CD34+ selected autologous peripheral blood stem cell transplantation for multiple sclerosis: report of toxicity and treatment results at one year of follow-up in 15 patients

BACKGROUND AND OBJECTIVES: Autologous stem cell transplantation (ASCT) is currently being evaluated as a therapy for patients with multiple sclerosis (MS). We report the results of a phase II trial to evaluate feasibility and toxicity of CD34+ selected ASCT (CD34+/ASCT) and treatment results at one year of follow-up. DESIGN AND METHODS: Patients with advanced secondary progressive (SP) or relapsing-remitting (RR) MS and confirmed worsening of the extended disability status scale (EDSS) in the previous year despite interferon or other immunotherapies were included. Peripheral blood stem cells were obtained by leukaphereses after mobilization with cyclophosphamide (Cy) and granulocyte colony-stimulating factor (G-CSF). CD34+ selection was performed by means of an Isolex 300 or CliniMACS device. BCNU, Cy and antithymocyte globulin (ATG) were administered as conditioning regimen. RESULTS: Fifteen patients (9 SPMS and 6 RRMS) with a median EDSS of 6.0 (4.5-6.5) and a median of 3 (1-7) relapses in the previous year were included. Mobilization was unsuccessful in one patient. During mobilization, one patient had a transient neurologic deterioration. The main complication during ASCT were engraftment syndrome, which developed in three patients, CMV reactivation in one, and neurologic deterioration in two patients coinciding with high-fever related to ATG. Hematologic recovery was fast and complete in all cases. At 12 months, the EDSS had improved in three patients, worsened in two and remained stable in nine. Despite withdrawal of all immunosuppressive therapy only two patients had relapses. Magnetic resonance imaging showed disappearance of enhanced T1 lesions but oligoclonal bands persisted in the cerebrospinal fluid of all evaluated cases. INTERPRETATION AND CONCLUSIONS: CD34+/ASCT using BCNU, Cy and ATG as conditioning regimen has an acceptable toxicity and clearly reduces the progression of MS. Further follow-up is necessary to establish the real impact of this procedure on the long-term evolution of the disease.     

Clinical outcome of autologous peripheral blood stem cell transplantation in opticospinal and conventional forms of secondary progressive multiple sclerosis in a Chinese population

To evaluate clinical outcomes of autologous peripheral blood stem cell transplantation (APBCST) between opticospinal multiple sclerosis (OSMS) and conventional multiple sclerosis (CMS) during disease progressive stage in a Chinese population. Thirty-six secondary progressive MS patients, among whom 21 were with OSMS and 15 with CMS, underwent APBSCT and were followed up for an average of 48.92 months (range, 10–91 months). Peripheral blood stem cells were obtained by leukapheresis after mobilization with granulocyte colony-stimulating factor. Modified BEAM conditioning regimen (Tiniposide, melphalan, carmustin, and cytosine arabinoside) were administered. Outcomes were evaluated using the expanded disability status scale (EDSS). No maintenance treatment was administered if there was no disease progression. No treatment-related mortality occurred. Among the 36 patients, one OSMS patient dropped during the follow-up. Among the 22 relapse-free patients, 20 were with continuous neurological improvement without any relapse events, and two remained in neurologically stable states. Among the 13 relapse patients, seven had experienced of neurological relapse, but with no progression during the follow-up period; and six experienced neurological deterioration after transplantation and needed further immunosuppressant treatment. The confirmed relapse-free survival rate was 62.9% and progression-free survival rate was 83.3% after 91 months according to Kaplan and Meier survival curves. Eleven of the 20 OSMS patients (55%) and two of the 15 CMS patients (13.3%) stayed in disease active group (P = 0.014). For the 20 OSMS patients, the overall EDSS score decreased significantly after transplantation (P = 0.016), while visual functions had no significant improvement (P = 0.716). Progressive OSMS has a higher relapse rate than CMS following APBSCT.     

