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

CD34+ selected versus unselected autologous stem cell transplantation in patients with advanced-stage mantle cell and diffuse large B-cell lymphoma

Novel strategies aiming to increase survival rates in patients with advanced-stage mantle cell lymphoma (MCL) and relapsing diffuse large B-cell lymphoma (DLBCL) are a clinical need. High-dose chemotherapy (HDCT) with autologous stem cell transplantation (ASCT) has improved progression-free (PFS) and overall survival (OS) in MCL and relapsed DLBCL. However, the role of CD34+ cell selection before ASCT in MCL and DLBCL is unclear. We retrospectively analyzed the outcome of 62 consecutive patients with advanced-stage MCL or relapsed DLBCL undergoing ASCT with (n=31) or without (n=31) prior CD34+ selection. All patients had stage III or IV disease, with 47% having DLBCL and 53% MCL. The median duration for neutrophil and platelet recovery was 12 and 16 days in CD34+ selected patients, and 11 (P<.001) and 14 days (P=.012) in the group without selection, respectively. No differences in toxicities were observed. The 5-year PFS for CD34+ selected versus not selected patients was 67% and 39% (P=.016), and the 5-year OS was 86% and 54% (P=.007). Our data suggest that using CD34+ selected autografts for ASCT in advanced stage MCL and DLBCL is associated with longer PFS and OS without increased toxicity.

Role of hematopoietic stem cell transplant in the management of follicular lymphoma

Despite decades of published data regarding the application of autologous and allogeneic stem cell transplant in patients with follicular lymphoma, there remain no uniform indications for its use in this disease. Autologous transplant has been shown to lead to longer progression-free survival times in randomized trials when compared with postremission interferon-based chemoimmunotherapy. However, the development of rituximab and its use in frontline, salvage, and maintenance therapy complicates the decision to pursue autologous transplant, a modality developed prior to the advent of anti-CD20 monoclonal antibodies. Allogeneic transplant offers the advantages of lymphoma-free grafts and the immunologic graft-versus-lymphoma effect. These factors may confer the possibility of long-term remission, though historically they have been accompanied by high rates of upfront morbidity and mortality, especially in heavily pretreated patients with a poor performance status or chemotherapy-refractory disease. Advances in patient selection, human leukocyte antigen (HLA) matching, conditioning regimens, and supportive care have reduced transplant-related mortality and the incidence of graft-versus-host disease. Recently published data focus on the incorporation of rituximab and radioimmunoconjugates prior to, during, and following autologous transplant. Furthermore, reduced-intensity allogeneic stem cell transplantation has increasingly been used for relapsed follicular lymphoma patients with comorbidities or advanced age. Several recent reports suggest that reduced-intensity regimens may provide a high likelihood of long-term disease-free survival for patients up to 70 years of age with a good performance status, chemotherapy-sensitive disease, and HLA-matched sibling donors. Such patients with relapsed disease should be referred to a transplant center that can enroll them in one of the forthcoming clinical trials that aim to confirm these outcomes.

Positive selection and transplantation of autologous highly purified CD133(+) stem cells in resistant/relapsed chronic lymphocytic leukemia patients results in rapid hematopoietic reconstitution without an adequate leukemic cell purging

