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The objectives of this study were to review epidemiological, clinical and biological aspects associated with the development of bisphosphonate-related osteonecrosis of the jaw (BRONJ) in multiple myeloma (MM) patients, with special emphasis on the genetic aspects. A detailed review of previously described risk factors as well as recent genetic findings mostly comprises this work. The most recent meeting abstracts and relevant articles published in journals covered by the Science Citation Index and Medline are also examined. The review pays special attention to the genetic component of BRONJ. A total of 15 series and 14 guidelines or revisions were selected to fit the aims of the review. Gene variability was reviewed in depth to give a clinical illustration on the genetic aspects of BRONJ. Crude prevalence and 5-year cumulative incidence were considered as the most important end points for predictive purposes. Several acquired factors were recognized as predictors for BRONJ in MM, especially intravenous bisphosphonates, dental trauma and advanced age. Among genetic factors, polymorphisms on CYP2C8 gene arise as a promising risk factor. Bisphosphonate-related osteonecrosis of the jaw can be predicted with a conjunction of genetic and environmental risk factors. [ABSTRACT FROM AUTHOR]

Melphalan & Prednisone (MP) is considered as the standard therapy for Multiple Myeloma (MM) patients not eligible for high-dose therapy. Here, we report the results of a phase I-II study to evaluate the feasibility and efficacy of the association of PLD to the conventional MP regimen during the first six cycles of the front-line therapy for untreated MM patients older than 70. Thirty patients were included in the study with a median age of 77 years (71-84) and a M/F ratio of 17/13. The phase I of the study demonstrated that the maximum tolerable dose of PLD in this setting was 30 mg/m2, so it was the final dose evaluated in the study. Twenty-nine patients were valuable for response, which was: complete in 4 (14%) partial in 15 (52%) minor/no changes in 7 (24%) and progressive in 3 (10%). The median progression free survival (PFS) was 24 months. The median overall survival (OS) has not been reached yet, with a 3-year probability for OS and PFS of 52 and 37%, respectively. Haematological toxicity was frequent but usually weak/moderate (grades 1 & 2 of the WHO scale) and it was resolved only with dose delays. Infection was a relatively frequent event (30% of patients), but only in 4 cases it was of grade 3. No cases of palmar-plantar erythrodysesthesia were observed. In conclusion, pegylated liposomal doxorubicin can be safely added to the other chemotherapeutic drugs in the treatment of elderly MM patients, which can be very useful for patients in whom novel agents are not tolerated or inefficient. Copyright © 2006 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Background: Almost all automated hematology cell analyzers use methods based on either the impedance (PLTi) or the optical (PLTo) properties of the cells for performing platelet counts. To improve the accuracy of platelet counts in peripheral blood (PB), the use of CD61 (GPIIIa) MoAbs (ImmunoPLT method) has recently been introduced in an automated hematology blood-analyzer system (Cell-Dyn 4000, Abbott Diagnostics).Study Design and Methods: A comparative evaluation was made of the accuracy and precision of the three methods currently available in the Cell-Dyn 4000 automated hematology cell analyzer for counting the number of platelets per microliter of PB in a total of 47 patients with chemotherapy-induced thrombocytopenia. A flow cytometric PB platelet count was also performed in parallel and used as an external reference.Results: PB platelet counts showed a good correlation among the PLTo, CD61-ImmunoPLT, and flow cytometric methods. In contrast, the PLTi procedure usually provided an overestimation of the number of platelets per microliter. Although a good correlation was observed between the flow cytometric reference method and both the ImmunoPLT and PLTo methods, the highest degree of agreement was found for the ImmunoPLT techniques (94% vs. 67%). A comparative analysis of the PLTo and CD61-ImmunoPLT methods with regard to their value for predicting platelet transfusion needs on the basis of specific flow cytometric platelet count thresholds showed a good correlation when the cutoff level of 10,000 platelets per microL was used. In contrast, at the threshold of 20,000 platelets per microL, slight differences were observed between the PLTo and CD61-ImmunoPLT procedures for predicting transfusion needs.Conclusion: Such results indicate that, if the CD61-ImmunoPLT method is used in the platelet transfusion decision-making process, unnecessary platelet transfusions could be avoided in up to 17.5 percent of persons with a PLTo count of <20,000 platelets per microL. [ABSTRACT FROM AUTHOR]

The impact of measurable residual disease (MRD) in relapse/refractory multiple myeloma (RRMM) patients treated with T-cell redirecting immunotherapy is uncertain. We analyzed MRD dynamics using next-generation flow in 201 patients treated in clinical trials with chimeric antigen receptor (CAR) T cells and T-cell engagers (TCE). Achieving MRD negativity at 10 -6 was associated with 89% reduction in the risk of progression and/or death. Survival outcomes were improved in patients with sustained versus transient MRD negativity and were dismal in those who remained MRD positive. The intent-to-treat MRD negative rates were higher in patients treated with CAR T cells versus TCE. However, among patients achieving MRD negativity, there were no differences in survival outcomes when stratified according to treatment with CAR T cells versus TCE. In multivariate analysis including the number of prior lines of treatment, International Staging System, cytogenetic risk, extramedullary disease and type of T-cell redirecting immunotherapy, only the complete remission (CR) and MRD statuses showed independent prognostic value for progression-free and overall survival. In conclusion, our study shows that deep and sustained MRD negative CR is the most relevant prognostic factor and should be considered as the treatment endpoint in RRMM patients treated with CAR T cells and TCE., (© 2024 The Author(s). American Journal of Hematology published by Wiley Periodicals LLC.)

Loss and/or mutation of the TP53 gene are associated with short survival in multiple myeloma, but the p53 landscape goes far beyond. At least 12 p53 protein isoforms have been identified as a result of a combination of alternative splicing, alternative promoters and/or alternative transcription site starts, which are grouped as α, β, γ, from transactivation domain (TA), long, and short isoforms. Nowadays, there are no studies evaluating the expression of p53 isoforms and its clinical relevance in multiple myeloma (MM). We used capillary nanoimmunoassay to quantify the expression of p53 protein isoforms in CD138-purified samples from 156 patients with newly diagnosed MM who were treated as part of the PETHEMA/GEM2012 clinical trial and investigated their prognostic impact. Quantitative real-time polymerase chain reaction was used to corroborate the results at RNA levels. Low and high levels of expression of short and TAp53β/γ isoforms, respectively, were associated with adverse prognosis in MM patients. Multivariate Cox models identified high levels of TAp53β/γ (hazard ratio [HR], 4.49; p < .001) and high-risk cytogenetics (HR, 2.69; p < .001) as independent prognostic factors associated with shorter time to progression. The current cytogenetic-risk classification was notably improved when expression levels of p53 protein isoforms were incorporated, whereby high-risk MM expressing high levels of short isoforms had significantly longer survival than high-risk patients with low levels of these isoforms. This is the first study that demonstrates the prognostic value of p53 isoforms in MM patients, providing new insights on the role of p53 protein dysregulation in MM biology., (© 2022 The Authors. American Journal of Hematology published by Wiley Periodicals LLC.)

