High-dose therapy with peripheral blood stem cell transplantation for patients with relapsed or refractory Hodgkin's disease: long-term outcome and prognostic factors

From March 1986 to March 1998, 82 patients with relapsed or refractory Hodgkin's disease underwent high-dose chemotherapy (HDCT) with peripheral blood stem cell (PBSC) transplantation in our center. This is a retrospective analysis of the long-term clinical outcome. There were 52 males and 30 females with a median age of 32 years (range 18-59 years). Prior to transplantation, 36 patients were in complete remission (CR), 34 in partial remission (PR), and 12 had refractory disease after salvage therapy. For HDCT, 78 patients were treated with CBV (cyclophosphamide, 6.0-6.8 g/ m2; etoposide, 1.0-1.6 g/m2; carmustine, 0.45-0.8 g/m2), while four patients received different regimens. Probability of freedom from progression (FFP), overall survival (OS), and event-free survival (EFS) at 5 years of the entire group was 63%, 61%, and 54%, respectively. Early mortality rate ( < or = 100 days) declined from 17% to 6% after 1992. Five patients died of late transplant-related complications (> 100 days), including secondary lymphoma and leukemia in two patients. None of the refractory patients survived beyond 3.5 years. Multivariate analyses identified extranodal sites of disease at relapse and refractory disease status prior to transplantation as significant prognostic factors for FFP, EFS, and OS. As we have shown in our study, remarkable progress was achieved in reducing early morbidity and mortality over time, but this was associated with only a slight, not significant improvement of long-term outcome (OS 66% vs 57% at 5 years for patients undergoing PBSC transplantation before and after 1992, P = 0.26). Although the results as a whole are encouraging for chemosensitive patients, new therapeutic strategies are needed to reduce toxicity and improve the clinical outcome of patients, especially of those with a less favorable prognosis.

Evaluation of the kinetics of the bone marrow tumor load in the course of sequential high-dose therapy assessed by quantitative PCR as a predictive parameter in patients with multiple myeloma

The aim of this investigation was to examine the possible clinical significance of the kinetics of bone marrow (BM) tumor load during the course of sequential high-dose therapy (HDT) as assessed by quantitative PCR in patients with multiple myeloma. In 20 patients with multiple myeloma (MM) treated with two consecutive cycles of HDT followed by autologous peripheral blood stem cell transplantation (PBSCT), clonotypic cells in the peripheral blood (PB) and BM were quantitated by PCR using allele-specific oligonucleotides (ASO) prior to the first, immediately prior to the second, and after the second HDT. The median proportion of clonotypic cells in the BM was 1.27% before the first HDT (range, 0.03-70%), 0.17% after the first (range, 0.001-22%), and 0.05% after the second HDT (range, 0.00009-1.44%). The median number of circulating clonotypic cells was 65/ml (range, 0.9-10842) prior to HDT, 2.7/ml (range, 0-315) after the first, and 3.5/ml PB (range, 0.7-97) after the second HDT. While the median BM tumor load decreased during the first (P = 0.03) and second (P = 0.044) HDT cycles, only the first cycle resulted in a reduction of clonotypic cells in the PB (P = 0.00078 and P= 1.0, respectively). In seven patients, the BM tumor load did not decrease below the initial level after one or two cycles of HDT. All of these patients developed progressive disease (median, 19 months post first cycle; range, 10-21). Of the remaining 13 patients, only four relapsed (18, 19, 21 and 22 months after the first cycle of HDT), while nine remain in response (median followup, 29 months; range, 18-41) (log-rank test P = 0.0009). Our results indicate that the kinetics of the BM tumor load is a predictive parameter in patients with MM and identifies those patients who could benefit from further therapy including new treatment modalities.

