UV sensitivity of human keratinocyte and Langerhans cell-expressed HLA-DR antigens: a comparison.

HLA-DR expression on human keratinocytes (KC) was induced in vivo by intradermal injection of purified protein derivative of tuberculin (PPD). Neither preceding nor subsequent exposure of the PPD injection site to a dose of approximately 2 MED of UVB radiation abolished KC HLA-DR, though subsequent irradiation caused a slight diminution in the intensity of the antigen expression. By contrast, epidermal Langerhans cell (LC) HLA-DR and T6 expressions in normal epidermis were greatly reduced by an identical dose of UVB. Pemphigus antigen on the surface of KC was not affected by irradiation or PPD injection.