Summary.  Background: Thromboembolism can occur during acute leukemia, especially acute lymphoid leukemia (ALL) treated with l‐asparaginase. Yet, most reports are anecdotical and scarce data are available on the risk of thrombosis in acute myeloid leukemia (AML). Objectives: To evaluate the risk of thrombosis in patients with acute leukemia. Patients and methods: Three‐hundred and seventy‐nine consecutive adult patients with newly diagnosed acute leukemia were recruited in an observational cohort study conducted from January 1994 to December 2003. Diagnosis was ALL in 69 patients, acute promyelocytic leukemia (APL; FAB subtype M3) in 31, and non‐M3 AML in 279. All first or recurrent symptomatic thromboembolic events objectively diagnosed were recorded. Results: Twenty‐four patients of the overall 379 (6.3%; 95% CI 4.1%–9.2%) had a first thrombosis, venous in 80% of the cases and arterial in 20%. At diagnosis, thrombosis was a presenting manifestation in 13 cases (3.4% of the whole cohort): 1.4% in ALL, 9.6% in APL, and 3.2% in non‐M3 AML patients. Follow‐up was carried out on 343 patients without thrombosis at diagnosis and further 11 thrombotic events (3.2%) were recorded. At 6 months from diagnosis, the cumulative incidence of thrombosis was 10.6% in ALL, 8.4% in APL, and 1.7% in non‐M3 AML patients. The patients who received l‐asparaginase had a 4.9‐fold increased risk of thrombosis in comparison with those who did not (95% CI 1.5–16.0). The fatality rate due to thrombosis was 0.8%. Conclusions: In patients with acute leukemia, the risk of thrombosis is not negligible. Thombosis can be a presenting symptom at diagnosis in a significant portion of cases with APL (9.6%) and non‐M3 AML (3.2%); a similar rate of thrombosis can occur during the subsequent course of the disease. The incidence of symptomatic thrombosis at diagnosis is relatively low in ALL patients (1.4%), but is significantly increased by further treatment up to 10.6%. Strategies of antithrombotic prophylaxis should be investigated in this setting.

283 The clinical course of chronic lymphocytic leukemia (CLL) ranges from very indolent, with a nearly normal life expectancy, to rapidly progressive leading to death and occasionally undergoing transformation to Richter syndrome (RS). TP53 disruption identifies a fraction of high risk CLL destined to experience a very short survival. High risk CLL, however, cannot be fully recapitulated by TP53 disruption and other lesions of cancer genes may be implicated in this aggressive phenotype. Analysis of the CLL coding genome has recently disclosed that the NOTCH1 proto-oncogene is recurrently mutated at CLL presentation. Here we assessed the prognostic role of NOTCH1 mutations in CLL. Two series of previously untreated CLL were utilized as training (n=309, median follow-up 6 years) and validation (n=230, median follow-up 7 years) cohorts. NOTCH1 mutations were analyzed by DNA Sanger sequencing in blind with respect to clinical data. In the training series, NOTCH1 mutations occurred in 34/309 (11.0%) patients, being mostly represented (26/34, 76.5%) by a recurrent two bp frameshift deletion (c.7544_7545delCT). The remaining NOTCH1 mutations (8/34, 23.5%) were frameshift deletions other than c.7544_7545delCT (n=7) and frameshift insertions (n=1). All mutations were predicted to disrupt the NOTCH1 PEST domain. CLL with NOTCH1 mutations preferentially carried unmutated IGHV genes (76.5%, p<.001). Other characteristics at presentation associated with NOTCH1 mutations were advanced Rai stage (26.5%, p=.006) and trisomy 12 (44.1%, p<.001). By univariate analysis, NOTCH1 mutations associated with an increase in the hazard of death (HR: 3.77; 95% CI: 2.14–6.66) and a significant overall survival OS shortening (p<.001) (Fig. 1A). Multivariate analysis selected NOTCH1 mutations as an independent risk factor of OS (HR: 4.22; 95% CI: 2.15–8.28; p<.001), after adjusting for age (p<.001), Rai stage (p=.005), IGHV mutation status (p=.465), 11q22-q23 deletion (p=.128), trisomy 12 (p=.183) and TP53 disruption (p<.001). The poor prognosis conferred by NOTCH1 mutations was attributable, at least in part, to a shorter time to progression requiring treatment (p<.001), and a higher cumulative probability of RS development (p=.026). Although NOTCH1 mutated patients were devoid of TP53 disruption in 31/34 (91.2%) cases, the OS predicted by NOTCH1 mutations was similar to that of TP53 mutated/deleted CLL (Fig. 1C). Analysis of the validation series confirmed: i) the prevalence of NOTCH1 mutations at CLL presentation (26/230, 11.3%); ii) the spectrum of NOTCH1 mutations at CLL presentation (c.7544_7545delCT: 21/26, 80.7%; other mutations: 5/26, 19.3%) iii) the adverse prognostic impact of NOTCH1 mutations in CLL both by univariate analysis (Fig. 1B) and by multivariate analysis (HR: 2.08; 95% CI: 1.10–3.93; p=.023); iv) the preferential mutually exclusive distribution of NOTCH1 mutations and TP53 disruption (25/26, 96.2%); v) that OS of NOTCH1 mutated CLL is similarly poor as that of TP53 disrupted CLL (Fig. 1D). The current study on 539 CLL documents that NOTCH1 mutations: i) represent one of the most frequent cancer gene mutations known to be involved at CLL presentation; ii) identify a subgroup of patients showing poor OS similar to that of TP53 disrupted cases; iii) exert a prognostic role independent of widely accepted clinical and genetic risk factors; iv) predict OS in series from different institutions, as documented by the training-validation approach chosen for the design of this study. Disclosures: No relevant conflicts of interest to declare.