Bone marrow-derived cells as carriers of recombinant immunomodulatory cytokine genes to lymphoid organs

The purpose of this study was to determine the feasibility of cytokine gene delivery to lymphatic tissue using transduced bone marrow-derived cells. MBAE and pBABE retroviral vectors carrying the genes for murine interleukin-4 and the selection marker neomycin phosphotransferase (neo) were used to transduce bone marrow-derived dendritic cells (DC) and hematopoietic stem cells (HSC). A transduction efficiency of 11-33% for HSC and 2-10% for DC was achieved. Transduced HSC and DC released 55-170 pg of recombinant interleukin-4 per 1 x 10(6) cells/mL in vitro. To study the migration of the cells in vivo, we introduced the transduced cells into syngenic mice. DC were injected subcutaneously into the front limbs of unconditioned mice and HSC were intravenously administered to irradiated mice. The distribution of the transduced cells was studied by quantitative polymerase chain reaction for the neo gene as a marker. After 3 days, DC migrated to the axillary lymph nodes in the drainage area of the injection site and were detectable up to 5 days. After intravenous administration of transduced HSC, the neo gene could be found in up to 100 copies/5 x 10(3) cells in mesenterial lymph node, spleen, bone marrow, thymus, and liver. The distribution of the transduced cells was heterogenous: in different mice, different organs showed high copies of the neo gene after 10 and 13 days. After 39 days, two of three mice were negative for neo in all organs analyzed. In conclusion, bone marrow-derived cells can be genetically engineered ex vivo to deliver recombinant cytokine genes to lymphoid organs in vivo. In particular, DC might be candidate cells for use in immunomodulatory gene therapy for autoimmune diseases and cancer.

[Functional magnetic resonance tomography in the diagnosis and therapy monitoring in multiple myeloma]

AIM OF THE STUDY

Investigation of the quantitative microcirculation parameters amplitude A and exchange rate constant k21 determined by contrast-enhanced dynamic magnetic resonance imaging (d-MRI) in multiple myeloma (MM).

METHODS

d-MRT of lumbar spine and right spina iliaca superior posterior of 16 controls (ctr) and 35 patients with active MM. Generation of colour-coded images of microcirculation parameters superimposed onto static MRI images.

RESULTS

Amplitude A and k21 parameters were significantly increased in patients with MM and down modulated by therapy in 7 of 8 MM cases in a follow-up investigation [p < 0.01; median Actr = 0.2 (0.09-0.4); median AMM = 0.93 (0.2-1.52); median k21ctr = 0.09 min-1 (0.03-0.9); median k21MM = 4.57 min-1 (0.21-23.8)]. Thirteen patients revealed a "diffuse" and 22 a "focal" pattern of distribution of microcirculation parameters. Bone marrow biopsies in 8 cases revealed an correlation between bone marrow plasma cell infiltration and increased microcirculation parameters.

CONCLUSION

Identification of microcirculation changes by d-MRI is a novel imaging technique for the detection and monitoring of MM bone lesions.

Microchimerism in bone marrow-derived CD34(+) cells of patients after liver transplantation

Lymphoid and dendritic cells of donor origin can be detected in the recipient several years after a solid organ transplantation. This phenomenon is termed microchimerism and could play a role in the induction of tolerance. The fate of other hematopoietic cells transferred by liver transplantation, in particular of stem and progenitor cells, is unknown. For this reason, we studied peripheral blood and bone marrow samples of 12 patients who had received a liver transplant from an HLA-DR mismatched donor. Eight patients were long-term survivors between 2.8 and 10.1 years after allografting. CD34(+) cells from bone marrow were highly enriched with the use of a 2-step method, and a nested polymerase chain reaction was applied to detect donor cells on the basis of allelic differences of the HLA-DRB1 gene. Rigorous controls with DRB1 specificities equal to the donor and host were included. In 5 of 8 long-term liver recipients, donor-specific CD34(+) cells could be detected in bone marrow. Microchimerism in the CD34(+) cell fraction did not correlate to the chimeric status in peripheral blood. In conclusion, our results demonstrate a frequent microchimerism among bone marrow-derived CD34(+) cells after liver transplantation. The functional role of this phenomenon still needs to be defined. (Blood. 2000;96:763-767)

Efficacy of continuous infusion of ceftazidime for patients with neutropenic fever after high-dose chemotherapy and peripheral blood stem cell transplantation

