Reversal of MYB-dependent suppression of MAFB expression overrides leukaemia phenotype in MLL-rearranged AML

The transcription factor MYB plays a pivotal role in haematopoietic homoeostasis and its aberrant expression is involved in the genesis and maintenance of acute myeloid leukaemia (AML). We have previously demonstrated that not all AML subtypes display the same dependency on MYB expression and that such variability is dictated by the nature of the driver mutation. However, whether this difference in MYB dependency is a general trend in AML remains to be further elucidated. Here, we investigate the role of MYB in human leukaemia by performing siRNA-mediated knock-down in cell line models of AML with different driver lesions. We show that the characteristic reduction in proliferation and the concomitant induction of myeloid differentiation that is observed in MLL-rearranged and t(8;21) leukaemias upon MYB suppression is not seen in AML cells with a complex karyotype. Transcriptome analyses revealed that MYB ablation produces consensual increase of MAFB expression in MYB-dependent cells and, interestingly, the ectopic expression of MAFB could phenocopy the effect of MYB suppression. Accordingly, in silico stratification analyses of molecular data from AML patients revealed a reciprocal relationship between MYB and MAFB expression, highlighting a novel biological interconnection between these two factors in AML and supporting new rationales of MAFB targeting in MLL-rearranged leukaemias.

Daratumumab plus bortezomib or daratumumab plus lenalidomide as salvage therapy for patients with myeloma: initial follow-up of an Italian multicentre retrospective clinical experience by 'Rete Ematologica Pugliese'

We report herein a multicentre retrospective analysis of 192 consecutive patients with symptomatic refractory/relapsed multiple myeloma (RRMM) treated with daratumumab in combination with bortezomib or lenalidomide as salvage therapy at 9 haematological centres in Puglia. Choice of both regimens was based on previous treatment and/or physicians' preference. Considering the under-representation of older patients (very old patient ≥ 80 years) in clinical trials and the prognostic and predictive importance and value of frailty status, here, we further characterised the patient cohort by age. The overall response rate (ORR) was generally lower than what was previously reported in the CASTOR (ORR 72.6% vs 85%) and POLLUX (ORR 86.5% vs 93%) trials. The lower ORR in our analysis compared to the CASTOR and POLLUX trials could be related to a less selected population. Similarly, amongst very old patients, the ORR was encouraging: ORR to treatment with DVd (daratumumab + bortezomib + dexamethasone) was 66.7%, and ORR to treatment with DRd (daratumumab + lenalidomide + dexamethasone) was 92.3%. Median TTP (time to progression) was 10.8 months (1-year TTP: 44.7%; 2-year TTP: 25.3%) in the DVd group; median TTP was not reached in the DRd group (1-year TTP: 82.7%; 2-year TTP: 71.4%). Median OS (overall survival) was not reached either in the DRd group (1-year OS: 85.9%; 2-year OS: 73.7%) or the DVd group (1-year OS: 70.2%; 2-year OS: 58.9%).

Dissection of DLBCL microenvironment provides a gene expression-based predictor of survival applicable to formalin-fixed paraffin-embedded tissue

Background

Gene expression profiling (GEP) studies recognized a prognostic role for tumor microenvironment (TME) in diffuse large B-cell lymphoma (DLBCL), but the routinely adoption of prognostic stromal signatures remains limited.

Patients and methods

Here, we applied the computational method CIBERSORT to generate a 1028-gene matrix incorporating signatures of 17 immune and stromal cytotypes. Then, we carried out a deconvolution on publicly available GEP data of 482 untreated DLBCLs to reveal associations between clinical outcomes and proportions of putative tumor-infiltrating cell types. Forty-five genes related to peculiar prognostic cytotypes were selected and their expression digitally quantified by NanoString technology on a validation set of 175 formalin-fixed, paraffin-embedded DLBCLs from two randomized trials. Data from an unsupervised clustering analysis were used to build a model of clustering assignment, whose prognostic value was also assessed on an independent cohort of 40 cases. All tissue samples consisted of pretreatment biopsies of advanced-stage DLBCLs treated by comparable R-CHOP/R-CHOP-like regimens.

Results

In silico analysis demonstrated that higher proportion of myofibroblasts (MFs), dendritic cells, and CD4⁺ T cells correlated with better outcomes and the expression of genes in our panel is associated with a risk of overall and progression-free survival. In a multivariate Cox model, the microenvironment genes retained high prognostic performance independently of the cell-of-origin (COO), and integration of the two prognosticators (COO + TME) improved survival prediction in both validation set and independent cohort. Moreover, the major contribution of MF-related genes to the panel and Gene Set Enrichment Analysis suggested a strong influence of extracellular matrix determinants in DLBCL biology.

