Orthogonal and complementary measurements of properties of drug products containing nanomaterials.

Quality control of pharmaceutical and biopharmaceutical products, and verification of their safety and efficacy, depends on reliable measurements of critical quality attributes (CQAs). The task becomes particularly challenging for drug products and vaccines containing nanomaterials, where multiple complex CQAs must be identified and monitored. To reduce (i) the risk of measurement bias and (ii) the uncertainty in decision-making during product development, the combination of orthogonal and complementary analytical techniques are generally recommended by regulators. However, despite frequent reference to "orthogonal" and "complementary" in guidance documents, neither term is clearly defined. How does one determine if two analytical methods are orthogonal or complementary to one another? Definitions are needed to design a robust characterization strategy aligned to regulatory needs. Definitions for "orthogonal" and "complementary" are proposed that are compatible with existing metrological terminology and are applicable to complex measurement problems. Orthogonal methods target the quantitative evaluation of the true value of a product attribute to address unknown bias or interference. Complementary measurements include a broader scope of methods that reinforce each other to support a common decision. Examples of the application of these terms are presented, with a focus on measurement of physical properties of nano-enabled drug products, including liposomes and polymeric nanoparticles for cancer treatment, lipid-based nanoparticles (LNPs) and virus-like particles for nucleic acid delivery. The proposed framework represents a first step in advancing the assessment of the orthogonality and complementarity of two measurements and it can potentially serve as the basis for a future international standard. This framework may help product developers to implement more efficient product characterization strategies, accelerate the introduction of novel medicines to the clinic and be applicable to other therapeutics beyond nanomaterial-containing pharmaceuticals.

Diffusion of multiwall carbon nanotubes (MWCNTs) through a high density polyethylene (HDPE) geomembrane.

The new applications for carbon nanotubes (CNTs) in various fields and consequently their greater production volume have increased their potential release to the environment. Landfills are one of the major locations where carbon nanotubes are expected to be disposed and it is important to ensure that they can limit the release of CNTs. Diffusion of multiwall carbon nanotubes (MWCNTs) dispersed in an aqueous media through a high-density polyethylene (HDPE) geomembrane (as a part of the landfill barrier system) was examined. Based on the laboratory tests, the permeation coefficient was estimated to be less than 5.1×10-15 m2/s. The potential performance of a HDPE geomembrane and geosynthetic clay liner (GCL) as parts of a composite liner in containing MWCNTs was modelled for six different scenarios. The results suggest that the low value of permeation coefficient of an HDPE geomembrane makes it an effective diffusive barrier for MWCNTs and by keeping the geomembrane defects to minimum during the construction (e.g., number of holes and length of wrinkles) a composite liner commonly used in municipal solid waste landfills will effectively contain MWCNTs.

Chironomus riparius exposure to fullerene-contaminated sediment results in oxidative stress and may impact life cycle parameters.

A key component of understanding the potential environmental risks of fullerenes (C60) is their potential effects on benthic invertebrates. Using the sediment dwelling invertebrate Chironomus riparius we explored the effects of acute (12h and 24h) and chronic (10d, 15d, and 28d) exposures of sediment associated fullerenes. The aims of this study were to assess the impact of exposure to C60 in the sediment top layer ((0.025, 0.18 and 0.48) C60 mg/cm2) on larval growth, oxidative stress and emergence rates and to quantify larval body burdens in similarly exposed organisms. Oxidative stress localization was observed in the tissues next to the microvilli and exoskeleton through a method for identifying oxidative stress reactions generated by reactive oxygen species. Rapid intake of fullerenes was shown in acute experiments, whereas body residues decreased after chronic exposure. Transmission electron microscopy analysis revealed oxidative damage and structural changes in cells located between the lipid droplets and next to the microvilli layer in fullerene exposed samples. Fullerene associated sediments also caused changes in the emergence rate of males and females, suggesting that the cellular interactions described above or other effects from the fullerenes may influence reproduction rates.