Neutropenia is an important complication of high-dose chemotherapy (HDCT). Neutropenic patients presenting with fever are routinely hospitalized for treatment with broad-spectrum antibiotics. Neutropenia up to 10 days is associated with a low-risk profile, and antimicrobial therapy administered on an outpatient basis might be an alternative to admission to hospital. This prospective study evaluates the safety of a continuous infusion of ceftazidime in neutropenic patients after HDCT and peripheral blood stem cell transplantation (PBSCT). From September 1995 to October 1999, 81 patients received a 2 g intravenous bolus of ceftazidime, followed by a 4 g continuous infusion per 24 h of ceftazidime using a portable infusion pump. If the fever persisted for 72 h, a glycopeptide antibiotic was added. The median patients' age was 44 years. Fifty-two of 81 patients (64%) responded to the monotherapy with ceftazidime. After addition of a glycopeptide antibiotic, a further 17 patients (21%) became afebrile. The causes of fever were septicaemia in 11 patients, pneumonia in two and fever of unknown origin in 68 patients. Fifty-eight episodes (72%) were successfully managed by outpatient treatment alone. The reason for admission to hospital was the change to imipenem/cilastin, which had to be administered three times per day (12 patients), severe mucositis with parenteral nutrition (eight patients), or a Karnovsky index </=60 (three patients). In six of these cases, outpatient treatment was resumed after a brief period of in-patient care. In no case was the treatment terminated because of failure of the pump. With daily follow-up and close monitoring for development of complications, it is possible to discharge patients earlier after HDCT and PBSCT, thereby decreasing costs.

In vivo depletion of B cells using a combination of high-dose cytosine arabinoside/mitoxantrone and rituximab for autografting in patients with non-Hodgkin's lymphoma

We performed a pilot study including rituximab (Mabthera; IDEC-C2B8, Hoffmann-La Roche) with a sequential high-dose therapy protocol in 15 patients with follicular and three patients with mantle cell lymphoma and studied the potential of the chemoimmunotherapy to induce depletion of malignant B cells in vivo. Our treatment protocol included induction with three cycles of CHOP (cyclophosphamide, doxorubicin, vincristine and prednisone) chemotherapy, followed by peripheral blood stem cell (PBSC) mobilization using high-dose cytosine arabinoside (2 g/m2 every 12 h, days 1 and 2) and mitoxantrone (10 mg/m2, days 2 and 3) (HAM), preceeded by rituximab (375 mg/m2). The proportion of CD19+ B cells in blood and bone marrow decreased from 1.2 +/- 0.4% to 0.13 +/- 0. 1% (P = 0.01) and from 2.7 +/- 0.8% to 0.8 +/- 0.5% (P = 0.03) respectively. The number of t(14;18)-positive cells in blood and bone marrow progressively decreased with treatment, as assessed by the quantitative real-time PCR assay in four patients. Conversion to PCR-negativity was achieved in the peripheral blood (PB) of seven informative patients. Leucaphereses were performed during the granulocyte colony-stimulating factor (G-CSF)-supported leucocyte recovery phase. In 17 of 18 patients, a median of 15.1 x 106 CD34+ cells/kg body weight (BW) could be harvested by a single procedure for enrichment by an immunomagnetic method. Leucapheresis products contained 51.3 +/- 28.8 x 104 CD19+ B cells/kg BW (mean) and were t(14;18) PCR negative in all seven informative patients. These data compare favourably with results obtained in patients treated with the same regimen without rituximab. The high-dose therapy (n = 12 patients), including total body irradiation (14.4 Gy) and cyclophosphamide (200 mg/kg BW), was also preceeded by rituximab. Recovery of neutrophils to > 0.5 x 109/l and of platelets to > 20 x 109/l required a median of 13.5 and 11.5 d (range 11-24 and 9-24 d) respectively. In conclusion, the addition of the CD20 antibody to chemotherapy ensured tumour depletion in vivo and allowed the collection of PBSCs devoid of tumour cells and with conserved engraftment capability.

