Excellent long-term survival of 170 patients with Waldenström's macroglobulinemia treated in private oncology practices and a university hospital

The purpose of this study was to compare treatment and outcome of patients with Waldenström's macroglobulinemia (WM) in four private oncology practices (PP) and a university hospital (UH) in southwest Germany. We retrospectively reviewed the charts of all patients with WM of the last two decades of four PP in Mannheim, Heidelberg, Karlsruhe, and Speyer and the Department of Hematology of the University of Heidelberg. One hundred seventy patients could be identified, 74 from PP, 96 from the UH. Median age was 63.3 years. Patients from PP were older (median 65.3 vs. 62.5 years, p = 0.01). Only 54 % of patients from PP have received treatment during the observation time, as compared to 78.1 % of the UH (p < 0.001). In PP, 35 % of treated patients have received rituximab, as compared to 62.6 % of the patients of the UH (p < 0.001). Sixty percent of treated patients of PP have received bendamustine, as compared to only 8 % of the patients of the UH (p < 0.001). Time to first treatment was significantly shorter in patients from the UH compared to PP (median 13.7 vs. 52.9 months, p = 0.05). A trend towards a better overall survival was observed for patients treated with a rituximab-containing first-line regimen. The International Prognostic Scoring System for WM had significant prognostic value. Median overall survival was 25.0 years and did not differ between PP and UH. Despite different treatment strategies between PP and UH today overall survival of patients with WM is excellent, and better than previously reported.

Primary mediastinal B-cell lymphoma treated with CHOP-like chemotherapy with or without rituximab: results of the Mabthera International Trial Group study

BACKGROUND

The aim of this subgroup analysis of the Mabthera International Trial Group study was to evaluate the impact of chemotherapy and rituximab in primary mediastinal B-cell lymphoma (PMBCL) in comparison to other diffuse large B-cell lymphoma (DLBCL).

METHODS

Patients were randomly assigned to six cycles of CHOP-like regimens with or without rituximab.

RESULTS

Of 824 patients enrolled, 87 had PMBCL and 627 other types of DLBCL. Rituximab increased the rates of complete remission (unconfirmed) in both PMBCL (from 54% to 80%, P = 0.015) and DLBCL (from 72% to 87%, P < 0.001). In PMBCL, rituximab virtually eliminated progressive disease (PD) (2.5% versus 24%, P < 0.001), whereas without rituximab, PD was more frequent in PMBCL than in DLBCL (24% versus 10%, P = 0.010). With a median observation time of 34 months, 3-year event-free survival (EFS) was improved by rituximab for PMBCL (78% versus 52%, P = 0.012) and for DLBCL (81% versus 61%, P < 0.001). Overall survival benefit was similar for DLBCL (93% versus 85%, P < 0.001) and PMBCL (89% versus 78%, P = 0.158).

CONCLUSION

In young patients with PMBCL (age-adjusted International Prognostic Index 0-1), rituximab added to six cycles of CHOP-like chemotherapy increases response rate and EFS to the same extent as other DLBCL. The combination of rituximab with CHOP chemotherapy is an effective treatment in PMBCL with good prognosis features.

Plerixafor (Mozobil) for stem cell mobilization in patients with multiple myeloma previously treated with lenalidomide

Lenalidomide and other new agents have considerable activity in multiple myeloma (MM) and have changed the landscape of treatment. Data suggest that lenalidomide therapy before autologous hematopoietic stem cell transplantation has a detrimental effect on stem cell mobilization. This retrospective study examined the efficacy of plerixafor in combination with G-CSF among patients with MM previously treated with lenalidomide (median, 4 cycles; range, 1-20 cycles). Data were analyzed for 60 patients who received plerixafor plus G-CSF for frontline mobilization in a phase 3 clinical trial or an expanded access program (n=20) or for remobilization in a compassionate use program (n=40). The overall median number of CD34+ cells collected was 5.6 × 10(6) per kg (range, 0.45 × 10(6)-37.2 × 10(6)). The minimum number of CD34+ cells (2 × 10(6) per kg) was collected from 86.7% of patients in a median of 1 day. This minimum was collected from 100% of patients who underwent frontline mobilization and 80% of patients who underwent remobilization. These data suggest that CD34+ hematopoietic stem cells can be successfully and predictably collected with combination plerixafor plus G-CSF for primary or secondary mobilization in the majority of patients with MM who have been previously treated with lenalidomide.

