In vitro proliferative and differentiating characteristics of CD133(+) and CD34(+) cord blood cells in the presence of thrombopoietin (TPO) or erythropoietin (EPO). Potential implications for hematopoietic cell transplantation.

We investigated the characteristics of cord blood (CD) CD133(+) and CD34(+) cells, by flow cytometry, clonogenic assays and assessment of the replating ability (area under the curve (AUC)) following 7-day liquid culture in the presence of early acting growth factors and either thrombopoietin (TPO) or erythropoietin (EPO). The CD34(+) population showed a more effective proliferation in all parameters tested and TPO proved to be more effective than EPO. On the contrary, the CD133(+) cell fraction retained and expanded more immature elements in a modest but consistent manner with either TPO or EPO. We conclude that CD133(+) and CD34(+) expanded cord blood cells could potentially be used in combination to overcome the shortcomings of cord blood transplantation in older children and adults.