Assessment of imatinib as first-line treatment of chronic myeloid leukemia: 10-year survival results of the randomized CML study IV and impact of non-CML determinants

Chronic myeloid leukemia (CML)-study IV was designed to explore whether treatment with imatinib (IM) at 400 mg/day (n=400) could be optimized by doubling the dose (n=420), adding interferon (IFN) (n=430) or cytarabine (n=158) or using IM after IFN-failure (n=128). From July 2002 to March 2012, 1551 newly diagnosed patients in chronic phase were randomized into a 5-arm study. The study was powered to detect a survival difference of 5% at 5 years. After a median observation time of 9.5 years, 10-year overall survival was 82%, 10-year progression-free survival was 80% and 10-year relative survival was 92%. Survival between IM400 mg and any experimental arm was not different. In a multivariate analysis, risk group, major-route chromosomal aberrations, comorbidities, smoking and treatment center (academic vs other) influenced survival significantly, but not any form of treatment optimization. Patients reaching the molecular response milestones at 3, 6 and 12 months had a significant survival advantage. For responders, monotherapy with IM400 mg provides a close to normal life expectancy independent of the time to response. Survival is more determined by patients' and disease factors than by initial treatment selection. Although improvements are also needed for refractory disease, more life-time can currently be gained by carefully addressing non-CML determinants of survival.

Emergence of linezolid- and vancomycin-resistant Enterococcus faecium in a department for hematologic stem cell transplantation

Background

Prevalence of vancomycin-resistant enterococci has increased in Germany. Here, we report the cluster of linezolid- and vancomycin-resistant Enterococcus faecium (LVRE) in a German department for hematologic stem cell transplantation (HSCT).

Methods

In this retrospective analysis we included all patients with LVRE in a university-based department for HSCT in 2014 and 2015. Patients chart reviews were used to investigate the epidemiology and clinical outcome. Available LVRE isolates underwent detailed microbiological characterization and genotyping by pulsed-field gel electrophoresis (PFGE).

Results

In total, 20 patients with LVRE were identified within the observed time period. All except two patients underwent allogeneic HSCT. Surveillance culture results from incoming patients and chart review revealed that 10 of 20 patients were colonized at hospital admission. Eight of 10 patients with in-hospital acquired LVRE had previous linezolid treatment. Analysis of spatio-temporal patterns showed no evidence for LVRE patient-to-patient or environment-to-patient transmission within the HSCT department. In five cases (25 %) LVRE bloodstream infection occurred. Nine LVRE isolates could be saved for characterization. Eight isolates carried vanA, one isolate vanB. PFGE analysis showed that four different LVRE clones were responsible for the cluster. One single genotype was present in six LVRE isolates whereupon the corresponding patients were all referred from the same hospital to the HSCT department.

Conclusions

This is the first report demonstrating the emergence of LVRE in a German HSCT department. (L)VRE screening at patients’ admission and appropriate infection control strategies were sufficient to prevent any transmission. Further studies in this predisposed patient collective are warranted.

Increased susceptibility for aspergillosis and post-transplant immune deficiency in patients with gene variants of TLR4 after stem cell transplantation

INTRODUCTION

Toll-like receptors (TLRs) detect invading pathogens through several pattern-recognition mechanisms and play a central role in the regulation of the immune system. In allogeneic hematopoietic stem cell transplantation (HSCT), the frequent opportunistic fungal infections remain an important cause of mortality and morbidity in these highly immunocompromised patients.

METHODS

We analyzed 154 patients after allogeneic HSCT for acute leukemia for TLR4 gene variants 1063A/G (D299G) and 1363C/T (T399I) with their respective donors, and correlated the results with the incidence of invasive aspergillosis (IA) infection after transplant.

RESULTS

Probable and proven IA in recipients was significantly increased if either recipients or donors exhibited one of the two TLR4 gene variants. In addition, recipients with TLR gene variants and IA showed a delayed T cell and NKT cell immune reconstitution after transplant. Increased susceptibility for IA was not associated with an increased rate of death-in-remission or decreased estimate for overall survival.

CONCLUSION

These findings reinforce the importance of genetic variants in innate immunity and IA among the recipients of allogeneic HSCT.

Bone marrow or peripheral blood stem cell transplantation from unrelated donors in adult patients with acute myeloid leukaemia, an Acute Leukaemia Working Party analysis in 2262 patients

BACKGROUND

No survival benefit of using blood stem cells instead of bone marrow (BM) has been shown in matched unrelated donor (MUD) transplantation.

DESIGN AND METHODS

In a retrospective registry analysis, we compared the use of blood stem cells (n = 1502) and BM (n = 760) from unrelated donors in patients aged 18-60 years with acute myeloid leukaemia (AML) undergoing myeloablative conditioning between 1997 and 2008. The blood stem cell recipients were older (P < 0.01), had more advanced disease (P < 0.0001) and received less total body irradiation (P < 0.0001) and more antithymocyte globulin (P = 0.01).

RESULTS

Recovery of neutrophils and platelets was faster with blood stem cells (P < 0.0001). The incidence of acute graft-versus-host disease (GVHD) was similar, but there was more chronic GVHD in the blood stem cell group [hazard ratio (HR) = 1.29, P = 0.02]. There were no significant differences in nonrelapse mortality (NRM), relapse incidence and leukaemia-free survival (LFS) between the two groups amongst patients with AML in remission. In patients with advanced leukaemia, NRM was lower (HR = 0.61, P = 0.02) and LFS was prolonged (HR = 0.67, P = 0.002) when blood stem cells were used. At 3 years, LFS for all patients, regardless of remission status, was 41% for both treatment groups. The outcome was not affected after multivariable analysis adjusted for confounders.

CONCLUSION

Blood stem cells compared with BM in MUD transplantation for patients with AML in remission resulted in the same rates of LFS. In patients with advanced leukaemia, the blood stem cell group had reduced NRM and improved LFS.