Efficacy of cisplatin-based immunochemotherapy plus alloSCT in high-risk chronic lymphocytic leukemia: final results of a prospective multicenter phase 2 HOVON study.

Allogeneic stem cell transplantation (alloSCT) remains the only curative option for CLL patients. Whereas active disease at the time of alloSCT predicts poor outcome, no standard remission-induction regimen exists. We prospectively assessed outcome after cisplatin-containing immune-chemotherapy (R-DHAP) followed by alloSCT in 46 patients (median age 58 years) fulfilling modified European Society for Blood and Marrow Transplantation (EBMT) CLL Transplant Consensus criteria being refractory to or relapsed (R/R) <1 year after fludarabine or <2 years after fludarabine-based immunochemotherapy or R/R with del(17p). Twenty-nine patients received ⩾3 cycles of R-DHAP and sixteen <3 cycles (4 because of disease progression, 8 for toxicity and 4 toxic deaths). Overall rate of response to R-DHAP was 58%, 31 (67%) proceeded to alloSCT after conditioning with fludarabine and 2 Gy TBI. Twenty (65%) remained free from progression at 2 years after alloSCT, including 17 without minimal residual disease. Intention-to-treat 2-year PFS and overall survival of the 46 patients were 42 and 51% (35.5 months median follow-up); del(17p) or fludarabine refractoriness had no impact. R-DHAP followed by alloSCT is a reasonable treatment to be considered for high-risk CLL patients without access or resistance to targeted therapies.

Biomarker profiling of steroid-resistant acute GVHD in patients after infusion of mesenchymal stromal cells.

We performed a prospective phase II study to evaluate clinical safety and outcome in 48 patients with steroid-refractory grade II-IV acute graft-versus-host disease (aGVHD) treated with mesenchymal stromal cells (MSCs). Clinical outcomes were correlated to comprehensive analyses of soluble and cellular biomarkers. Complete resolution (CR) of aGVHD at day 28 (CR-28) occurred in 12 (25%) patients, CR lasting >1 month (CR-B) occurred in 24 (50%) patients. One-year overall survival was significantly improved in CR-28 (75 versus 33%, P=0.020) and CR-B (79 versus 8%, P<0.001) versus non-CR patients. A six soluble biomarker-panel was predictive for mortality (HR 2.924; CI 1.485-5.758) when measured before MSC-administration. Suppression of tumorigenicity 2 (ST2) was only predictive for mortality 2 weeks after but not before MSC-administration (HR 2.389; CI 1.144-4.989). In addition, an increase in immature myeloid dendritic cells associated with decreased mortality (HR 0.554, CI 0.389-0.790). Patients had persisting T-cell responses against defined virus- and leukemia-associated antigens. In conclusion, our data emphasize the need to carefully assess biomarkers in cohorts with homogeneous GVHD treatments. Biomarkers might become an additional valuable component of composite end points for the rapid and efficient testing of novel compounds to decrease lifecycle of clinical testing and improve the success rate of phase II/III trials.

Impact of diameter on carbon nanotube transport in sand.

Carbon nanotubes are the subject of intense research due to their unique properties: light weight, significant strength, excellent conductivity, and outstanding chemical resistance. This has led to their application in a wide variety of industries (e.g., in composite materials). As a result of their potential impact to humans and ecosystems, there is increasing interest in understanding the factors that control the transport of carbon nanotubes in the environment, and of particular interest to this study, their transport in porous media. In this work, the transport behavior of multiwall carbon nanotubes (MWCNTs) is investigated in sand packed column experiments. To determine the importance of MWCNT diameter, experiments were conducted using four commercially available MWCNTs. Results suggest that smaller MWCNTs are less mobile than their larger counterparts, likely due to the increase in Brownian motion leading to more MWCNT collisions with the porous media with decreasing MWCNT size. A numerical model was used to simulate observed MWCNT transport behavior and facilitate comparison with published studies. These results suggest that careful characterization of MWCNT characteristics (i.e., dimensions and initial MWCNT mass in suspension) is essential to adequately interpret observed results. Results from this study suggest that MWCNTs may be mobile under conditions expected in subsurface aquifers.