Isolation of human mesenchymal stromal cells is more efficient by red blood cell lysis

BACKGROUND

Human mesenchymal stromal cells (MSC) have raised high hopes for tissue engineering and clinical therapy. Their isolation usually involves density fractionation of mononuclear cells (MNC) but this is difficult to standardize, especially under good manufacturing practice (GMP) conditions. MSC represent a heterogeneous mixture of cell types and the composition of subpopulations is affected by the initial steps of cell preparation.

METHODS

This study describes a straightforward method for isolation of human MSC based on red blood cell (RBC) lysis with ammonium chloride. Colony formation was compared directly with Ficoll density fractionation and culture of an untreated whole bone marrow (BM) aspirate.

RESULTS

After 7 days the number of fibroblastic colony-forming units (CFU-F) per milliliter of BM aspirate was slightly higher upon RBC lysis and the colonies were significantly larger compared with density fractionation, possibly because of maintenance of platelets. In contrast, colony formation was much lower in untreated BM. The heterogeneous composition of subpopulations was reflected by differences between the initial colonies with regard to growth pattern (tight or disperse) and cell morphology (round or elongated). This heterogeneous composition was not affected by the three different isolation methods. Furthermore, enrichment of CD271(+) cells resulted in the same morphologic heterogeneity. All cell preparations demonstrated the same immunophenotype using a panel of surface markers and displayed adipogenic and osteogenic differentiation potential.

DISCUSSION

This study demonstrates that human MSC can be efficiently isolated by RBC lysis. This technique is faster and can be standardized more easily for clinical application of MSC.

Mobilization of peripheral blood stem cells for autologous transplant in non-Hodgkin's lymphoma and multiple myeloma patients by plerixafor and G-CSF and detection of tumor cell mobilization by PCR in multiple myeloma patients

This report describes the first investigational use of plerixafor in Europe and the determination of tumor cell mobilization by polymerase chain-reaction after plerixafor treatment in a subset of patients with multiple myeloma (MM). Thirty-five patients (31 MM and 4 NHL) received granulocyte colony-stimulating factor (G-CSF) (10 microg/kg) each morning for 4 days. Starting the evening of Day 4, patients recieved plerixafor 0.24 mg/kg. Apheresis was initiated 10-11 h later, in the morning of Day 5. This regimen of G-CSF treatment each morning before apheresis and plerixafor treatment in the evening was repeated for up to 5 consecutive days. Mobilization with plerixafor and G-CSF resulted in a median 2.6-fold increase in peripheral blood (PB) CD34+ cell count compared with before plerixafor treatment. All patients collected > or =2 x 10(6) CD34+ cells/kg and 32 of 35 patients collected > or =5 x 10(6) CD34+ cells/kg. After plerixafor treatment, 3 of 7 patients had a small increase and 4 of 7 patients had a small decrease in PB tumor cells. No G-CSF was given post transplant. The median number of days to polymorphonuclear leukocyte and platelet engraftment was 14.0 and 11.0, respectively. There were no reports of graft failure. Plerixafor was generally well tolerated. Mobilization of PB CD34+ cells was consistent with previous clinical trials. The addition of plerixafor did not significantly increase the relative number of PB MM tumor cells.

