The orphan nuclear receptor EAR-2 (NR2F6) inhibits hematopoietic cell differentiation and induces myeloid dysplasia in vivo.

BACKGROUND: In patients with myelodysplastic syndrome (MDS), bone marrow cells have an increased predisposition to apoptosis, yet MDS cells outcompete normal bone marrow (BM)-- suggesting that factors regulating growth potential may be important in MDS. We previously identified v-Erb A related-2 (EAR-2, NR2F6) as a gene involved in control of growth ability. METHODS: Bone marrow obtained from C57BL/6 mice was transfected with a retrovirus containing EAR-2-IRES-GFP. Ex vivo transduced cells were flow sorted. In some experiments cells were cultured in vitro, in other experiments cells were injected into lethally irradiated recipients, along with non-transduced bone marrow cells. Short-hairpin RNA silencing EAR-2 was also introduced into bone marrow cells cultured ex vivo. RESULTS: Here, we show that EAR-2 inhibits maturation of normal BM in vitro and in vivo and that EAR-2 transplant chimeras demonstrate key features of MDS. Competitive repopulation of lethally irradiated murine hosts with EAR-2-transduced BM cells resulted in increased engraftment and increased colony formation in serial replating experiments. Recipients of EAR-2-transduced grafts had hypercellular BM, erythroid dysplasia, abnormal localization of immature precursors and increased blasts; secondary transplantation resulted in acute leukemia. Animals were cytopenic, having reduced numbers of erythrocytes, monocytes and granulocytes. Suspension culture confirmed that EAR-2 inhibits granulocytic and monocytic differentiation, while knockdown induced granulocytic differentiation. We observed a reduction in the number of BFU-E and CFU-GM colonies and the size of erythroid and myeloid colonies. Serial replating of transduced hematopoietic colonies revealed extended replating potential in EAR-2-overexpressing BM, while knockdown reduced re-plating ability. EAR-2 functions by recruitment of histone deacetylases, and inhibition of differentiation in 32D cells is dependent on the DNA binding domain. CONCLUSIONS: This data suggest that NR2F6 inhibits maturation of normal BM in vitro and in vivo and that the NR2F6 transplant chimera system demonstrates key features of MDS, and could provide a mouse model for MDS.

Management of newly diagnosed high-risk and intermediate-risk follicular lymphoma with 90 Y ibritumomab tiuxetan in a phase II study.

Five-year overall survival for high-risk Follicular Lymphoma International Prognostic Index follicular lymphoma is only approximately 50% compared with 90% for low risk. To evaluate an approach to improve upon this poor outcome, we completed an exploratory phase II trial of intensified treatment for patients with intermediate and high-risk follicular lymphoma. Front-line treatment with chemo-immunotherapy consisting of rituximab, cyclophosphamide, vincristine, doxorubicin, and prednisone was followed by radio- immunotherapy with 90-Yttrium ibritumomab tiuxetan consolidation, and 2 years of rituximab maintenance. The 5-year overall survival for intermediate and high-risk patients was 88% and 83%, respectively. Of 33 enrolled patients, 3 were off study before receiving radio-immunotherapy. Three months post radio-immunotherapy, 28/33 (85%) patients had achieved complete response including 6 patients who had only a partial response to chemo-immunotherapy and converted to complete response after radio-immunotherapy. The 5-year progression-free survival for intermediate and high risk was 79% and 58%, respectively. Nine of 19 patients with molecular markers patients remain in molecular and clinical complete remission with a median follow-up of 48 months (range 3-84 months). Post radio-immunotherapy, hematologic toxicities were mostly grade 1 and 2. However, asymptomatic grade 3 or 4 thrombocytopenia and neutropenia occurred in 11%-36% and 10%-24% of patients, respectively. Myelodysplastic syndrome occurred in 1 patient 4 years post treatment. Whereas many patients had prolonged B-cell reduction and low immunoglobulin levels post treatment, previous immunities to rubella were maintained. More aggressive upfront approaches such as this may benefit higher risk follicular lymphoma, but confirmatory trials are required. http://www.clinicaltrials.gov: NCT01446562.

