Quantification of T-cell progenitors during ontogeny: thymus colonization depends on blood delivery of progenitors.
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An in vivo thymus reconstitution assay based on intrathymic injection of hematopoietic progenitors into irradiated chicks was used to determine the number of T-cell progenitors in peripheral blood, paraaortic foci, bone marrow (BM), and spleen during ontogeny. This study allowed us to analyze the regulation of thymus colonization occurring in three waves during embryogenesis. It confirmed that progenitors of the first wave of thymus colonization originate from the paraaortic foci, whereas progenitors of the second and the third waves originate from the BM. The analysis of the number of T-cell progenitors indicates that each wave of thymus colonization is correlated with a peak number of T-cell progenitors in peripheral blood, whereas they are almost absent during the periods defined as refractory for colonization. Moreover, injection of T-cell progenitors into the blood circulation showed that they homed into the thymus without delay during the refractory periods. Thus, thymus colonization kinetics depend mainly on the blood delivery of T-cell progenitors during embryogenesis. (+info)
Idiotype vaccination using dendritic cells after autologous peripheral blood stem cell transplantation for multiple myeloma--a feasibility study.
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The idiotype (Id) determinant on the multiple myeloma (MM) protein can be regarded as a tumor-specific marker. Immunotherapy directed at the MM Id may stem the progression of this disease. We report here on the first 12 MM patients treated at our institution with high-dose therapy and peripheral blood stem cell transplantation (PBSCT) followed by Id immunizations. MM patients received PBSCT to eradicate the majority of the disease. PBSCT produced a complete response in 2 patients, a partial response in 9 patients and stable disease in 1 patient. Three to 7 months after high-dose therapy, patients received a series of monthly immunizations that consisted of two intravenous infusions of Id-pulsed autologous dendritic cells (DC) followed by five subcutaneous boosts of Id/keyhole limpet hemocyanin (KLH) administered with adjuvant. Between 1 and 11 x 10(6) DC were obtained by leukapheresis in all patients even after PBSCT. The administration of Id-pulsed DC and Id/KLH vaccines were well tolerated with patients experiencing only minor and transient side effects. Two of 12 patients developed an Id-specific, cellular proliferative immune response and one of three patients studied developed a transient but Id-specific cytotoxic T-cell (CTL) response. Eleven of the 12 patients generated strong KLH-specific cellular proliferative immune responses showing the patients' immunocompetence at the time of vaccination. The two patients who developed a cellular Id-specific immune response remain in complete remission. Of the 12 treated patients, 9 are currently alive after autologous transplantation with a minimum follow-up of 16 months, 2 patients died because of recurrent MM and 1 patient succumbed to acute leukemia. These studies show that patients make strong anti-KLH responses despite recent high-dose therapy and that DC-based Id vaccination is feasible after PBSCT and can induce Id-specific T-cell responses. Further vaccine development is necessary to increase the proportion of patients that make Id-specific immune responses. The clinical benefits of Id vaccination in MM remain to be determined. (+info)
BACKGROUND AND OBJECTIVE: In children it is very important to optimize PBPC harvesting and to reduce the number of leukaphereses per patient. The value of pre-apheresis peripheral blood CD34+ cell concentration as a predictor of PBPC yield was studied in 23 pediatric patients with hematologic and non-hematologic malignancies in order to optimize duration of PBPC collection. DESIGN AND METHODS: The patients underwent 25 stem-cell mobilization episodes with G-CSF alone and 40 large-volume leukapheresis procedures. Peripheral blood and harvested CD34+ cell concentrations were analyzed by means of flow cytometry. RESULTS: Using linear regression analysis, a highly significant correlation was found between the peripheral blood CD34+ cell count and the CD34+ cells/kg patient body weight collected on the apheresis day (r = 0.826, p = 0.0001). The results indicate that at least 1 x 10(6)/kg CD34+ cells can be harvested during one leukapheresis procedure in all patients if the pre-apheresis blood CD34+ cell count is > or = 30/microL and a CD34+ cell target of > or = 5 x 10(6)/kg is achieved in at least 80% of patients if this value is > or = 50 CD34+ cells/microL processing a median blood volume of 438.7 mL/kg (range, 207-560) over a median time of 232.5 minutes (range, 182-376). INTERPRETATION AND CONCLUSIONS: Our results suggest that the number of CD34+ cells harvested in a single large-volume leukapheresis can be predicted from the measurement of peripheral blood CD34+ cell concentration on the collection day. (+info)
Treatment of multiple myeloma.