Allogeneic hematopoietic SCT in patients with AML following treosulfan/fludarabine conditioning

An alternative reduced-toxicity conditioning regimen for allogeneic transplantation, based on treosulfan and fludarabine, has recently been identified. The safety and efficacy of this new conditioning regimen has been investigated prospectively in patients with AML. A total number of 75 patients with AML in CR were treated with 3 × 14 g/m(2) treosulfan and 5 × 30 mg/m(2) fludarabine, followed by matched sibling or unrelated SCT. Patients were evaluated for engraftment, adverse events, GVHD, and for non-relapse mortality, relapse incidence, overall and disease-free survival (DFS). All patients showed primary engraftment of neutrophils after a median of 20 days. Non-hematological adverse events grade III-IV in severity included mainly infections (59%) and gastrointestinal symptoms (7%). Acute GVHD grade II-IV occurred in 21% and extensive chronic GVHD occurred in 16% of the patients. After a median follow-up of 715 days, the 2-year overall and DFS estimates were 61% and 55%, respectively. The 2-year incidences of relapse and non-relapse mortality reached 34% and 11%, respectively. In summary, our data confirm promising safety and efficacy of the treosulfan-based conditioning therapy in AML patients, ClinicalTrials.gov Identifier: NCT01063660.

Improved outcome of hematopoietic SCT in patients with homozygous gene variant of Toll-like receptor 9

Toll-like receptor 9 (TLR9) is part of the innate immune system, which is activated by CpG oligonucleotides (ODNs) and produces potent Th1-type innate and adaptive immune responses. It is reported that TLR9 gene variants, T1486C and T1237C, are associated with a reduced TLR9 expression compared with the wild-type gene. In two cohort analyses, we evaluated the influence of these gene variants on the outcome of transplant in 413 patients and donors. A retrospective analysis of the first cohort (n=293) showed that the homozygous CC gene variant of TLR9 (1486) compared with TC/TT gene variants was significantly associated with a markedly improved 5-year TRM (11.7 versus 36.4%, P<0.003), 5-year OS (86.1 vs 48.3%, P<0.001) and a lower relapse rate (13.2 vs 33.3%, P<0.007), whereas the occurrence of acute GVHD was not different. A prospectively performed analysis of the second cohort (n=120) and multivariate analyses confirmed the influence of the CC gene variant on these end points. Compared with patients with TC/TT gene at position 1486 of TLR9, patients with the homozygous CC gene variant had a lower TLR9 mRNA expression and a delayed T-cell immune reconstitution after transplant, which might prevent them from overwhelming immune responses as sepsis or systemic inflammatory response syndrome (SIRS) associated with an increased TRM. In vitro studies using CpG-rich ODNs showed an upregulation of TLR9 expression in cell lines with CC gene variant, but not in cell lines with wild-type gene.

Cytochrome P450 2C19 loss-of-function polymorphism is associated with an increased treatment-related mortality in patients undergoing allogeneic transplantation

The polymorphic gene expression of CYP2C19 causes individual variability in drug metabolism and thereby in pharmacologic and toxicologic responses. We genotyped 286 patients and their donors for the CYP2C19 gene who underwent allogeneic transplantation for various diseases and analyzed their outcome. Patients were classified as: poor metabolizers (PMs; 3.1%), intermediate metabolizers (IMs; 24.5%) and extensive metabolizers (EMs; 72.5%). Patients genotyped as PMs had significant higher hepato- and nephrotoxicities compared to IMs or EMs. Maximum bilirubin and serum creatinine levels measured after transplant were approximately twofold higher than those of EMs or IMs. The increased toxicity resulted in an increased 4-year estimate for transplant-related mortality (TRM) with 50+/-18.6% for PMs compared to 25.1+/-3.7% for EMs (P<0.018) and 22.7 +/-5.6% for IMs (P<0.042), whereas no significant influence for relapse rate, overall survival or incidence of acute graft-versus-host disease grade 2-4 were found between the groups. Multivariate analysis including all potential factors that might influence TRM confirmed that the genotype of CYP2C19 is an independent factor, which influenced TRM significantly. These results suggest that genotyping for CYP450 2C19 can help to identify patients with higher risk for TRM.

Therapeutic application of small interfering RNA directed against bcr-abl transcripts to a patient with imatinib-resistant chronic myeloid leukaemia

RNA interference is referred to as the recently discovered process of sequence-specific, post-transcriptional gene silencing that is initiated by double-stranded RNA molecules known as small interfering RNAs (siRNA). We herein present a first report on the in vivo application of targeted non-virally delivered synthetic bcr-abl siRNA in a female patient with recurrent Philadelphia chromosome-positive chronic myeloid leukaemia (CML) resistant to imatinib (Y253F mutation) and chemotherapy after allogeneic haematopoietic stem cell transplantation. We found a remarkable inhibition of the overexpressed bcr-abl oncogene resulting in increased apoptosis of CML cells. In vivo siRNA application was well tolerated without any clinically adverse events. Our findings imply that the clinical application of synthetic siRNA is feasible, safe and has real potential for genetic-based therapies using synthetic non-viral carriers.

Dualism of mixed chimerism between hematopoiesis and stroma in chronic idiopathic myelofibrosis after allogeneic stem cell transplantation

Scant knowledge exists concerning lineage-restricted mixed chimerism (mCh) after allogeneic peripheral blood stem cell transplantation (PSCT) in patients with chronic idiopathic myelofibrosis (CIMF). Following a sex-mismatched PSCT, a combined immunopheno- and genotyping by fluorescence in-situ hybridization (FISH) was performed on sequential bone marrow (BM) biopsies at standardized intervals. Results were compared with PCR analysis of corresponding peripheral blood samples in five patients. According to FISH, pretransplant specimens revealed a gender congruence of more than 99%, while in the first three months the total BM exhibited a persistent fraction of host cells (30% to 40%) with a tendency to decline after about one year. It is noteworthy that the majority of endothelial cells maintained a recipient origin, whereas CD34+ progenitors and especially CD61+ megakaryocytes exhibited only very few host-derived cells. In keeping with the prevalence of donor cells in the hematopoietic compartment, PCR analysis of peripheral blood cells displayed a non-significant degree of mCh. In conclusion, according to FISH and PCR analysis, successful PSCT in CIMF results in an almost complete chimeric (donor-derived) state of the hematopoietic cell population. The non-transplantable stromal compartment includes the vascular endothelium with a predominance of recipient cells. The minimal mCh of this population implies probably a donor-derived origin (endothelial progenitor cells).

