Large increase of Langerhans cells in human skin lymph derived from irritant contact dermatitis.

In order to monitor the kinetics of Langerhans cells in the afferent lymph during contact dermatitis, a superficial peripheral lymph vessel draining the skin of the upper and medial part of the foot was cannulated by means of microsurgery on the lower leg of four healthy volunteers. After 2 days an irritant contact dermatitis was induced by application of 10% sodium lauryl sulphate to the area of skin drained by the cannulated lymph vessel. Three days later the spontaneously regressing skin reaction was treated with clobetasol propionate in two of the subjects. Lymph was collected twice daily for 8 days. Langerhans cells were identified by immunofluorescence microscopy of cytocentrifuge slide preparations from the lymph, using a monoclonal anti-CD1a antibody. In the late phase of the contact dermatitis the output, i.e. both the absolute number and the percentage of Langerhans cells in the lymph dramatically increased. At the end of the experiment, when there were no remaining clinical signs of contact dermatitis, the Langerhans cell output still markedly exceeded the initial values. These results are the first direct evidence in humans that migration of Langerhans cells from the skin to the regional lymph nodes is a major feature of irritant contact dermatitis.