Microvascular leakage of plasma proteins after PUVA and UVA

Abstract

The transcapillary escape rate of albumin (TER(alb)), i.e., the fraction of intravascular albumin mass passing to the extravascular space per unit time, is a parameter of the leakage of macromolecules from the total microvasculature. In patients with psoriasis short-term PUVA treatment induces an increase in TER(alb). In this study TER(alb) was measured in 3 groups of normal humans treated with PUVA, UVA and 8-methoxypsoralen. Treatment with PUVA and UVA caused a statistically significant increase in TER(alb), whereas treatment with 8-methoxypsoralen did not induce any measurable changes. It is concluded that the UVA irradiation causes the abnormal leakage of macromolecules, whereas psoralen is not the responsible component. Furthermore, the phenomenon can be elicited in normals and is not based on a preexisting psoriasis.