Prognostic factors for the clinical outcome of patients with follicular lymphoma following high-dose therapy and peripheral blood stem cell transplantation (PBSCT)

This is a report on 111 patients with advanced stage follicular lymphoma who where autografted using PBSC. Seventy patients were enrolled in first remission, whereas 41 were treated in second or higher remission. High-dose therapy consisted of total body irradiation plus cyclophosphamide in 103 patients, while eight patients received BEAM (carmustine, etoposide, cytosine-arabinoside, melphalan). Autografts contained 8.1 +/- 0.6 x 106 CD34+ cells/kg body weight. At a median follow-up of 44.2 months from PBSCT (range 4.9-77.4 months), 93 patients are alive, with a probability of overall and relapse-free survival (RFS) of 83% and 64%, respectively. A significantly higher probability of relapse was associated with male gender, involvement of more than eight lymph node areas, extra-nodal manifestations other than bone marrow and PBSCT performed in second or higher remission. In the latter group of patients, previous radiotherapy was associated with poor prognosis. The relevance of chemosensitivity as a prognostic factor was reflected by a better RFS in patients who had achieved complete remission at the time of PBSC mobilization. In a multivariate analysis, involvement of eight or more lymph nodes and high-dose therapy performed in second or higher remission were independent prognostic factors.

Autologous and allogeneic stem cell transplantation in multiple myeloma

Multiple myeloma is still an incurable disease. The standard conventional chemotherapy comprises melphalan and prednisone (MP). Combination chemotherapy regimens could not improve the median survival of 36 months observed with MP. In the French IFM90 study, HD therapy with TBI plus melphalan 140 mg/m2 was shown to prolong overall survival and progression-free survival compared to conventional treatment. Nonetheless, most patients eventually succumb due to disease progression. Allogeneic transplantation may induce long-term remissions and even cure, but is hampered by a high transplantation-related mortality (TRM). Currently, efforts are made to reduce this TRM and to evaluate the graft-versus-myeloma effect.

Pentostatin (Nipent) in T-cell malignancies. Leukemia Cooperative Group and the European Organization for Research and Treatment of Cancer

Within this phase II trial of the European Organization for Research and Treatment of Cancer, we have investigated the safety and efficacy of pentostatin (Nipent; SuperGen, San Ramon, CA) in refractory lymphoid malignancies. Pentostatin was administered at a dosage of 4 mg/m2 every week for the first 3 weeks, then every 14 days, followed by maintenance therapy of 4 mg/m2 monthly for a maximum of 6 months. We have previously reported the results in T- and B-cell prolymphocytic leukemia, B-cell chronic lymphocytic leukemia, and hairy cell leukemia This report focuses on the outcome in T-cell malignancies: T-cell chronic lymphocytic leukemia, Sézary syndrome, mycosis fungoides, and T-zone lymphoma. Of 92 patients with these diagnoses enrolled, 76 were evaluable for response and toxicity, ie, 25 of 28 with T-cell chronic lymphocytic leukemia, 21 of 26 with Sézary syndrome, 22 of 26 with mycosis fungoides, and eight of 12 with T-zone lymphoma. All patients had progressive and advanced disease. Sixteen patients (21%) died during the first 9 weeks of treatment: 12 of progressive disease, two of infectious complications thought to be unrelated to treatment, one of myocardial infarction, and one of renal failure related to administration of intravenous contrast. Major toxicity (grades 3 and 4) included infection in 10.5% of patients, nausea/vomiting in 5%, and hepatotoxicity in 3%. One patient (1.3%) achieved a complete remission and 15 (19.7%) a partial remission. Better results were achieved in patients with Sézary syndrome or mycosis fungoides (complete remission + partial remission = 33.4% and 22.7%, respectively) than in patients with T-cell chronic lymphocytic leukemia (8%) or T-zone lymphoma (25%). We conclude that pentostatin is active in low-grade T-cell malignancies. Toxicities are mild to moderate at the dose schedule administered. Severe hematologic toxicity has not been observed. The efficacy at the present dose level is moderate. A higher dose might be necessary for some T-cell malignancies.