Bortezomib- and thalidomide-based therapies have significantly contributed to improved survival of multiple myeloma (MM) patients. However, treatment-induced peripheral neuropathy (TiPN) is a common adverse event associated with them. Risk factors for TiPN in MM patients include advanced age, prior neuropathy, and other drugs, but there are conflicting results about the role of genetics in predicting the risk of TiPN. Thus, we carried out a genome-wide association study based on more than 300 000 exome single nucleotide polymorphisms in 172 MM patients receiving therapy involving bortezomib and thalidomide. We compared patients developing and not developing TiPN under similar treatment conditions (GEM05MAS65, NCT00443235). The highest-ranking single nucleotide polymorphism was rs45443101, located in the PLCG2 gene, but no significant differences were found after multiple comparison correction (adjusted P = .1708). Prediction analyses, cytoband enrichment, and pathway analyses were also performed, but none yielded any significant findings. A copy number approach was also explored, but this gave no significant results either. In summary, our study did not find a consistent genetic component associated with TiPN under bortezomib and thalidomide therapies that could be used for prediction, which makes clinical judgment essential in the practical management of MM treatment., (Copyright © 2016 John Wiley & Sons, Ltd.)

Panobinostat in combination with bortezomib and dexamethasone demonstrated a significant and clinically meaningful progression-free survival benefit compared with placebo, bortezomib and dexamethasone in the phase 3 PANORAMA 1 (Panobinostat Oral in Multiple Myeloma 1) trial. Despite this benefit, patients in the panobinostat arm experienced higher rates of adverse events (AEs) and higher rates of discontinuation due to AEs. This PANORAMA 1 subanalysis examined AEs between 2 treatment phases of the study (TP1 and TP2), in which administration frequency of bortezomib and dexamethasone differed per protocol. The incidences of several key AEs were lower in both arms following the planned reduction of bortezomib dosing frequency in TP2. In the panobinostat arm, rates of thrombocytopenia (grade 3/4: TP1, 56·7%; TP2, 6·0%), diarrhoea (grade 3/4: TP1, 24·1%; TP2, 7·1%), and fatigue (grade 3/4: TP1, 16·3%; TP2, 1·8%) were lower in TP2 compared with TP1. Dose intensity analysis of panobinostat and bortezomib by cycle in the panobinostat arm showed reductions of both agent doses during cycles 1-4 due to dose adjustments for AEs. Exposure-adjusted analysis demonstrated a reduction in thrombocytopenia frequency in TP1 following dose adjustment. These results suggest that optimization of dosing with this regimen could improve tolerability, potentially leading to improved patient outcomes., (© 2017 John Wiley & Sons Ltd.)

This retrospective analysis aimed to establish the overall cardiac safety profile of bortezomib using patient-level data from one phase 2 and seven phase 3 studies in previously untreated and relapsed/refractory multiple myeloma (MM). Seven clinically relevant primary [congestive heart failure (CHF), arrhythmias, ischaemic heart disease (IHD), cardiac death] and secondary (hypertension, dyspnoea, oedema) cardiac endpoints were defined based on MedDRA v16.0 preferred terms. 2509 bortezomib-treated patients and 1445 patients in non-bortezomib-based control arms were included. The incidence of grade ≥3 CHF was 1·3-4·0% in studies in relapsed/refractory MM and 1·2-4·7% in previously untreated MM (2·0-7·6% all grades), with no significant differences between bortezomib- and non-bortezomib-based arms in comparative studies. Incidences of arrhythmias (1·3-5·9% grade ≥2; 0·6-4·1% grade ≥3), IHD (1·2-2·9% all grades; 0·4-2·7% grade ≥3) and cardiac death (0-1·4%) were low, with no differences between bortezomib-based and non-bortezomib-based arms. Higher rates of oedema (mostly grade 1/2) were seen in bortezomib-based versus non-bortezomib-based arms in one study and a pooled transplant study analysis. Logistic regression analyses of comparative studies showed no impact on cardiac risk with bortezomib-based versus non-bortezomib-based treatment. Bortezomib-based treatment was associated with low incidences of cardiac events., (© 2017 John Wiley & Sons Ltd.)

Immunomodulatory drugs have been shown to be of benefit in relapsed/refractory immunoglobulin light-chain (AL) amyloidosis. We designed a prospective, multicentre phase II trial of lenalidomide, dexamethasone and cyclophosphamide for newly diagnosed patients with AL amyloidosis not eligible for autologous stem-cell transplantation. Twenty-eight patients were included in the study. Cardiac involvement was present in 23 patients; 14 of them had cardiac stage III. The overall haematological response rate was 46%, including complete and very good partial responses in 25% and 18% of patients respectively. Haematological response was mainly associated with absence of cardiac stage III and lower tumour burden. Organ response was observed in 46% of patients. After a median follow-up of 24 months, median progression-free and overall survival have not been reached, both being significantly longer in responders (P < 0·001 and P = 0·001 respectively). Seventeen patients have discontinued treatment, mostly due to amyloid-related death, disease progression or lack of response. Only 14% of the patients discontinued treatment due to therapy-related adverse events. Our results support the efficacy of this regimen, with high quality responses and prolonged survival, as well as its tolerability, in patients with AL amyloidosis not eligible for stem cell transplant and without advanced cardiac involvement (clinicaltrials.gov identifier: NCT01194791)., (© 2015 John Wiley & Sons Ltd.)

This analysis, using data from the bortezomib-melphalan-prednisone (VMP) arm of the Phase III VISTA study, investigated whether increased cumulative bortezomib dose could improve overall survival (OS) in transplant-ineligible patients with previously untreated multiple myeloma. Median cumulative bortezomib dose received by the 340 patients was 39 mg/m(2); this was selected as the cut-off for defining the dose groups to be compared for OS. Patient characteristics were well balanced between dose groups except for age. OS was significantly longer in the higher (≥39 mg/m(2)) versus lower (<39 mg/m(2)) cumulative bortezomib dose group (median 66.3 vs. 46.2 months; hazard ratio (HR) 0.533, P < 0.0001; age-adjusted HR 0.561, P = 0.0002). To overcome confounding effects of early discontinuations/deaths, which were more common in the lower cumulative dose group (27 vs. 4% of patients discontinued due to adverse events (AEs) in the lower and higher cumulative dose groups, respectively), a landmark analysis was conducted at 180 days, eliminating patients who died or discontinued before this time from the analysis. OS from this landmark remained significantly longer in the higher dose group (median 60.4 vs. 50.3 months; HR 0.709, P = 0.0372). Thus, higher cumulative bortezomib dose, reflecting prolonged treatment duration and/or dose intensity, appears associated with improved OS. Approaches to achieve higher cumulative doses could include subcutaneous bortezomib administration, dose/schedule modifications, continuing therapy in responding patients, and proactive AE management., (© 2015 Wiley Periodicals, Inc.)