Conclusions

Our study identified new prognostic categories of DLBCL, providing an easy-to-apply gene panel that powerfully predicts patients’ survival. Moreover, owing to its relationship with specific stromal and immune components, the panel may acquire a predictive relevance in clinical trials exploring new drugs with known impact on TME.

Genetic landscape of ultra-stable chronic lymphocytic leukemia patients

Background

Chronic lymphocytic leukemia (CLL) has a heterogeneous clinical course. Beside patients requiring immediate treatment, others show an initial indolent phase followed by progression and others do not progress for decades. The latter two subgroups usually display mutated IGHV genes and a favorable FISH profile.

Patients and methods

Patients with absence of disease progression for over 10 years (10-34) from diagnosis were defined as ultra-stable CLL (US-CLL). Forty US-CLL underwent extensive characterization including whole exome sequencing (WES), ultra-deep sequencing and copy number aberration (CNA) analysis to define their unexplored genetic landscape. Microarray analysis, comparing US-CLL with non-US-CLL with similar immunogenetic features (mutated IGHV/favorable FISH), was also carried out to recognize US-CLL at diagnosis.

Results

WES was carried out in 20 US-CLL and 84 non-silent somatic mutations in 78 genes were found. When re-tested in a validation cohort of 20 further US-CLL, no recurrent lesion was identified. No clonal mutations of NOTCH1, BIRC3, SF3B1 and TP53 were found, including ATM and other potential progression driving mutations. CNA analysis identified 31 lesions, none with known poor prognostic impact. No novel recurrent lesion was identified: most cases showed no lesions (38%) or an isolated del(13q) (31%). The expression of 6 genes, selected from a gene expression profile analysis by microarray and quantified by droplet digital PCR on a cohort of 79 CLL (58 US-CLL and 21 non-US-CLL), allowed to build a decision-tree capable of recognizing at diagnosis US-CLL patients.

Conclusions

The genetic landscape of US-CLL is characterized by the absence of known unfavorable driver mutations/CNA and of novel recurrent genetic lesions. Among CLL patients with favorable immunogenetics, a decision-tree based on the expression of 6 genes may identify at diagnosis patients who are likely to maintain an indolent disease for decades.

Synthesis and biological evaluation of N-biphenyl-nicotinic based moiety compounds: A new class of antimitotic agents for the treatment of Hodgkin Lymphoma

We previously demonstrated that some N-biphenylanilides caused cell-cycle arrest at G2/M transition in breast cancer cells. Among them we choose three derivatives, namely PTA34, PTA73 and RS35 for experimentation in solid tumor cell lines, classical Hodgkin Lymphoma (cHL) cell lines and bona fide normal cell lines. Almost all tumor cells were sensitive to compounds in the nanomolar range whereas, they were not cytotoxic to normal ones. Interestingly the compounds caused a strong G2/M phase arrest in cHL cell lines, thus, here we investigated whether they affected the integrity of microtubules in such cells. We found that they induced a long prometaphase arrest, followed by induction of apoptosis which involved mitochondria. PTA73 and RS35 induced the mitotic arrest through the fragmentation of microtubules which prevented the kinethocore-mitotic spindle interaction and the exit from mitosis. PTA34 is instead a tubulin-targeting agent because it inhibited the tubulin polymerization as vinblastine. As such, PTA34 maintained the Cyclin B1-CDK1 regulatory complex activated during the G2/M arrest while inducing the inactivation of Bcl-2 through phosphorylation in Ser70, the degradation of Mcl-1 and a strong activation of BIML and BIMS proapoptotic isoforms. In addition PTA34 exerted an antiangiogenic effect by suppressing microvascular formation.