[Current diagnostic and therapy of light chain amyloidosis]

Amyloidoses are protein-folding disorders in which soluble proteins are deposited as insoluble fibrillar aggregates due to a change in protein conformation. This might occur intra- or extracellularly, systemically or in a localized manner. The light chain type is the most common form of systemic amyloidoses and has the worst prognosis. The underlying disease is a monoclonal, mostly non-malignant plasma cell disorder. The causative treatment is the reduction of the amyloidogenic light chains with conventional or high-dose chemotherapy. Meanwhile, the"new drugs" used in multiple myeloma are also successfully applied. Early diagnosis is important to be able to treat patients effectively and to avoid further deterioration of organ function. Patients with newly diagnosed amyloidosis should be referred to a specialized center for consultation, diagnosis and treatment recommendation.

Heterogeneity of mesenchymal stromal cell preparations

As an archetype of human adult stem cells that can readily be harvested, enriched and expanded in vitro, mesenchymal stromal cells (MSC) have been reported to be of significance for regenerative medicine. The literature is replete with reports on their developmental potentials in pre-clinical model systems. Different preparative protocols have been shown to yield MSC-like cell cultures or even cell lines, from starting materials as diverse as bone marrow, fat tissue, fetal cord blood and peripheral blood. However, MSC are still ill-defined by physical, phenotypic and functional properties. The quality of preparations from different laboratories varies tremendously and the cell products are notoriously heterogeneous. The source and freshness of the starting material, culture media used, presence of animal sera, cytokines, cell density, number of passages upon culture, etc., all have a significant impact on the (1) cell type components and heterogeneity of the initial population, (2) differential expansion of specific subsets, with different potentials of the end products, and (3) long-term functional fate of MSC as well as other types of progenitor cells that are co-cultivated with them. Consequently, there is an urgent need for the development of reliable reagents, common guidelines and standards for MSC preparations and of precise molecular and cellular markers to define subpopulations with diverse pathways of differentiation and divergent potentials.

[From basic research to the clinic. Regulations for preclinical and clinical studies with stem cells]

The discovery of human embryonic stem cells at the end of 1998 had a strong influence on the development of stem cell research and led to controversial discussions. The first therapeutic application of adult blood stem cells began after their discovery in 1963 and was accepted as an authorized therapy in the early 1980s. The way from basic research to therapeutic use needed about 20 years and was also discussed in a controversial way similar to the discussions of today. The regulatory environment at that time, however, allowed a quick translation of the results from basic research to the clinic. Today many new stem cell therapies for a multitude of diseases are under development. Their clinical realization is regulated by the AMG (Arzneimittelgesetz). For nonclinical research as well as for clinical research, specific regulations are enacted to guarantee a structured and safe launch. Time, know how and money for planning, request for authorization and conduction of a clinical trial should not be underestimated. For clinical application of stem cell products authorization by the proper authorities is mandatory.

Commercial LightCycler-based quantitative real-time PCR compared to nested PCR for monitoring of Bcl-2/IgH rearrangement in patients with follicular lymphoma

Translocation of chromosomes 14 and 18 [t(14;18)] for detection of minimal residual disease in follicular lymphoma patients can be analyzed by nested polymerase chain reaction (PCR) or by quantitative PCR like LightCycler-based assays. We have compared both methods in blood and bone marrow samples of 28 patients enrolled in a clinical study on immunochemotherapy. In 42% of samples, the bcl2-IgH rearrangement was detectable by nested PCR, but not by LightCycler PCR. Nested PCR was able to reveal a significant drop in positive bone marrow or peripheral blood samples after therapy. In contrast, with LightCycler PCR, the detected drop in t(14;18)-positive cells did not reach statistical significance. The majority of patients showed positive results with nested PCR of peripheral blood or bone marrow without any associations to presence or absence of histological bone marrow (BM) infiltration by lymphoma cells. With LightCycler PCR, the numbers of positive cells were higher in samples from patients with BM infiltration of lymphoma cells (1.9 x 10(-2)) compared to samples from patients without involvement (4.08 x 10(-5)). A similar trend was seen in samples derived from the peripheral blood. Positivity for t(14;18) after therapy in two patients correlated with clinical relapse 6 months later. The data shown here demonstrate a lower sensitivity of LightCycler vs. nested PCR for detection of t(14;18). The usefulness of nested PCR for t(14;18) for risk stratification after primary therapy has to be validated in larger trials.