Systemic vasculitis in myelodysplastic syndromes.

The development of immunological abnormalities in various neoplasms is a rather common phenomenon. The prevalence of life-threatening systemic vasculitis in malignancy, however, is much lower. Nonetheless we found an unexpected frequency of several autoimmune manifestations, including systemic vasculitis, in certain myelodysplastic syndromes. We illustrate this finding with the case of a 43-year-old man with signs of polyarteritis nodosa-like systemic vasculitis during progression of chronic myelomonocytic leukaemia. Subsequently, we review the literature on the combination of myelodysplastic syndromes and systemic vasculitis and discuss the prognostic consequences, considerations for treatment and possible pathophysiological mechanisms.

Adverse effects of fullerenes (nC60) spiked to sediments on Lumbriculus variegatus (Oligochaeta).

Effects of fullerene-spiked sediment on a benthic organism, Lumbriculus variegatus (Oligochaeta), were investigated. Survival, growth, reproduction, and feeding rates were measured to assess possible adverse effects of fullerene agglomerates produced by water stirring and then spiked to a natural sediment. L. variegatus were exposed to 10 and 50 mg fullerenes/kg sediment dry mass for 28 d. These concentrations did not impact worm survival or reproduction compared to the control. Feeding activities were slightly decreased for both concentrations indicating fullerenes' disruptive effect on feeding. Depuration efficiency decreased in the high concentration only. Electron and light microscopy and extraction of the worm fecal pellets revealed fullerene agglomerates in the gut tract but not absorption into gut epithelial cells. Micrographs also indicated that 16% of the epidermal cuticle fibers of the worms were not present in the 50 mg/kg exposures, which may make worms susceptible to other contaminants.

Prevalence and clinical significance of resistance to perforin- and FAS-mediated cell death in leukemia.

Killer lymphocytes play a central therapeutic role in graft-versus-leukemia following allogeneic hematopoietic stem cell transplantation (HSCT). The Perforin/Granzyme and FAS/CD95 pathways are of crucial importance in tumor cell elimination by killer cells. In this study, we have examined whether hematological malignancies are resistant to perforin and anti-FAS antibodies. Leukemic cells were studied from 29 patients suffering either from acute or chronic myeloid leukemia (AML or CML), acute or chronic lymphoid leukemia, or non-Hodgkin's lymphoma. An average of 49 vs 5% of specific cell killing was found when using perforin vs anti-FAS antibodies, respectively. Interestingly, resistance towards both perforin and anti-FAS antibodies was found exclusively in leukemic cells from patients with myeloid leukemia. Analysis of leukemic cells from patients with CML, suffering from leukemia relapse after HSCT and given donor lymphocyte infusion (DLI) to induce remission, indicated that the effectiveness of treatment with DLI was not associated with sensitivity of leukemic cells to perforin. In conclusion, resistance towards anti-FAS antibodies is a common phenomenon in leukemia/lymphoma, whereas perforin resistance occurs only in myeloid leukemia. However, as a single parameter, perforin resistance does not appear to be suitable to predict the outcome of DLI.

Low incidence of infectious complications after nonmyeloablative compared with myeloablative allogeneic stem cell transplantation.