Biochemical and Metabolic Aspects of Platelet Dysfunction in Chronic Myeloproliferative Disorders

Fifty-two patients with chronic myeloproliferative disorders (13 with polycythemia vera; 23 with primary thrombocythemia; 6 with myelofibrosis and 10 with chronic granulocytic leukemia) had low platelet levels of adenine nucleotides and serotonin and abnormal uptake and storage of the amine. The storage pool deficiency was confined to the substances contained in the platelet dense bodies, because α-granule and lysosome markers were present in normal amounts. In chronic granulocytic leukemia the storage defect was usually less marked but was accompanied by a decreased formation of thromboxane B2 and normal platelet aggregation in response to arachidonic acid. There was no clearcut relationship of these biochemical abnormalities to prolongation of bleeding time or to thrombotic and hemorrhagic symptoms. The defect was still present in 15 patients after treatment had returned the cell counts to the normal range. Normal levels of 5HT and adenine nucleotides were observed in 8 patients whose platelet counts were high after splenectomy for non-hematological reasons. These findings suggest that biochemical abnormalities are related to the presence in the bone marrow of abnormal clones, resulting in the production of defective platelets.

u-PAR expression in cancer associated fibroblast: new acquisitions in multiple myeloma progression

Background

Multiple Myeloma (MM) is a B-cell malignancy in which clonal plasma cells progressively expand within the bone marrow (BM) as effect of complex interactions with extracellular matrix and a number of microenvironmental cells. Among these, cancer-associated fibroblasts (CAF) mediate crucial reciprocal signals with MM cells and are associated to aggressive disease and poor prognosis. A large body of evidence emphasizes the role of the urokinase plasminogen activator (u-PA) and its receptor u-PAR in potentiating the invasion capacity of tumor plasma cells, but little is known about their role in the biology of MM CAF. In this study, we investigated the u-PA/u-PAR axis in MM-associated fibroblasts and explore additional mechanisms of tumor/stroma interplay in MM progression.

Methods

CAF were purified from total BM stromal fraction of 64 patients including monoclonal gammopathy of undetermined significance, asymptomatic and symptomatic MM, as well as MM in post-treatment remission. Flow cytometry, Real Time PCR and immunofluorescence were performed to investigate the u-PA/u-PAR system in relation to the level of activation of CAF at different stages of the disease. Moreover, proliferation and invasion assays coupled with silencing experiments were used to prove, at functional level, the function of u-PAR in CAF.

Results

We found higher activation level, along with increased expression of pro-invasive molecules, including u-PA, u-PAR and metalloproteinases, in CAF from patients with symptomatic MM compared to the others stages of the disease. Consistently, CAF from active MM as well as U266 cell line under the influence of medium conditioned by active MM CAF, display higher proliferative rate and invasion potential, which were significantly restrained by u-PAR gene expression inhibition.

Conclusions

Our data suggest that the stimulation of u-PA/u-PAR system contributes to the activated phenotype and function of CAF during MM progression, providing a biological rationale for future targeted therapies against MM.

Human lung carcinoma cells engineered to release IL2, IL7, GM-CSF and TNF alpha

A human lung adenocarcinoma cell line (LC89) was transduced with the IL2, IL7, GM-CSF and TNF alpha genes by retroviral vector mediated infection. This induced the constitutive and stable release of all cytokines. No difference or modulation was found in the parental and gene transduced LC89 cells with regard to cytokine receptor expression, in vitro cell growth and proliferation, nor in cell surface expression of different adhesion molecules. Following injection into immunosuppressed nu/nu mice, IL2 gene transduced LC89 cells lost their tumorigenic potential. LC89 cells engineered to release IL7 and TNF alpha grew in nu/nu mice, but in 40% of the animals tumor regression was observed. GM-CSF gene transduced LC89 cells showed a tumorigenic capacity identical to that of the parental clone. The levels of TGF beta(1) released by IL2, IL7 and GM-CSF gene transduced LC89 cells were markedly reduced compared to those of the parental and TNF alpha gene transduced cells. The results of this study support the concept that human lung cancer cells engineered with different cytokine genes maintain their intrinsic morphologic and proliferative features, while their tumorigenic and immunosuppressive capacities can be profoundly down-modulated. Both these effects are optimally achieved following insertion of the IL2 gene, suggesting that vaccination protocols with IL2 gene transduced tumor cells may be considered for the management of human lung cancer.

The genome of chemorefractory chronic lymphocytic leukemia reveals frequent mutations of NOTCH1 and SF3B1

Next-generation whole-exome sequencing has revealed two novel genes, namely NOTCH1 and SF3B1, whose mutations predict poor outcome and preferentially associate with chemorefractory chronic lymphocytic leukemia (CLL). Analysis of 539 CLL cases documents that NOTCH1 mutations i) represent one of the most frequent cancer gene mutations involved at presentation; ii) cluster with cases harboring trisomy 12 and tend to be mutually exclusive with TP53 disruption among genetic subgroups; iii) identify high-risk patients showing poor survival similar to that associated with TP53 abnormalities; and iv) exert a prognostic role independent of widely accepted clinical and genetic risk factors. Mutations of SF3B1, a splicing factor that is a critical component of the spliceosome, recurrently associate with fludarabine-refractory CLL, occur at a low rate at CLL presentation and have a minor role in Richter transformation, corroborating the notion that CLL histological shift is molecularly distinct from chemorefractory progression without the Richter transformation.

