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Granulocyte transfusion (GTX) is a therapeutic option for severe bacterial or fungal infection in patients with sustained neutropenia after chemotherapy or stem cell transplantation. However, high molecular weight hydroxyethyl starch (HES), which has been used for selective sedimentation of red blood cells during apheresis, is not easily available in many countries including Japan. In this study, we evaluated the efficiency of granulocyte collection using medium molecular weight HES (130 kDa) in combination with the Spectra Optia apheresis system. Apheresis was performed for 2 consecutive days from seven donors and the mean total neutrophil yield from the first and second apheresis was 5.27 ± 3.10 × 1010 and 2.91 ± 2.92 × 1010, respectively. Infusion of concentrates from the first apheresis resulted in a significant neutrophil count increase and concentrates from the second apheresis were enough for maintenance of the neutrophil counts in all the recipients. Although the number of cases is limited, our results clearly show that sufficient number of granulocytes can be harvested by using medium molecular weight HES and this strategy is a safe and effective clinical practice in countries where high molecular weight HES is not available.

The clinical application of mesenchymal stromal/stem cells (MSCs) has been extensively explored. In this study, we examined the availability of freshly donated umbilical cord blood (UCB) units that do not qualify for the Japanese banking system for transplantation because of their small volume as a source of MSCs. Forty-five UCB units were used. The median volume of each UCB unit and number of nucleated cells per unit were 40 mL and 5.39 × 10(8), respectively. MSCs were successfully isolated from 18 of 45 units (40 %). The MSC isolation rate was not affected by cell processing method or the interval between delivery and cell processing. The volume of the UCB unit and the mononuclear cell count were predictive factors of the MSC isolation rate. MSCs were effectively isolated by selecting UCB units with a volume of ≥54 mL and containing ≥1.28 × 10(8) mononuclear cells, yielding a MSC isolation rate of70 %. UCB-derived MSCs were similar to bone marrow-derived MSCs in terms of their morphology, surface marker expression, and differentiation potential, apart from adipogenesis. Our data indicate that UCB units that are currently discarded due to inadequate volume should be reconsidered as a source of MSCs using the well-established UCB banking system.