CD79A and systemic lupus erythematosus: We then used ELISA to measure IgG, IgM and IgA specific to Sip1 C-ter in patients with distinct autoimmune diseases characterized by the presence of serum anti-endothelial cell antibodies such as BD, systemic lupus erythematosus (SLE), systemic sclerosis (SSc), various forms of primary vasculitis as well as in patients with diseases that share clinical features with BD, such as inflammatory bowel disease and uveitis.