Minimal residual disease monitoring is becoming increasingly important in multiple myeloma (MM), but multiparameter flow cytometry (MFC) and allele-specific oligonucleotide polymerase chain reaction (ASO-PCR) techniques are not routinely available. This study investigated the prognostic influence of achieving molecular response assessed by fluorescent-PCR (F-PCR) in 130 newly diagnosed MM patients from Grupo Español Multidisciplinar de Melanoma (GEM)2000/GEM05 trials (NCT00560053, NCT00443235, NCT00464217) who achieved almost very good partial response after induction therapy. As a reference, we used the results observed with simultaneous MFC. F-PCR at diagnosis was performed on DNA using three different multiplex PCRs: IGH D-J, IGK V-J and KDE rearrangements. The applicability of F-PCR was 91·5%. After induction therapy, 64 patients achieved molecular response and 66 non-molecular response; median progression-free survival (PFS) was 61 versus 36 months, respectively (P = 0·001). Median overall survival (OS) was not reached (NR) in molecular response patients (5-year survival: 75%) versus 66 months in the non-molecular response group (P = 0·03). The corresponding PFS and OS values for patients with immunophenotypic versus non-immunophenotypic response were 67 versus 42 months (P = 0·005) and NR (5-year survival: 95%) versus 69 months (P = 0·004), respectively. F-PCR analysis is a rapid, affordable, and easily performable technique that, in some circumstances, may be a valid approach for minimal residual disease investigations in MM., (© 2013 John Wiley & Sons Ltd.)

The gene expression profiles (GEPs) of 96 selected genes were analysed by real-time quantitative polymerase chain reaction (qPCR) with a TaqMan low-density array card in isolated tumour plasma cells (PCs) from 157 newly diagnosed multiple myeloma (MM) patients. This qPCR-based GEP correctly classified cases following the Translocation-cyclin D classification. Classic prognostic parameters and qPCR-based GEP predicted MM patient outcome and, although multivariate analyses revealed that cytogenetic risk (standard vs. high risk) was the variable that most strongly predicted prognosis, GEP added significant information for risk stratification. Considering only the standard risk cytogenetic patients, multivariate analyses revealed that high β2-microglobulin, low CDKN1A and high SLC19A1 gene expression levels independently predicted a short time-to-progression (TTP), while high International Staging System stage, low CDKN2B and high TBRG4 gene expression predicted poor overall survival (OS). A gene expression risk score enabled the division of standard risk patients into two groups with different TTPs (83% vs. 38% at 3 years, P < 0·0001) and OS rates (88% vs. 61% at 5 years; P = 0·003). This study demonstrates that quantitative PCR is a robust, accurate and feasible technique for implementing in the daily routine as a surrogate for GEP-arrays., (© 2013 John Wiley & Sons Ltd.)

Although haematological toxicities, such as anaemia, are common in multiple myeloma (MM), no clear consensus exists on the use and impact of erythropoiesis-stimulating agents (ESA) on outcomes in MM. This analysis characterizes haematological toxicities and associated interventions in the phase III VISTA (Velcade(®) as Initial Standard Therapy in Multiple Myeloma: Assessment with Melphalan and Prednisone) study of bortezomib plus melphalan/prednisone (VMP, n = 344) versus MP (n = 338) in previously untreated MM patients ineligible for high-dose therapy, and evaluates the impact of ESA use or red-blood-cell (RBC) transfusions on outcomes and thromboembolic risk. Incidence of haematological toxicities was similar with VMP and MP; similar rates of interventions and associated complications (e.g. bleeding, febrile neutropenia) were observed. Two hundred thirty three patients received ESA; 204 had RBC transfusions. Frequency of thromboembolic events was low and not affected by ESA use. Median time-to progression (TTP) was similar between ESA/non-ESA [hazard ratio: 1·03 (95% confidence interval 0·76-1·39); P = 0·8478] in both arms (VMP: 19·9/not reached; MP: 15·0/17·5 months). Three-year overall survival (OS) rates were similar between ESA/non-ESA in each arm. Patients receiving RBC transfusions had significantly shorter OS (P < 0·0001) versus non-RBC-transfusion patients. In conclusion, bortezomib did not add to melphalan haematological toxicity. Concomitant ESA use with VMP/MP in previously untreated MM patients did not adversely affect TTP or OS, or increase thromboembolic risk. However, RBC transfusion was associated with significantly shorter survival., (© 2011 Blackwell Publishing Ltd.)

On February 25, 2009, a panel of international experts on plasma cell dyscrasia and skeletal disease met to discuss monoclonal gammopathy of undetermined significance (MGUS). This non-malignant B-cell disorder is the most common plasma cell dyscrasia and is associated with an increased risk of developing serious B-cell disorders. Individuals with MGUS also have an increased risk of osteoporosis and osteopenia associated with an increased likelihood of developing fractures especially in the vertebral column, peripheral neuropathy and thromboembolic events. The goal of the meeting was to develop a consensus statement regarding the appropriate tests to screen, evaluate and follow-up patients with MGUS. The panel also addressed the identification and treatment of MGUS-related skeletal problems, thromboembolic events and neurological complications. The following consensus statement outlines the conclusions and marks the first time that a consensus statement for the screening and treatment of MGUS has been clearly stated.

The present study explored the impact of two novel criteria; having >95% abnormal plasma cells by flow cytometry at diagnosis and the evolving subtype of the disease, as predictors of progression in 61 smouldering multiple myeloma (SMM) and 311 monoclonal gammopathy of unknown significance (MGUS) patients. Although both criteria were of prognostic value, the risk of progression was better identified by immunophenotyping [Hazard Ratio (HR) 6.2 and 17.2 for SMM and MGUS, respectively] than evolving subtype, which had independent prognostic value only in MGUS (HR 3.6). Immunophenotyping discriminated the different risk of progression within the evolving and non-evolving subgroups of SMM (P = 0.01) and MGUS (P < 0.001).