Hematopoietic stem cell transplantation for progressive multiple sclerosis: failure of a total body irradiation-based conditioning regimen to prevent disease progression in patients with high disability scores

There were 21 patients with rapidly progressive multiple sclerosis (MS) treated on a phase 1/2 study of intense immune suppressive therapy and autologous hematopoietic stem cell (HSC) support with no 1-year mortality. Following transplantation, one patient had a confirmed acute attack of MS. Neurologic progression defined by the expanded disability status scale (EDSS) did not increase in disability by 1.0 or more steps in any of 9 patients with a pretransplantation EDSS of 6.0 or less. In 8 of 12 patients with high pretransplantation disability scores (EDSS > 6.0), progressive neurologic disability as defined by at least a 1-point increase in the EDSS has occurred and was manifested as gradual neurologic deterioration. There were 2 patients with a pretransplantation EDSS of 7.0 and 8.0 who died from complications of progressive disease at 13 and 18 months following treatment. Our experience suggests that intense immune suppression using a total body irradiation (TBI)-based regimen and hematopoietic stem cell transplantation (HSCT) are not effective for patients with progressive disease and high pretransplantation disability scores. Further studies are necessary to determine the role of intense immune suppressive therapy and HSC support in ambulatory patients with less accumulated disability and more inflammatory disease activity. Specifically, more patients and longer follow-up would be required in patients with an EDSS of 6.0 or less before drawing conclusions on this subgroup.     

Autologous HSCT for severe progressive multiple sclerosis in a multicenter trial: impact on disease activity and quality of life

Hematopoietic stem cell transplantation (HSCT) has been proposed for the treatment of severe multiple sclerosis (MS). In a phase 2 multicenter study we selected 19 non-primary progressive MS patients showing high disease activity on the basis of both brain magnetic resonance imaging (MRI) and sustained clinical deterioration despite conventional treatments. After stem cell mobilization with cyclophosphamide (CY) and filgrastim, patients were conditioned with BCNU (1,3-bis(2-chloroethyl)-1-nitrosourea), cytosine arabinoside, etoposide, and melphalan (BEAM) followed by antithymocyte globulin (ATG). Unmanipulated peripheral blood stem cells (PBSCs) were then infused. No maintenance treatment was administered with a median follow-up of 36 months (range, 12 to 72 months). All patients showed clinical stabilization or improvement; 3 subsequently deteriorated, 1 beyond the baseline. No MRI active lesions were detected after the HSCT except in 1 patient who showed a new lesion at 4.5 years. Infections were limited and restricted to 3 months after HSCT. Health-related quality of life was assessed through the 54-item MS quality of life (MSQOL-54) questionnaire, showing a statistically significant improvement in both composite scores and in most of the individual domains. HSCT is able to induce a prolonged clinical stabilization in severe progressive MS patients, resulting in both sustained treatment-free periods and quality of life improvement.     

Peripheral Stem Cells in Bone Marrow Transplantation. Future prospects.

Mobilized peripheral blood cells are emerging to be the main haematopoietic progenitor cell sources in both autologous and allogeneic transplantation. The superior engraftment kinetics make high-dose therapy (HDT) safer and more cost-effective. Advances in mobilization protocols will enable an adequate, efficacious and predictable progenitor cell yield for most patients, and may even permit differential mobilization of normal and tumour cells. Peripheral blood stem cell transplantation is going to make an impact on tumour control by allowing dose escalation through multiple HDT and rescues, promoting various purging manoeuvres and facilitating immunomodulatory approaches to enhance graft-versus-tumour responses. Technological advances in ex vivo expansion and manipulation of haematopoietic progenitor cell grafts will add to our armamentarium of new therapeutic approaches and broaden our dimensions in the use of peripheral blood stem cell transplantation.     

High-dose immunosuppressive therapy and autologous peripheral blood stem cell transplantation for severe multiple sclerosis

