Antibodies to outer root sheath of hair. Distinct antigenic properties of the basal cell layer of the outer root sheath below the sebaceous gland canal.

By screening 1500 sera obtained from patients undergoing a bone marrow graft, five sera have been selected which contained antibodies to the basal cell layer (B.C.L.) of the outer root sheath (O.R.S.) of hair follicles. It was demonstrated that these sera reacted with the B.C.L. of the O.R.S. but not with the B.C.L. of the adjacent epidermis. The change in antigenic properties was situated at the orifice of the sebaceous gland canal; thus basal cells below this orifice express an antigen distinct from those expressed by the epidermal basal cells. This is a novel example of tissue specific differentiation antigens that are linked to the type of keratinocyte differentiation.