CEA-related cell adhesion molecule 8 (CEACAM8, CD66b) belongs to the carcinoembryonic antigen (CEA) gene family (1,3,4). It encodes a glycosylphosphatidylinositol (GPI)-linked glycoprotein with a Mr of 95,000 which is expressed in cells of the granulocyte-lineage. It is expressed in neutrophils and eosinophils and is characterized as a granulocyte-specific activation antigen. CEACAM8 could serve as a marker for granulocyte activities (2). Like all members of the CEA family, it consists of a single N domain, with structural homology to the immunoglobulin variable domains, followed by two immunoglobulin constant-like A and B do-mains.