mTOR as a target of everolimus in refractory/relapsed Hodgkin lymphoma

Despite impressive treatment advances, few options for refractory or relapsed Hodgkin Lymphoma (HL) are available and there is a need for new compounds development. A number of promising agents with multiple mechanisms of action are under investigation. Microenvironment and neoangiogenesis are acquiring a rising relevance in the pathophysiology and progression of HL. Everolimus (RAD001) is an oral antineoplastic agent derived from rapamycin, a macrocyclic lactone antibiotic, targeting the mammalian target of rapamycin (mTOR). Although the importance of mTOR signaling in the deregulated cell growth of human neoplastic cells has been recognized, this pathway is also emerging as a key regulator of the tumor response to hypoxia, as well as endothelial and stromal cells function, thereby regulating neoangiogenesis. Furthermore, mTOR plays an important role in anticancer drug resistance. The actions of everolimus within the mTOR pathway in HL result in decreased protein synthesis and cell cycle arrest, as well as in decreased angiogenesis. Everolimus has shown preliminary evidence of efficacy as a single-agent in heavily pretreated relapsed/refractory HL, with an overall fair safety profile. The purpose of this review is to discuss the employment of everolimus as an antiproliferative and antiangiogenic agent in HL and to report the critical role of the mTOR pathway and angiogenesis in this malignancy.

Four proteins governing overangiogenic endothelial cell phenotype in patients with multiple myeloma are plausible therapeutic targets

Bone marrow (BM) angiogenesis has an important role in the initiation and progression of multiple myeloma (MM). We looked at novel mechanisms of vessel formation in patients with MM through a comparative proteomic analysis between BM endothelial cells (ECs) of patients with active MM (MMECs) and ECs of patients with monoclonal gammopathy of undetermined significance (MGECs) and of subjects with benign anemia (normal ECs). Four proteins were found overexpressed in MMECs: filamin A, vimentin, α-crystallin B and 14-3-3ζ/δ protein, not yet linked to overangiogenic phenotype. These proteins gave a typical distribution in the BM of MM patients and in MMECs versus MGECs, plausibly according to a different functional state. Their expression was enhanced by vascular endothelial growth factor, fibroblast growth factor 2, hepatocyte growth factor and MM plasma cell conditioned medium in step with enhancement of MMEC angiogenesis. Their silencing RNA knockdown affected critical MMEC angiogenesis-related functions, such as spreading, migration and tubular morphogenesis. A gradual stabilization of 14-3-3ζ/δ protein was observed, with transition from normal ECs to MGECs and MMECs that may be a critical step for the angiogenic switch in MMECs and maintenance of the cell overangiogenic phenotype. These proteins were substantially impacted by anti-MM drugs, such as bortezomib, lenalidomide and panobinostat. Results suggest that these four proteins could be new targets for the antiangiogenic management of MM patients.

The effect of gestational age on developmental outcomes: a longitudinal study in the first 2 years of life

BACKGROUND

Extremely low and very low gestational age (ELGA and VLGA) constitutes a risk factor for development even in absence of cerebral damage, as an immature central nervous system is exposed to invasive and inadequate stimulation. We tested the hypothesis that GA impacts developmental outcomes and trajectories of preterms without major cerebral damage in the first 2 years of life, expecting poorer developmental outcomes and higher rate of impairment with the decreasing of GA. We also evaluated whether GA, together with developmental outcomes in the first year of life, was related to developmental outcomes at 24 months.

METHODS

Eighty-eight infants, divided into three GA groups (ELGA: ≤28 weeks; VLGA: 29-32 weeks; full term: >37 weeks) were assessed longitudinally at 6, 12, 18 and 24 months using the Griffiths Mental Development Scales.

RESULTS

Use of a repeated measure multivariate analysis of variance resulted in several significant findings. GA was associated with the developmental quotient (DQ) scores (P= 0.006); and locomotor (P < 0.001), eye and hand co-ordination (P= 0.016) and performance (P= 0.040) sub-scale quotient (SQ) scores; age of evaluation was also associated with DQ scores (P= 0.002), and locomotor (P < 0.001) and performance (P < 0.001) SQ scores. In particular, ELGAs exhibited lower DQ and SQ scores compared with the VLGA and full-term groups; some ELGAs showed mild, moderate or severe cognitive impairments, while few VLGAs mild impairments. Linear regression analysis showed that GA (P= 0.034) and 12-month developmental outcome (P < 0.001) were related to 24-month developmental outcome.

