Epigenetic regulation of PRAME in acute myeloid leukemia is different compared to CD34+ cells from healthy donors: effect of 5-AZA treatment

PRAME is a tumor associated antigen (TAA) of particular interest since it is widely expressed by lymphoid and myeloid malignancies. Several studies have associated high PRAME RNA levels with good prognosis in acute myeloid leukemia (AML). PRAME expression is regulated at the epigenetic level. For this reason inhibitors of DNA methylation, such as 5-azacytidine, can modulate the expression of this TAAs. In the current study we analyzed the effect of 5-azaC on the expression of PRAME in blasts versus CD34+ cells from healthy donors in an attempt to increase its expression, thus inducing a potential target for therapeutic strategies.

Donor age and degree of HLA matching have a major impact on the outcome of unrelated donor haematopoietic cell transplantation for chronic myeloid leukaemia

We analysed the outcome of 92 consecutive unrelated donor haematopoietic cell transplantations (UD-HCTs) performed in Spain to treat adult patients with CML in the first chronic phase (1CP). Patients' and donors' median age was 32 (15-49) and 36 (22-56) years, respectively. In all, 73 pairs (79%) matched for A, B+/-C and DRB1+/-DQB1 loci and 19 had > or =1 mismatch. Their probability of survival and disease-free survival at 4 years were 50 and 46%, respectively. Pretransplant factors associated with a better survival were patient age <25 years (P=0.035), donor age < or =36 years (P=0.012), use of cyclosporine since day -7 (P=0.001), and matching 8/8, 9/10 or 10/10 loci at allele level (P=0.003). In multivariate analysis only donor age (P=0.003; RR=3.1 (95% CI: 1.3-7.1)) and degree of HLA-matching (P=0.009; RR: 7.7 (95% CI: 1.8-33)) maintained their significance. The addition of these two variables to the EBMT prognostic score allowed an adequate risk assessment for patients receiving a UD-HCT during 1CP. Our analysis shows that in patients with a young and fully allele-matched donor, UD-HCT should be considered in the initial therapeutic algorithm due to its excellent outcome (92% survival at 2 years).

Relapse of chronic myeloid leukemia after allogeneic stem cell transplantation: outcome and prognostic factors: the Chronic Myeloid Leukemia Subcommittee of the GETH (Grupo Español de Trasplante Hemopoyético)

In order to analyze the outcome of patients with chronic myeloid leukemia (CML) who relapse after allogeneic stem cell transplantation (SCT), we investigated data from 107 patients reported to the Spanish Registry, GETH. In all, 93 (87%) patients were treated after relapse; 36 out of 49 that failed to achieve a response received a second relapse-treatment, and seven a third one. At the last follow-up, the number of patients in molecular or cytogenetic remission was 29 and 13, respectively. Overall survival and progression-free survival after relapse were 53.6% (95% CI: 42.9--64.2) and 52% (95% CI: 41-63) at 5 years, respectively. In multivariate analysis, survival was significantly related to CML phase at relapse (cytogenetic or chronic phase vs advanced phases) and time from transplant to relapse (<1 vs >or=1 year). Patients with no adverse factors had a better survival compared with patients with one or two adverse features (65 vs 35 vs 0%, respectively). We conclude that a significant proportion of CML patients that relapse after transplantation can regain complete and long-lasting remissions with one or more salvage therapies. Disease stage at relapse and time from transplant to relapse should be taken into account when comparing results of different salvage treatments.

Antibiotic prophylaxis with meropenem after allogeneic stem cell transplantation

In the present study, we analyze the efficacy of prophylaxis with meropenem in patients receiving a matched related donor allogeneic transplant. In total, 38 patients were sequentially treated with meropenem starting on the day of the first febrile episode (n=17, group A) vs prophylactic meropenem starting on the first day with <500/mm(3) granulocytes (n=21, group B), and maintained until resolution of fever or after granulocyte count >500/mm(3). Of these, 16 (94%) patients in group A developed fever as compared to 16 (76%) in group B (P=0.02). While only one patient in group A did not require first-line antibiotherapy, there were seven (33%) in group B who did not require it (P=0.01) since fever lasted less than 72 h. In addition, 52% patients in group B did not require second-line antibiotics as compared to 11% among patients in group A (P=0.04). In multivariate analysis prophylaxis with meropenem (HR=2.83, 95% CI (1-8.02); P=0.04) and disease status at transplant (HR for early stage=0.15, 95% CI (0.04-0.62); P=0.04) significantly influenced the development of fever. In conclusion, the current pilot study suggests that the use of prophylaxis with meropenem during the period of neutropenia in patients undergoing allogeneic transplantation favorably affects the morbidity of the procedure by reducing febrile episodes.