Allogeneic stem cell transplantation (SCT) using a myeloablative (MA) conditioning regimen is limited to relatively young patients because of increased transplant-related mortality in elderly patients. Nonmyeloablative (NMA) conditioning regimens have been developed aiming to reduce transplant mortality. In this study, we set out to evaluate the post-transplant occurrence of infectious complications in recipients of grafts from human leukocyte antigen (HLA)-identical sibling donors treated with either NMA or MA conditioning regimens. Data of 78 consecutively treated patients were analyzed. An NMA conditioning regimen was used in 40 patients and an MA regimen in 38 patients. A significantly lower rate of episodes of febrile neutropenia (0% vs. 34%, P<0.01) and post-transplant Epstein-Barr virus reactivations (0% vs. 18%, P<0.05) was found in SCT recipients treated with an NMA conditioning regimen compared with an MA conditioning regimen. Furthermore, fewer invasive fungal infections (2% vs. 12%, not significant) were diagnosed in the NMA group. The incidence of cytomegalovirus (CMV) reactivations and bacterial infections was low in both groups (CMV reactivations: 13% in both groups; bacterial infections: 10% in the NMA group vs. 8% in the MA group), while CMV disease developed in only 1 patient. Overall, compared to our MA regimen, we found a very low rate of infectious complications after NMA SCT.

[Allogeneic stem cell transplantation following non-myeloablative conditioning: favorable results in 21 high risk patients with hematological malignancies treated in the Utrecht University Medical Center, the Netherlands]. / Allogene stamceltransplantatie na niet-myeloablatieve conditionering: gunstige ervaringen bij 21 hoogrisicopatiënten met een hematologische maligniteit behandeld in het Universitair Medisch Centrum Utrecht.

OBJECTIVE: To describe the results of allogeneic stem cell transplantation after non-myeloblative conditioning in high-risk patients with a haematological malignancy. DESIGN: Prospective and descriptive. METHOD: In the Utrecht University Medical Centre 21 patients in an advanced stage of various haematological malignancies were treated with allogeneic stem cell transplantation following non-myeloablative conditioning. The patients were either younger than 55 but unsuitable for standard allogeneic stem cell transplantation because of co-existing disease, or between the ages of 55 and 70, and they had to have either a HLA-identical donor relative or a donor in which there was only one mismatched antigen. They were treated with a combination of fludarabine and a low dose of total body irradiation, followed by the administration of an unmanipulated stem cell transplantated. RESULTS: Engraftment of the stem cells was rapid in all patients but one, and 9 patients already showed complete donor cell chimerism 4 weeks after the infusion of stem cells. A total of 12 patients ultimately became completely donor chimeric, one of whom had received donor leucocytes; 7 patients were still mixed chimeric, with > 80% donor cells. 13 patients developed acute 'graft-versus-host disease' (GVHD), but in 10 of these it was mild and transitory. After a median follow-up of 9 months, 5 patients (24%) had died, 4 as a result of disease progression and one from a cause related to the transplantation. CONCLUSION: Allogeneic stem cell transplantation following non-myelaoblative conditioning is a convenient mode of therapy with a low mortality related to the transplantation. It is particularly suitable for the treatment of older patients at high risk with regard to their disease.

High-dose chemotherapy and autologous hematopoietic stem cell transplantation in patients with rheumatoid arthritis: results of an open study to assess feasibility, safety, and efficacy.

OBJECTIVE: To assess the feasibility, safety, and efficacy of high-dose chemotherapy and autologous hematopoietic stem cell transplantation (HSCT) in patients with severe, refractory rheumatoid arthritis (RA). METHODS: Fourteen patients (3 male, 11 female, mean age 43 years, mean disease duration 10 years) with active, destructive, refractory RA entered the study. Autologous hematopoietic stem cells were collected by leukapheresis after mobilization with a single infusion of cyclophosphamide (CYC; 4 gm/m2) and subcutaneous injections of filgrastim (granulocyte colony-stimulating factor). Immunomagnetic selection of CD34+ cells from the leukapheresis products was performed to deplete potentially autoreactive lymphocytes. The conditioning regimen consisted of intravenous administration of high doses of CYC (cumulative dose 200 mg/kg), with subsequent reinfusion of the graft. Patients were monitored for disease activity, disability, adverse effects, and hematopoietic and immunologic reconstitution. RESULTS: All 14 patients completed the mobilization and leukapheresis procedures successfully, and 12 proceeded to receive conditioning and transplantation. Engraftment occurred in all of these patients, with rapid hematologic recovery. No major unexpected toxicity was observed. Marked improvement of disease activity was recorded in 8 of 12 patients at >50% of the visits, with a followup ranging from 7 months to 21 months. The clinical responders included 2 patients who had previously failed treatment with tumor necrosis factor (TNF) blocking agents. CONCLUSION: High-dose chemotherapy followed by autologous HSCT is feasible and safe, and can result in long-term improvement of disease activity in patients whose condition previously did not respond to conventional antirheumatic drugs or TNF blocking agents. The persistence of active disease in some patients may reflect the heterogeneity of the underlying disease process.