CONCLUSIONS

Different developmental trajectories emerged in relation to GA, with poorer developmental outcomes and higher rates of impairment in ELGAs and few mild impairments in VLGAs. The relevance of taking into account both GA and repeated assessments in the first 2 years of life was shown.

Occurrence of thrombotic events in acute promyelocytic leukemia correlates with consistent immunophenotypic and molecular features

Although the occurrence of thrombosis in acute promyelocytic leukemia (APL) has been reported during retinoic acid treatment, no studies carried out in large clinical cohorts have specifically addressed this issue. We analyzed 124 APL patients treated with the all-trans retinoic acid and idarubicin protocol and compared clinico-biologic characteristics of 11 patients who developed thrombosis with those of 113 patients who had no thrombosis. In seven patients, the events were recorded during induction, whereas in four patients deep vein thrombosis occurred in the post-induction phase. Comparison of clinico-biological characteristics of patients with and without thrombosis revealed in the former group higher median white blood cell (WBC) count (17 x 10(9)/l, range 1.2-56, P=0.002), prevalence of the bcr3 transcript type (72 vs 48%, P=0.01), of FLT3-ITD (64 vs 28%, P=0.02), CD2 (P=0.0001) and CD15 (P=0.01) expression. No correlation was found with sex, age, French-American-British subtype, all-trans-retinoic acid syndrome or with thrombophilic state that was investigated in 5/11 patients. Our findings suggest that, in APL patients consistent biologic features of leukemia cells may predict increased risk of developing thrombosis.

Poor mobilization is an independent prognostic factor in patients with malignant lymphomas treated by peripheral blood stem cell transplantation

Haemopoietic stem cell therapy is an increasingly adopted procedure in the treatment of patients with malignant lymphoma. In this retrospective analysis, we evaluated 262 patients, 57 (22%) with Hodgkin's and 205 (78%) with non-Hodgkin's lymphomas (NHL), and 665 harvesting procedures in order to assess the impact of poor mobilization on survival and to determine the factors that may be predictive of CD34(+) poor mobilization. The mobilization chemotherapy regimens consisted of high-dose cyclophosphamide in 92 patients (35.1%) and a high-dose cytarabine-containing regimen (DHAP in 87 patients -(33.2%), MAD in 83 (31.7%)). The incidence of poor mobilizers (<2 x 10(6) CD34(+) cells/kg) was 17.9% overall, with a 10% of very poor mobilizers (< or = 1 x 10(6)/kg). Refractory disease status and chemotherapeutic load (>3 regimens) before mobilization played a negative role and were associated with poor mobilization. Survival analysis of all harvested patients showed an overall survival at 3 years of 71% in good mobilizers vs 33% in poor mobilizers (P=0.002). The event-free survival at 3 years was 23% in poor mobilizers and 58% in good mobilizers (P=0.04). We conclude that in NHL patients, poor mobilization status is predictive of survival.

Evidence of biased immunoglobulin variable gene usage in highly stable B-cell chronic lymphocytic leukemia

Recognition of biased immunoglobulin variable (IgV) gene usage in B-cell chronic lymphocytic leukemia (B-CLL) may yield insight into leukemogenesis and may help to refine prognostic categories. We explored Ig variable heavy (VH) and light (VL) chain gene usage in highly stable and indolent B-CLL (n=25) who never required treatment over 10 or more years. We observed an unexpectedly high usage of mutated VH3-72 (6/25; 24.0%), a gene that was otherwise rare in B-CLL (7/805; 0.87%; P<0.01), including mutated cases (6/432; 1.39%; P<0.01) and was exceptional among indolent (1/230, 0.435%; P<0.01), and aggressive B-cell lymphomas (0/105; P<0.01). Three of six VH3-72 B-CLL cases utilized the same VL Vkappa4-1 gene. Two V(H)3-72 B-CLL cases had highly homologous VH complementarity determining regions 3 (CDR3s), encoding Cys-XXXX-Cys domains, and utilized Vkappa4-1 genes with homologous IgVL CDR3s. An identical threonine to isoleucine change at codon 84 of V(H)3-72 framework region 3 (FR3) recurred in four cases of highly stable VH3-72 B-CLL. This mutation is expected to cause a conformational change of FR3 proximal to CDR3 that might critically affect high-affinity antigen binding. B-cell receptors encoded by VH3-72 may identify a specific B-CLL group and be implicated in leukemogenesis through an antigen-driven expansion of B cells.