Improved lentiviral transduction of human mesenchymal stem cells for therapeutic intervention in pancreatic cancer

Genetic modification of human bone marrow mesenchymal stem cells (MSC) is highly valuable for their exploitation in basic science and therapeutic applications, for example in cancer. We present here a new, fast and easy-to-use method to enrich a functional population of lentiviral (LV)-transduced MSC expressing enhanced green fluorescent protein (eGFP). We replaced the eGFP gene by a fusion gene of puromycin acetyltransferase and eGFP. Upon LV gene transfer and puromycin selection, we quickly obtained a pure transduced MSC population, in which growth, differentiation capacity and migration preferences were not compromised. Furthermore, we are the first to report the migration velocity of MSC among which 30% were moving and velocity of about 15 mum h(-1) was not altered by LV transduction. Manipulated MSC underwent senescence one passage earlier than non-transduced cells, suggesting the use for therapeutic intervention in early passage numbers. Upon tail vein application in nude mice, the majority of LV-transduced MSC could be detected in human orthotopic pancreatic tumor xenografts and to a minor extent in mouse liver, kidney and lung. Together, LV transduction of genes to MSC followed by puromycin selection is a powerful tool for basic research and improves the therapeutic prospects of MSC as vehicles in gene therapy.

Autoantigens are translocated into small apoptotic bodies during early stages of apoptosis

A dysregulation of apoptosis or an ineffective clearance of apoptotic material is suspected to be involved in the pathogenesis of systemic lupus erythematodes. Subcellular fragments such as apoptotic bodies (ABs) have been recognized as modulators of intercellular communication and immune function. In this context, we have been interested whether nuclear and cytoplasmic antigens are relocated into ABs. In the present study, we characterized ABs isolated from apoptozing lymphoblasts. We found an accumulation of the linker-histone (histone 1) as well as the core-histones (histone 2A, histone 2B, histone 3, histone 4) in ABs. Further, they contained DNA, RNA and the ribonuclear protein La/SSB. Proteins such as cytochrome c, HSP 70, prohibitin, p53, nuclear matrix antigen or lamin B were excluded from ABs. The content of ABs differed from that observed in membrane microparticles isolated from viable cells. Formation of ABs occurred early during apoptosis. It was observed before DNA-degradation or phosphatidylserine exposure was detected. ABs were engulfed by monocyte-derived phagocytes. These findings suggest that immunogenic molecules are actively translocated into ABs followed by a rapid engulfment of the latter by environmental phagocytes. In autoimmune diseases, a defect in the clearance of ABs or AB formation may contribute to the development of autoimmunity.

Lack of CD56 expression on myeloma cells is not a marker for poor prognosis in patients treated by high-dose chemotherapy and is associated with translocation t(11;14)

Lack of CD56 expression was reported to be associated with a poor prognosis in multiple myeloma (MM) patients treated with conventional chemotherapy. Aim of our retrospective study was to analyse whether CD56 expression on MM cells reveals as a prognostic factor in patients treated with high-dose chemotherapy. MM cells of 99 patients prior to treatment with high-dose chemotherapy were analysed for CD56 expression by flow cytometry. Multivariable analysis of event-free survival in these patients showed no statistically significant difference between the CD56(-) (n=28) and the CD56(+) (n=71) group. The lack of CD56 expression on MM cells of these patients correlated significantly with the presence of translocation (11;14) (t(11;14)) (estimated correlation coefficient=0.655 95%, confidence interval (0.481; 0.779)). In summary, our results indicate that lack of CD56 expression on MM cells is not a prognostic marker in patients treated with high-dose chemotherapy, but is associated with t(11;14).

