| Abstract: | Abstract: Natural killer (NK) and lymphokine-activated killer (LAK) activities in patients with seminoma were determined, and the timing of effective NK cell collection was evaluated, compared to autologus peripheral blood stem cell (PBSC) collection. After chemotherapy, patients were injected with granulocyte-colony stimulating factor (G-CSF). CD56 cells decreased in parallel with white blood cells and then were restored. After discontinuing the G-CSF, the CD56 cells increased and reached peak 3–5 days after PBSC collection. The peak showed higher levels than those at premedication. Recovery-peripheral blood lymphocytes (PBL) which were obtained 4 days after PBSC collection showed higher NK and LAK activities than the PBL obtained before chemotherapy (Before-PBL). They exhibited a high expression of CD2, CD 18, CD29, and CD49d. Furthermore, the LAK cells generated from the Recovery-PBL could aquire 9.6 folds of killer unit compared with the Before-PBL-LAK. These results suggest that, in order to obtain large numbers of NK cells, Recovery-PBL collection may be more advantageous than PBL collection in no relation with the chemotherapy. |
