Pierluigi Rossi Ferrini

Prospective identification of high-risk polycythemia vera patients based on JAK2(V617F) allele burden.

The aim of this study was to determine whether the burden of JAK2V617F allele correlated with major clinical outcomes in patients with polycythemia vera (PV). To this end, we determined JAK2 mutant allele levels in granulocytes of 173 PV patients at diagnosis. The mean (±s.d.) mutant allele burden was 52% (±29); 32 patients (18%) had greater than 75% mutant allele. The burden of JAK2V617F allele correlated with measurements of stimulated erythropoiesis (higher hematocrit, lower mean cell volume, serum ferritin and erythropoietin levels) and myelopoiesis (higher white cell count, neutrophil count and serum lactate dehydrogenase) and with markers of neutrophil activation (elevated leukocyte alkaline phosphatase and PRV-1 expression). As compared to those with less than 25% mutant allele, patients harboring greater than 75% JAK2V617F allele were at higher relative risk (RR) of presenting larger spleen (RR 4.7; P<0.001) or suffering from pruritus (RR 3.1; P<0.001). In these patients, the risk of requiring chemotherapy (RR 1.8; P=0.001) or developing major cardiovascular events (RR 7.1; P=0.003) during follow up were significantly increased. We conclude that a burden of JAK2V617F allele greater than 75% at diagnosis points to PV patients with high-risk disease.

A randomized double-blind placebo-controlled study with subcutaneous recombinant human erythropoietin in patients with low-risk myelodysplastic syndromes

To evaluate the effect of recombinant human erythropoietin (rHuEpo) on the haemoglobin level and transfusion requirement in low‐risk myelodysplastic syndromes (MDS), 87 patients were enrolled in a randomized double‐blind placebo‐controlled study. 44 patients were assigned to epoetin α (150 U/kg/d s.c. for 8 weeks) and 43 to placebo arms. MDS types were homogenous in both groups: refractory anaemia (RA) 47.7–48.8%, refractory anaemia with ringed sideroblasts (RAS) 20.5–25.6%, refractory anaemia with excess of blasts (RAEB) (blasts < 10%) 31.8–25.6%.

The influence of HLA-matched sibling donor availability on treatment outcome for patients with AML: an analysis of the AML 8A study of the EORTC Leukaemia Cooperative Group and GIMEMA

To determine whether patients with a HLA‐identical sibling donor have a better outcome than patients without a donor, an analysis on the basis of intention‐to‐treat principles was performed within the framework of the EORTC‐GIMEMA randomized phase III AML 8A trial. Patients in complete remission (CR) received one intensive consolidation course. Patients with a histocompatible sibling donor were then allocated allogeneic bone marrow transplantation (alloBMT), the patients without a donor were randomized between autologous BMT (ABMT) and a second intensive consolidation (IC2). 831 patients <46 years old and alive >8 weeks from diagnosis were included. HLA typing was performed in 672 patients. AlloBMT was performed during CR1 in 180 (61%) out of 295 patients with a donor. Another 38 patients were allografted: five in resistant disease, 14 during relapse and 19 in CR2. ABMT was performed in 130 (34%) out of 377 patients without a donor in CR1, in six (2%) patients during relapse and in 38 (10%) patients during CR2. The disease‐free survival (DFS) from CR for patients with a donor was significantly longer than for patients without a donor (46% v 33% at 6 years; P = 0.01, RR 0.78, 95% confidence interval 0.63–0.96). The overall survival from diagnosis for patients with a donor was longer, but not statistically significant, than for patients without a donor (48% v 40% at 6 years; logrank P = 0.24). When patients were stratified according to prognostic risk groups, the same trend in favour of patients with a donor was seen for survival duration and the DFS remained significantly longer for this group of patients.

Natural fluorescence of white blood cells: spectroscopic and imaging study

Autofluorescence has been proved to be an intrinsic parameter of biological substrates that may aid in both the characterization of the physiological state and the discrimination of pathological from normal conditions of cells, tissues and organs. In this work, the fluorescence properties of human white blood cells have been studied in suspension and on single cells at microscopy. The results indicate that suspensions of agranulocytes and granulocytes differ in the amplitude of the fluorescence signal on excitation at wavelengths in the range 250-370 nm. The differences are particularly enhanced when excitation is performed in the 250-265 nm range. Microspectrofluorometric analysis, performed on single cells, allows several leukocyte families to be characterized. Lymphocytes, monocytes, neutrophils and eosinophils can be distinguished according to the intensity and spectral shape of the autofluorescence emission in the visible range from 440 to 580 nm. Both the nature and extent of the differences change when the excitation wavelength is moved from 366 to 436 nm. Differences in the intrinsic metabolic engagement, rather than in the cell dimensions, seem to be responsible for the differences observed between the leukocyte populations. The results identify interesting perspectives for autofluorescence as a discriminating parameter in the differential counting of human white blood cells.