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BACKGROUND AND OBJECTIVE: Multiple myeloma (MM) accounts for about 10% of all hematologic malignancies. The standard treatment with intermittent courses of melphalan and prednisone (MP) was introduced more than 30 years ago and, since then there has been little improvement in event-free and overall survival (EFS & OS). The aim of this article is to review: 1) the role of initial chemotherapy (ChT), maintenance treatment with alpha-interferon and salvage ChT, 2) the results of high-dose therapy (HDT) followed by allogeneic or autologous stem cell transplantation (allo-SCT and auto-SCT), and 3) the most important supportive measures. EVIDENCE AND INFORMATION SOURCES: The authors of this review have been actively working and contributing with original investigations on the treatment of MM during the last 15 years. In addition, the most relevant articles and recent abstracts published in journals covered by the Science Citation Index and Medline are also reviewed. STATE OF THE ART AND PERSPECTIVES: The importance of avoiding ChT in asymptomatic patients (smoldering MM) is emphasized. The criteria and patterns of response are reviewed. MP is still the standard initial ChT with a response rate of 50-60% and an OS of 2-3 years. Combination ChT usually increases the response rate but does not significantly influence survival when compared with MP. Exposure to melphalan should be avoided in patients in whom HDT followed by auto-SCT is planned, in order to not preclude the stem cell collection. The median response duration to initial ChT is 18 months. Interferon maintenance usually prolongs response duration but in most studies does not significantly influence survival (a large meta-analysis by the Myeloma Trialists' Collaborative Group in Oxford is being finished). In alkylating-resistant patients, the best rescue regimens are VBAD or VAD. In patients already resistant to VBAD or VAD and in those in whom these treatments are not feasible we recommend a conservative approach with alternate day prednisone and pulse cyclophosphamide. While HDT followed by autotransplantation is not recommended for patients with resistant relapse, patients with primary refractory disease seem to benefit from early myeloablative therapy. Although results from large randomized trials are still pending in order to establish whether early HDT intensification followed by auto-SCT is superior to continuing standard ChT in responding patients, the favorable experience with autotransplantation of the French Myeloma Intergroup supports this approach. However, although the complete response rate is higher with intensive therapy, the median duration of response is relatively short (median, 16 to 36 months), with no survival plateau. There are several ongoing trials comparing conventional ChT with HDT/autoSCT in order to identify the patients who are likely to benefit from one or another approach. With allo-SCT there is a transplant-related mortality ranging from 30 to 50% and also a high relapse rate in patients achieving CR. However, 10 to 20% of patients undergoing allo-SCT are long-term survivors (> 5 years) with no evidence of disease and, consequently, probably cured. The use of allogeneic peripheral blood stem cells (PBSC) in order to speed the engraftment and also the use of partially T-cell depleted PBSC which can decrease the incidence of graft-versus-host disease are promising approaches. In the setting of allo-SCT, donor lymphocyte infusion is an encouraging strategy in order to treat or prevent relapses. Finally, important supportive measures such as the treatment of anemia with erythropoietin, the management of renal failure and the use of bisphosphonates are reviewed. (+info)
Autologous blood stem cell transplantation for acute myeloblastic leukemia in first complete remission. Intensification therapy before transplantation does not prolong disease-free survival.