Lenalidomide and metronomic melphalan for CMML and higher risk MDS: a phase 2 clinical study with biomarkers of angiogenesis.

Metronomic, low dose chemotherapy may have anti-angiogenic effects and augment the effects of lenalidomide in MDS and CMML. We evaluated the clinical efficacy, tolerability and anti-angiogenic effects of melphalan 2mg and lenalidomide 10mg for 21 days/28 in CMML (n=12) and higher risk MDS (n=8) patients in a prospective phase II study. The primary endpoint was overall response and secondary endpoints included survival, progression-free survival, toxicity and biomarkers of angiogenesis. The median age was 73 years, 55% were pretreated and transfusion dependent. The overall response rate was 3(15%) of 19 evaluable patients but 25% in CMML and 33% in pCMML. Dose reductions and/or delays were common due to myelosuppression. Transient spikes in circulating endothelial cells that declined below baseline were seen in responders and patients with CMML, suggesting anti-angiogenic activity. In conclusion, lenalidomide and metronomic low dose melphalan demonstrate signals of clinical and possible anti-angiogenic activity in patients with pCMML that require future validation. This trial was registered at clinicaltrial.gov under # NCT00744536.

Clinical utility of flow cytometry in the study of erythropoiesis and nonclonal red cell disorders.

Erythropoiesis involves proliferation and differentiation of small population of hematopoietic stem cells resident in the bone marrow into mature red blood cells. The determination of the cellular composition of the blood is a valuable tool in the diagnosis of diseases and monitoring of therapy. Flow cytometric analysis is increasingly being used to characterize the heterogeneous cell populations present in the blood and the hematopoietic cell differentiation and maturation pathways of the bone marrow. Here we discuss the role of flow cytometry in the study of erythropoiesis and nonclonal red blood cell disorders. First, we discuss flow cytometric analysis of reticulocytes. Next, we review salient quantitative methods that can be used for detection of fetal-maternal hemorrhage (FMH). We also discuss flow cytometric analysis of high hemoglobin F (HbF) in Sickle Cell Disease (SCD), hereditary spherocytosis (HS), red cell survival and red cell volume. We conclude by discussing cell cycle of erythroid cells.

Imaging genetics in multiple sclerosis: a volumetric and diffusion tensor MRI study of APOE ε4.

Evidence linking the ε4 allele of APOE to more severe brain MRI abnormalities in multiple sclerosis (MS) has been conflicting and limited to studies of lesion load and whole brain atrophy. The purpose of the present study was to determine whether the ε4 allele of APOE is associated with more extensive brain pathology in MS using structural and diffusion tensor MRI. Using a case-control design, 43 MS patients with the ε4 allele and 47 ε4 negative MS patients underwent structural and diffusion tensor imaging (DTI) at 3T. Hypo- and hyperintense lesion volumes, whole brain and medial temporal volumes, and DTI parameters (fractional anisotropy (FA) and mean diffusivity (MD)) in normal-appearing brain tissue and lesions were compared between the groups. ε4+ and ε4- MS patients were well-matched on demographic characteristics, disease variables, and proportions receiving disease-modifying therapy. ε4+ and ε4- patients did not differ on any MRI or DTI measure. This study refutes a role for the ε4 allele in MRI abnormalities in MS, particularly those linking ε4 to greater T1 hypointense lesion volume and brain atrophy. Previous work on this putative gene-MRI relationship is extended by comparing DTI measures within lesions and normal-appearing brain tissue. A lack of differences in medial temporal regions, areas that have been linked to ε4-associated changes in health and disease, further supports the conclusion that that ε4 is not associated with more subtle MRI markers of brain pathology in MS.

Recombinant factor VIIa is associated with an improved 24-hour survival without an improvement in inpatient survival in massively transfused civilian trauma patients.

