EXPRESSION OF LACTO-N-FUCOPENTAOSE-III (CD15)-LEWIS AND SIALYL-LEWIS X-BEARING MOLECULES AND THEIR FUNCTIONAL-PROPERTIES IN EOSINOPHILS FROM PATIENTS WITH THE IDIOPATHIC HYPEREOSINOPHILIC SYNDROME

As the carbohydrate lacto-N-fucopentaose III (CD15 antigen or X-determ inant) and its sialylated derivative sialyl-Lewis X are involved in th e adhesion of cells rolling along the surface of endothelial cells, ex periments were done to study the presence of these molecules on human eosinophils from patients with the idiopathic hypereosinophilic syndro me. Normal-density eosinophils from some patients showed higher levels of expression for lacto-N-fucopentaose III than light-density eosinop hils. In contrast, sialyl-Lewis X was highly expressed by light-densit y eosinophils. Activation of normal-density eosinophils with calcium i onophore A23187 resulted in increased expression of these molecules fo r a short time. Monoclonal antibodies to these carbohydrates stimulate d eosinophils to secrete eosinophil cationic protein, but not eosinoph il peroxidase, and acted as costimulatory signals for C3b-induced degr anulation of eosinophil cationic protein. It was suggested that CD15 a nd sialyl-Lewis X might contribute to eosinophil-mediated tissue injur y in patients with the idiopathic hypereosinophilic syndrome.