PERIPHERAL-BLOOD STEM-CELL CD34+ AUTOLOGOUS TRANSPLANT IN RELAPSED FOLLICULAR LYMPHOMA

To evaluate CD34+ selection of peripheral blood stem cells (PBSC) as a graft for autologous transplantation. Eight relapsing follicular lymp homa (FL) patients were submitted to CD34+ autologous stem cell transp lantation (ASCT). All patients received at least two front line conven tional therapies; mean time to treatment failure (TTF) was 4.5 months. Patients had disseminated stage III-IV disease after a median number of 2.1 relapses. Chemotherapy and G-CSF were used as mobilization for leukapheresis. CEPRATE SC concentrator (CellPro, Inc, Bothell, WA) was used to select CD34+ cells from leukapheresis products. With a mean o f 1.8 leukaphereses per patient, 8.1 x 10(8) mononuclear cells (MNCs)/ kg were collected. After the selection process, the median number of M NCs was 9.4 x 10(6)/kg; 4.3 x 10(6)/kg CD34+ cells and 17 x 10(4)/kg C FU-GM, with a purity of 83.7% and a viability of 89.2%. Mbr bcl2/IgH P CR analysis of 5 grafts showed that initial buffy-coat, and CD34- frac tions were negative in 3 cases and positive in 2 cases (from whom sele cted CD34+ fraction remained positive in 1 case). After a conditioning regimen including total body irradiation, cyclophosphamide and etopos ide, CD34+ selected cells were reinfused. All patients but one had suc cessful engraftment, median time to WBC > 1 x 10(9)/l was 12 days and platelets > 50 x 10(9)/l 17 days. No severe infectious complications w ere seen. After transplant, with a minimum follow up of 2 years, 5 pat ients are still in complete remission (CR). Three patients have relaps ed after 1 year of transplant with a mean TTF of 15.6 months. We concl ude that PBSC CD34+ selection for ASCT was a safe technique, capable o f reconstituting hemopoiesis without severe complications for high ris k FL patients included in this study. The effects of tumor cell purgin g need to be evaluated in a larger series.