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BACKGROUND AND OBJECTIVE: To compare the clinical results of two consecutive therapeutic protocols including autologous blood stem cell transplantation (ABSCT) for patients with de novo acute myeloblastic leukemia (AML) in first complete remission (CR1). DESIGN AND METHODS: Between November 1989 and January 1997, 50 patients with AML in CR1 underwent ABSCT using two consecutive protocols. In the first one (Group A, 25 patients) peripheral blood stem cells (PBSC) were collected after induction and consolidation chemotherapy courses, and ABSCT was performed immediately thereafter. In the subsequent 25 patients (Group B), PBSC were collected after consolidation alone, and a further chemotherapy course with intermediate dose cytarabine (Ara-C 1 g/m2/12 h x3 days) and mitoxantrone (12 mg/m2/d x3 days) was administered as early intensification. The conditioning regimen consisted of busulfan (16 mg/kg) and cyclophosphamide (200 mg/kg) in every case. RESULTS: Hematopoietic engraftment was slightly quicker in Group B, with median times to reach 0.5 x 10(9) neutrophils/L and 20 x 10(9) platelets/L being 13 and 12 days in Group A and 12 and 11 days in Group B, respectively. There were three graft failures (8%) (2 in Group A and 1 in Group B) and three transplant-related deaths (8%) (2 in Group A and 1 in Group B). No significant differences were observed between the groups in terms of relapse (64% at 4-years in Group A and 81% in Group B). Likewise, the actuarial 4-year disease-free survival (DFS) was not significantly different between the two groups (32% v 18%). INTERPRETATION AND CONCLUSIONS: Our study confirms that AML patients in CR1 receiving ABSCT have rapid engraftment with low mortality. However, autologous transplants with PBSC collected after consolidation chemotherapy were still associated with a high rate of relapse (RR). This RR was not apparently reduced by the administration of intermediate dose Ara-C before transplantation. (+info)
Costs of high-dose salvage therapy and blood stem cell transplantation for resistant-relapsed malignant lymphomas in a southern Italian hospital.
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BACKGROUND AND OBJECTIVE: Analysis of costs of high technological procedures such as peripheral blood stem cell (PBSC) autotransplantation in lymphomas are generally finalized at disclosing whether the improvement of survival in a subset of patients is cost effective and whether the cost of the procedure could be reduced. With the aim of revealing a possibility of reducing costs with respect to conditions of safety, we present our experience with PBSC autotransplantation in a particularly poor prognosis subset of patients with lymphoma. DESIGN AND METHODS: The expenses are analyzed for groups of cost and main resources necessary at unitary cost are considered separately. Groups of cost include various phases of the PBSC autotransplantation such as preparative procedures, execution of myeloablative therapy, reinfusion of CD34 cells, supportive therapy after reinfusion until discharge of the patient, general support for the management of patient. All costs are calculated according to 1997 prices and salaries and reported in dollars. The analysis was conducted on 21 patients with lymphoma resistant to other therapies treated by myeloablative therapy and PBSC autotransplantation in an hematologic unit in an open ward; the assistance was provided by staff not exclusively dedicated to bone marrow transplant procedures, with some help from a family member. RESULTS: The PBSC procedure, including all phases, costs from $17,761.9 to $18,259.9 depending on the type of myeloablative therapy employed; the mean cost was $18,092.6. The preparative phase with mobilization of CD34 cells, cryopreservation and reinfusion costed $3,538.7 (19.6% of the total cost); a major cost of this phase was cryopreservation and CD34 manipulation ($857.1). The second phase with myeloablative therapy and reinfusion of CD34 cells had a mean cost of $2,785.9 (15.4% of the total cost); a major cost of this phase was the hospitalization ($1,119.8). The third phase of patient's support after treatment had a total cost of $7,649 (42.3% of the cost of the total procedure) with the major cost being due to hospitalization ($2,571) calculated on a mean of 15 days after the reinfusion of CD-34. The last group of costs, including management support, accounted for $4,119 (22.7%) with a major cost being amortization of the structure ($1,600). The general cost for nurse's assistance to the patient was $1,355.1 (7.5%). INTERPRETATION AND CONCLUSIONS: A procedure of PBSC autotransplantation in resistant lymphoma is affordable without the strict precautions generally given in intensive care units. This provides a substantial reduction of expenses because of the low number of specifically trained staff members and the generally low cost of the necessary supplies. Before, however, proposing PBSC autotransplantation in most patients with resistant lymphoma, an evaluation of whether costs could be further reduced and whether the procedure has a cost benefit impact is needed. (+info)
Autologous and allogeneic transplantation with peripheral blood CD34+ cells: a pediatric experience.