Chronic myeloid leukemia cells resistant to interferon-alpha lack STAT1 expression

INTRODUCTION

Interferon-alpha (IFN) plays a role in the management of different neoplasias, particularly those of hematological origin. The mechanisms of action of IFN are still poorly understood and the individual response is unpredictable. In the present study, the pattern of intracellular gene expression following in vitro and in vivo exposure of chronic myeloid leukemia (CML) cells to IFN was evaluated and correlated with the response to in vivo treatment with IFN.

MATERIALS AND METHODS

CML patients in different phases of the disease were studied. The pattern of expression of two IFN-inducible proteins involved in IFN-mediated biological activities, the p91 and p84 proteins (STAT1alpha and STAT1beta), components of the IFN-stimulated gene factor 3 (ISGF3) complex and the enzyme 2'-5' oligoadenylate synthetase (2'-5' OASE) were investigated by Western blot in peripheral blood mononuclear cells stimulated or not in vitro by IFN.

RESULTS AND CONCLUSIONS

In 6/9 patients evaluated before starting treatment, STAT1 was expressed either constitutively or after in vitro stimulation by IFN. In three cases, STAT1 remained negative even after in vitro activation. The pattern of protein expression correlated with the subsequent hematological response to prolonged in vivo IFN administration: the presence of STAT1 being associated with the clinical response to IFN and the absence and non-inducibility of STAT1 with resistance to IFN. This was further substantiated by studies carried out in ten patients analyzed at the time of a documented clinico-hematological response or resistance to the in vivo administration of IFN. Finally, in order to establish whether the pattern of response to IFN treatment could be predicted at diagnosis, cells cyropreserved at diagnosis from patients with a documented complete response, confirmed also by cytogenetic negativity, or resistance, were studied. While complete responders proved STAT1 positive, none of the four resistant cases ever expressed STAT1. The expression of 2'-5' OASE did not correlate with the clinical response to IFN. This study documents the pivotal role of STAT1 in the in vitro and in vivo responses of CML cells to IFN. The constitutive or induced presence or absence of STAT1 shows a predictive correlation with the response or resistance to treatment with IFN and could be utilized to identify, at diagnosis, resistant patients who may be spared an expensive and unnecessary prolonged IFN administration.

Mobilization of peripheral blood stem cells with high-dose cyclophosphamide or the DHAP regimen plus G-CSF in non-Hodgkin's lymphoma

Our study analyzes the mobilization of hematopoietic stem cells after two chemotherapeutic regimens in non-Hodgkin's lymphoma (NHL) patients. The study included 72 patients with NHL (42 follicular and 30 large cells). The mean age was 37 years (range 17-60). Sixty-four patients (88.9%) had stage III-IV disease. Forty-eight patients (66.7%) had bone marrow involvement. Systemic B symptoms were present in 42 patients (58.3%). Mobilization chemotherapy regimens were randomly assigned as DHAP in 38 patients (52.7%) or cyclophosphamide (CPM) (5 g/m(2)) in 34 (47.2%) and the results of 132 procedures were analyzed. At the time of PBSC mobilization, 46 patients (63.9%) were considered to be responsive (complete remission, partial remission or sensitive relapse) and 26 (36.1%) not responsive (refractory relapse or refractory to therapy). Pre-apheresis CD34+ blood cell count and number of previous chemotherapy treatments were used to predict the total number of CD34+ cells in the apheresis product. The mobilizing regimens (CPM or DHAP) were similar in achieving the threshold CD34+ cell yield, for optimal engraftment. Since DHAP was very effective as salvage treatment, we suggest using DHAP as a mobilizing regimen in patients with active residual lymphoma at the time of stem cell collection.

Developmental approaches in immunological control of acute myelogenous leukaemia

After many years of hope and disillusionment, the possibility of utilizing immune-mediated approaches to control neoplastic clones has become a reality in various haematological malignancies. This is largely a consequence of the continuous advances in knowledge and the progressive development of more refined technologies that have led to a better understanding of the biology of the malignant cells and of the host immune system, to a more precise definition of disease entities and to the design of innovative therapeutic programmes. In this chapter, we will review different immunological strategies that have reached clinical practice in patients with acute myelogenous leukaemia (AML), the focus of this volume, and discuss pre-clinical developments that may in the near future translate into the design of new immunotherapeutic protocols for the management of AML. Treatment of AML with antibody directed therapy will also be discussed.