Chimerism and minimal residual disease monitoring after reduced intensity conditioning (RIC) allogeneic transplantation

Since graft-versus-leukemia (GVL) is the main weapon for disease eradication after reduced intensity conditioning (RIC) allogeneic SCT, the availability of sensitive and specific techniques to monitor changes in tumor load after transplant are especially helpful. These minimal residual disease techniques would allow an early intervention in the event of low tumor burden, for which immunotherapy is highly effective. Some authors have found an association between persistence of MRD, mixed chimerism and risk of relapse. Nevertheless, data from the literature remain contradictory and further correlations should be established, especially in RIC transplants. In this study we have analyzed the impact of MRD and chimerism monitoring on the outcome of 34 patients undergoing RIC allogeneic SCT who were considered poor candidates for conventional transplantation due to advanced age or other concurrent medical conditions. At day +100 25 (75%) patients reached complete remission (CR), there were five (15%) partial responses and three patients progressed. Incidence of grade 2-4 aGVHD and extensive cGVHD were 35% and 58%, respectively. Sixteen percent of patients developing aGVHD relapsed as compared to 47% in those without aGVHD (P = 0.03) and also 10% of patients developing cGVHD relapsed as compared to 50% relapses in those without cGHVD (P = 0.03). Four patients (12%) died due to early (n = 1) and late (n = 3) transplant-related mortality. After a median follow-up of 15 months, 24 out of the 34 patients remain alive. Projected overall survival and disease-free survival at 3 years are 68% and 63%, respectively. Early chimerism analysis showed 67% of patients with complete chimerism (CC) in bone marrow (BM), 86% in peripheral blood (PB), 89% in granulocytes and 68% in T lymphocytes. On day +100, these figures were 68%, 79%, 90% and 73%, respectively, and on day +180 there were 83% patients with CC in BM, 100% in PB, 100% in granulocytes and 100% in T lymphocytes. We observed a trend to a higher incidence of relapse in patients with mixed chimerism (MC) as compared to patients with CC. MRD monitoring by flow cytometry and/or RT-PCR analysis was performed in 23 patients. MRD assessment on days +21 to +56 after transplant allowed identification of patients at risk of relapse. In this sense, seven out of 12 patients (58.3%) who had positive MRD on days +21 to +56 relapsed as compared to none out of 11 patients who had negative MRD (P = 0.002). Of the seven patients with criteria to monitor MRD who relapsed after transplant, all but one remained MRD positive until relapse. By contrast, 10 patients remained MRD negative and all of them are in continuous CR. In nine additional patients, persistence of MRD or mixed chimerism was observed after transplant and withdrawal of cyclosporin with or without DLI was performed. Only two out of these nine patients relapsed. MRD clearance was preceded by CC and GVHD. In conclusion, in our study we found that RIC allogeneic transplantation can be used in patients considered poor candidates for conventional transplantation due to advanced age or other concurrent medical conditions with both low toxicity and low transplant-related mortality. Simultaneous studies of both chimerism and MRD are a useful tool in order to predict risk of relapse in patients undergoing RIC transplants and so can be helpful for individualizing treatment strategies after transplant.

Early immunophenotypical evaluation of minimal residual disease in acute myeloid leukemia identifies different patient risk groups and may contribute to postinduction treatment stratification

Early response to therapy is one of the most important prognostic factors in acute leukemia. It is hypothesized that early immunophenotypical evaluation may help identify patients at high risk for relapse from those who may remain in complete remission (CR). Using multiparametric flow cytometry, the level of minimal residual disease (MRD) was evaluated in the first bone marrow (BM) in morphologic CR obtained after induction treatment from 126 patients with acute myeloid leukemia (AML) who displayed aberrant phenotypes at diagnosis. Based on MRD level, 4 different risk categories were identified: 8 patients were at very low risk (fewer than 10(-4) cells), and none have relapsed thus far; 37 were at low risk (10(-4) to 10(-3) cells); and 64 were at intermediate risk (fewer than 10(-3) to 10(-2) cells), with 3-year cumulative relapse rates of 14% and 50%, respectively. The remaining 17 patients were in the high-risk group (more than 10(-2) residual aberrant cells) and had a 3-year relapse rate of 84% (P =.0001). MRD level not only influences relapse-free survival but also overall survival (P =.003). The adverse prognostic impact was also observed when M3 and non-M3 patients with AML were separately analyzed, and was associated with adverse cytogenetic subtypes, 2 or more cycles to achieve CR, and high white blood cell counts. Multivariate analysis showed that MRD level was the most powerful independent prognostic factor, followed by cytogenetics and number of cycles to achieve CR. In conclusion, immunophenotypical investigation of MRD in the first BM in mCR obtained after AML induction therapy provides important information for risk assessment in patients with AML.

