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There is a progressive increase in the use of selected hematopoietic progenitor cells after myeloablative therapy in patients affected by malignancies. Our goal was to determine which blood parameters, in the starting cell population, influence the concentration of CD34+ progenitors and the removal of unwanted cells in the final product. Also, we evaluated the hematopoietic recovery and toxicity associated with peripheral blood stem cell infusion. We retrospectively reviewed 53 procedures of positive selection of CD34+ cells, performed with the Ceprate SC immunoadsorption system, in 47 paticnts affected by various hematologic malignancies and solid tumors. An increased percentage of CD34+ cells in the starting fraction was associated both with the final purity and enrichment of CD34+ cells and with a decreased percentage of CD3+ and CD19+ cells in the final product. A low platelet count before selection had a borderlinc influence on the recovery of CD34+ cells. Forty patients received a median of 5 x 10(6) CD34+ cells per kg; the absolute neutrophil count (ANC) reached 0.5 x 10(9)/l in a median of 10 days whereas a PLT count above 20 x 10(9)/l was observed in 14 days. The reinfusion of selected CD34+ cells, containing a very low amount of dymethylsulfoxide. was well tolerated and no adverse reactions were observed. Autologous transplantation with selected CD34+ cells is a safe and well-tolerated procedure in patients affected by hematologic malignancies and solid tumors. Positive selection of CD34+ cells seems to be related to the quality of the apheresis products, particularly to the initial CD34+ cell and PLT content.

Three different methods for determination of CD34+ cells in G-CSF-mobilized peripheral blood were compared. The methods were: the Milan/Mulhouse protocol, the ISHAGE guidelines for CD34+ cells enumeration and our own protocol. The procedure we have adopted is essentially a Milan/Mulhouse protocol-derived methodology combined with a multiparametric approach using the PAINT-A-GATE software analysis program. The samples were collected from 70 patients affected by acute leukemia, non-Hodgkin's lymphoma, Hodgkin's lymphoma, myeloma and breast cancer who were scheduled to receive autologous PBSC transplantation. PBSC collection was performed following mobilization with subcutaneous G-CSF at 5-10 microg/kg/day. A minimum target of 2 x 10(6)/kg CD34+ cells was considered an acceptable harvest to ensure a safe transplant. On average, three aphereses per patient were performed and a total of 204 apheresis samples were analyzed. Regression analysis of the percentage and absolute number of CD34+ cells, as calculated with each method, achieved an excellent correlation in spite of methodological differences. In fact, both CD34+dim and CD34+CD45- events were included in our gating strategy. In the setting of a triple staining associating CD34, CD38 and CD45, we identified a variable fraction of CD34+CD38+CD45- cells which would be otherwise undetected due to its CD45 negativity. To this end, we used a new technology referred to as laser-scanning cytometry (LSC) which allowed the isolation and morphological identification of CD34+CD45- cells. By comparing CD34+CD45+ and CD34+CD45- cells, we found that they share a common morphology, thus confirming the hypothesis that the latter are to be considered for CD34+ cell calculation. The median number of CD34+ cells/kg, as calculated by the three methods, was: 4.79 x 10(6)/kg (range 1-570) for the Milan/Mulhouse protocol, 3.9 x 10(6)/kg (range 0.8-498) for the ISHAGE one, and 5.17 x 10(6)/kg (range 2-599) for our protocol. The median time to ANC and PLT engraftment was 11 (range 9-24) and 20 (range 10-70) days, respectively. Our protocol achieved the best correlation between CD34+ cells/kg and time to ANC/PLT recovery according to the Spearman's rank test (r = -40 and P < 0. 015 for ANC, r= -46 and P = 0.005 for PLT). We conclude that (1) CD45 does not appear the ideal partner of HPCA-2 for determination of hematopoietic progenitors in mobilized peripheral blood; and (2) for clinical application, a single staining with 8G12 appears simple, reliable and feasible when rigorous procedures for sample preparation and acquisition are followed and an adequate software for multiparametric analysis is available.

Objectives: To evaluate the therapeutic activity and toxicity of human leucocyte interferon-alpha (lIFN-alpha) in patients with polycythaemia vera (PV) aged less than 60 years., Design: An open clinical study., Setting: Department of Medical Sciences, Regina Apostolorum Hospital, Albano Laziale, and Chair of Haematology, University of Rome 'Tor Vergata', S. Eugenio Hospital, Rome, Italy., Subjects: Fourteen patients with PV and aged < 60 years who had active disease as indicated by the need for phlebotomy and/or cytoreductive therapy., Interventions: lIFN-alpha administered subcutaneously at the starting dose of 3 MU thrice weekly. The interferon dose could be escalated to six MU thrice weekly if it was well tolerated and disease was not controlled after three months of treatment at the lower dose., Main Outcome Measures: Change in phlebotomy requirements, spleen size, pruritus score and haematological parameters after 6 months of treatment. Evaluation of lIFN-alpha side effects., Results: Complete or partial disease control was achieved in 13 patients. Six patients achieved a complete response (CR) and four a partial response (PR) after 3 months of therapy. Dose escalation in partial or nonresponders resulted in two patients switching from a status of PR to CR, and three other patients achieving a partial response after being unresponsive to the lower dosage. Human leucocyte interferon-alpha therapy significantly improved (P < 01) phlebotomy requirements, the degree of splenomegaly, pruritus scores, iron stores and MCV values, and platelet and leucocyte counts. A mild flu-like syndrome (low-grade fever, nausea and myalgias) appeared during the early phase of therapy in the majority of patients, but no patient had to discontinue lIFN-alpha because of intolerance., Conclusions: Subcutaneous human leucocyte interferon-alpha appears an effective and well tolerated therapy in the management of PV-associated myeloproliferation and pruritus in patients aged less than 60 years.

Preliminary BM processing to produce an enriched MNC fraction from large BM volumes improves subsequent pharmacological and/or immunological "ex vivo" treatment and cryopreservation. We detail on a multicenter study (6 Transplant Centers) performed to establish an effective and reliable protocol using a CS 3000 continuous flow separator on a large series of BM processed for autologous (96) and allogeneic (12) transplantation. The reduction in volume was 78.6 + 7.2% while 28.9 + 12.4% of the original nucleated cells were found in the final product. A mean of 84.3 + 13.2% of the staring MNC was yielded in a fraction containing over 81% MNC. Cloning efficiency indicated than the final graft was highly enriched in progenitor cells committed to the granulocyte/macrophage pathway (> 100%) as assessed in vitro (CFU-GM). Removal of RBC and PLT was 98.3 + 1.1 and 37.7 + 14.6%, respectively. The mean dose of MNC and CFU-GM was 0.6 + 0.37 x 10(8) and 0.96 + 1 x 10(5) recipient weight. The entire process was accomplished in 87.5 + 20 min. We concluded that this automated device is a simple and reproducible method for BM processing suitable as first step for further "ex vivo" automated negative and/or positive cell selections.