Phenotypic and functional characterization of the host immune compartment of chronic myeloid leukaemia patients in complete haematological remission

The role of the host immune compartment in the control of chronic myeloid leukaemia (CML) has been suggested by numerous biological and clinical evidence. In the present study, the phenotypic and functional machinery of both T and cytotoxic lymphocytes was evaluated in a series of CML patients in complete haematological, and frequently also in cytogenetic, remission after treatment with interferon (IFN) alpha or hydroxyurea, and compared with the profile observed in patients at diagnosis and in normal controls. In particular, the lymphocyte subset distribution, the cytotoxic activity and the intracellular production of tumour necrosis factor (TNF)alpha and IFN gamma by CD4(+), CD8(+) and CD56(+) cells were investigated. CML patients in complete haematological remission showed a normalized CD4/CD8 T-cell subset distribution, as well as a restored spontaneous and interleukin 2 (IL-2) induced cytotoxic function compared with the pattern observed at diagnosis. This was associated with a significantly increased proportion of activated CD4(+) lymphocytes (CD25(+)). TNF alpha and IFN gamma production by CD4(+), CD8(+) and CD56(+) lymphocytes was significantly enhanced compared with that of patients at diagnosis. However, the values were lower than those of normal controls. These results indicate that, in contrast to the observations at presentation, CML patients, at the time of the best possible response to treatment, show a normalized T-cell subset distribution associated with an activated CD4 T-cell compartment and a restored cytotoxic activity. In addition, they also show a markedly increased intracellular cytokine production by the lymphoid populations that play an important role in the process of specific tumour recognition. The design of therapeutic strategies aimed at stimulating the host immune compartment finds a further rationale for CML patients responsive to treatment with both IFN alpha and hydroxyurea.

Accessory cells, cytokine loops and cell-to-cell interactions in chronic lymphocytic leukemia

In addition to the extensive work that has been conducted in order to understand better the biological features of the leukemic population in B-cell chronic lymphocytic leukemia (CLL), over the years considerable interest has been directed towards other related studies that may have important implications for the accumulation of the leukemic clone and for the immunoparesis typical of this disease. In the present review article, we discuss some of these areas of investigation and, in particular, we focus on: (1) the multiple abnormalities recorded within the T and cytotoxic compartment of patients with CLL; (2) cytokine loops occurring in this disease, with particular emphasis on the cytokines that appear to play a more critical role; and (3) the cell-to-cell cross talk that may be actively operational in CLL. These findings will be discussed in relation with the possible implications that each of them have in the expansion and clinical behavior of a disease that is increasingly proving its heterogeneity.

Interleukin-2 gene-transduced human leukemic cells induce major histocompatibility complex-restricted and -unrestricted anti-leukemic effectors in mixed lymphocyte-tumor cultures

To explore the feasibility of designing vaccination protocols in acute leukemia patients with cytokine gene-transduced leukemic cells, we studied in vitro the growth potential of human leukemic cells transduced with the interleukin-2 (IL-2), IL-7, or IL-7 plus IL-2 genes, as well as the capacity of generating both autologous and allogeneic cytotoxic lymphocytes directed against the parental cells. A lymphoblastic T-cell line, ST4, obtained from a patient in long-lasting complete remission, was retrovirally engineered with the IL-2, IL-7, and IL-7 plus IL-2 genes; in addition, clones releasing different amounts of the cytokines were obtained by limiting dilution. Mixed lymphocyte-tumor cultures (MLTCs) were set up with parental or transduced leukemic cells as stimulators and with autologous or allogeneic lymphocytes as responders. When nonirradiated ST4 parental cells or clones producing <50 international units (IU)/mL/10(6) cells/72 hours of IL-2 were used as stimulators, leukemic overgrowth was observed in MLTCs within 16 days of culture. When clones producing >80 IU/mL/10(6) cells/72 hours of IL-2 were used as stimulators, the proliferation of leukemic cells was blocked and the transduced leukemic cells were completely cleared from the cultures by day 16; repeated restimulations with IL-2-producing leukemic cells were required to sustain long-term lymphocyte survival. On the contrary, when IL-7- or IL-7-IL-2-producing cells were used as stimulators, only a delay in leukemic cell overgrowth was observed, and lymphocytes were completely cleared from the cultures after day 60. IL-7 production by the different clones ranged between 11 and 36 ng/mL/10(6) cells/72 hours, whereas the highest IL-2-producing IL-7-IL-2 clone released 50 IU/mL/10(6) cells/72 hours of IL-2. When the stimulator efficacy of the highest IL-2-producing clone (ST4/IL-2#A7) was compared with that of exogenous IL-2 plus parental cells, a 7-fold higher amount of exogenous IL-2 was required to achieve the same results obtained with IL-2-producing leukemic cells. Autologous and allogeneic long-term MLTCs (up to 35 days) with ST4/IL-2#A7 as the stimulator were capable of generating cytotoxic effectors equally endowed with both major histocompatibility complex (MHC) class I-unrestricted and -restricted activity against parental ST4 cells. By day 18 of both autologous and allogeneic cultures, a substantial proportion of CD56+ cells was consistently recorded; this was coupled to a predominantly MHC-unrestricted cytotoxic activity directed against parental ST4 cells. CD56+ cells decreased considerably at the end of the different MLTCs, together with the unrestricted cytotoxic activity. At this time, >50% of the cells were CD8+, and 55% of the activity could be blocked by an anti-MHC class I monoclonal antibody. The results of this study demonstrate that IL-2 gene-transduced human acute leukemia cells cocultured with both autologous and allogeneic lymphocytes are capable of inducing a strong MHC-unrestricted anti-leukemic activity and subsequently "educating" MHC class I-restricted anti-leukemic effectors. The evidence that the immunogenic potential of human leukemic blasts can be boosted after transfer of the IL-2 gene suggests that the possibility of using leukemic cells engineered to release IL-2 as a therapeutic vaccine needs to be explored further.