OBJECTIVE: To determine whether recombinant factor VIIa (rFVIIa) is associated with increased survival and/or thromboembolic complications. INTRODUCTION: Uncontrollable hemorrhage is the main cause of early mortality in trauma. rFVIIa has been suggested for the management of refractory hemorrhage. However, there is conflicting evidence about the survival benefit of rFVIIa in trauma. Furthermore, recent reports have raised concerns about increased thromboembolic events with rFVIIa use. METHODS: Consecutive massively transfused (> 8 units of red blood cells within 12 h) trauma patients were studied. Data on demographics, injury severity scores, baseline laboratory values and use of rFVIIa were collected. Rate of transfusion in the first 6 h was used as surrogate for bleeding. Study outcomes included 24-hour and in-hospital survival, and thromboembolic events. A multivariable logistic regression analysis was used to determine the impact of rFVIIa on 24-hour and in-hospital survival. RESULTS: Three-hundred and twenty-eight patients were massively transfused. Of these, 72 patients received rFVIIa. As expected, patients administered rFVIIa had a greater degree of shock than the non-rFVIIa group. Using logistic regression to adjust for predictors of death in the regression analysis, rFVIIa was a significant predictor of 24-hour survival (odds ratio (OR) = 2.65; confidence interval 1.26-5.59; p = 0.01) but not of in-hospital survival (OR = 1.63; confidence interval 0.79-3.37; p = 0.19). No differences were seen in clinically relevant thromboembolic events. CONCLUSIONS: Despite being associated with improved 24-hour survival, rFVIIa is not associated with a late survival to discharge in massively transfused civilian trauma patients.

Recombinant factor VIIa is associated with an improved 24-hour survival without an improvement in inpatient survival in massively transfused civilian trauma patients

OBJECTIVE: To determine whether recombinant factor VIIa (rFVIIa) is associated with increased survival and/or thromboembolic complications. INTRODUCTION: Uncontrollable hemorrhage is the main cause of early mortality in trauma. rFVIIa has been suggested for the management of refractory hemorrhage. However, there is conflicting evidence about the survival benefit of rFVIIa in trauma. Furthermore, recent reports have raised concerns about increased thromboembolic events with rFVIIa use. METHODS: Consecutive massively transfused (> 8 units of red blood cells within 12 h) trauma patients were studied. Data on demographics, injury severity scores, baseline laboratory values and use of rFVIIa were collected. Rate of transfusion in the first 6 h was used as surrogate for bleeding. Study outcomes included 24-hour and in-hospital survival, and thromboembolic events. A multivariable logistic regression analysis was used to determine the impact of rFVIIa on 24-hour and in-hospital survival. RESULTS: Three-hundred and twenty-eight patients were massively transfused. Of these, 72 patients received rFVIIa. As expected, patients administered rFVIIa had a greater degree of shock than the non-rFVIIa group. Using logistic regression to adjust for predictors of death in the regression analysis, rFVIIa was a significant predictor of 24-hour survival (odds ratio (OR) = 2.65; confidence interval 1.26-5.59; p = 0.01) but not of in-hospital survival (OR = 1.63; confidence interval 0.79-3.37; p = 0.19). No differences were seen in clinically relevant thromboembolic events. CONCLUSIONS: Despite being associated with improved 24-hour survival, rFVIIa is not associated with a late survival to discharge in massively transfused civilian trauma patients.

Estimating the prevalence of myelodysplastic syndromes in patients with unexplained cytopenias: a retrospective study of 322 bone marrows.

Although unexplained anemia is common in the elderly, the prevalence of MDS is poorly defined. We reviewed 2267 bone marrows reviewed at our center between the years 2002 and 2005. Of these, 322 met our criteria for inclusion (14%). Seventy-three patients (22.6%) had a confirmed diagnosis of MDS and 32 (9.9%) had suspected MDS. Confirmed or suspected MDS was more likely in patients aged >65 (31.5% and 11%, respectively). Age, MCV, LDH and RDW were independently predictive of MDS. Extrapolation of our findings to the elderly anemic individuals in the community suggests MDS prevalence may be higher than previously postulated.