Cidofovir treatment of human polyomavirus-associated acute haemorrhagic cystitis

We report the case of an 18-year-old patient who received an allogeneic bone marrow transplant from an HLA-identical unrelated donor for a Ph+ acute lymphoblastic leukemia, in his third complete remission. Cyclophosphamide and busulfan were used as conditioning treatment. Acute graft-versus-host disease developed on day +9, and the response to adequate treatment (steroids) was favourable. On day +45 the patient developed an acute severe haemorhragic cystitis, and BK polyomavirus was demonstrated in urine samples using electron microscopy and polymerase chain reaction. Urinary symptoms did not improve in spite of palliative treatment, but a response was evident after 2 weeks of cidofovir treatment.

Cerebral toxoplasmosis and Guillain-Barré syndrome after allogeneic peripheral stem cell transplantation

We report an unusual case of cerebral toxoplasmosis associated with Guillain-Barré syndrome (GBS) in a 25-year-old patient diagnosed with chronic myelogenous leukaemia (CML), who underwent a mismatched allogeneic peripheral stem cell transplantation (PSCT). On day +83 he started with fever, and 7 days later tremor, muscular weakness, diplopia, dysarthria, respiratory difficulty, and universal arreflexia appeared, compatible with GBS. As the patient had a positive cytomegalovirus (CMV) antigenemia, this was the aetiology suspected for his neurologic findings, but specific treatment failed to improve his clinical situation, and he died on day +123. Necropsy demonstrated cerebral toxoplasmosis and axonal degeneration of nerve roots compatible with the axonal form of GBS. Interestingly, the polymerase chain reaction (PCR) signal for Toxoplasma gondii in two different cerebrospinal fluid (CSF) samples had been negative. In addition, this case showed unique magnetic resonance imaging (MRI) abnormalities. We conclude that a negative PCR on CSF cannot exclude toxoplasmosis in a transplant patient, and we emphasise the importance of considering Toxoplasma as an aetiology of fever and neurological symptoms in the transplant setting.

Allogeneic peripheral stem cell transplantation in a case of hereditary sideroblastic anaemia

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

Administration of recombinant human granulocyte colony-stimulating factor to normal donors: results of the Spanish National Donor Registry. Spanish Group of Allo-PBT

A Spanish National PBPC Donor Registry has recently been established for short- and long-term safety data collection in normal donors receiving rhG-CSF. To date, 466 donors have been included in the Registry. Median (range) dose and duration of rhG-CSF administration was 10 microg/kg/day (4-20) and 5 days (4-8), respectively. Donors underwent a median of two aphereses (range, 1-5). Adverse effects consisted mainly of bone pain (90.2%), headache (16.9%) and fever (6. 1%), but no donor discontinued rhG-CSF prematurely due to toxicity. Side-effects were more frequent in donors receiving >10 microg/kg/day than in those with lower doses (82.8% vs 61.8%; P = 0. 004). A significant decrease between baseline and post-apheresis platelet counts was the most important analytical finding (229 x 10(9)/l vs 140 x 10(9)/l; P < 0.0001), with a progressive reduction in platelet count with each apheresis procedure. One donor developed pneumothorax that required hospitalization due to central venous line placement. The mean CD34+ cell dose collected was 6.9 x 10(6)/kg (range, 1.3-36), with only 14 donors (2.9%) not achieving a minimum target of CD34+ cells of 2 x 10(6)/kg. No definitive information about potential long-term side effects is yet available. However, we hope this National Registry will serve as a useful basis for better monitoring of the efficiency and side-effects of cytokine administration in healthy people.

[Effect of chemotherapy on hematopoietic stem cells in peripheral blood]

PURPOSE

To analyze the effect of conventional chemotherapy on haematopoietic progenitor cells (HPC) from peripheral blood (PB).

PATIENTS AND METHODS

The present work studies the behaviour of CFU-GM from PB in 47 patients subjected to conventional chemotherapy with the following diagnoses: non-Hodgkin's lymphoma (NHL): 16; Hodgkin's disease (HD): 8; multiple myeloma (MM): 5; acute leukaemia (AL): 8; solid tumor (ST): 10. A total of 57 studies was performed. As controls, 51 samples of PB from healthy subjects were used. Cultures were made in semisolid medium (methylcellulose), using PHA-LCM as stimulant, evaluating the growth of clusters (cl) and colonies (col) on days 7 and 14.