Reliability of water volumetry and the figure of eight method on subjects with ankle joint swelling.

STUDY DESIGN: Single-group repeated measures with 2 raters. OBJECTIVES: To determine the interrater and intrarater reliability of water volumetry and the figure of eight method on subjects with ankle joint swelling. BACKGROUND: Measurements of ankle swelling are commonly performed to determine the nature and stage of injury and to monitor progress made during rehabilitation. Water volumetry and the figure of eight method are 2 techniques used to measure ankle swelling. METHODS AND MEASURES: Twenty-nine subjects with ankle swelling were measured by 2 raters with the hypothesis that both measurement techniques would be reliable. Each rater performed 3 measurements of the swollen ankle using both measurement techniques during a single test session. The order of the rater and of the measurement technique was randomized, and the raters were blinded to each other's measurements. RESULTS: We found high interrater reliability for both the water volumetry (ICC [intraclass correlation coefficient] = 0.99) and figure of eight methods (ICC = 0.98). Additionally, intrarater reliability was high for both raters using both methods (ICCs = 0.98-0.99). CONCLUSIONS: Both methods are reliable measures of ankle swelling. The authors recommend the figure of eight method because of its ease of use, time efficiency, and cost effectiveness. However, water volumetry may be more appropriate when measuring diffuse lower-extremity swelling. Reliability of these 2 methods was established using subjects with foot or ankle pathology. Therefore, the results are applicable and generalizable to the clinical setting.

Donor leukocyte infusions inducing remissions repeatedly in a patient with recurrent multiple myeloma after allogeneic bone marrow transplantation.

We describe a patient with recurrent relapses after allogeneic BMT for multiple myeloma who repeatedly went into CR after donor leukocyte infusions (DLI). The first bone marrow relapse, 24 months after allogeneic BMT, was treated successfully with the infusion of 1.2 x 10(8) donor T cells. The second extramedullary relapse, 18 months later with a pleural mass and midthoracic spine process, responded again to DLI, however, only after three courses were given, each with escalating doses of T cells. The pleural mass was treated successfully with radiation therapy after the second DLI but reappeared 3 months later and responded again to the final DLI course with 5 x 10(8) T cells/kg. Nevertheless, graft-versus-host disease (GVHD) did not occur. Retrospective analysis of minimal residual disease in bone marrow aspirates during CR periods using a sensitive quantitative tumor-specific PCR showed that BM tumor cell infiltration persisted. The possible clinical implications of this case report, like maintenance DLI and the aim for molecular remissions, are discussed.

Oerskovia xanthineolytica: a new pathogen in bone marrow transplantation.

A 53-year-old woman with non-Hodgkin lymphoma underwent an autologous bone marrow transplant (BMT). Incomplete reconstitution necessitated the use of a long-term central venous catheter. One year after BMT she presented with fever. Echocardiography revealed vegetations on the tricuspid valve. Gram-positive rods grown from blood cultures and catheter tip were identified as Oerskovia xanthineolytica. We report the first case of native valve endocarditis caused by this organism.

A retrospective Dutch study comparing T cell-depleted allogeneic blood stem cell transplantation vs T cell-depleted allogeneic bone marrow transplantation.