Traumatic brain injury, Apolipoprotein E-epsilon4, and cognition in older adults: a two-year longitudinal study.

Patients with mild-to-moderate traumatic brain injury (TBI) (N=69) were compared with age-, gender-, and education-matched healthy control group subjects (N=79) on performance of neuropsychological tests at one and 2 years following injury, and informant-rated functional abilities. All subjects were assessed for the presence of the Apolipoprotein E-epsilon4 (APOE-epsilon4) allele and rated for "mild cognitive impairment" (MCI) or dementia. Traumatic brain injury patients were no different from the comparison group on measures of cognition or functional impairment. Traumatic brain injury was not associated with higher rates of amnestic mild cognitive impairment or dementia, and APOE-epsilon4 was not associated with cognition.

External quality assessment of HLA-B*5701 reporting: an international multicentre survey.

OBJECTIVES: HLA-B*5701 strongly predicts abacavir hypersensitivity (HSR), but implementation of effective routine screening into clinical practice requires testing be practical and accurate. We tested the proficiency of HLA-B*5701 typing among laboratories using sequence-specific primer PCR. DESIGN AND METHODS: DNA panels (1 and 2) were distributed to seven laboratories (A to G) for blinded typing of the HLA-B*5701 allele. Panel 1 (n = 10 samples; n = 7 laboratories) included 3 positives and other closely related B17 subtypes (B*5702, B*5703, B*5704 and B*5801). Panel 2 (n = 96 samples; n = 4 laboratories) included 36 positives among a broad spectrum of other B alleles. Two laboratories (A and B) also submitted 96 routine samples, typed by the same methodology, to the reference centre for additional analysis by sequence-based typing. RESULTS: All laboratories correctly typed panel 1 for HLA-B*5701 carriage. Laboratories A, B and C identified HLA-B*5701 alleles in panel 2 with 100% sensitivity and 100% specificity. Laboratory D reported one false negative, reportedly due to a sampling error. The results obtained for routine samples typed by laboratories A and B and those generated by the reference laboratory using sequencing were fully concordant. CONCLUSIONS: Detection of HLA-B*5701 alleles among laboratories was 100% specific and 99.4% sensitive, indicating that participating HIV testing laboratories were currently offering effective primary screening to identify individuals at high risk of abacavir HSR. Accurate reporting of HLA-B*5701 status is critical for the safe administration of this drug and participation in quality assurance programmes by all sites who report HLA-B*5701 status should be promoted.

Pathological splenic rupture: a rare complication of chronic myelomonocytic leukemia.

Chronic myelomonocytic leukemia (CMML) is an uncommon disorder characterized by monocytosis of the peripheral blood, absence of the Philadelphia chromosome, fewer than 20% blasts, and one or more lineages showing dysplastic features. Splenomegaly is frequently seen and may be massive. A 56-year-old man with stable CMML and moderate splenomegaly presented to the emergency department with generalized abdominal pain and abrupt drop in hemoglobin. Abdominal imaging revealed splenic rupture and emergency splenectomy was undertaken, with complete recovery. Atraumatic rupture of the spleen has rarely been reported as a complication of CMML or other myelodysplastic disorders. This report should alert physicians to consider this diagnosis in patients with CMML and acute abdominal pain.

Multiply relapsing hairy cell leukemia responsive to repeated courses of rituximab: a case report.

While cladribine is a highly effective therapy for patients with symptomatic hairy cell leukemia (HCL), up to 37% of patients ultimately relapse and incompletely responding patients relapse more frequently. Rituximab is a monoclonal antibody against CD20 that has been shown to be effective in patients with relapsed HCL. We present an unusual case of successful multiple re-treatments with rituximab in a patient with heavily pre-treated HCL and briefly review the relevant literature.

Association of clinical status of follicular lymphoma patients after autologous stem cell transplant and quantitative assessment of lymphoma in blood and bone marrow as measured by SYBR Green I polymerase chain reaction.