RESULTS

Our findings show that in the overall series of patients the number of clusters from days 7 and 14 and of colonies-7--that is the most differentiated progenitor cells--were decreased with respect to the controls while colonies-14 were slightly increased. When the patients were separated by diagnostic groups, the col-14 were found to be increased in ST (p = 0.03) and in AL; in NHL col-14 were the same as in the controls. In the patients with HD all progenitor cells, including col-14 were much lower than the control values (p = 0.005). In order to determine whether the kind or the amount of chemotherapy received might affect these progenitor cells, we have analyzed the cases of NHL, 11 patients treated with moderate chemotherapy versus 12 patients receiving intensive chemotherapy: a stronger degree of growth in the latter, although with no significant differences. On comparing the cases that had received little previous chemotherapy (< 5 courses) against those who had received more than 5 courses growth was seen to be stronger in the patients who had received the fewest courses (p = 0.04).

CONCLUSIONS

These results indicate that the HPC from PB are scanty in certain diseases, such as HD and that in all lymphomas the collection of these cells for transplantation purposes should be performed before they have damaged by an excessive number of chemotherapy courses.

Phenotypic analysis of CD34 subpopulations in normal human bone marrow and its application for the detection of minimal residual disease

In the past, studies on CD34+ cells have been based on the use of monoclonal antibodies conjugated with different fluorochromes that show different fluorescence intensity and yield variable results. Moreover, most of these studies have neither specifically focused on adult human BM samples nor have they used combinations to explore specifically the phenotype of myeloid committed CD34+ cells. The aim of the present study has been to characterize the normal human CD34+ precursor cells from adult BM in order to identify missing or extremely rare phenotypes that can be used for detecting minimal residual disease (MRD) in patients with AML. For this purpose we have utilized the fluorochrome conjugates that provide the most sensitive signals for identifying low antigenic expression, and the technique has been adapted to the characterization of cells present at very low frequencies. Normal human BM samples from 13 adult healthy volunteers have been analyzed using triple stainings at flow cytometry. The mean percentage of CD34+ cells detected was 0.72 +/- 0.33%; these cells displayed an heterogeneous light-scatter distribution. Most CD34+ cells coexpressed CD38 (96.7 +/- 5.7%), HLADR (81.6 +/- 14.0%), CD33 (84.7 +/- 18.3%), CD13 (84.6 +/- 16.2%) and CD71 antigens (65.5 +/- 9.1%). In addition, almost half of CD34+ cells were CD117+ (60 +/- 26.8%). Only a small proportion of CD34+ cells coexpressed CD4 (15.5 +/- 11.7%, CD36 (31.7 +/- 6.2%), CD61 (16.3 +/- 12.9%), CD41 (6.5 +/- 5.5%) or the lymphoid associated markers CD10 (18.6 +/- 11.8%) and CD19 (12.3 +/- 13.2%). Reactivity for the CD15 antigen was observed in a small population of CD34+HLADR+ cells (11.6 +/- 11.2%) although its intensity of expression was lower than that of the more mature granulocytic cells. No CD34+ cells displayed CD14, CD65, CD20, strong CD22, CD3 and CD56 antigens. Accordingly, most adult bone marrow CD34+ cells appeared to be committed to the myeloid lineage (CD13+/CD33+) and displayed an intermediate-to-large FSC/SSC while the lymphoid-committed CD34+ cells (CD19+, CD10+) were in a minority with low FSC/SSC values. By triple marker stainings several phenotypes of CD34+ precursor cells were found to be either undetectable or present at very low frequencies (< 1 x 10(-3)) in the normal human adult bone marrow. These data may be of great value for defining leukemia 'associated' phenotypes used to detect minimal residual disease in adult acute leukemia patients.

[Study of leukemic colony-forming units (CFU-L) in non-lymphoblastic malignant hemopathies]

CFU-L is considered as the clonogenic cell of acute non-lymphoblastic leukaemias (ANLL). Twenty-five malignant myelogenous hemopathies (5 blast crisis and 20 "de novo" ANLL) were studied in order to assess the proliferative capability of these cells and its relationship to FAB types and the achievement or not of complete remission (CR). The proliferative capability was assessed by culture on methylcellulose using conditioned leucocyte medium stimulated with phytohaemagglutinin as stimulating agent. Cell proliferation was observed in 21 cases, reaching 100% of the blast crisis and 80% (i.e., 16 cases) of the "de novo" ANLL. As regards the FAB types, it was found that the leukaemias with monocytic cells showed higher cell-growth than those of granulocytic lineage (90%, vs 60%). Of the patients not achieving CR (12 cases) colonies were formed in 66.6% (8 cases), while of the 8 patients who attained CR only in 3 (37.5%) were colonies observed. It was concluded that the FAB types of ANLL show different proliferative capability, which might influence the prognosis of the disease.