Reduced-toxicity conditioning with fludarabine and treosulfan prior to allogeneic stem cell transplantation in multiple myeloma

In recent years, reduced-intensity conditioning (RIC) regimens before allogeneic stem cell transplantation (SCT) are increasingly used in patients not eligible for conventional conditioning. We did a retrospective, multicenter analysis to assess the feasibility of conditioning with fludarabine and treosulfan before allogeneic SCT in multiple myeloma patients. Thirty-four patients with a median age of 51.5 years were included in the analysis. All patients underwent myeloablation after conditioning followed by stable engraftment, and 29 of 31 evaluable patients (94%) showed early complete hematopoietic chimerism. Non-hematological toxicities were limited and encompassed mainly fever in neutropenia and infections. Grade II-IV acute and chronic graft-versus-host disease was observed in 33 and 39%, respectively. With a median follow-up of 708 days (range 60-1729 days), the median progression-free survival was 180 days. The treatment-related mortality was 10% on day 100 and 25% after 1 year. The median overall survival has not yet been reached. Our data indicate that conditioning with fludarabine and treosulfan before allogeneic SCT is feasible in intensively pretreated multiple myeloma patients and leads to stable engraftment and complete hematopoietic chimerism. Randomized trials are warranted to determine if this approach might be incorporated in an algorithm of multiple myeloma treatment.

Cytogenetic response to prior treatment with interferon-α is predictive for survival after allogeneic hematopoietic stem cell transplantation in chronic myeloid leukemia

We investigated the impact of a cytogenetic response (CyR) to IFN prior to and at the time of allogeneic hematopoietic stem cell transplantation (HSCT) on transplant-related mortality (TRM), relapse rate and survival probability after HSCT in 162 transplanted patients with chronic myeloid leukemia. One-hundred-one patients (62.3%) achieved a CyR prior to HSCT. Survival probabilities were higher in patients, who achieved any CyR prior to HSCT than in patients without CyR (63.6 vs 49.2%: P = 0.019). Survival probabilities in patients, who achieved a major CyR were better than in patients with minimal and minor CyR or in patients with no CyR (69.4 vs 58.8% vs 49.2%: P = 0.040). TRM and survival of chronic phase patients without CyR at the time of HSCT were similar to that of patients transplanted in advanced phase. Both groups combined had an outcome inferior to patients with at least minimal CyR (TRM, Gray test: P = 0.016, survival, log-rank test: P = 0.002). Univariate and multivariate analyses identified CyR prior to or at HSCT as a strong and independently favorable prognostic factor. We therefore conclude that allogeneic HSCT in CyR should be investigated prospectively as an alternative treatment option in defined patient groups.

Successful treatment of patients with respiratory failure due to fungal infection after allogeneic hematopoietic stem cell transplantation

The mortality rate associated with respiratory failure due to invasive fungal infections after allogeneic hematopoietic stem cell transplantation (HSCT) is exceedingly high. We present a retrospective analysis of 4 HSCT recipients who survived long-term artificial respiration subsequent to pulmonary mycosis, and compare our current findings with historic data. Several clinical parameters indicate a remarkable improvement in the clinical courses of those patients in recent years: weaning time, extubation rate, and improvement of additional organ failures were all significantly better in patients treated after the emergence of new antimycotic agents, resulting in prolonged overall survival. We propose that our observations reflect an improved management of these patients, mainly because of the use of new antimycotics with alternative mechanisms of action and decreased toxicity, allowing for earlier, more aggressive, and more effective antifungal treatment approaches. In addition, the optimized use of new technologies designed to augment spontaneous breathing efforts by patients, mechanical ventilation, as well as the advantages of early tracheotomy will contribute to better outcomes in the treatment of respiratory failure due to pulmonary mycoses following allogeneic HSCT.

Myeloablative allogeneic hematopoietic stem cell transplantation in elderly patients

This study aimed to evaluate the outcome following myeloablative allogeneic hematopoietic stem cell transplantation (SCT) among patients older than 50 yr of age. A total of 215 patients with a median age of 57 yr underwent allogeneic hematopoietic SCT for early (41%) or advanced (59%) hematologic malignancies. After a median follow-up of 36 months a 10-yr survival estimate of 56 +/- 6% could be assessed for patients in early disease stages while patients with advanced diseases showed a significantly decreased survival probability of 31 +/- 5% (p < 0.0002). Transplant related mortality (TRM) at day 100 and 365 post-transplant was 13% and 30% for early but increased to 21% and 49% for advanced disease stages. As major determinants of TRM advanced disease stage (p < 0.0001) and occurrence of grades II-IV graft-vs.-host disease (GVHD) (p < 0.0001) were identified. These results show that hematopoietic SCT following myeloablative conditioning is also applicable to elderly patients whereas disease stage and high-grade GVHD represent the essential prognostic factors for outcome.

Dynamics of bone marrow changes in patients with chronic idiopathic myelofibrosis following allogeneic stem cell transplantation

Scant knowledge exists about the dynamics of fibro-osteosclerotic bone marrow (BM) lesions and regeneration of hematopoiesis following allogeneic peripheral stem cell transplantation (SCT) in chronic idiopathic myelofibrosis. Therefore, an immunohistochemical and morphometric study was performed on BM biopsies in 20 patients before and at standardized intervals (days 30 through 384) following SCT. In responding patients, a total regression of the pretransplant increased fibrosis was completed in the posttransplant period after about six months, while the extent of osteosclerosis did not change significantly during observation time. The quantity of CD61+ megakaryocytes including precursors was strikingly variable after SCT and, by using planimetric methods, atypical microforms exhibiting a dysplastic aspect could be demonstrated. These anomalies may be responsible for posttransplant thrombocytopenia. CD34+ progenitor cells were increased before transplantation, however, their number declined rapidly to normal values in responding patients. Nucleated erythroid precursors revealed a decreased amount before and after SCT accounting for anemia. Large clusters of this cell lineage indicated an initial hematopoietic reconstitution comparable with the expansion of the neutrophil granulopoiesis. Proliferative activity and apoptosis showed an increase until one year after SCT that implied a still regenerating hematopoiesis in keeping with an enhanced cell turnover.

