In order to investigate the immune accessory function of CD154, we loaded B-CLL cells from an HLA II DR13+ donor either with 293 exosomes, with exosomes from 293 cells transfected with an expression plasmid for gp350 (gp350+ exo) or transfected with expression plasmids for gp350 and CD154 (CD154+/gp350+ exo). The gene discussed is CD40LG; the disease is B-cell chronic lymphocytic leukemia.