There were 26 patients enrolled in a pilot study of high-dose immunosuppressive therapy (HDIT) for severe multiple sclerosis (MS). Median baseline expanded disability status scale (EDSS) was 7.0 (range, 5.0-8.0). HDIT consisted of total body irradiation, cyclophosphamide, and antithymocyte globulin (ATG) and was followed by transplantation of autologous, granulocyte colony-stimulating factor (G-CSF)-mobilized CD34-selected stem cells. Regimen-related toxicities were mild. Because of bladder dysfunction, there were 8 infectious events of the lower urinary tract. One patient died from Epstein-Barr virus (EBV)-related posttransplantation lymphoproliferative disorder (PTLD) associated with a change from horse-derived to rabbit-derived ATG in the HDIT regimen. An engraftment syndrome characterized by noninfectious fever with or without rash developed in 13 of the first 18 patients and was associated in some cases with transient worsening of neurologic symptoms. There were 2 significant adverse neurologic events that occurred, including a flare of MS during mobilization and an episode of irreversible neurologic deterioration after HDIT associated with fever. With a median follow-up of 24 (range, 3-36) months, the Kaplan-Meier estimate of progression (>/= 1.0 point EDSS) at 3 years was 27%. Of 12 patients who had oligoclonal bands in the cerebrospinal fluid at baseline, 9 had persistence after HDIT. After HDIT, 4 patients developed new enhancing lesions on magnetic resonance imaging of the brain. The estimate of survival at 3 years was 91%. Important clinical issues in the use of HDIT and stem cell transplantation for MS were identified; however, modifications of the initial approaches appear to reduce treatment risks. This was a heterogeneous high-risk group, and a phase 3 study is planned to fully assess efficacy.     

CD34+-enriched-CD19+-depleted autologous peripheral blood stem cell transplantation for chronic lymphoproliferative disorders: high purging efficiency but increased risk of severe infections

OBJECTIVE: The main objective of this work was to decrease the incidence of relapse after autologous stem cell transplantation with a "double purging" procedure. METHODS: We used a "positive" (CD34) and "negative" (CD19) double selection method to improve the efficacy of "single purging" of hematopoietic harvests in poor-prognosis lymphoproliferative disorders. All patients included in the study had a positive molecular marker of their disease. Minimal residual disease (MRD) was studied by flow cytometry and PCR techniques during the purging procedure and after transplantation. RESULTS: Twenty-six patients fulfilled entry criteria. Median age of patients was 50 years (range: 33-66); 17 were male and 9 female. Thirteen (50%) of the patients mobilized an adequate number of CD34+ cells (>or=3 x 10(6)/kg) to proceed with the double-selection protocol. Twelve of the 13 harvests became PCR negative after purging. Ten patients were grafted with the selected products and all but one engrafted without delay. After a median follow-up of 30 months, 2 of 10 patients suffered a molecular relapse at 7 and 19 months respectively. The earlier relapse was observed in the patient who received a MRD+ product. Only one patient experienced a clinical relapse. Three patients died due to obliterans bronchiolitis, pneumococcal sepsis, and septic shock of unknown origin, respectively, and three others presented life-threatening infections. CONCLUSION: Therefore, CD34+/CD19+ positive/negative selection is an effective purging approach in patients with chronic lymphoproliferative disorders. This favorable effect is, however, counterbalanced by the high frequency of life-threatening infections.     

Peripheral blood stem cell transplantation in 16 patients with POEMS syndrome, and a review of the literature

POEMS syndrome is characterized by peripheral neuropathy (PN), a clonal plasma cell disorder (PCD), organomegaly, endocrinopathy, skin changes, edema, sclerotic bone lesions, and thrombocytosis. Based on the improved response rates observed with peripheral blood stem cell transplantation (PBSCT) in patients with other PCDs, autologous PBSCT may be an attractive treatment option for this syndrome. Sixteen patients with POEMS syndrome have undergone PBSCT at Mayo. Of these patients, 15 had a severe rapidly progressive sensorimotor PN (9 were wheelchair dependent) and 14 were male. Median age was 51 years (range, 19-62 years). The median number of prior therapies was 3 (range, 0-7). From first symptoms and from diagnosis of POEMS the times to transplantation were 42 months and 5 months (ranges, 8-185 months and 2-149 months), respectively. There were 15 patients who had significantly abnormal pretransplant pulmonary function tests. There was one transplant-related death. During the peritransplant period, 5 patients required intubation for respiratory compromise, including one who required intubation during his stem cell mobilization period. Another patient required noninvasive biphasic positive airway pressure throughout his course. Of the 14 evaluable patients, all have had neurologic improvement or stabilization. Other features have improved substantially. PBSCT for POEMS syndrome is effective therapy but may also be associated with significant morbidity.     