Outcome of hematopoietic stem cell transplantation in patients with atypical chronic myeloid leukemia

Atypical chronic myeloid leukemia (aCML) occurs rarely and is associated with a poor prognosis when treated with conventional chemotherapy. We evaluated the outcome of aCML after allogeneic hematopoietic stem cell transplantation (HSCT). Nine patients were transplanted from HLA-identical siblings (n = 4), HLA-compatible unrelated donors (n = 4) or twin brother (n = 1). Median follow-up was 55 months after transplant (range, 9.1-118.1 months). One patient who was transplanted in advanced disease with bone marrow from his twin brother relapsed 19 months post transplant. This patient was successfully retransplanted from the original donor. All patients remained in complete remission. Analysis of the leukocyte chimerism of peripheral white blood cells and bone marrow buffy coat cells by VNTR-polymerase chain reaction (PCR) and single-nucleotide polymorphism real-time PCR revealed complete chimerism in all patients who had received an allogeneic transplant. One patient suffering from cerebral toxoplasmosis died 9 months post transplant. All other patients were alive at the time of analysis. Our findings suggest that the outcome of allogeneic or syngeneic transplantation in patients with aCML may not be worse than the outcome of transplantation for BCR-ABL-positive CML.

Outcome of allogeneic stem cell transplantation in patients with myelofibrosis

Myelofibrosis, either de novo or following pre-existing hematologic diseases, can be cured by allogeneic hematopoietic stem cell transplantation (SCT), but SCT is associated with significant morbidity and mortality, making the choice and timing of transplantation difficult. In all, 20 patients (seven female and 13 male), with a median age of 45 years (range 22-57 years), with idiopathic myelofibrosis (n = 12), post-thrombocythemic (n = 3) or post-polycythemic (n = 2) myeloid metaplasia or leukemic transformation (n = 3), underwent allogeneic SCT at our center between 1994 and 2003. With regard to the pre-transplant presence of risk factors such as hemoglobin levels < or =10 mg/dl, grade III marrow fibrosis or peripheral blast counts >1%, patients were divided into high- and low-risk groups. The estimated 3-year survival post transplant was 38.5% for all patients. The 3-year probability of survival within the high-risk group (n = 11) characterized by the presence of at least two risk factors was 16%. Low-risk patients (n = 9) with at most one risk factor had an estimated 3-year survival of 67%. Thus, previously defined risk determinants for the outcome of allogeneic transplantation for myelofibrosis may provide useful information facilitating treatment strategies. Our data suggest that transplantation should be taken into consideration before poor prognostic variables develop.

Caspofungin as second-line therapy for fever of unknown origin or invasive fungal infection following allogeneic stem cell transplantation

Caspofungin (CAS) is the first of a new class of antifungal agents, the echinocandins, that interfere with fungal cell wall synthesis by inhibition of glucan synthesis. Here, we report the results of 31 patients treated with CAS following allogeneic SCT. CAS was administered as a second-line agent to patients with invasive fungal infection (IFI) (n=15) or fever of unknown origin (n=16) who were recalcitrant to or intolerant of prior antifungal therapy. Unsuccessful first-line regimes included amphotericin B (n=17), liposomal amphotericin B (n=5), fluconazole (n=3), itraconazole (n=1), and voriconazole (n=2). All patients received concomitant immunosuppressive therapy for graft-versus-host disease. In 23 patients, cyclosporin A (CSA) and CAS were administered concurrently without any major side effects detected. Observed increases in GPT were not clinically significant. Normalization of serum creatinine and significant reductions in C-reactive protein were observed in response to CAS. Favorable outcome to CAS were documented in eight of 15 patients with IFI and in 15 of 16 patients with fever of unknown origin. CAS is a promising alternative in patients with IFI and fever of unknown origin in the setting of allogeneic SCT.

Dose-escalated treosulphan in combination with cyclophosphamide as a new preparative regimen for allogeneic haematopoietic stem cell transplantation in patients with an increased risk for regimen-related complications

Treosulphan has recently demonstrated antileukaemic activity and potent haematopoietic stem cell toxicity. Dose-escalated treosulphan (3 x 12 or 3 x 14 g/m2) combined with cyclophosphamide (Cy) was chosen for a new preparative regimen before allogeneic haematopoietic stem cell transplantation in 18 patients (median age 44, range 19-64 years) with haematological malignancies, considered ineligible for other myeloablative preparative regimens. Pharmacokinetic studies demonstrated rapid treosulphan plasma clearance and a dose-dependent increase of its maximum plasma concentrations and area under the concentration-time curves. Rapid and sustained white blood cell and platelet recovery and full donor chimerism was attained in all evaluable patients. Nonhaematological regimen-related CTC grades 3-4 adverse events were transient and predominantly consisted of cardiac (28%), gastrointestinal (39%), and hepatic (39%) toxicities. The 1-year nonrelapse mortality was 22%. Principal causes of transplant-related lethal events were infections in three of four affected patients. Only one patient died from regimen-related cardiac toxicity. The 1-year relapse estimate is 22%, overall and progression-free survival estimates are 67 and 56%, respectively. In conclusion, this new treosulphan and Cy combination is an effective, comparatively well-tolerated myeloablative preparative regimen even in patients with an increased risk for regimen-related toxic complications.