Retrospectively, a cohort of 43 hematological patients receiving an allogeneic T cell-depleted (TCD)-PBSCT between 1994 and 1997, was compared to a cohort of 435 patients, who received an allogeneic TCD-BMT between 1990 and 1996. Both cohorts were comparable with respect to diagnosis, risk status, age and sex. PB grafts contained four to five times more hematopoietic progenitor cells and T cells as compared to BM grafts. T cell depletion was performed by either elutriation, CD34 selection, E-rosetting, or Campath serotherapy. Conditioning was cyclophosphamide/TBI in the majority of patients of both cohorts. All patients received cyclosporin A as GVHD prophylaxis until day 90 post-transplant. Engraftment was significantly faster in the PBPCT cohort with a median time to neutrophil recovery (>0.5 x 10(9)/l) of 16 vs 21 days in the BMT cohort (P = 0.0009). Platelet recovery to 50 x 10(9)/l was 16 vs 34 days for the PB and BM cohort respectively (P < 0.0001). A median percentage of 76% of BMT patients recovered to 50 within 100 days post-BMT vs 91% of patients receiving a PB graft. The incidence of acute GVHD grades II, III and IV was similar in both cohorts. In contrast, the probability of developing chronic GVHD was 21% in the BM cohort vs 37% in the PB cohort. Relapse incidence was reduced in the PB cohort (9 vs 29%), while treatment-related mortality was not different for both cohorts. These favorable results require confirmation by a prospective randomized trial, which is currently being performed by several European centers.

Immunoglobulin and T cell receptor gene rearrangement patterns in acute lymphoblastic leukemia are less mature in adults than in children: implications for selection of PCR targets for detection of minimal residual disease.

In order to gain insight into immunoglobulin (Ig) and T cell receptor (TCR) gene rearrangements in adult acute lymphoblastic leukemia (ALL), we studied 48 adult patients: 26 with precursor-B-ALL and 22 with T-ALL. Southern blotting (SB) with multiple DNA probes for the IGH, IGK, TCRB, TCRG, TCRD and TAL1 loci revealed rearrangement patterns largely comparable to pediatric ALL, but several differences were found for precursor-B-ALL patients. Firstly, adult patients showed a lower level of oligoclonality in the IGH gene locus (five out of 26 patients; 19%) despite a comparable incidence of IGH gene rearrangements (24 out of 26 patients; 92%). Secondly, all detected IGK gene deletions (n = 12) concerned rearrangements of the kappa deleting element (Kde) to Vkappa gene segments, which represent two-thirds of the Kde rearrangements in pediatric precursor-B-ALL and only half of the Kde rearrangements in mature B cell leukemias. Thirdly, a striking predominance of immature Ddelta2-Ddelta3 cross-lineage recombinations was observed (seven out of 16 TCRD rearrangements; 44%), whereas more mature Vdelta2-Ddelta3 gene rearrangements occurred less frequently (six out of 16 TCRD rearrangements; 38% vs >70% in pediatric precursor-B-ALL). Together these data suggest that the Ig/TCR genotype of precursor-B-ALL is more immature and more stable in adults than in children. We also evaluated whether heteroduplex analysis of polymerase chain reaction (PCR) products of rearranged Ig and TCR genes can be used for identification of molecular targets for minimal residual disease (MRD) detection. Using five of the major gene targets (IGH, IGK, TCRG, TCRD and TAL1 deletion), we compared the SB data and heteroduplex PCR results. High concordance between the two methods ranging from 96 to 100% was found for IGK, TCRG and TAL1 genes. The concordance was lower for IGH (70%) and TCRD genes (90%), which may be explained by incomplete or 'atypical' rearrangements or by translocations detectable only by SB. Finally, the heteroduplex PCR data indicate, that MRD monitoring is possible in almost 90% of adult precursor-B-ALL and >95% of adult T-ALL patients.