A phase II study of two cycles of high-dose chemotherapy with autologous stem cell support in patients with metastatic breast cancer who meet eligibility criteria for a single cycle

Multi-cycle high-dose chemotherapy with autologous stem cell support (HDC-ASCS) may improve the results obtained with single-cycle HDC-ASCS in metastatic breast cancer (MBC). However, the tolerability and efficacy of additional cycles of HDC-ASCS in patients selected using standard eligibility criteria for single cycle HDC-ASCS is uncertain. Twenty-nine patients with MBC and a CR or PR to induction chemotherapy were selected by standard institutional eligibility criteria for single-cycle HDC-ASCS. Cycle 1 HDC-ASCS (cyclophosphamide 6 g/m2; mitoxantrone 70 mg/m2; carboplatin 800 mg/m2) was followed by a planned second cycle (etoposide 1.6 g/m2; thiotepa 800 mg/m2; carboplatin 800 mg/m2 modulated by tamoxifen 120 mg/m2/day x 5 days) with a median interval of 3.2 months. CR rate was 20% after induction chemotherapy and 33% and 54% after HDC cycles I and II, respectively. Sixteen patients (55%) failed to complete HDC cycle II within 200 days because of disease progression, toxicity, inadequate stem cell collection, insurance denials or patient choice. Median progression-free survival (PFS) for all 29 patients entered is 301 days from date of HDC cycle I and actuarial PFS at 2 years is 35%. For the 13 patients who received the two cycles of HDC-ASCS, actuarial PFS at 2 years was 54% (P = NS compared to those receiving only one cycle). These data show that a second cycle of full-dose intensity HDC-ASCS may increase the proportion of patients with MBC that achieve CR and may increase PFS. However, a large proportion of patients that complete HDC-ASCS cycle I may fail to proceed to cycle II in a timely fashion. Bone Marrow Transplantation (2000) 25, 519-524.

Pentostatin in T-cell malignancies--a phase II trial of the EORTC. Leukemia Cooperative Group

PURPOSE

Within this phase II EORTC trial, we have investigated the safety and efficacy of pentostatin in lymphoid malignancies. We have previously reported the results in T- and B-cell prolymphocytic leukemia, B-cell chronic lymphocytic leukemia (B-CLL) and hairy cell leukemia. This report focuses on the outcome in T-cell malignancies: T-CLL, Sézary syndrome (Sézary), mycosis fungoides (MF) and T-zone lymphoma (TZL).

PATIENTS AND METHODS

Of the 92 patients with these diagnoses enrolled, 76 were evaluable for response and toxicity, i.e., 25 of 28 with T-CLL, 21 of 26 with Sézary, 22 of 26 with MF, and 8 of 12 with TZL. All patients had progressive and advanced disease. Pentostatin was administered at a dosage of 4 mg/m2 every week for the first 3 weeks, then 4 mg/m2 every 14 days for another 6 weeks, followed by maintenance therapy of 4 mg/m2 monthly for a maximum of 6 months.

RESULTS

Response rates (complete and partial responses) in patients with Sézary (n = 22) or MF (n = 21) were 33% and 23%, respectively, and in patients with T-CLL (n = 21) or TZL (n = 8) 8% and 25%, respectively. Sixteen (21%) patients died during the first ten weeks of treatment: twelve of progressive disease, two of infectious complications with progressive disease, one of myocard infarction and one of renal failure related to administration of i.v. contrast. Major toxicity (grade 3-4) included infection in 11% of patients, nausea/vomiting in 4%, diarrhea in 3%. Hematologic toxicity was mild to non-existent.

CONCLUSIONS

We conclude that pentostatin is active in Sézary and MF but showed marginal activity in T-CLL or TZL. Toxicities are mild to moderate at the dose schedule administered. Due to its relatively specific lympholytic effect and its favorable toxicity spectrum, pentostatin might be especially useful for the palliative treatment of T-cell malignancies.

Correlation between IL-3 receptor expression and growth potential of human CD34+ hematopoietic cells from different tissues