Impact of HLA-A,B,C Allele Mismatches on Outcome after Unrelated Blood Stem Cell Transplantation in Whites

At our institution the selection of unrelated donors for hematopoietic stem cell transplantation (HSCT) relies on low resolution human leukocyte antigen (HLA)-A,B and high resolution HLA-DRB1,DQB1 DNA-based typing. To answer the question of whether routine high resolution HLA-A,B,C typing might improve HSCT outcome, 171 white "HLA-identical" donor/recipient pairs, as stated by our pretransplant tissue typing routine, were retyped for HLA-A,B,C using sequence based typing (SBT). The numbers of HLA-A,B,C allele mismatches detected by SBT were correlated to established clinical endpoints of HSCT outcome. We found 33.9% of the study transplants to be fully HLA-A,B,C matched, whereas 66.1 % exhibited one through four donor/recipient HLA-A,B,C allele mismatches. However, statistical analysis could not demonstrate an impact of the number of HLA-A,B,C allele mismatches on overall survival and other analyzed endpoints. Thus, our series of white donor/recipient pairs does not suggest the routine use of HLA-A,B,C SBT to improve HSCT outcome substantially.

Regeneration of heart muscle tissue: quantification of chimeric cardiomyocytes and endothelial cells following transplantation

Persuasive evidence has been recently provided that adult bone marrow (BM) cells exert greater plasticity than previously assumed. This review is focused on the quantification of mixed chimerism (mCh) in the hearts (cardiomyocytes and endothelial cells) of patients after orthotopic heart to heart transplantation (HHT) in comparison to full (unmanipulated) allogeneic BM and peripheral blood stem cell (PBSC) transplants. Following a sex-mismatched transplantation constellation heart muscle tissue obtained at autopsy was examined. Evaluation of mCh was most often performed by immunophenotyping combined with fluorescence in-situ hybridization (FISH) applying x- and y-chromosome-specific DNA probes. When comparing our data with the results of former studies that were regularly based on the detection of the y-chromosome alone, the quantity of chimeric cardiomyocytes after HHT ranged from 0% to 9%. On the other hand, after full BM transplantats (chimeric) cardiomyocytes of donor-type origin appeared at an incidence between 0.23% to 6.4%. These disturbing inconsistencies were assumed to be related to methodology: the restriction to the y-chromosome, disregard of the plane of section (detection sensitivity ranging between 35% and 67%) and state of tissue preservation (cadaver hearts). Therefore, when strictly applying dual color FISH and limiting the recognition of chimeric cardiomyocytes and endothelial cells to the presence of two distinctive signals detection sensitivity was significantly enhanced. Contrasting a total congruence with the genotyping in control specimens of normal cadaver hearts, a striking disparity in the extent of mCh was found depending on the different modes of transplantation. After allografting with PBSC a considerably low incidence (1.6%) of chimeric cardiomyocytes was determined contrasting with 5.3% of donor-derived cells after full BM transplants. Following HHT host-type endothelial cells (16.2%) of the intramural and subepicardial vessel walls were more often encountered than following BM and PBSC allografting. These findings are in keeping with the assumption of a sprouting and migration of vascular structures into the donor heart from the site of surgical aligment and injury between retained host and donor atrial walls. When considering the other methods of transplantation (BM, PBSC) the data on chimeric endothelial cells support the hypothesis of a common hemangioblast. Concerning the cardiomyocytes it seems most reasonable to assume that primitive mesenchymal stem cells of the BM play a pivotal role in the development of mCh. This phenomenon is more extensively expressed than previously expected and may be related to an enforced repair of the damaged myocardium during the post-transplant period as the sequel of myeloablative (cardiotoxic) conditioning.

Disease- or therapy-related bone marrow damage cannot be overcome by changes in stem cell source or dose in allogeneic transplantation

OBJECTIVE

To test whether the functional impairment of the host bone marrow (BM) microenvironment pre-existing at the time of transplantation could be overcome by the increased content of immature cells in allogeneic peripheral blood stem cell transplantation (PBSCT) when compared with bone marrow transplantation (BMT).

METHODS

Cobble stone area forming cells (CAFC) were assayed in normal BM and BM after allogeneic BMT and PBSCT after stable engraftment. Groups were compared by two-tailed t-test.

RESULTS

While BM from 11 normal controls contained an average of 778.8 CAFC-d35 per 10(6) low density bone marrow cells (LDBMC, range 453-1231 per 10(6) LDBMC), BM from patients after BMT contained an average of 123.7 CAFC-d35 per 10(6) LDBMC (range 38-257) per 10(6) LDBMC. BM from patients transplanted with PBSC after myeloablative conditioning contained 128.3 (range 46-305) CAFC-d35 per 10(6) LDBMC (P = 0.89 compared with BMT). Similar results were obtained when patients after PBSCT with non-myeloablative conditioning were included (P = 0.62 compared with BMT). CAFC numbers in patients transplanted in early stages of myeloid leukaemia (acute myeloid leukaemia first remission, chronic myeloid leukaemia first chronic phase) were significantly higher than CAFC numbers in patients transplanted in more advanced stages (P = 0.008) or myelodysplastic syndrome (P = 0.023). The lowest CAFC numbers were found in two cases of retransplantation.

CONCLUSION

Our findings indicate that the functional state of the BM microenvironment rather than stem cell dose or source is limiting for the homing and engraftment of immature haemopoietic cells in clinical transplantation.

Allogeneic CD34-enriched peripheral blood stem cell transplantation in a patient with paroxysmal nocturnal haemoglobinuria

Paroxysmal nocturnal haemoglobinuria (PNH) is an acquired clonal disorder of haematopoietic stem cells associated with a somatic mutation in the phosphatidylinositol glycan complementation class A (PIG-A) gene. The only curative option is an allogeneic stem cell transplant (SCT), although treatment is hazardous. A 46-year-old male patient with PNH and obvious signs of severe, progressive haemolysis was transplanted in July 2002 with highly purified CD34 T-cell depleted peripheral blood stem cells from his HLA-identical brother. Prior to transplantation, the PNH was resistant to immunosuppressive therapy. The patient received 6.1 x 10(6)/kg bodyweight CD34-positive cells with a proportion of CD3-positive cells of 0.81 x 10(4)/kg bodyweight. After engraftment, 12 days post transplant (neutrophils>1.0/nl) the patient's physical condition steadily improved and parameters of haemolysis decreased. No glycophosphatidylinositol-deficient cells in peripheral blood could be detected by flow cytometry 40 and 100 days after transplant. We conclude that PNH may be cured by allogeneic CD34-enriched SCT from a sibling donor attempting to avoid acute GVHD and to reduce cumulative organ toxicity by using this transplantation modality.

