DISTRIBUTIONAL CHANGES OF LANGERHANS CELLS IN HUMAN SKILL DURING IRRITANT CONTACT-DERMATITIS

We used light and electron microscopic immunocytochemistry to study di stributional changes in the human Langerhans cell (LC) system during t he first 14 days of a mild irritancy caused by sodium lauryl sulphate (SLS). A marked initial decrease in epidermal LC was noted possibly re sulting from migration from the epidermis to the dermis and from irrev ersible cell damage. Several studies have previously found an unchange d number of LC in SLS-induced contact irritant dermatitis, but these s tudies may not have taken into account the fact that SLS is effectivel y absorbed from the test chamber. Unless certain precautions are taken the SLS concentration rapidly falls to topical levels that have no ef fect on the LC system. Simultaneously with the decrease in the epiderm is we observed an increase in dermal CD1a+ cells, confirming an often reported finding. There is, however, no consensus as to the identity o f these cells; and several authors have reported that such cells lack LC granules and thus these cells have often been classed as indetermin ate cells. We found that, during irritant contact dermatitis, provided an adequate number of sections were scrutinized in the electron micro scope, all dermal CD1+ cells contained Birbeck granules.