Investigation of skin-derived lymph: an approach to get insight into the skin immune system.

The skin acts as a mechanical, physicochemical and immunological control and defense system, and its lymphatic vessels play a role in the regulation of cell hydration and osmosis, as well as in immunological responses. Skin-derived signals, produced in response to various agents acting on the skin, arrive with the afferent lymph at the regional lymph nodes. These signals reflect the immunological processes in the skin and may also determine the reactions in the lymph node. By analyzing afferent lymph derived from specific skin lesions it should therefore be possible to get insight into local pathomechanisms as well as the signal transmission in skin disorders. In this report, we present methodological aspects of such skin-derived lymph studies and review the results obtained from studies of sodium-lauryl-sulfate-induced irritative contact dermatitis in humans.