Mixed chimerism of erythro- and megakaryopoiesis following allogeneic bone marrow transplantation

Until now, studies on mixed chimerism (MCh) after allogeneic bone marrow transplantation (BMT) have predominantly focused on the B- and T-lymphocyte population, but not on distinct myeloid cell lineages like nucleated erythroid precursors and megakaryocytes. To evaluate the lineage-restricted MCh more explicitly in 10 patients with chronic myelogenous leukemia (CML), a quantitative analysis was performed on bone marrow biopsies following a sex-mismatched host/donor constellation. Techniques included immunophenotyping (antiglycophorin C, CD61) for the identification of erythro- and megakaryopoiesis and a simultaneously conducted genotyping with x- and y-chromosome-specific DNA probes. Normal bone marrow and specimens taken before BMT served as controls. Contrasting a total gender-dependent sex-typing in the latter samples in the early and late posttransplant period (up to 586 days), 3-9% erythroid precursors and about 16% megakaryocytes revealed a host-type origin. This significantly higher number of host megakaryocytes is explained by their polyploidy generating an increased probability to detect positive signals at a certain section level of the corresponding biopsies. A striking conversion of MCh to a recipient cell type was found in leukemic relapse with a more than 90% host-derived erythroid and megakaryocytic cell population in 4 patients approximately 643 days after BMT.

Reduced intensity conditioning for allogeneic hematopoietic stem cell transplantation in patients with acute myeloid leukemia: disease status by marrow blasts is the strongest prognostic factor

We analyzed predictive factors for the outcome of 113 acute myeloid leukemia patients receiving reduced-intensity conditioning prior to allogeneic hematopoietic stem cell transplantation (HSCT). Patients were ineligible for conventional-intensity HSCT. Conditioning consisted of fludarabine and 50% of the conventional dose of busulfan (n=93) or total body irradiation (n=20). The source of stem cells was blood in 102 patients, marrow in 10, and both in one. In total, 50 (44.2%) donors were HLA-matched siblings, 50 (44.2%) unrelated fully matched and 13 (11.5%) partially mismatched family (n=1) or unrelated (n=12) donors. In all, 107 (94.6%) patients showed neutrophil and platelet engraftment after a median time of 13.5 and 13 days. The probabilities of event-free survival (EFS) (median follow-up: 12 months) were 49% for patients with less than 5% blasts in the marrow, 24% for patients with 5-20% blasts (P=0.002) and 14% with >20% blasts (P<or=0.001). Death occurred because of relapse in 29 patients (25.6%), infection in 12 patients (10.6%), acute graft-versus-host disease in eight patients (7.0%) and organ toxicity in nine patients (7.9%). In multivariate analysis, higher number of blasts in the marrow, alternative donors and low Karnofsky performance score were independent adverse prognostic factors for EFS.

Dynamics of lineage-restricted mixed chimerism following sex-mismatched allogeneic bone marrow transplantation

Scant knowledge is available about the dynamics of lineage-specific mixed chimerism (Ch) following bone marrow transplantation (BMT). This review is focused on findings derived from bone marrow (BM) biopsies in patients with chronic myeloid leukemia (CML) including a sex-mismatched host/donor constellation. Appropriate techniques involved immunophenotyping by monoclonal antibodies to identify the various cell lineages, dual color fluorescence in situ hybridization (FISH) with x- and y-chromosome-specific DNA-probes and a proper detection system for a simultaneous labeling of the bcr/abl locus. A significant degree of Ch with more than 20% host CD34+ progenitors was found in the early and late (up to 200 days after BMT) posttransplant period. However, only 10% of these cells harbored the bcr/abl translocation gene. This result fits well with corresponding molecular biological findings of so-called minimal residual disease. Conversion of Ch evolved during leukemic relapse with 90% host progenitors of which 50% revealed the bcr/abl locus. A Ch of nucleated erythroid percursors (5%) and CD68+ macrophages (8%) was expressed to a significantly lower degree. The slightly increased frequency found in CD61+ megakaryocytes (16%) was probably due to the polyploid state of these cells. Similar to the CD34+ progenitor cells abrupt changes from donor to host type was associated with an insidious transformation into recurrent leukemia. The CD34+ endothelial cells showed a minor degree of Ch, because donor-derived elements ranged from 18% to 25%. Leukemic relapse was characterized by an almost complete conversion of the endothelial cells to a host type. These findings point towards a CD34+ progenitor cell origin of the (leukemic) endothelial cell layer and suggests that their dysfunction may contribute to an expansion of the neoplastic clone.

Allogeneic stem cell transplants in chronic myeloid leukemia

Indisputable advances in the conventional therapy of chronic myeloid leukemia (CML), like the establishment of interferon-alfa as the standard treatment for first chronic phase patients and the introduction of imatinib-mesylate as a highly active compound in patients failing interferon-alfa treatment or with more advanced disease are challenging allogeneic stem cell transplantation (SCT) as the single treatment modality, which currently offers long-term remissions below the threshold of sensitive molecular methods for the detection of BCR-ABL transcripts. Since stable molecular remissions are thought to be a prerequisite for cure of CML, allogeneic SCT remains the only curative treatment option for younger patients (i.e. beyond the age of 55 years), who have an HLA-matched related or unrelated donor. Nowadays, suitable HLA-matched unrelated donors can be identified for 70% to 75% of caucasian patients lacking an HLA-identical sibling donor, which substantially has promoted the broader application of allogeneic SCT.

Indoleamine 2,3-dioxygenase expression in patients with acute graft-versus-host disease after allogeneic stem cell transplantation and in pregnant women: association with the induction of allogeneic immune tolerance?