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BACKGROUND AND OBJECTIVE: Peripheral blood stem cells (PBSC) have replaced bone marrow (BM) as the primary form for autologous hematopoietic stem cell transplantation. Furthermore, the use of allogeneic PBSC transplantation is now rapidly expanding and several centers have adopted this procedure. A new strategy in the use of PBSC is positive selection of CD34+ hematopoietic progenitor (CD34+) cells, and indeed large-scale devices for the clinical exploitation of CD34+ cell selection are now commercially available. In the autologous setting, the primary advantage of using CD34+ selected PBSC is reduced tumor cell contamination during PBSC preparation. On the other hand, in the allogeneic setting, CD34+ selection methods are used to reduce the incidence and severity of GvHD. Initial trials of CD34+ selected PBSC transplants have mainly been performed in adult cancer patients, and experience with CD34+ selected PBSC transplantation in pediatric populations is still limited. The purpose of this review is to clarify the status of CD34+ selected PBSC transplantation in the pediatric population. EVIDENCE AND INFORMATION SOURCES: All authors of the present review work in the field of pediatric stem cell transplantation and in a stem cell processing laboratory, and have contributed to original papers published in peer-reviewed journals. The materials examined in the present review include articles and abstracts published in journals covered by the Science Citation Index and Medline. However, since there is still limited experience with CD34+ cell selection in pediatric populations, information on experience in adults will be discussed regarding the CD34+ cell-selection procedures and transplantation. Pediatric experience with transplants with CD34+ selected cells will be presented and discussed primarily based on our own experience. Specific problems related to PBSC mobilization and collection in children will also be discussed. STATE OF THE ART: A review of the literature shows that with current CD34+ selection methods, purity of the CD34+ cell fraction can range from 30% to 90%, and two to three logs of T-cell depletion can be achieved. Tumor cell contamination has not yet been fully evaluated. The clonogenic activity of progenitor cells after CD34+ selection from PB remains high. Transplantation of autologous selected CD34+ cells from PBSC gives prompt and stable engraftment. The long-term therapeutic efficacy should be evaluated with regard to tumor recurrence. Allogeneic CD34+ selected cells successfully engraft immunomyeloablated recipients though a mega-cell dose effect between HLA-matched pairs. The results of allogeneic CD34+ selected cell transplantation from HLA-mismatched donors are, so far, not satisfactory because of the high rate of rejection, severe infectious complications and relapse of the disease. CD34+ selection may also be used as a target of gene therapy, as a source of dendritic cells for cancer immunotherapy and for the treatment of patients with autoimmune disease. (+info)
Ifosfamide and etoposide-based chemotherapy as salvage and mobilizing regimens for poor prognosis lymphoma.
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We treated 40 patients with poor prognosis lymphomas. Patients with non-Hodgkin's lymphoma (NHL, n = 14) received MINE chemotherapy (mesna, ifosfamide 1330 mg/m2 and etoposide 65 mg/m2 by i.v. infusions on days 1-3, mitoxantrone 8 mg/m2 i.v. on day 1), and those with Hodgkin's disease (HD, n = 26) received VIM chemotherapy (mesna, ifosfamide 1200 mg/m2 by i.v. infusion on days 1-5, etoposide 90 mg/m2 by i.v. infusion on days 1, 3 and 5, and methotrexate 30 mg/m2 i.v. on days 1 and 5). Chemotherapy was followed by G-CSF (10 or 16 microg/kg in two divided doses daily) to mobilize PBSC. We performed 134 aphereses (median three leukaphereses per patient) starting on either day 13 (median; VIM) or day 12 (median; MINE). The median yield was 9.9x10(6) CD34+ cells/kg and 53.2x10(4) CFU-GM/kg for VIM, and 13.5x10(6) CD34+ cells/kg and 53.4x10(4) CFU-GM/kg for MINE. Except for predictable myelosuppression, no serious toxicity was seen. Response rate using MINE was 63% (18% CR, 45% PR) and using VIM 50% (17% CR, 33% PR). We conclude that VIM and MINE are effective and well-tolerated salvage regimens in patients with lymphomas and, followed by G-CSF, they also exhibit good capacity to mobilize stem cells in a predictable time interval. (+info)