Abstract: Specimens of skin lesion on the scalp were taken from 9 untreated alopecia areata (AA) and areata totalis patients by punch biopsy.T cell subsets of 9 patients were identified by APAAp technique (OKT4,8,11) and indirect immunoperoxidase technique (Leu 2a,3a,4);and the deposition of immune complex in hair follicle was examined by direct immunofluorescence technique in 7 patients.The results were as follows: (1) 70% cellular infiltrates around hair follicles were T cells,pan T (OKT11⁺).Most of them were Thelper (OKT4⁺).62.4%;the other were T-suppresser (OKT8⁺),11.8%.(2) The OKT4: OKT8 ratio was about 2.8-18.6.(3) In 6 of 9 patients there were many OKT11⁺ and/or OKT4⁺ positive cells migrated into the hair follicles.It is the authous' opinion that the abnormal T cells play an important role in AA.