Determination of the core sequence of an antagonist of selectin-dependent leukocyte adhesion and correlation of its structure with molecular modeling studies

Loss of Endothelial Surface Expression of E-Selectin in a Patient With Recurrent Infections

Neutrophil accumulation at sites of inflammation is mediated by specific groups of cell adhesion molecules including the β2 (CD18) integrins on leukocytes and the selectins (P- and E-selectin on the endothelium and L-selectin on the leukocyte). This is supported by studies of patients with leukocyte adhesion deficiency syndromes whose leukocytes are genetically deficient in the expression of β2 integrins or selectin carbohydrate ligands (eg, sialyl-Lewisx). However, inherited deficiency or dysfunction of endothelial cell adhesion molecules involved in leukocyte recruitment has not been previously described. In this report we describe a child with recurrent infections and clinical evidence of impaired pus formation reminiscent of a leukocyte adhesion deficiency syndrome, but whose neutrophils were functionally normal and expressed normal levels of CD18, L-selectin, and sialyl-Lewisx. In contrast, immunohistochemical staining of inflamed tissue from the patient showed the absence of E-selectin from the endothelium, although E-selectin mRNA was present. However, E-selectin protein was expressed as significantly elevated levels of circulating soluble E-selectin were detected, the molecular size of which was consistent with a proteolytically cleaved form of E-selectin. Gene sequencing failed to show evidence of a secreted mutant variant. These data represent, to our knowledge, the first description of a potentially inherited dysfunction of an endothelial cell adhesion molecule involved in leukocyte recruitment and provide additional human evidence of the importance of endothelial selectins in the inflammatory response.

Pharmacological modulation of cell adhesion molecules

Cell adhesion molecules mediate the contact between two cells or between cells and the extracellular matrix. They are essential for morphogenesis, organization of tissues and organs, regulation of immune cell responses and migration of inflammatory cells from the blood vessels into inflamed tissues. Many diseases have been shown to be associated with dysfunction or with overexpression of certain adhesion molecules. Increased cell adhesion molecule function and number are found in clinical disorders in which inflammation and immune cells are involved. Several possible therapeutic agents are described here which have been shown to reduce the expression and/or function of cell adhesion molecules. Anti-adhesion treatment can lead to diminished infiltration and activation of inflammatory immune cells resulting in decreased tissue injury and malfunction.