Clinical applications of CD34+ cell-selected peripheral blood stem cells

Peripheral blood stem cells (PBSC) are increasingly used for stem cell transplantation after high dose chemotherapy. CD34+ cell selection has also been done for use in autologous transplantation studies Bone marrow (BM) may contain tumor cells at the time of harvesting, and on re-infusion, these cells could contribute to a subsequent relapse. Similarly, tumor cell contamination of PBSC collections has been found in a number of studies. Therefore, purging contaminating tumor cells may prevent cases of relapse. As most tumor cell types do not express CD34 antigen, one of the most widespread applications of CD34+ cell selection is likely to be in tumor cell purging. Similarly, CD34+ cell selection has aided allogeneic transplantation studies. Acute graft-versus-host disease (aGVHD) is a major cause of morbidity and mortality in cases of allogeneic transplantation. As aGVHD is mediated by donor T cells, removal of T cells from the graft by CD34+ cell selection may ensure prophylaxis against aGVHD. Further, high-dose immunosuppression followed by CD34+ cell-selected stem cell rescue is theoretically reasonable as a therapeutic tool for patients with autoimmune disease resistant to conventional therapy. However, patients given T cell-depleted transplantation have an increased risk of opportunistic infection as well as malignancies related to immunosuppression; therefore, close monitoring is warranted. We describe here clinical applications of CD34+ cell-selected PBSC for a variety of diseases, with special emphasis on the efficacy as well as drawbacks of this novel technique.     

Treatment and follow‐up of 18 severe systemic lupus erythematosus patients with stem cell transplantation

Aim: To investigate the feasibility, efficacy and safety of high‐dose immunosuppressive therapy and autologous peripheral blood stem cell transplantation (PBSCT) with CD34⁺ cell selection in patients with refractory and severe autoimmune diseases. Methods: Eighteen patients with persistent systemic lupus erythematosus refractory to conventional treatment were enrolled into the study of peripheral blood stem cell transplantation in Peking Union Medical College Hospital from 1999 to 2005. After mobilization and conditioning, the enriched CD34⁺ cells were reinfused. Disease activity, adverse effects, haematopoietic and immunologic reconstitution were monitored and followed up for at least 6 months. Results: Overall treatment‐related mortality was 5.6% with one patient dying of cytomegalovirus infection. The overall remission rate was 95.8% in the first year after PBSCT. Relapse occurred in three patients (17.6%) in 37, 26, and 19 months post‐transplantation, respectively. Disease Activity Index scores of systemic lupus erythematosus survivors were decreased significantly (P  <  0.001). Conclusions: Short‐term effect of autologous peripheral blood stem cell transplantation is promising although treatment‐related mortality and relapses are observed in a subset of patients. High‐dose immunosuppressive therapy followed by autologous peripheral blood stem cell transplantation with CD34⁺ cell selection is feasible and relatively safe in the treatment of severe and refractory autoimmune diseases. The long‐term effect needs further evaluation and multicentre study.     

Rituximab: enhancing stem cell transplantation in mantle cell lymphoma

Mantle cell lymphoma (MCL) responds poorly to standard chemotherapy regimens used in non-Hodgkin's lymphoma. As a result, a combination of high-dose chemotherapy (HDT) with autologous stem cell transplantation (ASCT) is being investigated in patients with MCL. So far, however, there is no evidence for long-term remission -- believed, in part, to be due to contamination of the transfusion product with residual cancer cells. Many ex-vivo purging methods have been developed to remove tumour cells, but these are complicated, time-consuming and expensive. This study describes an in vivo purging method using rituximab to produce a tumour-free stem cell product for re-infusion following HDT. The regimen is split into a purging phase and a myeloablative phase, which together consist of four-step high-dose sequential chemotherapy (sHDT) and six infusions of rituximab immunotherapy. The sHDT comprises cyclophosphamide, cytosine arabinoside, melphalan and mitoxantrone plus melphalan. There are two separate stem cell harvests and three reinfusions. In a pilot study 28 patients with untreated MCL received standard chemotherapy followed by sHDT with rituximab in vivo purging. Preliminary results indicate that in PCR analyses of leukaphereses from 20 assessable patients, 100% lymphoma-negative harvests were achieved following in vivo purging. PCR analyses of the bone marrow following the four-step high-dose regimen with purging and transplantation showed that all patients achieved molecular remission. After a median follow-up of 22 months (range 10-42 months), two patients had died while 26 were alive and disease free. This method allows efficient in vivo purging in the context of an effective chemotherapy regimen and may have a role as first-line therapy in MCL patients who respond poorly to standard treatment.     