We assessed the capacity of positively selected autologous CD133(+) hematopoietic stem cells (HSCs) to reconstitute lymphomyelopoiesis in chronic lymphocytic leukemia (CLL) patients receiving myeloablative chemotherapy. Ten resistant/relapsed CLL patients underwent HSC mobilization with chemotherapy and granulocyte-colony stimulating factor (G-CSF). Positive selection of circulating CD133(+) HSCs was performed by immunomagnetic technique. Highly purified HSCs were reinfused after busulphan/melphalan myeloablative treatment. A median number of 4.2 x 10(6) CD34(+) cells/kg and of 3.14 x 10(6) CD133(+) cells/kg were collected. Immunomagnetic selection resulted in the reinfusion of a median number of 2.45 x 10(6) CD133(+) cells/kg (median purity: 94.8%; median recovery: 84%) and 2.4 x 10(6) CD34(+) cells/kg (median purity: 93%; median recovery: 71%). HSC selection resulted in a median T cell and CD19(+)/CD5(+) cell depletion of 3.85 log and 2.8 log, respectively. At the molecular level, however, 7 of 8 valuable purified HSC fractions were contaminated by leukemic cells. All CLL patients showed rapid and sustained myeloid engraftment after reinfusion of purified CD133(+) cells. Immunologic reconstitution was comparable to that routinely observed in patients reinfused with unmanipulated leukapheresis products and no late infectious complications were observed. With a median follow-up of 28 months for transplanted patients, 5 patients are in clinical complete remission, 3 are in partial remission, and 1 is in progression. In conclusion, the reinfusion of highly purified CD133(+) HSCs allowed the rapid and sustained recovery of hematopoiesis after myeloablative treatment in resistant/relapsed CLL patients. However, the purging potential of positive selection of CD133(+) cells is not adequate to achieve tumor-free autografts.

Molecular purging of multiple myeloma cells by ex-vivo culture and retroviral transduction of mobilized-blood CD34+ cells

Background

Tumor cell contamination of the apheresis in multiple myeloma is likely to affect disease-free and overall survival after autografting.

Objective

To purge myeloma aphereses from tumor contaminants with a novel culture-based purging method.

Methods

We cultured myeloma-positive CD34⁺ PB samples in conditions that retained multipotency of hematopoietic stem cells, but were unfavourable to survival of plasma cells. Moreover, we exploited the resistance of myeloma plasma cells to retroviral transduction by targeting the hematopoietic CD34⁺ cell population with a retroviral vector carrying a selectable marker (the truncated form of the human receptor for nerve growth factor, ΔNGFR). We performed therefore a further myeloma purging step by selecting the transduced cells at the end of the culture.

Results

Overall recovery of CD34⁺ cells after culture was 128.5%; ΔNGFR transduction rate was 28.8% for CD34⁺ cells and 0% for CD138-selected primary myeloma cells, respectively. Recovery of CD34⁺ cells after ΔNGFR selection was 22.3%. By patient-specific Ig-gene rearrangements, we assessed a decrease of 0.7–1.4 logs in tumor load after the CD34⁺ cell selection, and up to 2.3 logs after culture and ΔNGFR selection.

Conclusion

We conclude that ex-vivo culture and retroviral-mediated transduction of myeloma leukaphereses provide an efficient tumor cell purging.

Role of stem cells in cancer therapy and cancer stem cells: a review

For over 30 years, stem cells have been used in the replenishment of blood and immune systems damaged by the cancer cells or during treatment of cancer by chemotherapy or radiotherapy. Apart from their use in the immuno-reconstitution, the stem cells have been reported to contribute in the tissue regeneration and as delivery vehicles in the cancer treatments. The recent concept of 'cancer stem cells' has directed scientific communities towards a different wide new area of research field and possible potential future treatment modalities for the cancer. Aim of this review is primarily focus on the recent developments in the use of the stem cells in the cancer treatments, then to discuss the cancer stem cells, now considered as backbone in the development of the cancer; and their role in carcinogenesis and their implications in the development of possible new cancer treatment options in future.

Recent advances in chronic lymphocytic leukemia

Chronic lymphocytic leukemia is a low-grade B-lineage lymphoid malignancy. Based on recent findings, the disease appears to be more heterogeneous than previously thought. Many cases may require no treatment at all unless patients become symptomatic or develop signs of rapid progression. Even in this setting, treatment is noncurative and is directed at reducing the symptoms. Recently described molecular risk features may help delineate at initial diagnosis which patients will have a more aggressive course. Newer treatment regimens incorporating purine nucleoside analogs and monoclonal antibodies have increased the rate of molecular complete remissions, which may lead to increased survival. Reduced intensity conditioning regimens have made the potentially curative modality of allogeneic transplantation more widely available. All of these recent treatments have significant risks of infectious complications, which must be carefully weighed against the risks posed by the underlying disease, and many low-risk asymptomatic patients do not require any treatment. A proposed risk-based treatment algorithm will be discussed.