Indoleamine 2,3-dioxygenase (IDO) is an interferon-gamma (IFN-gamma)-induced enzyme, which is suggested to play an important role in the prevention of allogeneic fetal rejection. IDO effects the suppression of T-cell activity by catabolizing the essential amino acid l-tryptophan. We studied IDO expression by reverse transcription polymerase chain reaction (RT-PCR) in dendritic cells and by real-time RT-PCR in monocytes of patients undergoing allogeneic transplantation for leukaemia, who developed acute graft-versus-host disease (aGvHD), and compared the IDO expression with that of pregnant women and healthy volunteers. A spontaneous IDO expression was detected in the monocytes of 20 pregnant women with an IDO/glyceraldehyde-3-phosphate dehydrogenase (GAPDH) ratio at a median of 1.0%, whereas none of 15 healthy volunteers or patients after allogeneic transplant had any detectable spontaneous IDO expression. The IDO expression increased by in vitro IFN-gamma stimulation in pregnant women (median 116%), healthy volunteers (median 11.7%) and patients with a low-grade aGvHD (grades 0-II) 28 days after transplant (median 433%) but not in patients with a severe aGvHD (grades III-IV) (median 0%), which was highly significant (P < 0.01). IDO expression was also measured in dendritic cells by qualitative RT-PCR, where a spontaneous IDO expression was detected in 16 of 31 (52%) pregnant women versus none of 17 healthy volunteers and none of 62 studied patients after transplant. IFN-gamma-induced IDO expression was detected in all pregnant women, all volunteers and 47 of 49 (96%) patients with a low-grade aGvHD (grades 0-II) after transplant, whereas only in two of 13 (16%) patients with aGvHD grade III-IV was IFN-gamma-induced IDO expression observed. These data suggest that IDO expression might be involved in the development of allogeneic immune tolerance.

Influence of intestinal decontamination using metronidazole on the detection of methanogenic Archaea in bone marrow transplant recipients

Methane-forming microbes of the phylogenetic domain Archaea are part of the strictly anaerobic microflora of the human intestine. In bone marrow transplant (BMT) recipients, the regimen of intestinal decontamination with metronidazole is targeted to anaerobic bacteria. The effect on the anaerobic methanoarchaea, however, is unknown. Therefore, the faeces of patients undergoing BMT were investigated for methane production. The anoxic Hungate technique and an archaeal growth medium were used to culture faecal specimens. Methane production was measured in the head space of the culture bottles by gas chromatography using a thermal conductivity detector. In a testing serial specimen of 100 patients, 13 patients were found to bear methanogens, and 11 of these patients received metronidazole. The methane-producing faecal specimens occurred before metronidazole use in three patients, during the first week in five patients, and after cessation in three patients. No specimen of the 11 patients that was obtained during the 2nd-5th week of gut decontamination showed methane production. It is concluded that use of metronidazole directed against faecal anaerobic bacteria also suppresses or eliminates faecal methanogenic Archaea.

Nonmyeloablative stem cell transplantation in adults with high-risk ALL may be effective in early but not in advanced disease

The feasibility of nonmyeloablative stem cell transplantation (NST) was evaluated in 22 adults with high-risk ALL. 16/22 patients had advanced disease and 11/22 had Ph+ ALL. Eleven patients received NST as first stem cell transplantation (SCT). Eleven patients had relapses after allogeneic or autologous SCT and underwent a salvage NST. 18/22 patients (82%) engrafted after NST. 13/16 patients (81%) with active disease reached complete remission (CR). 11 of 13 patients developed GVHD. After first NST 10/11 patients (91%) engrafted. Six of seven patients with active disease reached CR. Three of five relapsing patients reached subsequent CR after donor lymphocyte infusions, termination of immunosuppression or imatinib. Three of 11 patients (27%) are alive in CR 5 to 30 months after NST. Eight of 11 patients have died, 3/8 from leukemia and 5/8 from transplant-related causes. After salvage NST, 8/11 patients (73%) engrafted. Seven of nine patients with active disease reached CR. Only one of 11 patients transplanted, who was in CR before undergoing salvage NST is alive 19 months after NST. Five of 11 have died from leukemia, one of 11 after graft failure and four of 11 from transplant-related causes. Four of 22 patients (18%) are alive in CR 5, 14, 19 and 30 months after NST. NST is feasible in adults with high risk ALL. However, transplant-related mortality remains high and only patients transplanted in CR seem to have long-term disease-free survival.

Filgrastim mobilization and collection of allogeneic blood progenitor cells from adult family donors: first interim report of a prospective German multicenter study

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) mobilized peripheral blood progenitor cells (PBPCs) from healthy individuals are a rapidly emerging alternative source to bone marrow for allogeneic transplantation. Although widely applied in the meantime, only limited information on feasibility and safety of mobilization and collection of PBPCs is currently available from prospective multicenter studies specifically designed to investigate this donation modality. This ongoing multicenter study on the performance as well as the short- and long-term safety profile of rhG-CSF-induced mobilization and collection of PBPCs was initiated in October 1999. The study is designed to recruit a total of 300 healthy family donors who will be followed regularly for a period of 5 years after donation. The first interim report presented here summarizes results obtained after enrollment of 150 donors from nine German institutions. The study protocol allowed the individual choice between two dose regimens of rh-CSF (10 micro g/kg per day vs 2x8 micro g/kg per day of donor body weight). The primary endpoint was defined as a yield of > or =5x10(6) CD34(+) cells/kg of recipient body weight in a single leukapheresis product. This endpoint was attained by 50% of donors receiving the lower rhG-CSF dose regimen and by 75% of donors with the higher dose regimen ( p<0.0009). A total of 478 acute adverse events attributable to the mobilization procedure were recorded and manifested predominantly as transient bone pain and headaches (80%). No persistent hematologic or nonhematologic adverse events have occurred in this study so far. Thus, the current experience in a prospective multicenter study supports previous single-center and retrospective registry reports in that the collection of PBPCs after rhG-CSF mobilization is feasible and associated with frequent, but generally mild and acceptable side effects.

