Typical cutaneous small‐vessel vasculitis induced by combined injection of antiphosphatidylserine/prothrombin complex antibody and anti‐LAMP‐2 antibody in normal rats

Abstract We previously reported that IgA vasculitis and cutaneous arteritis could be dependently associated with the presence of the antiphosphatidylserine/prothrombin complex (anti‐PS/PT) antibody and lysosomal‐associated membrane protein‐2 (LAMP‐2). The copy number of LAMP‐2 mRNA in skin tissue samples from rats with cutaneous vasculitis induced by intravenous administration of anti‐PS/PT antibody after subcutaneous histone injection was significantly higher than in those without cutaneous vasculitis. We found LAMP‐2 protein overexpression in neutrophils and vascular endothelial cells of the affected blood vessels in rats with cutaneous vasculitis induced by intravenous administration of anti‐PS/PT antibody after cutaneous priming by histones. We found typical cutaneous small‐vessel vasculitis in the skin of rats given intravenous injection of both anti‐PS/PT antibody and anti‐LAMP‐2 antibody after cutaneous priming by histones. We suggested that the introduction of skin local histones and anti‐PS/PT antibody in serum could move LAMP‐2 to the cell surface of neutrophils and vascular endothelial cells, and that anti‐LAMP‐2 antibody could bridge these cells through antigen‐specific binding in typical cutaneous small‐vessel vasculitis.