Analysis of the LB-ECGF-1H–specific immune response in vivo. PBMCs from the patient obtained at various time points before and after DLI were stained with anti-CD8 antibody and LB-ECGF-1H/B7 tetramers (•) or, as a control, HY/B7 tetramers (□). M-protein (⋄) is expressed in grams per liter in peripheral blood.