Autologous stem cell transplantation in patients with chronic lymphocytic leukaemia: the Finnish experience

Although autologous stem cell transplantation (ASCT) has gained some popularity as a treatment option in patients with chronic lymphocytic leukaemia (CLL), limited multicentre data are available on the feasibility and efficacy of this approach. Between January 1995 and June 2005, 72 patients with CLL received ASCT in five Finnish centres. There were 45 men and 27 women with a median age of 57 years (38-69). The median time from diagnosis to ASCT was 32 months (6-181) and the median number of prior regimens 1 (1-4). All patients received blood stem cell grafts and CD34+ selection had been performed in 44 patients (61%). The most common high-dose regimen was a total body irradiation plus cyclophosphamide (38 patients, 53%). No early treatment-related deaths were observed. With a median follow-up of 28 months from ASCT, a relapse or progression has been observed in 27 patients (37%). The projected progression-free survival is 48 months (confidence interval (CI) 30-66). The projected median overall survival is 95 months (CI 74-101) from ASCT and is not influenced by graft selection or conditioning regimen used. Autologous stem cell transplantation is a feasible treatment option for CLL. Randomized trials against alternative treatments are needed to assess the impact of ASCT on the clinical course of CLL.

Randomised comparison of two B-cell purging protocols for patients with B-cell non-Hodgkin lymphoma: in vivo purging with rituximab versus ex vivo purging with CliniMACS CD34 cell enrichment device

We investigated the feasibility, safety and efficacy of two B-cell purging methods in patients with CD20+ non-Hodgkin lymphoma (NHL) receiving autologous stsem cell transplantation. Myeloid and immune recoveries between the methods were compared. Twenty-seven patients were randomised to either in vivo purging with rituximab or ex vivo purging by CD34+ cell selection. Both purging methods were efficient at eliminating B-cells in infusates. When compared with in vivo purging, ex vivo purging was associated with CD34+ cell loss and delayed median neutrophil (10 d vs. 11 d) and platelet (12.5 d vs. 17 d) count recoveries. Lymphocyte recovery was similar in both groups, but immunoglobulin recovery was delayed after in vivo purging. Late-infectious complications were few in both arms. At a median follow-up of 27 months, 2-year probabilities of event-free survival (EFS) rates were 81% for in vivo purging and 76% for ex vivo purging (P = 0.66). When compared with 53 unpurged patients, all 27 purged patients had improved 3-year probabilities of overall survival (89% vs. 70%, P = 0.014) and a trend for improved EFS (78% vs. 57%, P = 0.075). In conclusion, although both purging methods were feasible and safe, rituximab purging was superior as it did not impair CD34+ cell mobilisation and was associated with faster myeloid recovery. Further studies are needed to determine whether rituximab purging is more effective than the use of unpurged autografts.

Chronic Lymphocytic Leukemia: Recent Advances in Diagnosis and Treatment

Chronic lymphocytic leukemia (CLL) is a low-grade B-lineage lymphoid malignancy but may have more heterogeneity than previously thought. Many cases require no treatment at all because of an indolent course, while other patients become symptomatic or develop signs of rapid progression. Treatment is usually noncurative and is directed at reducing the symptoms. Some molecular risk features may help delineate, at initial diagnosis, which patients will have a more aggressive course. Newer CLL treatment regimens incorporating purine nucleoside analogues and monoclonal antibodies have increased the rate of molecular complete remissions, which may lead to better survival times. Reduced intensity allogeneic transplant conditioning regimens have made the potentially curative modality more widely available. All these treatments have significant risks for infectious complications, which must be carefully weighed against the risks posed by the underlying disease. A proposed risk-based treatment algorithm is discussed.

