Decreased epidermal aryl hydrocarbon hydroxylase and localized pustular psoriasis

Microsomal aryl hydrocarbon hydroxylase (AHH) activity was measured in suction separated epidermis from forearm skin of thirteen patients with localized palmo--plantar pustular psoriasis and thirteen normal subjects before and after induction by benzanthracene. AHH activity had a mean value of 2 . 32 micrometer 30H-BP/mg microsomal protein/h +/- 0 . 23 (s.e.) in the patients and 3 . 41 +/- 0 . 23 in the normal subjects. AHH induction was also decreased with a mean value of 1 . 15 +/- 0 . 1 (s.e.) compared with 1 . 98 +/-- 0 . 14 for the normal subjects. Since in twelve of the patients the psoriasis had always been localized to the palms and soles, the decreased basal and induced AHH activity appears to be a primary characteristic of psoriatic skin; AHH activity initiate an increase in epidermal cell turnover through modulation of prostaglandin and adenylate cyclase activity.