Retinol binding protein in normal human skin and in cutaneous disorders.

Circulating vitamin A is transported by a carrier termed retinol binding protein (RBP). Autoradiography and immunofluorescence studies showed that, in normal human skin, RBP is confirmed exclusively to the dermis. Following oral vitamin A loading, a large increase in dermal RBP but only a very small rise of serum RBP was found. Serum RBP was slightly decreased in eczema patients and markedly decreased in patients with porphyria cutanea tarda. Values in other dermatoses, including psoriasis, were normal.