Evaluation of potential risk factors for early infectious complications after autologous peripheral blood stem cell transplantation in patients with lymphoproliferative diseases

A number of risk factors for the occurrence of neutropaenic fever after haematopoietic stem cell transplantation (HSCT) have been proposed. We were interested in whether these factors remain valid for several early infection-related outcomes when applied to a homogeneous group of patients in uni- and multivariate analyses. Therefore, we analysed 144 consecutive patients with lymphoproliferative disorders receiving autologous peripheral blood HSCT. Variables tested as potential risk factors for the occurrence of fever, documented infection (DI), microbiologically documented infection (MDI) or failure of first-line antimicrobial therapy were sex, conditioning regimen, prolonged neutropaenia, low number of CD34+ cells transplanted, purging, lack of selective gut decontamination, higher age and increased body mass index. In uni- and multivariate analyses, conditioning including total body irradiation was the only risk factor for the occurrence of fever, and neutropaenia >or=10 days was the only factor associated with failure of first-line antimicrobial therapy. None of the variables tested was associated with an increased risk for DI or MDI. This analysis suggests that a number of previously proposed risk factors actually are of minor clinical relevance for early infections in the majority of patients receiving autologous HSCT.

Advances in the diagnosis and treatment of chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is a low-grade B-lineage lymphoid malignancy, which is often not treated until patients become symptomatic or develop signs of rapid progression. Even in this setting, treatment is non-curative and is directed at reducing the symptoms from an increasing disease burden. Newer treatment regimens incorporating purine nucleoside analogs have increased the rate of successful remission induction in CLL patients. Recent combination chemoimmunotherapy regimens have produced frequent complete molecular remissions, and early evidence suggests this may result in an improved long-term survival. Allogeneic hematopoietic cell transplantation is the only curative therapy for CLL but is infrequently used due to the older age of most patients, although reduced intensity conditioning regimens have reduced the toxicity of allogeneic transplantation. This review will summarize recent advances in the management of CLL, including prognostic factors, combination chemotherapy including nucleoside analogs and monoclonal antibodies, and reduced intensity allogeneic transplant conditioning regimens.

B-cell purging in autologous stem-cell transplantation for non-Hodgkin lymphoma

Autologous stem-cell transplantation is a common therapy for B-cell non-Hodgkin lymphoma. However, a concern with the procedure is the potential of malignant cells to reinfuse with the stem-cell graft. Thus attempts have been made to purge, or eliminate, malignant cells from the graft. The oldest, and most well studied, method for prevention of reinfusion is in vitro use of antibodies against B cells that bind or lyse malignant B cells and healthy cells, while leaving T cells and stem cells to be reinfused. In the past 5 years, investigators have used rituximab, an antibody against CD20, to purge malignant cells in vivo without any manipulation in vitro. Both conventional and new techniques have shown promise, but their exact role remains to be defined. We analysed data on the purging of B cells by use of antibodies in the setting of autologous transplantation, with emphasis on the emerging technique of in vivo purging.

Stem cell transplantation in autoimmune diseases: an update

Immunosuppressive or immunomodulatory treatments are often used in patients with various autoimmune diseases (AID). However, since conventional treatments are rarely curative, alternative treatment methods have been looked for. Based on animal experiments and anecdotal case reports, stem cell transplantation (SCT) has received considerable attention in the treatment of severe autoimmune diseases during the last decade. This review summarizes current experience of SCT in patients this field. Although early experience shows some promise, randomized studies are necessary to evaluate the real value of autologous SCT in various autoimmune diseases. Since autologous SCT may not be curative in patients with AID, also evaluation of allogeneic SCT is important in the future.

Quantitative Molecular Evaluation of Minimal Residual Disease in Patients with Chronic Lymphocytic Leukemia

