Urokinase could increase the yield of progenitor cells during red cell depletion in elapsed and anticoagulated cord blood.

We assessed whether the urokinase could increase the yield of progenitor cells during processing in elapsed, anticoagulated cord blood (CB) after collection, and we also determined the optimal dose of urokinase. The total nucleated cell (TNC) counts after red cell depletion in 48-hr-elapsed CB were significantly higher in samples treated with 10,000 and 50,000 IU of urokinase/mL than in untreated samples or treated with 5,000 IU of urokinase/mL. The CD34(+) cell counts were significantly higher in samples treated with 10,000 IU of urokinase/mL than in untreated samples and in samples treated with 5,000 or 50,000 IU of urokinase/mL. In 6-, 12-, and 24-hr-elapsed CB, however, there were no significant differences of TNC, CD34(+) cells, or CFU-GM counts between untreated samples and samples treated with 10,000 IU of urokinase/mL. These findings suggest that the addition of 10,000 IU of urokinase/mL before red cell depletion in 48-hr-elapsed, anticoagulated CB could increase the yield of progenitor cells. However, there are no advantages in using urokinase for processing CB prior to 24 hr after collection.