Platelet transfusions, main therapy of Glanzmann Thromboasthenia (GT), can induce an allo-immunization against human leucocyte antigen and integrin alphaIIbbeta3. We have investigated in our GT patients the rate of allo-immunization and of refractoriness to platelet transfusions. From 1975 until December 2005, we have followed 17 GT patients: 14 type 1, 3 variant type; nine females, eight males; median age at diagnosis 9.8 years (range 1-44.5); median age at the time of the study 35.5 years (range 23.6-68.5). In our patients, 121 bleeding episodes occurred (24 severe, 37 moderate, and 60 mild). Ten major and 22 minor surgical procedures have been performed. Two spontaneous deliveries and three caesarian sections with five live births were performed; moreover, one late foetal loss occurred, and one voluntary abortion was performed. Sixteen of 17 patients have been transfused at least once in life with platelets and/or red blood cells (RBC). All transfused patients have been investigated for the presence of anti-HLA and anti-integrin alphaIIbbeta3 allo-antibodies. The positiveness of allo-antibodies has been demonstrated in 4/16 transfused patients (25%): isolated for anti-HLA in two; isolated for anti-integrin alphaIIbbeta3 in one; and combined in one. In spite of the presence of allo-antibodies, platelet transfusions have always been effective and the haemostasis was not compromised.

712 The identification of NOTCH1, SF3B1, MYD88 and BIRC3 genetic lesions in chronic lymphocytic leukemia (CLL) prompts a comprehensive and dynamic prognostic algorithm including gene mutations, chromosomal abnormalities, and their changes during clonal evolution. The study utilized both time-fixed (637 newly diagnosed CLL) and time-dependent (257 CLL provided with 524 sequential samples) approaches. Each sample was investigated for TP53, NOTCH1, SF3B1, MYD88, and BIRC3 mutations by Sanger sequencing and for 17p13, 11q22-q23, 13q14 and BIRC3 deletions and +12 by FISH. Del13q14 and +12 distributed in a mutually exclusive fashion (p<0.0001), and identified three main genetic subgroups: cases harboring del13q14, cases harboring +12 and cases lacking both del13q14 and +12. With the sole exception of the expected association between NOTCH1 mutations and +12 CLL (p=0.0014), the prevalence of the other genetic lesions did not differ among molecular subgroups. FISH abnormalities segregated patients in distinct prognostic groups according to Döhner (Fig 1A). Among new genetic lesions, survival analysis confirmed the independent prognostic value of NOTCH1, SF3B1 and BIRC3 lesions in this study cohort. MYD88 mutations had no prognostic effect (p=0.1728). Recursive partitioning analysis followed by random survival forest validation established the hierarchical order of relevance of the genetic lesions, and created an integrated mutational and cytogenetic (MUCY) model that classified newly diagnosed CLL into four prognostic subgroups (Fig 1B). High risk patients harbored TP53 disruption and/or BIRC3 disruption independent of co-occurring lesions (10-year survival: 29.1%). When the demographic effects of age, sex and year of diagnosis were compensated, the 10-year life expectancy of high risk patients was only 37.7% of that expected in the matched general population (p<0.0001). Intermediate risk patients harbored NOTCH1 and/or SF3B1 mutations and/or del11q22-q23 in the absence of TP53 and BIRC3 abnormalities (10-year OS: 37.1%). The 10-year life expectancy of intermediate risk patients was reduced to 48.5% compared to the matched general population (p<0.0001). The low risk category comprised both patients harboring +12 and patients wild type for all genetic lesions (i.e. normal) (10-year OS: 57.3%), with a 10-year life expectancy of 70.7% compared to the matched general population (p<0.0001). Very low risk patients harbored del13q14 as the sole genetic lesion (10-year OS: 69.3%), with a 10-year life expectancy only slightly (84.2%) and not significantly (p=0.1455) lower than that expected in the matched general population. Multivariate analysis selected the MUCY model as one of the most important independent risk factor of CLL OS (HR: 1.38; 95% CI: 1.18–1.60; p<0.0001; 99% bootstrap selection), along with age (HR: 1.06; 95% CI: 1.04–1.07; p<0.0001; 100% bootstrap selection), Rai stage (HR: 1.36; 95% CI: 1.23-1-51; p<0.0001; 100% bootstrap selection) and unmutated IGHV genes (HR: 1.63; 95% CI: 1.17–2.26; p=0.0039; 92% bootstrap selection). Overall, 21.5% (105/488) low risk patients according to the FISH model (del13q14, normal and +12) were reclassified into high risk genetic subgroups by the MUCY model because of the co-occurrence of NOTCH1 (64/488, 13.1%), SF3B1 (35/488, 7.1%), and TP53 (17/488, 3.4%) mutations or BIRC3 disruption (14/488, 2.8%). Consistently, the inclusion of NOTCH1, SF3B1 and BIRC3 lesions in addition to FISH abnormalities significantly improved the model accuracy of OS prediction (c-index: 0.617 vs c-index: 0.642 p<0.0001). At 10 years from diagnosis, 24.5% CLL of the very low and low risk genetic subgroups developed new TP53, NOTCH1, SF3B1, BIRC3 or del11q22-q23 lesions due to clonal evolution, and therefore switched to a higher risk category of the MUCY model. By time-dependent and landmark analysis, the MUCY model retained a statistically significant impact on CLL OS (HR: 1.52; 95% CI: 1.21–1.90; p=0.0003) at any time from diagnosis and independent of its dynamic changes due to clonal evolution. The MUCY model classifies CLL patients into more precise subgroups, advances our understanding of CLL biology, and improves current prognostic algorithms. These findings have relevant implications for the design of clinical trials aimed at assessing the use of mutational profiling to inform therapeutic decisions based on risk stratification. Disclosures: No relevant conflicts of interest to declare.