Impact of different strategies of second-line stem cell harvest on the outcome of autologous transplantation in poor peripheral blood stem cell mobilizers

The optimal approach to obtain an adequate graft for transplantation in patients with poor peripheral blood stem cell (PBSC) mobilization remains unclear. We retrospectively assessed the impact of different strategies of second-line stem cell harvest on the transplantation outcome of patients who failed PBSC mobilization in our institution. Such patients were distributed into three groups: those who proceeded to steady-state bone marrow (BM) collection (group A, n = 34); those who underwent second PBSC mobilization (group B, n = 41); those in whom no further harvesting was carried out (group C, n = 30). PBSC harvest yielded significantly more CD34+ cells than BM collection. Autologous transplantation was performed in 30, 23 and 11 patients from groups A, B and C, respectively. Engraftment data and transplantation outcome did not differ significantly between groups A and C. By contrast, group B patients had a faster neutrophil recovery, required less platelet transfusions and experienced less transplant-related morbidity, as reflected by lower antibiotics needs and shorter hospital stays. In conclusion, remobilization of PBSC constitutes an effective approach to ensure a rapid hematopoietic engraftment and a safe transplantation procedure for poor mobilizers, whereas unprimed BM harvest does not provide any clinical benefit in this setting.     

Blood stem cell transplantation as therapy for primary systemic amyloidosis (AL)

This study investigated the response rate and toxicity of blood cell transplantation as treatment for primary amyloidosis (AL). Twenty-three patients had stem cells collected between November 1995 and September 1998. Conditioning included melphalan and total body irradiation in 16 and melphalan alone in 4. Three patients did not undergo stem cell infusion because of poor performance status. Two died of progressive amyloid at 1 and 3 months. One patient is alive on hemodialysis. Fourteen males and six females (median age, 57 years) underwent transplantation. Renal, cardiac (by echocardiography), peripheral neuropathy or liver amyloidosis occurred in 14, 12, 3, and 1, respectively. Echocardiography demonstrated an interventricular septal thickness > or = 15 mm in six patients, five of whom died post transplantation. Three patients died of progressive amyloidosis at 7, 7, and 21 months. Thirteen patients are alive with a follow-up of 3 to 26 months. Twelve (60%) fulfilled the criteria of a hematologic or organ response. Severe gastrointestinal tract toxicity was seen in five (25%). We conclude that blood cell transplantation for amyloidosis had a much higher morbidity and mortality compared with transplantation for myeloma. The best results appear to occur in patients with nephrotic syndrome as the only manifestation of their disease.     

Effect of rituximab on peripheral blood stem cell mobilization and engraftment kinetics in non-Hodgkin's lymphoma patients

Rituximab is used for in vivo tumor cell purging for non-Hodgkin's lymphoma (NHL) patients prior to autologous peripheral blood stem cell transplantation (PBSCT). However, its effects on PBSC mobilization and function are poorly understood. We compared the mobilization characteristics and engraftment kinetics of 13 NHL patients receiving and 34 NHL patients not receiving rituximab 6 months before PBSC mobilization. In the rituximab group, there was a significantly longer time to neutrophil engraftment (P=0.0466), a trend toward the need for BM harvest to supplement low-yield PBSC collections (31 vs 9%, P=0.08) and a significantly increased rate of bacteremia episodes (62 vs 26%, P=0.025). Median progression-free survival (PFS) and overall survival (OS) were significantly longer in the rituximab compared to the nonrituximab patients (P=0.049 and 0.042, respectively). However, patients in the nonrituximab group were at high risk for recurrence and expected to have shorter survival. Rituximab used within 6 months prior to collection may have a detrimental effect on PBSC mobilization and engraftment. However, rituximab is a major therapeutic breakthrough for NHL treatment and this negative effect may be offset by improved survival. Further studies are warranted in larger populations to determine the impact of rituximab on engraftment, PFS and OS.     

