Human microvascular endothelial cells were isolated from children's brain and examined for their morphological characteristics and upregulation of cell adhesion molecules in response to TNF alpha. Our human brain microvascular endothelial cells (HBMEC) were positive for factor VIII-Rag, carbonic anhydrase IV, Ulex Europeus Agglutinin I, took up fluorescently labeled acetylated low density lipoprotein and expressed gamma glutamyl transpeptidase, demonstrating their brain endothelial cell characteristics. Upon treatment with TNF alpha. VCAM and ICAM but little ELAM was expressed on HBMEC, while VCAM, ICAM and ELAM were clearly evident on HUVEC. This selective expression of cell adhesion molecules was also demonstrated by in situ stimulation of brain tissues. In conclusion, microvascular endothelial cells from childrens brains display selective expression of cell adhesion molecules, which differ from macrovascular endothelial cells. This may have consequences for leukocyte trafficking into the central nervous system.