FUNCTIONAL-STUDIES OF SKIN MAST-CELLS IN LICHEN-PLANUS

In order to identify possible functional differences between mast cell s obtained from the skin of lichen planus (LP) patients and healthy do nors, biopsies from lesional skin of 11 lichen planus patients and fro m normal skin of 7 healthy donors were sampled. Mast cells were obtain ed from the skin using an enzymatic dispersion technique, The cells we re challenged in vitro with substance P (SP), tumor necrosis factor al pha (TNF-alpha) and anti-IgE. Their reactivity was estimated on the ba sis of histamine release, LP skin mast cells and healthy skin mast cel ls showed similar sensitivity to stimulation with TNF-alpha at a conce ntration of 10(-7) M (15.2% histamine release, as a proportion of tota l cellular content vs 15.9%) and to stimulation with anti-IgE at a dil ution of 1:100) (38.8% vs 37.0%), Spontaneous histamine release was al so very similar in both the populations of mast cells (10.2% vs 12.7%, respectively), However, LP skin mast cells showed significantly highe r (P < 0.01) sensitivity towards stimulation with SP at a concentratio n of 10(-4) M than healthy skin mast cells (15.9% histamine release vs 7.0%), This finding could suggest that neurogenic inflammatory mechan isms contribute to the pathogenesis of LP.