The stem cell collection will go from 1 to 4 days until enough immature cells have been collected, but will not be done on any day the donor's platelet count falls below 75,000. The stem cell is called a CD34(+) cell. These cells will then be processed over a cell-processing machine to try to purify the immature fraction of cells and remove the T-lymphocytes that are part of the fatal graft versus host disease. The T-cell is called a CD3(+) cell.