Chronic myeloid leukemia cells resistant to interferon-alpha lack STAT1 expression

INTRODUCTION

Interferon-alpha (IFN) plays a role in the management of different neoplasias, particularly those of hematological origin. The mechanisms of action of IFN are still poorly understood and the individual response is unpredictable. In the present study, the pattern of intracellular gene expression following in vitro and in vivo exposure of chronic myeloid leukemia (CML) cells to IFN was evaluated and correlated with the response to in vivo treatment with IFN.

MATERIALS AND METHODS

CML patients in different phases of the disease were studied. The pattern of expression of two IFN-inducible proteins involved in IFN-mediated biological activities, the p91 and p84 proteins (STAT1alpha and STAT1beta), components of the IFN-stimulated gene factor 3 (ISGF3) complex and the enzyme 2'-5' oligoadenylate synthetase (2'-5' OASE) were investigated by Western blot in peripheral blood mononuclear cells stimulated or not in vitro by IFN.

RESULTS AND CONCLUSIONS

In 6/9 patients evaluated before starting treatment, STAT1 was expressed either constitutively or after in vitro stimulation by IFN. In three cases, STAT1 remained negative even after in vitro activation. The pattern of protein expression correlated with the subsequent hematological response to prolonged in vivo IFN administration: the presence of STAT1 being associated with the clinical response to IFN and the absence and non-inducibility of STAT1 with resistance to IFN. This was further substantiated by studies carried out in ten patients analyzed at the time of a documented clinico-hematological response or resistance to the in vivo administration of IFN. Finally, in order to establish whether the pattern of response to IFN treatment could be predicted at diagnosis, cells cyropreserved at diagnosis from patients with a documented complete response, confirmed also by cytogenetic negativity, or resistance, were studied. While complete responders proved STAT1 positive, none of the four resistant cases ever expressed STAT1. The expression of 2'-5' OASE did not correlate with the clinical response to IFN. This study documents the pivotal role of STAT1 in the in vitro and in vivo responses of CML cells to IFN. The constitutive or induced presence or absence of STAT1 shows a predictive correlation with the response or resistance to treatment with IFN and could be utilized to identify, at diagnosis, resistant patients who may be spared an expensive and unnecessary prolonged IFN administration.

Primary non Hodgkin's lymphoma of the vagina

The genital tract as a primary site of malignant lymphoma in women is extremely rare. This report concerns a 64 year old patient with a primary vaginal non-Hodgkin lymphoma (large cell B lineage according to the REAL classification--centroblastic type according to the Kiel classification--"G" according Working Formulation) with an unusual clinical presentation--pelvic discomfort accompanied by frequent ureteral-like colic. Due to gynecological onset symptoms and the rarity of this extranodal primary site misinterpretation of a primary vaginal lymphoma as a benign inflammatory disease or endometriosis may occur. We emphasize the importance of their recognition and also the differential diagnosis of cervical lymphoma from other neoplastic and non-neoplastic lesions.