Molecular remission in the autograft and bone marrow after transplant are predictive of durable clinical remission in relapsed follicular lymphoma. Thus, a simple reliable method to quantify minimal residual disease (MRD) would improve prognostication in these patients. Fluorescent hybridization probes have been used in real-time quantitative polymerase chain reaction (RQ-PCR) to monitor MRD with a reproducible sensitivity of 0.01%; however, these techniques are expensive and require additional experiments to examine clonality. We describe a SYBR Green I detection method that is more universal, checks clonal identity, yields the same sensitivity for monitoring MRD, and is more economically attractive. Using this method to follow 14 follicular lymphoma patients treated with autologous stem cell transplantation, molecular markers were successfully defined for 12 patients. Median contamination of stem-cell grafts was 0.1% (range, 0 to 13%). Six patients with measurable graft contamination became PCR-negative in blood and bone marrow within 12 months after autologous stem cell transplantation. Three patients free of disease progression (median follow-up of 75 months) are in molecular remission. Increasing fractions of RQ-PCR-positive blood and bone marrow cells reliably predicted morphological and clinical relapse. In one case, both clinical relapse and spontaneous regression were reflected by changes in MRD levels. Thus, our RQ-PCR method reproducibly distinguishes different levels of MRD.

Versican G3 domain promotes blood coagulation through suppressing the activity of tissue factor pathway inhibitor-1.

We have detected versican, a member of the large chondroitin sulfate proteoglycans, and its degraded C-terminal G3 fragments in human plasma and observed that the versican G3 domain promoted blood coagulation. Silencing G3 expression with small interfering RNA reduced the effect of G3 on coagulation. Plasma coagulation assays suggest that G3 enhances coagulation irrespective of its actions on platelets and white blood cells. To examine how versican affected blood coagulation, we used normal human plasma and different types of coagulation factor-deficient plasmas. The experiments indicated that versican enhanced coagulation through the extrinsic pathway, and that Factor VII was the target molecule. FVII activity assays showed that G3 activated FVII in the presence of plasma but not with purified FVII directly. Yeast two-hybrid, immunoprecipitation, and gel co-migration assays showed that G3 interacted with the tissue factor pathway inhibitor-1 (TFPI-1). TFPI-1 activity assays suggested that G3 inhibited TFPI-1 activity, allowing FVIIa and FXa to facilitate the coagulation process. G3-induced blood coagulation was further confirmed with a mouse model in a real-time manner. Taken together, these results indicate that versican may represent a new target for the development of therapies against atherosclerosis.

Comparison of enoxaparin versus heparin during elective percutaneous coronary intervention performed with either eptifibatide or tirofiban (the ACTION Trial).

Limited data are available with regard to the pharmacodynamics and safety of combining enoxaparin with glycoprotein IIb/IIIa inhibition during elective percutaneous coronary interventions (PCIs). We randomized 200 patients to receive open-label enoxaparin (0.75 mg/kg intravenous bolus) or unfractionated heparin (60 U/kg intravenous bolus) and eptifibatide or tirofiban during PCI. This yielded 4 groups of combination therapy (50 patients/group). The first 10 patients per group had anti-Xa activity and inhibition of platelet aggregation measured at baseline, and at 5 minutes, 10 minutes, 4 hours, and 24 hours. All patients received aspirin and clopidogrel therapy before PCI. Patients who received enoxaparin and heparin achieved therapeutic peak anti-Xa activity observed shortly after drug administration. At 4 hours, a differential anticoagulant effect was observed, with patients who received enoxaparin having a more gradual decrease in anti-Xa activity. Patients who received eptifibatide achieved >80% inhibition of platelet aggregation soon after initiation of therapy more often than did those who received tirofiban. Type of heparin did not affect inhibition of platelet aggregation. Compared with patients who received heparin, periprocedural myocardial infarction and bleeding events occurred less frequently among those who received enoxaparin (14% vs 8% and 10% vs 5%); however, these differences were not statistically significant. Three cases of intraprocedural thrombus occurred among patients who received enoxaparin. Two patients received concomitant tirofiban therapy. Compared with unfractionated heparin, similar levels of anticoagulation and platelet inhibition are achieved with enoxaparin when concomitant therapy with eptifibatide or tirofiban is used during elective PCI, without an observed increase in early bleeding events or periprocedural ischemic complications.