Health-related quality of life (HRQL) was prospectively measured during the phase III APEX trial of bortezomib versus dexamethasone in relapsed multiple myeloma patients. The European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire - Core (QLQ-C30) and Functional Assessment of Cancer Therapy/Gynecologic Oncology Group-Neurotoxicity (NTX) side-effects questionnaires were administered at baseline and every 6 weeks up to 42 weeks. Patients receiving bortezomib (1.3 mg/m(2), days 1, 4, 8 and 11 for eight 3-week cycles, then days 1, 8, 15 and 22 for three 5-week cycles; n = 296) demonstrated significantly better mean Global Health Status over the study versus patients receiving dexamethasone (40 mg/d, days 1-4, 9-12, and 17-20 for four 5-week cycles, then days 1-4 only for five 4-week cycles; n = 302), plus significantly better physical health, role, cognitive, and emotional functioning scores, lower dyspnoea and sleep symptom scores, and better NTX questionnaire score, using multiple imputation to account for missing data. Results were similar using available-data analyses. Sensitivity analyses suggested that improved HRQL with bortezomib is at least partially explained by improved survival. These results show that bortezomib was associated with significantly better multidimensional HRQL compared with dexamethasone, consistent with the better clinical outcomes seen with bortezomib.

Multiple myeloma (MM) is a B-cell malignancy characterized by accumulation of monoclonal plasma cells in the bone marrow (BM). Despite recent advances in the treatment, MM represents an incurable disease for which development of new therapies is required. We report the antimyeloma effect of NVP-AEW541, a small molecule that belongs to the pyrrolo[2,3-d]pyrimidine class, identified as a selective inhibitor of the insulin-like growth factor-I receptor (IGF-IR) in vitro kinase activity. NVP-AEW541 had a potent cytotoxic effect on fresh cells and in a murine MM model. NVP-AEW541 partially abrogated the proliferative advantage conferred by the coculture with BM stromal cells and the presence of growth factors produced by the BM microenvironment. In addition, NVP-AEW541 potentiated the action of drugs, such as bortezomib, lenalidomide, dexamethasone or melphalan. Moreover the triple combination of NVP-AEW541, dexamethasone and bortezomib resulted in a significant increase in growth inhibition. Mechanistic studies indicated that NVP-AEW541 provoked a marked cell cycle blockade accompanied by pRb downregulation. Interestingly, NVP-AEW541 increased the levels of p27 associated with a reduction in the CDK2 activity. Finally, NVP-AEW541 induced cell death through caspase-dependent and -independent mechanisms. All these data, suggest the potential effect of IGF-IR kinase inhibitors as therapeutic agents for MM patients.

RAN, ZHX2 and RCBTB2 (CHC1L) expression was evaluated by quantitative real time reverse transcription polymerase chain reaction in plasma cells from 85 monoclonal gammopathies: 58 symptomatic multiple myeloma (MM) (52 untreated, six relapsed), eight smouldering MM, five monoclonal gammopathy of undetermined significance, four plasma cell leukaemias and 10 myeloid cell lines. ZHX2 was weakly expressed in high-risk/proliferative disease compared to low-risk or indolent disease. High ZHX2 expression was associated with better response and longer survival after high-dose therapy. RCBTB2 expression was weaker in hyperdiploid versus non-hyperdiploid cases while RAN was more expressed in symptomatic MM and cell lines.

Adverse prognostic factors in multiple myeloma include advanced age, number of prior therapies, and higher International Staging System (ISS) disease stage. In the international, randomised, phase-3 Assessment of Proteasome Inhibition for Extending Remissions (APEX) study, bortezomib demonstrated significantly longer time to progression (TTP), higher response rates and improved survival compared with high-dose dexamethasone in patients with relapsed multiple myeloma following one to three prior therapies. In this APEX subgroup analysis, efficacy of bortezomib and dexamethasone was compared in elderly (age > or =65 years) and high-risk (>1 prior line of therapy; ISS stage II/III; refractory to prior therapy) patients. Bortezomib demonstrated substantial clinical activity in these patients. Response rate (34-40% vs. 13-19%), including complete response rate (5-8% vs. 0-1%), was significantly higher with bortezomib versus dexamethasone in all four subgroups. Similarly, median TTP was significantly longer with bortezomib versus dexamethasone, and 1-year survival probability was significantly higher in all subgroups. As in the total APEX population, rates of grade 3/4 adverse events were higher in bortezomib- versus dexamethasone-treated patients aged > or =65 years and with >1 prior line, while rates of serious adverse events were similar; toxicities generally proved manageable. Bortezomib should be considered an appropriate treatment for elderly and high-risk patients with relapsed multiple myeloma.

Waldenström macroglobulinaemia (WM) malignant cells have been considered incapable of undergoing class switch recombination (CSR). However, we report a WM patient who developed an IgG M-component 4 years after diagnosis. When the second monoclonal component appeared, reverse transcription-polymerase chain reaction showed the presence of pre (Cmu) and postswitch (Cgamma) clonotypic isotypes; sequencing of these isotypes demonstrated that both corresponded to the single clone amplified at diagnosis, including the same complementarity-determining region 3 and somatic mutation pattern. This proves that WM cells can undergo a functional in vivo CSR.

Fluorescence in situ hybridisation (FISH) is an effective technique for the cytogenetic analysis of Waldenström macroglobulinemia (WM), but the potential impact of molecular cytogenetics on disease evolution and as a prognostic marker is still unknown. Deletion of the long arm of chromosome 6 (6q-) is the most frequent cytogenetic abnormality in WM. This study analysed the prevalence of this aberration in 102 WM patients, and correlated it with disease characteristics. The incidence of 6q21 deletion was 7% by conventional cytogenetics and 34% when analysed by FISH (54% when cytoplasmic immunoglobulin M-FISH was used). Patients with deletion of 6q displayed features of adverse prognosis, such as higher levels of beta2-microglobulin and monoclonal paraprotein and a greater tendency to display anaemia and hypoalbuminemia. Interestingly, there was a correlation between the presence of 6q deletion and the International Staging System prognostic index (incidence of 6q- among patients stratified in stages 1, 2 and 3 was 24%, 42% and 67% respectively). Those patients diagnosed with smouldering WM who displayed the abnormality showed a trend to an earlier requirement of treatment. Finally, the survival analysis did not show differences between the two groups of patients, probably due to the short follow up of our series.

