The level of phospholipase A2 activity is raised in the uninvolved epidermis of psoriasis

The activity of phospholipase A2 was measured in uninvolved psoriatic epidermis and normal epidermis. The mean phospholipase A2 activity in uninvolved psoriatic epidermis, expressed as nmol fatty acid released per mg protein per h, was raised compared with normal epidermis (7.88±s.e. 1·20 vs 2.18±s.e. 0·38; P<0·01). This observation is, we believe, the first demonstration of an abnormality in the uninvolved untreated psoriatic epidermis which could account for the pathology of the disease.