Donor leukocyte infusions for recurrent hematologic malignancies after allogeneic bone marrow transplantation: impact of infused and residual donor T cells.

We evaluated the efficacy and toxicity of different doses of donor T cells given with donor leukocyte infusions (DLI) as treatment for relapse of various hematologic malignancies after allogeneic bone marrow transplantation (BMT). We also studied whether DLI treatment was more effective if circulating T cells were exclusively of donor origin (complete donor T cell chimeras) as compared with T cells originating from both donor and recipient (mixed T cell chimeras). Twenty-eight patients were studied of whom 24 had a complete donor T cell chimerism. The malignancies were as follows: chronic myeloid leukemia (CML) in chronic phase (CP) (n = 9); more advanced CML (n = 5); multiple myeloma (MM) (n = 5); acute leukemia (AL) (n = 9). T cell doses varied from 0.1 x 10(7) to 33 x 10(7) T cells/kg. Eight patients received two to four DLI courses because they failed to respond to one course. Thirteen of 14 patients with CML, including four patients with more advanced CML, achieved complete remission (CR). All five patients with MM responded, including three CRs. Six patients (three with CML, three with MM) responded only after two to four DLI courses. Patients with CML-CP were likely to respond to as few as 1 x 10(7) T cells/kg whereas patients with MM generally responded when they received > or = 10 x 10(7) T cells/kg. However, despite the infusion of high T cell doses (up to 32 x 10(7) T cells/kg), practically all patients with AL failed to respond. The likelihood of response was strongly related to the occurrence of graft-versus-host disease (GVHD) in patients with CML and MM (P = 0.0002), although GVHD was not helpful for patients with AL. Higher T cell doses (> or = 10 x 10(7)/kg) induced serious GVHD (n = 17) and marrow aplasia (n = 5), and GVHD was directly or indirectly the cause of death for six patients. Finally, there were no obvious differences in responses between complete donor T cell chimeras and mixed T cell chimeras.

Allogeneic versus autologous bone marrow transplantation for refractory and recurrent low-grade non-Hodgkin's lymphoma.

Patients with recurrent or refractory low-grade non-Hodgkin's lymphoma (NHL) are increasingly treated with myeloablative therapy and autologous stem cell transplantation. However, allogeneic bone marrow transplantation (BMT) is only sporadically performed in such patients. Therefore, we wish to compare treatment results of patients with recurrent or refractory low-grade NHL who underwent allogeneic BMT with those who underwent autologous BMT in our center. Twenty-eight patients were studied. The patients had received 2 to 5 lines of conventional chemotherapy before the BMT procedure. Eighteen patients, all with chemotherapy-sensitive disease at the time of transplantation, underwent autologous BMT and 10 patients, of whom 7 with chemotherapy-resistant disease at the time of transplantation, underwent allogeneic BMT. Furthermore, all allogeneic BMT patients had overt lymphoma infiltration of the BM at the time of transplantation. The conditioning regimen consisted of cyclophosphamide plus total body irradiation in all 28 patients. All allogeneic BMT patients achieved complete remission, 3 patients had a treatment-related death, and 7 patients are alive and disease-free with a median follow-up of 41 months. In contrast, none of the autologous BMT patients died of transplant-related complications. However, despite the fact that all autologous BMT patients had chemotherapy-sensitive disease and partial remission was converted to complete remission by the BMT procedure in 67% of them, only 3 of 18 patients are alive and disease-free. The probability of relapse or disease-progression among allogeneic BMT patients was 0% compared with 83% for autologous BMT patients (P = .002). Progression-free survival rates 2 years after BMT were 68% for allogeneic BMT patients and 22% for autologous BMT patients (P = .049). Although the numbers of patients are small, this study suggests that allogeneic BMT offers a better chance for cure than autologous BMT for patients with poor-prognosis low-grade lymphoma, and the difference in relapse or disease progression is strongly suggestive for the existence of a graft-versus-low-grade lymphoma effect.