Larsson A, Möller H, Björkner B, Bruze M.
DOI: 10.2340/0001555577474479

In a double-blind study, 20 patients with contact allergy to gold were given an intramuscular injection of gold sodium thiomalate or placebo, inducing a clinical and histological flare-up of healed patch test sites in the gold-injected but not in the placebo group. The test area of the placebo group showed some perivascular lymphocytic foci (UCHL-1+) and vascular endothelial ELAM-1 staining. The gold group, with flare-up, showed larger and more extensive lymphocytic foci with ELAM-1+ endothelium as well as lymphocytic epidermotropism. CD1a+ LC cells were downgraded, tryptase+ mast cells accumulated and CD68+ monocytes/macrophages markedly increased. Probably, a significant part of the tissue priming as a result of patch testing comprises memory T-cells and endothelial ELAM-1 upgrading, but blood-borne CD68+ monocytes may also be instrumental in the flare-up.