[Chimerism of cardiomyocytes and endothelial cells after allogeneic bone marrow transplantation in chronic myeloid leukemia. An autopsy study]

The results of a number of animal experimental studies are in keeping with the finding that hematopoietic progenitors can generate cardiomyocytes and endothelial cells. As a consequence innovative therapeutic strategies have been suggested to possibly ameliorate the outcome of coronary artery disease. However, there is no information available at present whether this pathomechanism is also effective in humans, in particular without prior ischemic lesion of the myocardium. Therefore an autopsy study was performed on cadaver hearts derived from five male patients with chronic myeloid leukemia who received full unmanipulated bone marrow grafts from female donors 21-631 days before death. The purpose of this investigation was to detect and quantify a putative chimerism of cardiomyocytes and endothelial cells (intramural and subepicardial vessels). Genotyping was carried out by applying X- or Y-chromosome-specific DNA probes (fluorescence in-situ hybridisation) on routinely formalin-fixed specimens of the myocardium. To test the sensitivity of our method, cadaver hearts from two males and two females without a history of transplantation served as controls. In contrast to a totally corresponding sex-matched genotyping in 780 cardiomyocytes and 155 endothelial cells of the control group, the five male patients with a previous transplantation revealed significantly different results. A mixed chimerism was identifiable in 57 out of 890 counted cardiomyocytes (6.4%) and in 19 out of 322 endothelial cells (5.8%). These findings support the assumption that in addition to endothelial cells there is also a cardiomyogenic potential of bone marrow stem cells which exists without prior (ischemic) damage to the heart. However, further investigations are necessary to identify, isolate and enrich the cardiomyocytic stem cells more specifically for future curative therapeutic options in patients with severe ischemic cardiomyopathy.

[Laparoscopic splenectomy by the "Essen-manoeuvre" for treatment of benign and malignant haematological diseases]

Despite its early description, laparoscopic splenectomy has not yet reached the level of a standard operation as a therapeutic option for haematological disease, especially for malignant disorders. We performed laparoscopic splenectomies in a modified 4 port technique and dissection of the splenic vessels by the "Essen-Manoeuvre" and report on 68 attempted laparoscopic splenectomies for benign (n = 42) and malignant (n = 26) haematological disorders. Conversion rate was 9 %, 30-days-mortality was 1.4 %, perioperative morbidity was 11 %, respectively. Accessory spleens were found and resected in 17 % of our patients. Laparoscopic splenectomy is a new minimally invasive option for patients with benign and malignant haematological disease fraught with a special risk of intraoperative bleeding.

Second German consensus on immunogenetic donor search for allotransplantation of hematopoietic stem cells

The present paper summarizes the results of the second German consensus meeting on immunogenetic donor search for allotransplantation of hematopoietic stem cells held in Essen in November 1999 under the auspices of the German Society for Immunogenetics (DGI) and the German Working Party for Blood and Marrow Transplantation (DAG-KBT). Immunogeneticists and transplant physicians from all over the country agreed to update the national standards for: (1) search strategy including the role of unrelated and extended family donor search after unsuccessful core family donor search, (2) histocompatibility loci to be typed, (3) histocompatibility typing techniques to be used (HLA serology vs DNA-based HLA typing, cellular tests, serum cross-match), and (4) acceptable HLA mismatches in the context of a defined underlying disease, donor type, and conditioning regimen.

No difference in graft-versus-host disease, relapse, and survival comparing peripheral stem cells to bone marrow using unrelated donors

The clinical results in 107 patients receiving a peripheral blood stem cell (PBSC) graft mobilized by granulocyte colony-stimulating factor (G-CSF) from HLA-A, -B, and -DR-compatible unrelated donors were compared to 107 matched controls receiving unrelated bone marrow (BM) transplants. Engraftment was achieved in 94% of the patients in both groups. The PBSC graft contained significantly more nucleated cells, CD34(+), CD3(+), and CD56(+) cells (P <.001), and resulted in a significantly shorter time-to-neutrophil (15 versus 19 days) and platelet engraftment (20 versus 27 days), compared to the BM control group (P <.001). Probabilities of acute graft-versus-host disease (GVHD) grades II to IV were 35% and 32% (not significant [NS]) and of chronic GVHD 61% and 76% (NS) in the PBSC and BM groups, respectively. There was no difference between the 2 groups in bacteremia, cytomegalovirus reactivation or disease, and fungal infection. The 3-year transplant-related mortality (TRM) rates were 42% in the PBSC group and 31% in the BM controls (P =.7) and the survival rates were 46% and 51%, respectively. The probability of relapse was 25% and 31% in both groups (NS), resulting in disease-free survival rates of 43% in the PBSC group and 46% in the BM controls (NS). In the multivariate analysis, early disease, acute GVHD grade 0 to I, and presence of chronic GVHD were independent factors associated with a better disease-free survival in this study. PBSC from HLA-compatible unrelated donors can be used safely as an alternative to BM for stem cell transplantation.

Estimating the relapse stage in chronic myeloid leukaemia patients after allogeneic stem cell transplantation by the amount of BCR-ABL fusion transcripts detected using a new real-time polymerase chain reaction method

We have used a new single-step real-time reverse transcription polymerase chain reaction (RT-PCR) method to quantify BCR-ABL transcripts, thereby estimating the relapse stage in chronic myeloid leukaemia patients after allogeneic transplants. In 402 samples from 172 patients, BCR-ABL expression was determined and normalized, using the GAPDH housekeeping gene product as an endogenous reference. In our real-time RT-PCR assay, serial dilutions of RNA of the K562 cell line remained positive down to 7.5 pg. The median normalized BCR-ABL amount differed significantly (P < 0.001) between the various disease stages and was 0.06% (range 0.001-1.55%), 3.2% (range 1.4-5.6%) and 21.5% (range 6.8 -827%) in 17 patients with a molecular relapse, in eight patients with a cytogenetic relapse and in 10 patients with a haematological relapse respectively.