CD123 (alpha-subunit of IL-3 receptor) expression on primitive and committed human hematopoietic cells was studied by multicolor sorting and single-cell culture. The sources of cells included fetal liver (FLV), fetal bone marrow, umbilical cord blood, adult bone marrow and mobilized peripheral blood. Three subsets of CD34+ cells were defined by the levels of surface CD123: CD123negative, CD123low, and CD123bright. Coexpression of lineage markers showed that a majority of CD34+CD123bright cells were myeloid and B-lymphoid progenitors, while erythroid progenitors were mainly in the CD34+CD123negative subset. The CD34+CD123low subset contained a heterogeneous distribution of early and committed progenitor cells. Single CD34+ cells from the CD123 subsets were cultured in a cytokine cocktail of stem cell factor, interleukin 3 (IL-3), IL-6, GM-CSF, erythropoietin, insulin-like growth factor-1, and basic fibroblast growth factor. After 14 days of incubation, a higher cloning efficiency (CE) was observed in the CD34+CD123negative and CD34+CD123low fractions (37+/-23% and 44+/-23%, respectively) than in the CD34+CD123bright fraction (15+/-21%). Using previously published criteria that colonies containing dispersed, translucent cells (dispersed growth pattern, DGP) were derived from primitive cells and that colonies composed solely of clusters were from committed cells, early precursors were distributed evenly in the CD34+CD123negative and CD34+CD123low subsets. When CD38 and CD90 (Thy-1) were used for further characterization of CD34+ cells from FLV, CE increased from 37+/-23% in CD123negative to 70+/-19% in CD123negativeCD38- and from 44+/-23% in CD123low to 66+/-19% in CD123lowCD38-. No significant increase in CE or DGP progenitors was observed when CD34+ cells were sorted by CD90 and CD123. We concluded that: A) high levels of CD123 were expressed on B-lymphoid and myeloid progenitors; B) early erythroid progenitors had little or no surface CD123, and C) primitive hematopoietic cells are characterized by CD123negative/low expression.

Symmetry of initial cell divisions among primitive hematopoietic progenitors is independent of ontogenic age and regulatory molecules

We have developed a time-lapse camera system to follow the replication history and the fate of hematopoietic stem cells (HSC) at a single-cell level. Combined with single-cell culture, we correlated the early replication behavior with colony development after 14 days. The membrane dye PKH26 was used to monitor cell division. In addition to multiple, synchronous, and symmetric divisions, single-sorted CD34(+)/CD38(-) cells derived from fetal liver (FLV) also gave rise to a daughter cell that remained quiescent for up to 8 days, whereas the other daughter cell proliferated exponentially. Upon separation and replating as single cells onto medium containing a cytokine cocktail, 60.6% +/- 9.8% of the initially quiescent cells (PKH26 bright) gave rise again to colonies and 15.8% +/- 7.8% to blast colonies that could be replated. We have then determined the effects of various regulatory molecules on symmetry of initial cell divisions. After single-cell sorting, the CD34(+)/CD38(-) cells derived from FLV were exposed to flt3-ligand, thrombopoietin, stem cell factor (SCF), or medium containing a cytokine cocktail (with SCF, interleukin-3, interleukin-6, granulocyte-macrophage colony-stimulating factor, and erythropoietin). Whereas mitotic rate, colony efficiency, and asymmetric divisions could be altered using various regulatory molecules, the asymmetric division index, defined as the number of asymmetric divisions versus the number of dividing cells, was not altered significantly. This observation suggests that, although lineage commitment and cell proliferation can be skewed by extrinsic signaling, symmetry of early divisions is probably under the control of intrinsic factors.

Favorable therapeutic index of a p210(BCR-ABL)-specific tyrosine kinase inhibitor; activity on lineage-committed and primitive chronic myelogenous leukemia progenitors

PURPOSE

In order to assess the effect of the tyrosine kinase inhibitor CGP57148B on lineage-committed and primitive chronic myelogenous leukemia (CML) progenitor cells, peripheral blood progenitor cells (PBPC) mobilized in chronic phase CML were exposed to this compound in vitro.

METHODS

Both short-term (</=1 week) and long-term exposure (>/=2 weeks) to CGP57148B were investigated using suspension culture, semisolid (methylcellulose) assay or stroma-dependent long-term culture (LTC). The proportion of bcr/abl-positive progenitors was determined after direct plating [2 weeks in colony-forming cell (CFC) assay] as well as after 2 or 6 weeks LTC (LTC always followed by CFC replates).

