Cell line supernatants were volume reduced 3- to 10-fold in centrifugal spin cartridges (Ultrafreë Biomax-5K NMWL membranes, Millipore Corp, Bedford, MA) and media conditioned by neutrophils (Neut) was volume reduced 30-fold before analysis in the ELISA; however values shown in Table 3 are corrected for volume reduction. PBSC samples were analyzed without volume reduction. PBSC samples 1, 2, and 6 correspond to samples 1, 2, and 6 in Figure 3. PBSC Samples 1, 6, 7, 10 = donors for autologous transplant. Samples 2, 8, 9, 11 = donors for allogeneic transplant. ND = not detected. All samples were analyzed in duplicate and variance between individual wells did not exceed the established intra-assay precision (Table 2).