儿童难治性自身免疫性疾病自体外周血干细胞动员采集和分选的临床研究

目的 探讨儿童难治性自身免疫性疾病进行自体外周血干细胞动员采集的安全性和CD34+细胞分选纯化的可行性及其临床意义.方法 8例儿童难治性自身免疫性疾病,包括4例系统性红斑狼疮、2例皮肌炎,1例幼年型类风湿关节炎和1例多发性硬化,予行CD34+细胞纯化的自体外周血干细胞移植.首先采用环磷酰胺(CTX)联合粒细胞集落刺激因子(G-CSF)方案动员外周血干细胞,然后采用CS-3000血细胞分离机采集外周血,通过CliniMACS细胞分选仪分选自体外周血CD34+细胞,将其用保养液配置冻存于-80℃冰箱.采用非清髓内去除T的预处理方案,即卡氮芥+足叶乙苷+阿糖胞苷+马法兰+抗胸腺球蛋白(ATG)或CTX+ATG或CTX+马法兰+ATG,于第0天回输自体外周血CD34+细胞.结果 儿童能够耐受自体外周血干细胞动员采集过程,无动员相关死亡,动员后获得的单个核细胞数和CD34+细胞数的平均值分别为8.35×108/kg和7.92×106/kg,纯化后的白体外周血CD34+和CD3+细胞数的平均值分别为6.28×106/kg和0.71×105/kg.回输后中性粒细胞和血小板的植入中位时间分别为+11d和+15 d.结论 经CTX联合G-CSF方案可动员出足量的外周血干细胞,经CS-3000血细胞分离机采集可获得足够的单个核细胞,在动员过程中原发病无明显进展恶化,患儿能耐受动员方案,采集过程顺利安全;经CliniMACS细胞分选仪分选的自体外周血CD34+细胞纯度高,移植后造血恢复;采用CD34+细胞纯化的自体外周血移植治疗是常规治疗无效的儿童难治性自身免疫性疾病的可选择治疗措施之一.     

Human herpesvirus 8 (KSHV) contamination of peripheral blood and autograft products from multiple myeloma patients

Human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus (KSHV), has recently been identified within the bone marrow dendritic cells of multiple myeloma (MM) patients. This virus contains homologues to human cytokines such as IL-6 that could potentially stimulate myeloma cell growth and contribute to disease pathogenesis. Since mobilization chemotherapy may increase circulating dendritic cell numbers, we searched for HHV-8 in peripheral blood mononuclear cells (PBMCs) before and after mobilization chemotherapy given to MM patients. Furthermore, we determined if autograft purging using the CEPRATE SC device would reduce the percentage of HHV-8 infected stem cell products. Only two of the 39 PBMC samples collected prior to mobilization chemotherapy contained PCR detectable virus, yet nine of 37 PBMCs collected on the first day of leukapheresis had detectable HHV-8 (P = 0.016). HHV-8 was more frequently identified in autograft products before vs after Ceprate SC selection (40% vs 15%, P = 0.016). Although the role HHV-8 plays in myeloma pathogenesis remains unclear, these results imply that mobilization chemotherapy increases the numbers of circulating HHV-8-infected dendritic cells within the peripheral blood. In addition, CD34 selection of autograft products in MM patients may reduce the reintroduction of virally infected cells following high-dose chemotherapy. Bone Marrow Transplantation (2000) 25, 153-160.     

Delayed stem cell transplantation for the management of relapsed or refractory multiple myeloma

The optimal timing of stem cell transplantation for multiple myeloma is controversial. Late stem cell collection is undesirable because of the inability to mobilize stem cells. We report on 64 recipients of stem cells collected within 1 year after diagnosis, none of whom had transplantation in plateau phase of their disease. Patients seen within 12 months after diagnosis received four cycles of standard vincristine, doxorubicin, and dexamethasone (VAD) chemotherapy and then had stem cells mobilized. Patients were then placed on maintenance vincristine, BCNU, melphalan, cyclophosphamide, and prednisone or melphalan and prednisone chemotherapy for 12 cycles. At the sign of first progression, transplantation occurred. Fourteen patients were refractory to VAD chemotherapy, 20 relapsed on maintenance chemotherapy, and 30 relapsed off chemotherapy. The time to platelet engraftment was not affected by the duration of stem cell cryopreservation or extent of chemotherapy exposure after mobilization. The complete response rate was 34%. The actuarial median survival from initial diagnosis, from transplant day 0, and post-transplant progression-free survival was 51, 20 and 11.4 months, respectively. The patient status at transplantation and percentage of plasma cells circulating in the blood at apheresis influenced post-transplant survival; circulating plasma cells, status at transplantation and plasma cell labeling index influenced progression-free survival. Response duration was shorter in patients relapsing on chemotherapy.     