Efficient mobilization of peripheral blood stem cells following CAD chemotherapy and a single dose of pegylated G-CSF in patients with multiple myeloma

High-dose chemotherapy followed by autologous blood stem cell transplantation is the standard treatment for myeloma patients. In this study, CAD (cyclophosphamide, adriamycin, dexamethasone) chemotherapy and a single dose of pegfilgrastim (12 mg) was highly effective in mobilizing peripheral blood stem cells (PBSCs) for subsequent transplantation, with 88% of patients (n = 26) achieving the CD34+ cell harvest target of > or = 7.50 x 10(6) CD34+ cells/kg body weight, following a median of two apheresis procedures (range 1-4) and with first apheresis performed at a median day 13 after CAD application (range 10-20). Patients treated with pegfilgrastim showed a reduced time to first apheresis procedure from mobilization compared with filgrastim-mobilized historical matched controls (n = 52, P = 0.015). The pegfilgrastim mobilization regimen allowed for transplantation of a median of 3.58 x 10(6) CD34+ cells/kg body weight while leaving sufficient stored cells for a second high-dose regimen and back-ups in most patients. Engraftment following transplantation was comparable to filgrastim, with a median time of 14 days to leucocyte > or =1.0 x 10(9)/l (range 10-21) and 11 days to platelets > or = 20 x 10(9)/l (range 0-15). The results of this study thus provide further support for the clinical utility of pegfilgrastim for the mobilization of PBSC following chemotherapy in cancer patients scheduled for transplantation.

The initial phase of graft-versus-host disease is associated with a decrease of CD4+CD25+ regulatory T cells in the peripheral blood of patients after allogeneic stem cell transplantation

The mechanisms that induce and control the alloimmune inflammation of graft-versus-host disease (GvHD) after allogeneic stem cell transplantation (allo-SCT) are still incompletely understood. In the murine system, GvHD can be suppressed by CD4(+)CD25(+) regulatory T cells (TREG), which are generally involved in the suppression of inflammatory reactions. A disruption of the homeostasis between TREG and conventional T cells might therefore be associated with the inflammatory reactions of GvHD. We repetitively measured the frequency of TREG in the peripheral blood of 29 patients within the first 71-373 days after allo-SCT and correlated the results with the clinical course. We demonstrate that the initial phase of GvHD is associated with a significant reduction of TREG in the peripheral blood, while at later stages and during intensified immunosuppressive therapy, increased numbers of TREG appear. These results might indicate a pathogenic role for reduced numbers of TREG in the induction of human GvHD.

Retroviral vector insertions in T-lymphocytes used for suicide gene therapy occur in gene groups with specific molecular functions

Graft-versus-host disease (GvHD) is a severe complication in the context of allogeneic stem cell transplantation and adoptive immunotherapy. The transfer of a suicide gene into donor T-lymphocytes (TLCs) allows selective elimination of GvHD-causing cells. As retroviral gene transfer into hematopoietic stem cells can induce leukaemia, there is an urgent need also to analyze retroviral integration sites in TLCs. We examined suicide gene-transduced TLCs in four grafts and from four transplanted patients. One-hundred and fifteen integration sites were detected in vitro. Of these 90 could be mapped to the human genome; 50% (45) were located in genes and 32% (29) were detected 10 kb upstream or downstream of transcription start sites. We found a significant overrepresentation of genes encoding for proteins with receptor activity, signal transducer activity, transcription regulator activity, nucleic acid binding activity and translation regulator activity. Similar data were obtained from patient samples. Our results point to preferred vector integration patterns, which are specific for the target cell population and probably independent of selection processes. Thus, future preclinical analysis of the integration repertoire with abundant amounts of transduced cells could allow a prediction also for the in vivo situation, where target cells are scarce.