Induction of Endothelial Cell Adhesion Molecules by Serum and Immunoglobulins G from a Patient with Vasculitis and Monoclonal Gammapathy: Potential Relevance to Vasculitis

Summary Interactions between endothelial cell adhesion molecules and their β2 integrin adhesive receptors on leukocytes are thought to play a role in the pathogenesis of inflammatory diseases and probably vasculitis. We describe a case in whom leukocytoclastic vasculitis was associated to a monoclonal immunoglobulin G2 kappa (IgG2K). During the vasculitic crisis, the patient’s serum and the isolated IgG from this serum induced the expression of E-selectin, VCAM-1 and ICAM-1 at the HUVEC surface, but not tissue factor activity, whereas normal, control serum and patient serum at remission were without any effect. A close relationship between the vasculitis and the serum level of the monoclonal IgG was observed. We suggest that the monoclonal IgG might induce the vasculitis by increasing the expression of E-selectin, VCAM-1 and ICAM-1 which facilitate the interaction of leukocytes with vascular endothelium.