DIFFERENTIATION THERAPY OF MYELODYSPLASTIC SYNDROMES: FACT OR FICTION?

Few therapies for haematological diseases are as unsatisfactory and frustrating as those for the myelodysplastic syndromes (MDS), whose elusive clinical behaviour and biological characteristics hamper many attempts at cure. Current knowledge of maturation induction in the myelodysplastic syndromes has derived from data developed in vitro using acute myeloid leukaemia models. The most recent opinion considers acute myeloid leukaemia and the myelodysplastic syndromes, especially high-risk ones, as identical and unique diseases, whose clinical treatment has therefore to be the same (Mufti, 1992; De Witte et al, 1995). Although this concept was probably based on final outcome of the disease, the biology and pathogenesis of myelodysplasia differs from that of acute leukaemia, especially in its susceptibility to therapies which do not aim at aggressively attacking the dysplastic clone. The transformed clone is not usually endowed with high proliferative potential, and shows a block in maturation, without giving rise to a threatening neoplastic burden. These observations and perplexities are shared by a large number of investigators, indicated by the regular publication of new studies both in vivo and in vitro, exploring the possibility of treating myelodysplastic syndromes with differentiating agents, in an attempt to overcome the maturation blockade and improve the pancytopenia, instead of eradicating the transformed clone (Sachs, 1987). In this sense, the success of differentiation therapy in MDS is easily judged by increased numbers of platelets, erythrocytes and leucocytes, leading the patient to independence from supportive care. These end-points simplify the clinical evaluation of the therapies, but do not take into account the rate of maturation (if any) induced in bone marrow and peripheral blood blasts of treated patients. Only a few clinical studies have used cytogenetic analysis to assess differentiation of the myelodysplastic clone (Schmetzer et al, 1997). The hypothesis of therapeutic induction of maturation, founded on in vitro data, should be supported by in vivo proof, i.e. by the identification of terminally mature cells with an abnormal karyotype. This concept is important, because what may be considered as a successful maturative effect is, in fact, the recovery of normal haemopoiesis after ablation of the dysplastic clone. The molecules inducing in vivo maturation in MDS can be divided into the following categories: interferons (IFN-alpha and IFN-gamma); polar planar compounds such as HMBA; homoarringtonine; 5-azacytidine; low-dose ara-C; butyrates; amifostine; haem-arginine; vitamins, including retinoids, vitamin D3 and vitamin E; and haemopoietic growth factors such as Epo, G-CSF, GM-CSF and IL-6. Recently combinations of growth factors and differentiation molecules have been introduced.

Multispectral imaging autofluorescence microscopy for the analysis of lymph-node tissues.

Abstract Although histochemical and immunohistochemical methods are the standard procedures in diagnosis of lymphoproliferative disorders, useful improvements in evidencing histopathologic manifestations can be obtained with the introduction of tissue autofluorescence analyses. We used microspectrofluorometry and a Multispectral Imaging Autofluorescence Microscopy (MIAM) technique to analyze lymph-node biopsies from patients with lymphoadenopathy of different origins. Images of tissue autofluorescence were obtained by excitation at 365 nm of lymph-node sections and sequential detection with interference filters (50 nm bandwidth) peaked at 450, 550 and 658 nm. Monochrome images were combined together in a single red–green–blue color image. Most of the fluorescence was observed within the blue spectral band because of large contributions from extracellular collagen and elastin fibers as well as from reduced form of intracellular nicotinamide adenine dinucleotide (phosphate). Autofluorescence imaging shows morphological differences between neoplastic and non-neoplastic tissues. The reactive hyperplasia samples show the typical lymph-node organization with weak fluorescent follicles separated by high fluorescent connective trabeculae. In the neoplastic lymph nodes the loss of follicle organization is observed. Consequently, MIAM permits to discriminate between non-neoplastic and neoplastic tissues on the basis of their autofluorescence pattern. Multispectral imaging of tissue autofluorescence may present some advantages with respect to standard histochemical microscopy since it (1) does not require any chemical manipulation of samples; (2) gives real-time results performing the analysis immediately upon specimen resection; and (3) supplies a representation of the biological structure organization linked to endogenous fluorophores.