The graft-versus-host disease (GVHD) characteristics of 150 consecutive patients undergoing reduced intensity conditioning allogeneic (allo-RIC) transplants and 88 patients undergoing myeloablative conditioning regimen were analysed. All patients received the same GVHD prophylaxis and peripheral blood stem cells from a human leucocyte antigen identical sibling. The cumulative incidence of acute GVHD (aGVHD) was 67% and 44% in the myeloablative and allo-RIC regimen groups, respectively (P < 0.001), and was 39% vs. 29%, respectively (P = 0.043), for grades 2-4 aGVHD. Only conditioning type (myeloablative versus allo-RIC) significantly influenced the incidence of aGVHD in multivariate analysis: Hazard ratio (HR) = 2.16 [95% confidence interval (CI): 1.52-3.07], P < 0.0001. The cumulative incidence of chronic GVHD (cGVHD) was 63% and 71% among myeloablative and allo-RIC patients respectively (P = 0.084). This trend was because of the higher incidence of limited cGVHD, but not extensive cGVHD among allo-RIC recipients [HR = 3.3 (95% CI: 1.42-8.08), P = 0.0017]. Moreover, among patients who developed cGVHD, the cumulative incidence of limited cGVHD was significantly lower in the myeloablative group than in the allo-RIC group (7% vs. 25%, P = 0.007). Duration of immunosuppression was shorter among allo-RIC patients (35.5% vs. 68.8% required systemic immunosuppression 36 months after transplant, P = 0.028). Although prospective controlled trials are required to further evaluate the effect of the conditioning regimen on GVHD, our results suggest that RIC modifies the incidence and characteristics of both acute and cGVHD after allogeneic transplantation, and decreases the immunosuppression requirements in long-term follow up when compared with myeloablative conditioning.

Multicentric Castleman disease (MCD) is an uncommon lymphoproliferative disorder for which the best therapeutic option is not yet well established. Immune-related disorders are rare complications of MCD. We report on an MCD case in a 23-year-old patient with extensive abdominal involvement and associated immune hemolytic anemia and Raynaud phenomenon. He was negative for human immunodeficiency virus (HIV) and human herpesvirus-8 (HHV-8). After 8 courses of the anti-CD20 monoclonal antibody (rituximab), the patient achieved complete remission. Interestingly, Raynaud phenomenon disappeared under treatment and no new hemolytic events occurred. Anti-CD20 antibody treatment could be an attractive therapeutic approach for MCD, mainly when immune-related disorders are associated.

Melphalan-prednisone (MP) has been the gold standard treatment for more than 30 years in elderly multiple myeloma (MM) patients. In order to assess whether the combination of dexamethasone with melphalan (MD) could improve on the efficacy of MP, we have carried out a randomized trial comparing both treatment approaches. A total of 201 patients >/=70 years old were included in the study. The overall response rate was similar after six cycles (MP: 67.9%versus MD: 64.5%) and after 12 cycles (MP: 49.4%versus MD: 46.1%). However, the proportion of complete responses (CR) was higher in the MD arm, particularly after 12 cycles (MD: 22.4%versus MP: 9.1%; P < 0.05). There was no significant difference in event-free survival (MP: 15.9 months versus MD: 23.3 months). The median overall survival in both arms was almost identical (MP: 29.4 months versus MD: 27.2 months; P = 0.63). No significant differences in haematological toxicity were observed, but non-haematological toxicity was significantly higher in the MD arm. According to these results MP remains as the gold standard for treatment of MM and should be the reference for comparison of new therapeutic approaches involving novel agents.

c-Kit has been shown to be mutated in several types of tumours, and its activity has been correlated with increased proliferation rates in a subset of multiple myeloma (MM) patients. We have investigated the effect of imatinib mesylate (STI571), an inhibitor of c-Kit, on MM cells. STI571 inhibited the proliferation of MM cells by arresting cell cycle progression. Western blotting of cell cycle proteins showed that STI571 increased the levels of p21 and p16. MM cells expressed abl, but its level of tyrosine phosphorylation was low and unaffected by treatment with STI571. c-Kit was also expressed in certain MM cell lines, and its phosphorylation was stimulated by stem cell factor. However, the failure to detect the receptor protein in other MM cell lines in which cell proliferation was inhibited by STI571 suggests that its effect on these c-Kit-negative MM cell lines might be caused by the action of the drug on yet unknown targets. STI571 inhibited the proliferation of MM cells resistant to dexamethasone or melphalan and had an additive effect when combined with dexamethasone. Efforts to understand the action of STI571 in MM cells may help to identify these potentially useful targets in the treatment of this and other disorders.

The outcome of 29 multiple myeloma patients receiving fludarabine and melphalan-based non-myeloablative allogeneic transplant (NMT) was evaluated. Event-free survival (EFS) at 24 months was 33%, being significantly higher for patients who developed chronic graft-versus-host disease (cGVHD) when compared with those who did not [51%vs 0% respectively, P = 0.02; hazard rate = 3.16 (95% confidence interval = 1.09-9.15, P = 0.03)] as well as for patients transplanted in complete remission/partial response (CR/PR) or stable disease (SD), compared with those with refractory/progressive disease (43%vs 0% respectively, P = 0.02). Overall survival (OS) at 24 months was 60%[72%vs 42% for patients who did and did not develop cGVHD respectively (P = 0.1); 63%vs 41% for patients in CR/PR or SD vs refractory/progressive disease at transplant respectively (P = 0.013)]. At a median follow-up of 366 d, 13 patients remained in CR/PR (45% overall response rate). Nine patients have died, three of them as a result of disease progression and six (21%) as a result of transplant-related mortality (TRM). Actuarial incidence of TRM was 37% for patients who developed acute GVHD vs 13% for those who did not (log rank, P = 0.04). The present study suggests that graft-versus-myeloma effect is the main weapon for disease control after NMT in MM patients and the efficacy of this immune effect depends on tumour burden before transplant.

Currently, no information is available regarding the influence of the different CD34+ cell subsets infused on the haematopoietic recovery, following non-myeloablative allogeneic peripheral blood stem cell transplantation (allo-PBSCT). We have explored, in a group of 13 patients receiving non-myeloablative allo-PBSCT from human leucocyte antigen-identical sibling donors, the influence of the total dose of CD34+ haematopoietic progenitor cells (HPC) infused, compared with that of the different CD34+ HPC and CD34- leucocyte subsets in the leukapheresis samples, on both engraftment and clinical outcome. The overall numbers of total CD34+ HPC (P = 0.002) and myelomonocytic-committed CD34+ HPC infused (P = 0.0002) were strongly associated with neutrophil recovery (> 1 x 109 neutrophils/l), the latter being the only independent parameter influencing neutrophil recovery. Regarding long-term engraftment, only the number of immature CD34+ HPC infused/kg correlated with the duration of hospitalization in the first 2 years after discharge (r = -0.75, P = 0.005). Both the overall amount of CD34+ HPC and the number of myelomonocytic CD34+ HPC infused showed a significant influence on the risk of graft-versus-host disease (GVHD). Thus, the overall probability of GVHD was 100%vs 25% for patients receiving >/= 5 x 106 CD34+ HPC or >/= 3.5 x 106 of myelomonocytic-committed CD34+ HPC vs lower doses (P = 0.013). None of the other CD34+ and CD34- cell subsets analysed correlated with development of GVHD. In summary, our results suggest that in non-myeloablative allo-PBSCT, high numbers of CD34+ HPC, especially the myelomonocytic-committed CD34+ progenitors, lead to rapid neutrophil engraftment. However, they also strongly impair clinical outcome by increasing the incidence of GVHD.

