To study the expression of the α1–α6 chains of type IV collagen in the dermoepidermal junction (DEJ) during human foetal skin development, human foetal (10 and 20 weeks of gestation) and adult skin was immunostained with specific monoclonal antibodies to the α1–α6 chains of type IV collagen. Intense expression of the α4 chain and weak expression of the α2 and α6 chains were observed in the DEJ of 10 weeks gestational skin. In contrast, the α1, α2, α5 and α6 chains were detected in the DEJ of 20 weeks gestational and adult skin. Preferential expression of α4 during the early phase of development (10 weeks of gestation) may suggest a chain-specific regulatory mechanism for type IV collagen expression and its potential role in DEJ formation during development. [ABSTRACT FROM AUTHOR]