Recombinant human erythropoietin has little influence on megakaryocytopoiesis in mice

Summary. The availability of a preparation of recombinant human erythropoietin (rEp) prompted us to investigate the role of Ep in the regulation of megakaryocytopoiesis in mice, using experimental procedures by which the effects on the mitotic and post‐mitotic compartment of megakaryocytes could be evaluated separately. In agar cultures of murine bone marrow cells, either serum‐depleted or serum‐supplemented, rEp (0.1–2 U/ml) did not stimulate megakaryocyte colony formation and when it was added to suboptimal amount of spleen cell‐conditioned medium (SCM), it failed to show a significant synergistic activity. On the contrary, rEp increased the number of megakaryocytic colonies developed from splenic precursors in the presence of suboptimal amounts of SCM, although it was unable per se to stimulate colony formation.

Pharmacokinetics, thrombogenicity and safety of a double-treated prothrombin complex concentrate.

The pharmacokinetic profile, the thrombogenicity and the virus safety of Preconativ, a PCC subjected both to virus removal procedure and dry-heat treatment were studied. Preconativ is produced from plasma pool, negative both for HBsAg and for antibodies to HIV. To further reduce the risk of virus transmission, the manufacturing process includes hydrophobic gel chromatography and dry-heat treatment at +68 degrees C for 48 hours. Nine patients with hemophilia B participated in a single dose, pharmacokinetic study. The decay curves of factor IX clotting activity were evaluated by model-independent methods. The Clearance and the Mean Residence Time were very similar to those previously reported for untreated PCC. The Volume of Distribution Area and In Vivo Recovery resulted inversely correlated and respectively larger and smaller than those of untreated PCC. A slight fall in platelet count and Antithrombin III level and an increase of Beta-Thromboglobulin and Fibrinopeptide A concentration were found, indicating a clear-cut activation of the coagulation process during the first hours following Preconativ administration. Seven patients (2 of the ones enrolled in the pharmacokinetic study) were completely fulfilling the SSC-ISTH criteria for virus safety prospective study. The follow up of these patients did not show any transaminases elevation or seroconversion against HBV, HCV or HIV. These findings did not change over a 3-5 year follow up in 3 out of 7 patients, repeatedly infused with Preconativ.

Coexpression of erythroid and megakaryocytic genes in acute erythroblastic (FAB M6) and megakaryoblastic (FAB M7) leukaemias

There is evidence to suggest a close relationship between the erythroid and megakaryocytic lineages. Using RT‐PCR, we evaluated the coexpression of erythroid and megakaryocytic genes in blasts from 25 acute myeloid leukaemia (AML) cases (FAB M1–M7) and three unclassifiable leukaemias with trilineage dysplasia (trilineal AML). All FAB M6 and M7 and trilineal leukaemias expressed mRNAs for α‐globin, glycoprotein IIb (GpIIb), erythropoietin receptor (Epo‐R) and thrombopoietin receptor (c‐mpl), but not for myeloperoxidase (MPO) which in contrast was expressed in the other FAB‐subtype leukaemias. These data support the hypothesis that blasts from M7 and M6 leukaemias may derive from (or represent) a common progenitor cell with resident bipotentiality towards the megakaryocytic and erythrocytic lineages.

Genetic lesions associated with blastic transformation of polycythemia vera and essential thrombocythemia

Polycythemia vera (PV) and essential thrombocythemia (ET) are chronic myeloproliferative disorders that may progress to acute leukemia in a subset of patients. This study aimed at investigating the genetic lesions associated with the blastic transformation of PV and ET. A panel of PV and ET cases at different stages of disease was analyzed for the presence of genetic alterations of TP53, NRAS, KRAS, and MDM2 by a combination of mutational analysis and Southern blot hybridization. The occurrence of microsatellite instability (MSI) was also tested in selected cases. Samples of PV and ET analyzed in chronic phase disease were consistently devoid of all genetic lesions tested, suggesting that alterations of TP53, NRAS, KRAS, and MDM2 do not contribute significantly to development of chronic phase PV and ET. Conversely, mutations of TP53were detected in 7/15 (46.6%) blastic phase cases, including 3/5 PV and 4/10 ET. In blastic phase patients for whom the corresponding chronic phase DNA was also available, it could be documented that the genetic lesion had arisen at the time of blastic transformation. In addition to TP53 mutations, cases of blastic phase PV and ET occasionally harbored mutations of NRAS (one case of blastic phase ET) or displayed MSI (one case of blastic phase PV). These data indicate that inactivation of TP53 is a relatively frequent event associated with the blastic transformation of PV and ET and may be responsible for the tumor progression of these disorders. Genes Chromosom. Cancer 19:250–255, 1997.