Mobilization of peripheral blood stem cells in CLL patients after front-line fludarabine treatment

Autologous peripheral blood stem cell transplantation is performed in an increasing number of chronic lymphocytic leukaemia (CLL) patients who are in the first remission following fludarabine treatment. There are contradictory data about the adverse impact of fludarabine on stem cell harvest. We analysed retrospectively mobilization results in 56 poor-risk CLL patients (median age: 56 years) who underwent first-line treatment with fludarabine and cyclophosphamide. The mobilization, consisting of cyclophosphamide 3 g/m(2) and granulocyte colony-stimulating factor (G-CSF) 10 microg/kg per day, was performed with a median of 77 days following the last fludarabine course. The target yield was >or=2.0x10(6) CD34+ cells/kg. The procedure was successful in 23 (41%) patients. A median of 3.3x10(6) CD34+ cells/kg was collected per patient. The successful mobilization was associated with a longer interval from the last chemotherapy (>2 months). The mobilization result was not influenced by the number of fludarabine cycles. No correlation was found in other parameters such as disease stage at diagnosis, disease status at stimulation or age. The poorly mobilized patients had significantly lower prestimulation blood counts (platelets, WBC and haemoglobin). Our data show that fludarabine does not generally prevent the stem cell mobilization; nevertheless, mechanisms related to the impact of fludarabine on stem cell harvest must be further investigated.     

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 lymphoma (FL) patients were submitted to CD34+ autologous stem cell transplantation (ASCT). All patients received at least two front line conventional 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 of 1.8 leukaphereses per patient, 8.1 × 10⁸ mononuclear cells (MNCs)/kg were collected. After the selection process, the median number of MNCs was 9.4 × 10⁶/kg; 4.3 × 10⁶/kg CD34+ cells and 17 × 10⁴/kg CFU-GM, with a purity of 83.7% and a viability of 89.2%. Mbr bcl2/IgH PCR analysis of 5 grafts showed that initial buffy-coat, and CD34- fractions were negative in 3 cases and positive in 2 cases (from whom selected CD34+ fraction remained positive in 1 case). After a conditioning regimen including total body irradiation, cyclophosphamide and etoposide, CD34+ selected cells were reinfused. All patients but one had successful engraftment, median time to WBC > 1 × 10⁹/l was 12 days and platelets > 50 × 10⁹/l 17 days. No severe infectious complications were seen. After transplant, with a minimum follow up of 2 years, 5 patients are still in complete remission (CR). Three patients have relapsed after 1 year of transplant with a mean TTF of 15.6 months. We conclude that PBSC CD34+ selection for ASCT was a safe technique, capable of reconstituting hemopoiesis without severe complications for high risk FL patients included in this study. The effects of tumor cell purging need to be evaluated in a larger series.Research grant support from CellPro, Bothwel, WA, USA     

Early harvest and late transplantation as an effective therapeutic strategy in multiple myeloma

Transplantation after high-dose chemotherapy prolongs survival in patients with multiple myeloma compared with standard therapy. It is unclear whether the optimal timing of transplantation is immediately after induction chemotherapy or whether stem cells may be cryopreserved for transplantation at subsequent progression or relapse. In this study, stem cells were collected within 6 months of diagnosis, followed by transplantation only at progression of myeloma. One hundred and eighteen patients with multiple myeloma had stem cells collected and cryopreserved. Eleven had transplants early in the disease after they demonstrated failure to respond to primary therapy. The remaining 107 were eligible for transplants when there was evidence of progressive disease. Of the 118 patients, 67 had transplants, nine died of progressive disease before transplantation, and 42 remain alive in plateau phase. The median survival of the group is 58.5 months; 67 are alive. Serum beta2-microglobulin, bone marrow labeling index (S phase), and hemoglobin level predicted overall survival (P < 0.006, P < 0.001, and P < 0.01, respectively). We conclude that early cryopreservation of blood stem cells followed by transplantation at progression is a feasible approach to therapy in patients with myeloma. The underlying biology of the disease has a greater impact on survival than the timing of transplantation. A prospective randomized trial is required to answer definitively the question of the optimal timing of blood cell transplantation.