Six-month recovery from mild to moderate Traumatic Brain Injury: the role of APOE-epsilon4 allele.

The possession of at least one APOE-epsilon4 allele may be linked to poor outcome in patients with predominantly severe traumatic brain injury (TBI). In mild TBI, which accounts for approximately 85% of all cases, the role of the APOE-epsilon4 allele is less clear. Studies completed to date have relied on brief cognitive assessments or coarse measures of global functioning, thereby limiting their conclusions. Our study investigated the influence of the APOE-epsilon4 allele in a prospective sample of 90 adults with mild to moderate TBI in whom neuropsychiatric outcome 6 months after injury was assessed as follows: (i) a detailed neuropsychological battery; (ii) an index of emotional distress (General Health Questionnaire); (iii) a diagnosis of major depression (Structured Clinical Interview for DSM-IV); (iv) a measure of global functioning (Glasgow Outcome Scale); (v) an index of psychosocial outcome (Rivermead Head Injury Follow-up Questionnaire); and (vi) symptoms of persistent post-concussion disorder (Rivermead Post-Concussion Symptoms Questionnaire). No association was found between the presence of the APOE-epsilon4 allele and poor outcome across all measures. Given the homogeneous nature of our sample (mild to moderate injury severity), the uniform follow-up period (6 months) and the comprehensive markers of recovery used, our data suggest that the APOE-epsilon4 allele does not adversely impact outcome in this group of TBI patients.

Immunotherapy with rituximab following high-dose therapy and autologous stem-cell transplantation for mantle cell lymphoma.

Advanced-stage mantle cell lymphoma (MCL) is a disease for which no curative treatment strategy exists. Results with standard combination chemotherapy, with or without an anthracycline, are disappointing, and new and better therapies are needed. High-dose therapy and autologous stem-cell transplantation (ASCT) have been performed in patients with MCL both up front and at relapse with varying degrees of success. Rituximab (Rituxan; Genentech, Inc, South San Francisco, CA, and IDEC Pharmaceuticals, San Diego, CA) has shown moderate response rates in patients with MCL. It has also been used safely and effectively as an in vivo purge during ASCT for patients with lymphoma. We are currently investigating an aggressive protocol in patients with newly diagnosed, untreated MCL using a combination of two promising therapeutic modalities, high-dose therapy-ASCT and rituximab. Since 1999, 13 patients with newly diagnosed MCL have been enrolled in this phase II clinical trial. CHOP (cyclophosphamide/prednisone/vincristine/doxorubicin) is used as debulking chemotherapy. Stem cells are mobilized with 5 days of granulocyte colony-stimulating factor 10 microg/kg/d, with a single infusion of rituximab 375 mg/m(2) used as an in vivo purge before stem-cell collection by large-volume leukapheresis. The transplant conditioning regimen is cyclophosphamide/carmustine/etoposide. Post-transplant consolidative immunotherapy consists of rituximab 375 mg/m(2), administered as two 4-week cycles at 2 and 6 months post-transplant. So far, 12 patients (7 men/5 women) with a median age of 55 years (range, 41 to 65 years) have been transplanted. Patients were first assessed and then transplanted a median of 40 and 201 days, respectively, from diagnosis. International Prognostic Index at diagnosis was low (n = 3), low-intermediate (n = 8), and high-intermediate (n = 1). A median of six cycles of CHOP was required to debulk tumor sufficiently for transplant. Response to CHOP was 100% with six complete responses, one complete response unconfirmed, and five partial responses. Transplantation was well tolerated. Patients engrafted quickly, with a median of 11.5 days to neutrophil engraftment and 10 days to platelet independence. Patients had modest transfusion requirements, requiring a median of four units of packed red blood cells and two and a half platelet transfusions. Six to 8 weeks post-transplant, six patients were in complete response, four in complete response unconfirmed, and two in partial response. Eight patients have received all eight maintenance rituximab treatments, and four have received only their first cycle. Following rituximab, the two patients in partial response and two in complete response unconfirmed converted to complete response. With a median follow-up of 239 days from transplant (range, 61 to 727 days), all patients remain alive and well with no documented relapses. Samples for molecular monitoring have been drawn from the stem-cell graft, and serially from the peripheral blood and bone marrow of patients at baseline, preapheresis, pretransplant, and post-transplant at 3-month intervals. This data shows that ASCT followed by rituximab immunotherapy is feasible and safe in patients with MCL. Although patient numbers are low and follow-up time is short, preliminary results are encouraging. Rituximab may convert partial responders to complete responders. The durability of responses will be determined with longer follow-up.

