Prostaglandins in PUVA-treated psoriasis.

The biosynthesis of prostaglandins (PG) in biopsies from 9 patients with recalcitrant psoriasis was studied before, during, and after treatment with 8-methoxy-psoralen and long-wave ultraviolet light (UVA). No statistical difference was found between the results obtained before, during, and after the treatment. In PGE1-equivalents, the concentration in involved psoriatic skin was 2.16 +/- 0.31 ng (mean +/- S.E.M.) before, 2.01 +/- 0.33 ng during, and 2.85 +/- 0.31 ng per g wet weight after PUVA. In uninvolved skin the concentrations were 2.38 +/- 0.26 ng, 2.23 +/- 0.15 ng and 3.29 +/- 0.24 ng per g wet weight, respectively. In the presence of exogenous arachidonic acid in the incubation medium the activity formed was higher, but no statistical difference was found between pretreatment values and those obtained during and after PUVA treatment. The hypothesis that PUVA treatment stimulates PG biosynthesis, thus accounting for the beneficial therapeutic antipsoriatic effect, could not be confirmed.