RESULTS

Incubation of CML PBPC over 48 h in suspension culture with 100 microM CGP57148B reduced the proportion of bcr/abl-positive colonies to 4.4 +/- 4.3% (n = 5) after direct plating, 6.6 +/- 4.2% (n = 5) after 2 weeks LTC and 5 +/- 5.6% (n = 2) after 6 weeks LTC. At this dose, survival of drug-exposed normal PBPC was 53 +/- 4.2%, 51 +/- 2.8% and 54.5 +/- 4.9% (n = 2), respectively. Incubation with CGP57148B at a concentration of 10 microM over 1 week under LTC conditions reduced the number of bcr/abl-positive colonies to 11.8 +/- 6.1% (n = 5) after direct plating, 12 +/- 6.4% (n = 4) after 2 weeks LTC and 14.3 +/- 11.4% (n = 3) after 6 weeks LTC; survival of normal PBPC was 84.5 +/- 2.1%, 93 +/- 4.2% and 86 +/- 1.4% (n = 2), respectively. Following long-term exposure to CGP57148B at a concentration of 1 microM, the proportion of remaining bcr/abl-positive colonies was 35%, 9% and 25% of untreated CML samples after direct plating as well as after 2 and 6 weeks LTC, respectively. The respective values for 10 microM CGP57148B were 10%, 11% and 19%. Long-term exposure of normal progenitors to CGP57148B yielded a survival of 98%, 100% and 93% (1 microM) or 77%, 86% and 80% (10 microM), respectively.

CONCLUSION

The results support the use of CGP57148B either for short-term exposure in vitro (e.g. purging) or for continuous treatment of CML in vivo.

Incidence and clinical significance of 6q deletions in B cell chronic lymphocytic leukemia

Deletions affecting the long arm of chromosome 6 (6q) are among the most commonly observed chromosomal aberrations in lymphoid malignancies and have been identified as adverse prognostic factor in subsets of tumors. Whereas at least two regions of minimal deletion have been established, one in 6q21-q23 and another in 6q25-q27, no tumor suppressor gene that might be involved in the pathogenesis of lymphoid malignancies has been so far identified from these segments. For B cell chronic lymphocytic leukemia (B-CLL) conflicting data have been reported regarding the incidence and prognostic significance of 6q deletions. In the current study we have used two YAC clones mapping to deletion regions in bands 6q21 and 6q27 as probes for fluorescence in situ hybridization (FISH) in a large series of B-CLL cases to analyze the incidence, localization and clinical significance of 6q aberrations. Among 285 patients with B-CLL studied we identified 21 cases (7%) with 6q deletions. All deletions were found with the probe mapping to 6q21 while the 6q27 region was deleted only in a third of these cases. Analysis of the clinical characteristics and laboratory parameters showed that the patients with 6q deletions had higher white blood cell counts and more extensive lymphadenopathy. However, the overall survival and the treatment-free intervals were similar in the two groups. We conclude that deletions in 6q21 occur in 7% of B-CLL and identify a subgroup of patients characterized by a larger tumor mass but no inferior outcome.

Clonotypic CD20+ and CD19+ B cells in peripheral blood of patients with multiple myeloma post high-dose therapy and peripheral blood stem cell transplantation

The number of circulating clonotypic B cells in patients with multiple myeloma (MM) after high-dose therapy (HDT) with peripheral blood stem cell transplantation (PBSCT) was investigated. Peripheral CD19+ B cells have been reported to persist throughout conventional and HDT and might resemble a source of relapse in patients with MM. We assessed the proportion of malignant cells in CD20+ and CD19+ cell fractions of 14 peripheral blood (PB) samples from 12 patients after HDT and PBSCT. Nine samples were obtained from patients in continuous remission, and five patients were in progressive disease or beginning relapse. The CD20+ fractions obtained had a mean purity of 96.8%. The percentages of tumour cells were determined using a quantitative allele-specific oligonucleotide PCR assay based on the method of limiting dilutions. In the group of patients in continuous remission the median number of tumour cells in the CD20+ cell fractions was 1.9/ml (range 0-7.2 tumour cells/ml PB) higher than in the CD20- fractions (median 0; range 0-29 tumour cells/ml PB). Higher tumour cell numbers in both fractions, particularly pronounced in the negative ones, were found in patients with progressive disease or beginning relapse (CD20+: range 3.8-585; median 32 tumour cells/ml PB; CD20-: range 25-25527; median 334 tumour cells/ml PB). Enrichment with the anti-CD19 antibody as a second pan B-cell marker revealed comparable tumour cell numbers. In conclusion, an anti-CD20 antibody treatment could be a promising approach for the eradication of malignant cells in the PB of patients in continuous remission after HDT and PBSCT with low amounts of tumour cells in the B-cell compartment and an almost complete absence of tumour cells in the CD20- fractions.

