ELIMINATION OF BCL-2-IGH-POSITIVE FOLLICULAR LYMPHOMA-CELLS FROM BLOOD TRANSPLANTS WITH HIGH RECOVERY OF HEMATOPOIETIC PROGENITORS BY THE MILTENYI CD34(+) CELL SORTING SYSTEM

Contamination of autologous blood cell transplants with cells of folli cular non-Hodgkin's lymphoma (F-NHL) may contribute to relapse of the malignancy after potentially curative high doses of chemotherapy and r adiotherapy, In an attempt to circumvent this limitation, we have eval uated various techniques of selection of CD34(+) cells to eliminate ma lignant cells from blood cell transplants of five patients with F-NHL undergoing high-dose sequential therapy, The contamination of F-NHL ce lls was evaluated using a nested PCR assay for the detection of bcl-2- IgH rearrangement with a sensitivity of one F-NHL cell in 10(5) normal cells, In two experiments with blood cell transplant fractions of 0.5 x 10(9) nucleated cells, negative selection of CD34(+) cells by remov al of B cells and other mature cells that naturally adhere to nylon wo ol fibers decreased the number of CD19(+) B cells detectable by how cy tometry but failed to eliminate bcl-2-IgH-positive F-NHL cells detecta ble by PCR, In contrast, positive selection of CD34(+) cells by the Mi ltenyi MiniMACS high gradient magnetic cell sorting system in five sep arate experiments resulted in: (1) the elimination of F-NHL cells in f our out of five cases as detected both by how cytometry and bcl-2-IgH PCR; (2) a highly purified population of hematopoietic progenitors com prising 90.8% +/- 2.3% CD34(+) cells; and (3) the recovery of 77.9% +/ - 3.2% CD34(+) cells, These favorable results were confirmed on a larg e-scale with a blood cell transplant comprising 5.8 x 10(9) nucleated cells in which positive selection of CD34(+) cells by the Miltenyi Sup erMACS system resulted in: (1) the elimination of F-NHL cells as detec ted both by flow cytometry and bcl-2-IgH PCR; (2) a highly purified po pulation of hematopoietic progenitors comprising 94.6% CD34(+) cells; and (3) the recovery of 62.7% CD34(+) cells, These results, attained w ith the newly available SuperMACS system, compare favorably with previ ous techniques because they show the feasibility of eliminating F-NHL cells from blood cell transplants without relevant nonspecific loss of hematopoietic progenitors.