Using microsurgery a superficial peripheral lymph vessel draining the skin of the upper and medial part of the foot was cannulated on the lower leg of two healthy human volunteers. An irritant contact dermatitis was induced 2 days later by the application of 10% sodium iauryl sulphate to the drained skin area.
After a further 3 days the spontaneously regressing skin reaction was treated with clobetasol propionate. Lymph was continuously collected in two aliquots per day for 7 days. The levels of total protein, of albumin and globulins, and of complement components of the classical, the alternative and the lyric pathway as well as the C4A and C4B gene products and the regulatory proteins FB, CIINH, C4BP, FH and FI were determined by ELISA and radial immunodiffusion techniques. Postoperatively, the levels of complement proteins and globulins in the lymph were 5-10 times lower than those in normal human serum, but increased during the course of the skin reaction, while the irritant contact dermatitis did not induce a change in their plasma concentration. In comparison to the baseline, the mean values for Clq, Clr, C2, C5, C6, C7, C8, C9, FB, CIINH, C4BP, FH and FI exhibited a 3-5-fold increase, C3, total C4, albumin and the alphal-globulin fraction a 6-9-fold increase, and Cls, C4A, C4B, FB and alpha2-, betaand gamma-globulins a 10-20-fold increase. The increase in the levels of complement proteins, in contrast to IL-6 and TNF~z, did not occur in the early phase of the skin reaction, but correlated with the lymph flow, the output of cells and the levels of several other cytokines. These results suggest that complement proteins do not play a role in the initial pathomechanism of irritant contact dermatitis, but are locally involved in the inflammatory process and interact with inflammatory cells, cytokines and further soluble mediators transported to the regional lymph nodes.