Histamine metabolism and transport are deranged in human keratinocytes in oral lichen planus.

HOKs are histamine-producing cells. They release histamine via OCT3 channels in concentrations too low to activate the classical low-affinity H R and H R, but high enough to stimulate the high-affinity H R in autocrine and paracrine modes. The substantially deranged histamine metabolism and transport in OLP could, in part, contribute to the disease pathogenesis.