Although novel therapies for chronic lymphocytic leukemia have resulted in higher hematologic response rates, the complete eradication of disease rarely occurs. Alemtuzumab (Campath-1H) seems to be extremely effective in this role in pretreated patients. The authors used a molecular semiquantitative polymerase chain reaction (PCR) method to assess the ability of alemtuzumab to induce PCR negativity in eight patients pretreated with fludarabine. IgH rearrangement was coamplified with a housekeeping gene and fluorescent PCR products were analyzed on a DNA automatic sequencer. Each patient was evaluated at diagnosis, after fludarabine, and after Campath-1H. The median interval between the last therapy course with fludarabine and the start of Campath-1H was 14 weeks. Patients received subcutaneous doses up to 10 mg, three times a week, for 12 weeks, with a median dose of 190 mg. After six cycles with fludarabine, only one patient (12.5%) achieved molecular remission, and in three other patients IgH levels decreased by 0.5 to 1 log. At the beginning of Campath-1H administration, all patients were PCR positive, including the one previously found to be negative. At the end of treatment, five patients achieved molecular remission (62.5%), four of them within 1 month after the end of therapy. Seventy-two percent of responses, with 43% of complete responses, were documented on bone marrow smears. A significant reduction of lymph node and spleen diameters was noted in 50% and 33% of patients, respectively. Four patients showed grade 2 skin reaction at the site of the subcutaneous injection and grade 1 or 2 fever. Two patients developed neutropenia (grade 2 and 3) and two hemolytic episodes. Three patients showed cytomegalovirus and one herpes zoster and Epstein-Barr virus reactivation. These results show that Campath-1H represents an efficacious in vivo purging tool with a safe profile.

Adoptive transfer of costimulated T cells induces lymphocytosis in patients with relapsed/refractory non-Hodgkin lymphoma following CD34+-selected hematopoietic cell transplantation

We explored the feasibility and toxicity of administering escalating doses of anti-CD3/CD28 ex vivo costimulated T cells as a therapeutic adjunct for patients with relapsed, refractory, or chemotherapy-resistant, aggressive non-Hodgkin lymphoma (NHL) following high-dose chemotherapy and CD34+-selected hematopoietic cell transplantation (HCT). Sixteen patients had infusions on day 14 after HCT of autologous T cells that had been stimulated using beads coated with anti-CD3 and anti-CD28 monoclonal antibodies. At baseline, the subjects had severe quantitative and functional T-cell impairments. The culture procedure partially reversed impaired cytokine responsiveness in T cells in vitro and in vivo. Transient dose-dependent infusion toxicities were observed. There was a rapid reconstitution of lymphocytes; however, there were persistent defects in CD4 T cells. Most interestingly, 5 patients had a delayed lymphocytosis between day 30 and day 120 after HCT. Maximal clinical responses included 5 patients with a complete response (CR), 7 patients with a partial response (PR), and 4 patients with stable disease. At a median follow-up of 33 months (range, 26-60 months), 5 patients are alive with stable or relapsed disease and 3 patients remain in CR. In conclusion, this phase 1 trial demonstrates that adoptive transfer of autologous costimulated T cells (1) is feasible in heavily pretreated patients with advanced NHL, (2) is associated with a rapid recovery of lymphocyte counts, (3) reverses cytokine activation deficits in vitro, and (4) is associated with delayed lymphocytosis in a subset of patients.

Role of autologous stem cell transplantation in chronic lymphocytic leukemia

Autologous hematopoietic stem sell transplantation is increasingly considered for treatment of patients with high-risk chronic lymphocytic leukemia. Patients not eligible for allogeneic hematopoietic stem cell transplantation with poor prognosis disease, documented chemosensitivity, and a minimal tumor burden at the time of hematopoietic stem cell transplantation can be treated with autologous hematopoietic stem cell transplantation currently using peripheral blood stem cells. Different purging methods to obtain sources of stem cells free of tumor contamination are currently being evaluated. Major concerns are judicious selection of which patients may benefit from this approach, the subsequent risk of relapse of disease, and the long-term risk of development of secondary malignancies, including myelodysplastic syndrome and acute myelogenous leukemia. Recognizing and reducing the risk factors that contribute to relapse and complications of the procedure should improve outcome after autologous hematopoietic stem cell transplantation. With the increasing use, increasing effectiveness, and low treatment-related mortality associated with nonmyeloablative conditioning regimens, the question of whether a patient should be offered autologous or allogeneic hematopoietic stem sell transplantation can be a difficult one. Defining salvage settings for relapse and implementing a tandem autologous/allogeneic hematopoietic stem cell transplantation approach may provide a method to improve outcome for selected patients.