In order to gain further insights into the role of the p16 gene in cell cycle regulation and the prognostic implications of its inactivation, we investigated the methylation status of the p16 gene in 98 untreated patients using a polymerase chain reaction assay based on the inability of some restriction enzymes to digest methylated sequences. Forty-one patients showed a p16 methylated gene (42%). The percentage of S-phase plasma cells (PC) in these patients was almost three times higher than in those with an unmethylated p16 gene (4.16% +/- 3.37%vs 1.5% +/- 1.41%, P < 0.001). The presence of p16 methylation also correlated with both elevated beta2-microglobulin serum levels and high C-reactive protein values. Patients with a p16 methylated gene had shorter overall and progression-free survival than those patients without p16 methylation. However, this feature did not retain independent prognostic influence on multivariate analysis, probably due to its association with the S-phase PC, which had more potent statistical significance in the Cox model. These findings showed methylation of the p16 gene was a frequent event inMM patients at diagnosis, and was associated with an increased proliferative rate of plasma cells and a poor prognosis, indicating an important role for p16 gene in the cell cycle regulation of multiple myeloma tumour cells, and thus in the clinical outcome of the disease.

Twelve patients with smouldering or indolent multiple myeloma (MM) received 12 courses of intravenous pamidronate as a single agent to evaluate both the antitumour and bone metabolism effects. One patient achieved minor response, eight had stable disease, and three - all indolent MM - showed disease progression. Serum interleukin 6 (IL-6), IL-1beta and Oncostatin-M remained stable throughout the study, while tumour necrosis factor-alpha increased. Bone density significantly increased after four and 12 courses compared with baseline. Markers for bone resorption and bone formation decreased with treatment. These results suggest that pamidronate treatment reduces bone turnover in smouldering or indolent MM, but has no significant antitumour effect.

Methylenetetrahydrofolate reductase (MTHFR) plays an important role in carcinogenesis. A decreased incidence of cancer has been reported in the presence of MTHFR 677TT, 1298AC and 1298CC polymorphic variants. We have analysed the MTHFR genotype in 107 multiple myeloma (MM) patients and 86 controls. The MM and control polymorphisms frequencies were: 34% and 48% for 677CC, 53% and 41% for 677CT, 12% and 11% for 677TT; 36% and 43% for 1298AA, 51% and 44% for 1298AC; and 12% and 13% for 1298CC respectively. No statistically significant differences were observed. In addition, no differences were seen according to MM stage, presence of p16 gene hypermethylation or response to treatment.

Several studies have focused on investigation of the optimal salvage regimen to induce maximum response before autologous stem cell transplantation (ASCT) in patients with relapsed or refractory Hodgkin's disease (HD). However, in most of these studies, the follow-up is relatively short. In the present study, we report on long-term results of 55 consecutive patients with HD who received Mini-BEAM [BCNU (carmustine), etoposide, cytarabine, melphalan] as salvage therapy before ASCT. Eleven patients were refractory to front-line therapy, 17 were partial responders, and 27 patients had relapsed from HD. Twenty-eight patients achieved complete response, and 18 achieved partial response with a median of two cycles of Mini-BEAM, giving a total response rate of 84%. Significant factors predicting poor response (P < 0.05) were: initial treatment with MOPP (mechloroethamine, oncovin, procarbazine, prednisolone), > or = two previous chemotherapy regimens and three disease characteristics at Mini-BEAM treatment: presence of B symptoms, extranodal involvement or low serum albumin. However, only the last two factors retained independent influence on multivariate analysis. In total, 45/55 patients have been transplanted. Median follow-up after Mini-BEAM administration for living patients is 68 months. At the time of reporting, 31 out of 55 patients (56.4%) are still alive, 21 patients (38%) have relapsed, three (5.4%) have developed secondary neoplasias, and five have died of other complications not related to disease progression. The actuarial 7-year overall survival (OS) was 52%, the progression-free survival (PFS) 54% and the event-free survival (EFS) 36%. The response to Mini-BEAM was the most important prognostic factor for predicting the long-term probability of surviving the disease: none of the eight patients who did not respond to Mini-BEAM were alive at 3 years. On multivariate analysis, response to Mini-BEAM and extranodal involvement before Mini-BEAM had a significant influence on OS. Our results show the safety and efficacy of Mini-BEAM before ASCT for refractory or relapsed HD patients.

We report on a case of pyridoxine refractory hereditary sideroblastic anaemia (HSA) in a 19-year-old man who underwent peripheral blood stem cell transplantation (PBSCT) from his HLA-identical brother. By using short tandem repeat polymorphism, 100% donor cells were observed in peripheral blood on day +21; bone marrow showed mixed chimaerism from day +21 to day +221, when 100% cells of donor origin were observed. The patient developed extensive chronic graft-versus-host disease with favourable response to treatment. When the haemoglobin range was normal, a programme of phlebotomies reduced serum ferritin levels. Three years after transplantation, the patient has an ECOG rating of 0, with completely normal haemoglobin values (15 g/dl). To our knowledge, this is the first PBSCT reported in a case of hereditary sideroblastic anaemia.

We report on a series of Spanish patients with acute lymphoblastic leukaemia in whom the t(12;21) [TEL/AML1] translocation could not be identified with two sensitive techniques: reverse transcript-polymerase chain reaction (RT-PCR) and fluorescence in-situ hybridization (FISH). 101 cases were analysed: 38 children (29 B-cell precursor; nine T-cell precursor) and 63 adults (48 B-cell precursor; 15 T-cell precursor). Specific RT-PCR to amplify the TEL/AML1 fusion transcript was negative in all 101 cases. Moreover, all 38 paediatric samples were also negative by interphase FISH analysis for the presence of the TEL/AML1 fusion. These results suggest the existence of geographic/race variations in the genotype of acute lymphoblastic leukaemia (ALL).

