05 mL of a 0.1% solution of FK506 was applied 5 days per week on one f lank (62.5 mu g FK506/cm(2) per week) and control vehicle to the oppos ite flank for 8 weeks. Group III rats were treated as in group II exce pt that drug and vehicle were applied twice a week (25 mu g FK506/cm(2 ) per week) for 4 weeks. A positive control group received orally admi nistered cyclosporin A (CsA) (10 mg/kg daily) for 8 weeks and a furthe r group was left untreated, Rats were regularly examined and photograp hed with skin biopsies taken from groups II and III. All FK506-treated rats regrew hair at the site of drug application within 14-21 days. G rowth continued for 3 weeks beyond termination of treatment after whic h gradual hair loss was observed, No hair growth was seen as a result of vehicle application and hair loss continued on untreated areas and in the untreated control group, Immunohistology revealed a drastic red uction in the follicular inflammatory infiltrate at the site of the FK 506 application, The oral CsA group responded by simultaneous regrowth of hair over the whole body. Our findings suggest that FK506 may have considerable potential as a topical treatment for AA.