Expression of T6 antigen on keratinocytes in alopecia areata.

The expression of T6 antigen within hair follicles in alopecia areata was studied using the APAAP technique (alkaline phosphatase monoclonal anti-alkaline phosphatase method). Scalp biopsies were taken from 15 subjects with alopecia areata, nine in an active stage and 6 in a stationary stage of the disease. Six-micrometer-thick frozen sections were stained with OKT6 antiserum. OKT6 are monoclonal antibodies raised against human thymocytes; they cross-react with epidermal Langerhans cells and are a highly specific marker. Nine of the specimens displayed T6 staining on keratinocytes in the bulb matrix, and all nine were from the subjects presenting the active stage of disease. The specimens from the other six biopsies, from subjects in a stationary stage, did not show T6 staining of bulbar keratinocytes. Moreover, in four of the active-stage cases we found T6 staining also on epidermal keratinocytes.