Sensitive techniques for monitoring minimal residual disease (MRD) in multiple myeloma (MM) are needed to evaluate the effectiveness of new intensive treatment strategies. The aim of the present study was to explore the applicability and sensitivity of flow cytometry immunophenotyping and DNA ploidy studies for the investigation of residual myelomatous plasma cells (PC) in MM patients. Bone marrow (BM) samples from 61 untreated MM patients were immunophenotypically analysed with a panel of 21 monoclonal antibodies, using a high-sensitive method based on a two-step acquisition procedure through a SSC/CD38 -CD138+ 'live-gate'. Overall, in 87% of MM cases, PC displayed an aberrant phenotype at diagnosis. The most important aberrant criteria were: antigen over-expression of CD56 (62%), CD28 (16%) and CD33 (6%) and asynchronous expression of CD117 (28%), sIg (21%) and CD20 (10%). DNA aneuploidy was found in 62% of cases. The simultaneous use of these two techniques allowed the detection of aberrant/aneuploid PC in 95% of the cases. Based on dilutional experiments, the detection limit of both techniques ranged from 10(-4) to 10(-5). In 29 stem cells harvests and 19 BM samples obtained 3 months after autologous transplantation, we have investigated the presence of residual myelomatous PC; they were detected in 44% of the stem cell collections and in 61% of the BM samples obtained after transplant. The percentage of pathological PC did not significantly change during the days of harvest. In summary, the present study shows that the combined use of immunophenotyping and DNA ploidy studies is a suitable approach for MRD investigation in MM patients based on their applicability (95% of cases) and sensitivity (up to 10(-5)).

We have analysed the quantitative expression of surface CD69 antigen on human mast cells (MC), from both normal and pathological bone marrow (BM) samples, using flow cytometry. Our major aim was to analyse whether CD69 is constitutively expressed by normal BMMC and to explore the possible differences between CD69 expression by BMMC from normal controls and patients suffering from different pathological conditions. The constitutive expression of surface CD69 was clearly demonstrated in BMMC; however, systemic mast cell disease (SMCD) patients showed significantly higher levels of surface CD69 expression than healthy controls (P < 0.001), chronic lymphocytic leukaemia (P = 0.001), monoclonal gammopathy of unknown significance (P < 0.001), multiple myeloma (P < 0.001) patients, and myelodysplastic syndromes (P = 0.002). Furthermore, almost no overlap between the levels of CD69 expression on BMMC was observed between SMCD cases and the remaining groups of individuals except for the paediatric mastocytosis group (P > 0.05). From the other groups of patients, monoclonal gammopathy of unknown significance (P = 0.04), myelodysplastic syndromes (P = 0.03) and paediatric mastocytosis (P = 0.003) cases showed a significantly higher expression of surface CD69 as compared to normal subjects. In summary, our findings show that the CD69 antigen is overexpressed in SMCD patients.

Immunophenotypic investigation of minimal residual disease (MRD) has traditionally been based on the investigation of phenotypic aberrants at diagnosis to be used later as a target for MRD detection. This approach has several shortcomings (it is only applicable to patients with aberrant phenotypes, requires a diagnostic sample, and is patient-specific) and therefore a search for simpler alternatives is warranted. The present study is based on the hypothesis that in precursor-B-ALL patients the persistence of residual leukaemic cells may induce abnormalities in the precursor-B-cell compartment in bone marrow (BM) and these could be used as a criteria to predict relapse. These abnormalities may include: (1) the presence of an increase in the frequencies of immature B cells (CD34+/CD19+ or CD20-/CD19+) or (2) the existence of an altered B-cell differentiation pathway due to a blockade or to the presence of B cells outside the normal pathway. A total of 180 BM samples from 45 consecutive precursor-B-ALL patients who achieved morphological complete remission (CR) were analysed by multiparametric flow cytometry. Our results show that a significant increase in immature B-cell subsets or an altered B-cell differentiation predicts a high relapse rate (P<0.01) and a shorter disease-free survival (P<0.01). Moreover, abnormalities in either of these two criteria detected at specific time points during follow-up (end of induction, maintenance, or after treatment) were associated with a significantly shorter disease-free survival (P<0.01). In summary, the investigation of abnormalities in B-cell differentiation is a relatively simple and cheap approach for predicting relapse in precursor-B-ALL patients.

Bcl-2 protein plays a major role in the prevention of programmed cell death of differentiating cells. In the present study, the expression of cytoplasmic bcl-2 by human Bone Marrow Mast Cells (BMMC) from both normal and pathological bone marrow samples was examined. A total of 35 subjects corresponding to 9 healthy volunteers, 8 cases of adult indolent systemic mast cell disease (SMCD), 4 cases of pediatric mastocytosis (PM), 11 cases of hematological malignancies (HM), 2 cases of reactive bone marrow, and 1 case of mast cell leukemia (MCL) were analyzed. The expression of bcl-2 was studied using quantitative three-color flow cytometry. We also studied the molecular configuration of the bcl-2 gene and other relatives by Southern blot and polymerase chain reaction (PCR) in the MCL case. Bcl-2 expression was detected in BMMC from all samples analyzed. No significant differences on the expression of bcl-2 were detected between BMMC from healthy subjects and patients with SMCD, PM, HM, and reactive bone marrow. By contrast, bcl-2 protein was overexpressed in BMMC from MCL patient without gene rearrangement. Our results show that bcl-2 protein was constitutively expressed by BMMC. BMMC from MCL display overexpression of bcl-2, which could not be related to molecular rearrangements involving the bcl-2 gene. The expression of this protein by mature MC may play a role in the prevention of MC apoptosis and thus help to explain the long survival of these cells. The overexpression of bcl-2 by BMMC in MCL may help to explain their resistance to chemotherapy-induced apoptosis.

The in vitro growth characteristics of a large series of acute myeloid leukaemia (AML) patients and their relationship with other clinical and biological disease characteristics were analysed. Patients with AML were studied, 181 with de novo AML and 45 with secondary AML (24 myelodysplastic syndrome, sAML-MDS, 21 myeloproliferative disorder, sAML-MPD). Leukaemic colony forming units (L-CFU) were assayed by plating peripheral blood (PB) blast cells in methyl-cellulose and using LCM-PHA as stimulant. In each case parallel cultures were made with and without stimulating factors. Plating efficiency (PE) was defined as the number of clusters plus colonies/10(5) cells plated. Autonomous growth (AG) was the number of colonies plus clusters growing without stimulant. The autonomous proliferative index (API) was calculated as the number of clusters + colonies without stimulating factor divided by the number of clusters + colonies with stimulating factor. No significant differences in the PE between de novo and secondary AML were found. Autonomous growth was significantly higher in sAML-MPD. The FAB subtype M3 leukaemias displayed a significantly greater PE and a significantly lower API when compared with the other FAB subgroups (P=0.0002). Upon analysing the relationship with the immunophenotype, only CD33 expression showed a significant relationship with the in vitro growth pattern; CD33+ cases displayed a higher PE (P=0.0002) and AG (P=0.0003) than CD33- cases. When patients were grouped according to the level of rh123 efflux (MDR1) it was observed that cases with >30% elimination showed a higher AG and API than those with <30% (P=0.03). Finally we found that patients with higher API (>0.05) displayed a significantly shorter overall survival as compared with patients with API<0.05 (P=0.04). The in vitro study properties of clonogenic cells produces relevant clinical information of leukaemic cell biology in AML patients.

