Effect of 8-methoxypsoralen plus UVA on psoriasis leukotactic factor.

The effect of psoralen phototherapy on the chemotactic activity of psoriasis leukotactic factor (PLF) was studied. The chemotactic activity of PLF extracted from psoriasis scales was evaluated using modified Boyden chambers. Treatment of (1) psoriasis lesions, (2) psoriasis scale and (3) extracted PLF with 8-methoxypsoralen plus UVA irradiation reduced the chemotactic activity of PLF. These results may help define the mechanism of psoralen phototherapy in psoriasis.