A NEW 2-STEP PROCEDURE FOR 4.5 LOG DEPLETION OF T-CELL AND B-CELL IN ALLOGENEIC TRANSPLANTATION AND OF NEOPLASTIC-CELLS IN AUTOLOGOUS TRANSPLANTATION

To evaluate a new 'two step' method for purging T, B and neoplastic ce lls from hematopoietic progenitor cells (PC), PCs were collected by ap heresis and some suspensions were deliberately contaminated with 2-5% breast cancer cells, PCs were first processed through CellPro columns for positive selection of cells that express CD34, After this first st ep, the mean CD34(+) cell recovery was 68 +/- 12%, and CD34(+) cell pu rity was 61 +/- 11%; CD3(+) and neoplastic cell depletion were 2.1 +/- 0.4 and 1.9 +/- 0.4 logs, respectively. Cells were further processed through the StemSep device for direct depletion of T and B cells or of breast cancer cells, After the first and the second step, overall CD3 4(+) cell recovery was 50 +/- 7%, T and B cell removal was 4.7 +/- 0.4 log and neoplastic cell purging was 4.4 +/- 0.3 log, ie significantly superior to methods described in the past.