Background: Only little detailed information has been published by a small number of centers on experiences with the technical aspects of "in vitro" large-scale graft manipulation technologies.
Methods: We report our experiences with the graft engineering procedures performed and the results obtained after T cell depletion. We have analyzed data from 212 procedures (108 CD34+ cell selection and 104 CD3+/CD19+ cell depletion).
Results: We conclude that the final cell products after selection or depletion were completely different with regard to CD34+ cell purity (95.8% vs. 1.52%). The CD34+ cell recovery after CD34+ cell selection is negatively affected when the initial leukocyte and/or CD34+ cell counts exceed the threshold defined by the manufacturer (68.9% vs. 45.2%, p < 0.01). However, the cell count threshold defined for the depletion technique could be exceeded without seriously affecting final results (86.1% vs. 86.4% for those with more or less than 40 x 109 leukocyte before the procedure; p = 0.7). Another important conclusion from this study is that in both CD34+ cell selection and CD3+/CD19+ cell depletion better results were reached after having gained experience by performing the procedures several times. This means that a learning process can be expected when using these in vitro graft manipulation procedures.
Conclusions: It is extremely important to have experienced staff to perform these procedures. The expected results are different with each procedure so the decision on which of these T cell depletion approaches are used should be based on the characteristics of the final product wanted.