Presumably as a result of UV irradiation, the levels of filaggrin proteins and associated processing enzymes are increased on photoexposed facial skin in all three ethnic groups.

Obviously, the resulting elevated NMF levels are insufficient to correct the underlying biochemical abnormality in corneocyte maturation. We have previously shown that enzymes involved in corneocyte maturation are lowered in photoexposed facial skin of Caucasians. These enzyme levels are currently under investigation in the other two ethnicities. Our results demonstrate that increased levels of filaggrin proteins, their processing enzymes and the resulting NMF are insufficient to correct the cellular and biochemical abnormalities in photodamaged skin. Thus, we are focusing on other epidermal differentiation markers.