In the present study the incidence of abnormal karyotypes and the number and proportion of abnormal metaphases obtained in multiple myeloma (MM) using three culture conditions were compared: unstimulated culture (72 h), IL-6/GM-CSF-stimulated culture (120 h) and IL-4-stimulated culture (120 h). The three types of culture conditions were assessed simultaneously on bone marrow samples from 30 consecutive myeloma patients. In addition DNA content (DNA ploidy and cell cycle) was analysed by flow cytometry. The number of MM samples with clonal karyotypic abnormalities was higher after IL-4-stimulated cultures (53%) than it was after IL-6 + GM-CSF (37%) and unstimulated (30%) cultures. The benefit of IL-4 was also observed in cases with low numbers of plasma cells in the bone marrow, in early clinical stages and in untreated patients. In those cases in whom clonal chromosomal abnormalities were detected by the three culture methods. the cytogenetic findings were always identical. According to our results the addition of IL-4 to the cultures of bone marrow cells in MM increases the number of abnormal metaphases.

No previous studies have been reported on human alcoholism in which the pattern of cytokine secretion by natural killer (NK) cells is explored. The goal of the present study was to evaluate the role of NK cells in the production of cytokines in patients with chronic alcoholism, analyzing at the same time the possible relationship between cytokine production and both alcoholic liver disease and ethanol (EtOH) intake. A total of 30 chronic alcoholic patients-11 without liver disease [alcoholics without liver disease (AWLD) group] and 19 diagnosed of alcoholic liver cirrhosis-were included in this study. Twenty-five age- and sex-matched healthy volunteers were analyzed as controls. Production of interferon (IFN)-gamma, tumor necrosis factor-alpha (TNF-alpha), and interleukin (IL)-6 was performed on NK-enriched peripheral blood mononuclear cells (PBMC) after stimulation with IL-2 and IFN-alpha. In AWLD patients, the production of TNF-alpha was significantly reduced, compared with normal controls, under both IFN-alpha (p < 0.01) and IL-2 (p < 0.05) stimulation. In patients with cirrhosis, TNF-alpha production by PBMC enriched in NK cells varied depending on the EtOH intake status at the moment of evaluation. Accordingly, an increased concentration of this cytokine was detected in the supernatants of cirrhotic patients and active EtOH intake, particularly after IFN-alpha stimulation (p < 0.05); whereas, in patients with at least 1 year of alcohol withdrawal, TNF-alpha levels remained within normal range. The results on the production of IL-6 and IFN-gamma in AWLD and cirrhotic patients showed that only cirrhotic patients with a prolonged EtOH withdrawal period display abnormal production. Accordingly, in this group of patients, a significantly increased release of IL-6 was observed after both IFN-alpha and IL-2 stimulation (p < 0.01 and p < 0.05, respectively). By contrast, a lower IFN-gamma production (p < 0.005) was detected with respect to the control group. Our results point to the existence of an abnormal cytokine secretion by NK cells from chronic alcoholism patients, which depend on both the existence of liver disease and the status of EtOH intake.

The surface expression of CD117 on plasma cells (PCs) from normal individuals and patients with multiple myeloma (MM) has been analysed using triple-stained cells for flow cytometry. In addition, the clinical significance of CD117 expression in MM patients and its possible value for the evaluation of minimal residual disease was explored. A total of 11 healthy volunteers and 56 untreated MM patients were included in the study. The expression of CD117 was analysed by flow cytometry, using simultaneous staining with the MAbs BB4, CD117 and CD38. Cell acquisition was performed in two consecutive steps using a live gate drawn on SSC/CD38 cells and a total of 300,000 events were acquired. For data analysis, the Paint-a-Gate Plus software (Becton Dickinson) was used. PCs were identified according to their strong reactivity for CD38 and their positivity for BB4, as well as by their light scatter distribution. Dilution experiments of CD117+ myelomatous PCs with normal bone marrow (BM) cells were performed in order to assess the sensitivity level of the technique for detection of CD117+ residual PCs. None of the PCs from normal BM samples showed reactivity for the CD117 antigen. In contrast, CD117 antigen was present in 18/56 MM patients (32%), the proportion of positive cells in these cases being as high as 92.1 +/- 9%. Therefore, within PC lineage the c-Kit antigen would be restricted to the myelomatous population and thus could be considered as a 'tumour-associated marker' for monitoring minimal residual disease in about one third of MM patients. Dilution experiments indicate that the detection limit with this marker would be 10(-4) (one myelomatous PC/10(4) normal BM cells). Upon comparing the clinical and haematological disease characteristics of CD117-positive and CD117-negative cases, no significant differences were found.

Haemopoietic growth factors (HGFs) have been shown to accelerate recovery from severe neutropenia after autologous bone marrow transplantation (ABMT) but their effect on immune reconstitution is not well defined. The present study compares, through randomized trial, the in vivo effect of GM-CSF and G-CSF administration on the immune recovery of patients who underwent ABMT. For that purpose, we have sequentially analysed 14 different T, B and NK lymphoid cell subsets using appropriate dual staining during the first year following transplant (days +6, +17, +31, +66, +90, +120, +180, +360). 24 patients with lymphoproliferative disorders (20 lymphomas and four multiple myelomas) and who had undergone ABMT were included in the study. The median age was 43 years (range 22-62 years). All lymphoma patients were homogenously conditioned with BEAM. Our results show that both GM-CSF and G-CSF aid T-cell (CD3+/alpha beta) recovery though their contribution varies depending on the T-cell subset analysed. G-CSF contributed to a significantly faster recovery of CD8+ cells (P = 0.03). The CD8+ cell regeneration was produced mainly by activated cells (CD38+/HLA-DR+) which lacked the CD11b antigen. In contrast, GM-CSF favoured the regeneration of CD4+ cells (through both the CD45RO+ and CD45RA+ subset), leading to a higher CD4+:CD8+ ratio (P = 0.007). No statistically significant differences were detected in the three groups of patients as regards both the recovery of NK cells and NK activity. Furthermore, the use of HGF did not seem to exert a significant influence on the recovery of B lymphocytes. This recovery was based on the CD5+ subpopulation that showed a rapid rise after the first month. We suggest that G-CSF and GM-CSF not only influence myeloid recovery, but also regeneration of the immune system after ABMT.