sICAM-1, sE-selectin and sVCAM-1 are constitutively present in human skin lymph and increased in allergic contact dermatitis.

The expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and E-selectin is important for the regulation of the leucocyte traffic into and in inflammatory dermatoses. ICAM-1, VCAM-1 and E-selectin were initially identified as cell-surface proteins, but recent evidence suggests that they also exist in a soluble form. The collection of human afferent lymph exclusively deriving from a selected skin area allows insight into local pathomechanisms as well as signal transmission in skin disorders. In the present study we measured the concentrations of the soluble adhesion molecules (sAM) sICAM-1, sVCAM-1 and sE-selectin in human skin lymph derived from normal untreated skin, irritant contact dermatitis (CD) and the induction and elicitation phases of allergic CD. The strong elicitation reactions of allergic CD produced an increase in sAM output to about three times the baseline values but in the weaker irritant CD we observed no increase at all. In the induction phase of allergic CD the concentrations during the first 9 days of the experiment remained unchanged, as in the lymph derived from normal untreated skin, but were slightly increased thereafter. To our knowledge, no in vivo data exist on the local involvement of sAM in irritant and allergic CD in humans. Our results provide evidence of increased concentrations of sAM mainly in strong allergic CD.