Elimination of follicular non-hodgkin lymphoma (F-NHL) cells and high recovery of cd34+ cells from blood cell transplants by the miltenyi cell sorting system. m di nicola

Malignant celt contamination of aulologous blood cell transplants is likely to contribute to F-NHL relapse after potentially curative high-dose chemotherapy. In an attempt to circumvent this limitation, we have evaluated the capability of various techniques of negative and positive selection of CD34+ cells to eliminate F-NHL cells from blood cell transplants. The contamination of F-NHL cells was evaluated using nested PCR for the detection of bcA-2-lgH rearrangements. The assay was able to detect 1 F-NHL cell in 105 normal cells. Negative selection of CD34+ ceUs by removal of B-cells and other mature cells that naturally adhere to nylon wool fibers (Bone Marrow Transpl 14: 663, 1994) eliminated CD19+ B-cells detectable by flow cytometry but failed to achieve the negatMzatton of bcA2-lgH PCR. In contrast, in 5 experiments with a 0.5 x 109 blood cell transplant fraction, positive selection ot CD34+ cells by the Mittenyi high gradient magnetic system resulted in: a) the elimination of F-NHL cells as detected both by flow cytometry and oc/-2-lgH PCR in 4 experiments; b) a highly purified CD34+ cell population (90.8% ±2.3%); and c) the recovery of 77.9% ±3.2% CD34+ certs These results were confirmed on a large-scale with a 5.8 x 10a blood cell transplant processed with the Mittenyi SuperMacsn system in which positive selection of CD34+ ceils resulted in: a) the elimination of F-NHL cells; b) a highly purified CD34+ cell population (94.6%); and c) the recovery of 62.7% CD34+ cells. These results compare favorably with previous techniques that were either unable to eliminate F-NHL cells detectable by PCR, or caused unacceptable unspecifk: loss of hematopoietic progenitors.