Immunotherapy with rituximab following high-dose therapy and autologous stem-cell transplantation for mantle cell lymphoma.

Advanced-stage mantle cell lymphoma (MCL) is a disease for which no curative treatment strategy exists. Results with standard combination chemotherapy, with or without an anthracycline, are disappointing, and new and better therapies are needed. High-dose therapy and autologous stem-cell transplantation (ASCT) have been performed in patients with MCL both up front and at relapse with varying degrees of success. Rituximab (Rituxan; Genentech, Inc, South San Francisco, CA, and IDEC Pharmaceuticals, San Diego, CA) has shown moderate response rates in patients with MCL. It has also been used safely and effectively as an in vivo purge during ASCT for patients with lymphoma. We are currently investigating an aggressive protocol in patients with newly diagnosed, untreated MCL using a combination of two promising therapeutic modalities, high-dose therapy-ASCT and rituximab. Since 1999, 13 patients with newly diagnosed MCL have been enrolled in this phase II clinical trial. CHOP (cyclophosphamide/prednisone/vincristine/doxorubicin) is used as debulking chemotherapy. Stem cells are mobilized with 5 days of granulocyte colony-stimulating factor 10 µg/kg/d, with a single infusion of rituximab 375 mg/m2 used as an in vivo purge before stem-cell collection by large-volume leukapheresis. The transplant conditioning regimen is cyclophosphamide/carmustine/etoposide. Post-transplant consolidative immunotherapy consists of rituximab 375 mg/m2, administered as two 4-week cycles at 2 and 6 months post-transplant. So far, 12 patients (7 men/5 women) with a median age of 55 years (range, 41 to 65 years) have been transplanted. Patients were first assessed and then transplanted a median of 40 and 201 days, respectively, from diagnosis. International Prognostic Index at diagnosis was low (n = 3), low-intermediate (n = 8), and high-intermediate (n = 1). A median of six cycles of CHOP was required to debulk tumor sufficiently for transplant. Response to CHOP was 100% with six complete responses, one complete response unconfirmed, and five partial responses. Transplantation was well tolerated. Patients engrafted quickly, with a median of 11.5 days to neutrophil engraftment and 10 days to platelet independence. Patients had modest transfusion requirements, requiring a median of four units of packed red blood cells and two and a half platelet transfusions. Six to 8 weeks post-transplant, six patients were in complete response, four in complete response unconfirmed, and two in partial response. Eight patients have received all eight maintenance rituximab treatments, and four have received only their first cycle. Following rituximab, the two patients in partial response and two in complete response unconfirmed converted to complete response. With a median follow-up of 239 days from transplant (range, 61 to 727 days), all patients remain alive and well with no documented relapses. Samples for molecular monitoring have been drawn from the stem-cell graft, and serially from the peripheral blood and bone marrow of patients at baseline, preapheresis, pretransplant, and post-transplant at 3-month intervals. This data shows that ASCT followed by rituximab immunotherapy is feasible and safe in patients with MCL. Although patient numbers are low and follow-up time is short, preliminary results are encouraging. Rituximab may convert partial responders to complete responders. The durability of responses will be determined with longer follow-up. Semin Oncol 29 (suppl 2):56-69. Copyright © 2002 by W.B. Saunders Company.