Peripheral blood progenitor cell (PBPC) counts during steady-state haemopoiesis enable the estimation of the yield of mobilized PBPC after granulocyte colony-stimulating factor supported cytotoxic chemotherapy: an update on 100 patients

Peripheral blood progenitor cells (PBPC) can be mobilized using chemotherapy and granulocyte colony-stimulating factor (G-CSF). We and others previously reported a correlation of steady-state PBPC counts and the PBPC yield during mobilization in a small group of patients. Here we present data on 100 patients (patients: 25 non-Hodgkin's lymphoma (NHL), five Hodgkin's disease, 35 multiple myeloma (MM), 35 solid tumour) which enabled a detailed analysis of determinants of steady-state PBPC levels and of mobilization efficiency in patient subgroups. Previous irradiation (P = 0.0034) or previous chemotherapy in patients with haematological malignancies (P = 0.0062) led to a depletion of steady-state PB CD34+ cells. A correlation analysis showed steady-state PB CD34+ cells (all patients: r = 0.52, P < 0.0001; NHL patients, r = 0.69, P = 0.0003; MM patients: r = 0.66, P = 0.0001) and PB colony-forming cells can reliably assess the CD34+ cell yield in mobilized PB. In patients with solid tumour a similar trend was observed in mobilization after the first chemotherapy cycle (r = 0.51, P = 0.05) but not if mobilization occurred after the second or further cycle of a sequential dose-intensified G-CSF-supported chemotherapy regimen, when premobilization CD34+ counts were 18-fold elevated (P = 0.004). When the patients with MM (r = 0.63, P = 0.0008) or with NHL (r = 0.65, P = 0.006) were analysed separately, a highly significant correlation of the steady-state PB CD34+ cell count to the mean leukapheresis CD34+ cell yield was found, whereas no correlation was observed for patients with a solid tumour. For patients with haematological malignancies estimates could be calculated which, at a specific steady-state PB CD34+ cell count, could predict with a 95% probability a defined minimum progenitor cell yield. These results enable recognition of patients who mobilize PBPC poorly and may assist selection of patients for novel mobilization regimens.

Bone marrow derived dendritic cells from patients with multiple myeloma cultured with three distinct protocols do not bear Kaposi's sarcoma associated herpesvirus DNA

BACKGROUND

An association between Kaposi's sarcoma associated herpesvirus (KSHV) and the pathogenesis of multiple myeloma (MM) was postulated recently. The dendritic cells of patients with MM were proposed to be infected with the virus.

PATIENTS AND METHODS

Bone marrow mononuclear cells (MNC) of 23 patients, 22 with MM and one with MGUS, were cultured according to three distinct protocols for the generation of dendritic cells. One was essentially the stromal cell culture protocol described by Rettig et al. (Science 1997; 276: 1851-4), while the two other protocols comprised growth factors. Cultured cells were characterised by FACS analysis and assessed for the presence of KSHV DNA with a highly sensitive and specific nested PCR assay detecting the KS 330233 sequence of the virus genome followed by hybridisation with a KSHV specific oligonucleotide.

RESULTS

FACS analysis of the cells with the specific markers CD1a, CD86 and HLA-DR, characteristic for dendritic cells, revealed differences in the expression pattern depending on the protocol used. The proportion of CD1a+ cells was very low in the stromal cell cultures (median 0.4%), while a higher percentage of CD14+ cells could be observed (median 37.8%). Growth factor containing cultures revealed a distinctly higher median percentage of CD1a+ cells of 32.5%. The proportion of CD86+ cells varied between 10.4% and 78.5% and HLA-DR+ cells between 26% and 94.4%. Examination of those cells with PCR did not reveal positivity for KSHV in any of the 34 samples assessed. Amplification of seven samples revealed PCR products of approximately the size of the KS 330(233), which, however, could not be confirmed as KSHV specific after hybridisation.

CONCLUSION

We have no evidence that bone marrow derived dendritic cells from patients with MM are infected with KSHV.