The aim of our study was to evaluate the feasibility and the safety of the use of peripherally inserted central catheters (PICCs) during autologous peripheral blood stem cell transplantation. Sixty PICCs were inserted in 57 patients (23 females and 34 males; mean age 48, range 19-68 years) and remained in place for an overall period of 1,276 days. All PICCs were positioned by a team of specifically trained physicians and nurses and utilized by specifically trained nurses of our hematology unit. No major insertion-related complications were observed; the only complication during insertion was one local hematoma (1.6 %) due to accidental arterial puncture. Late complications were accidental catheter removal (5 %, 2.3 per 1,000 PICC days), symptomatic catheter-related venous thrombosis (5 %, 2.3 per 1,000 PICC days), and catheter-related bloodstream infection (CRBSI; 3.3 %, 1.5 CRBSI per 1,000 PICC days). The reasons for catheter removal were completion of therapy (42 patients, 70 %), fever of unknown origin (9 patients, 15 %), catheter-related thrombosis (2 patients, 3.3 %), CRBSI (2 patients, 3.3 %), accidental removal (3 patients, 5 %), lumen occlusion (1 patient, 1.6 %), positive culture from peripheral blood (1 patient, 1.6 %), and death (1 patient, 1.6 %). Our data suggest that PICCs are a safe and effective alternative to conventional central venous catheters even in patients particularly prone to infective and hemorrhagic complications such as patients receiving autologous stem cell transplantation.

Cellular immune responses are induced during hepatitis C virus (HCV) infection and acute-phase CD8 + T cells are supposed to play an important role in controlling viral replication. In chimpanzees, failure of CD8 + T cells to control HCV replication has been associated with acquisition of mutations in MHC class I-restricted epitopes. In humans, although selection of escape mutations in an immunodominant CTL epitope has been recently described, the overall impact of immune escape during acute HCV infection is unclear. Here, by performing an in depth analysis of the relationship between early cellular immune responses and viral evolution in a chronically evolving HCV acutely infected individual, we demonstrate: (i) the presence of a potent and focused CD8 + T cell response against a novel epitope in the NS3 protein, (ii) the elimination of the quasispecies harboring the original amino acid sequence within this epitope, and (iii) the selection for a virus population bearing amino acid changes at a single residue within the cytotoxic T cell epitope that strongly diminished T cell recognition. These results support the view that acute-phase CD8 + T cell responses exert a biologically relevant pressure on HCV replication and that viruses escaping this host response could have a significant survival advantage.

All-trans retinoic acid (ATRA) has shown a synergistic activity in combination with cytosine arabinoside in vitro in the treatment of acute myeloid leukaemia (AML). In this paper we report the results of treatment with low dose cytosine arabinoside (LDAC) with or without ATRA in 28 patients with acute myeloid leukaemia aged over 60 years: 14 patients received only LDAC and the other 14 LDAC + ATRA. The patients of the 2 groups showed similar clinical features: in 10 patients AML developed after a myelodysplastic form and 4 patients presented a previous malignancy. All the patients received subcutaneous (sc) LDAC (15 mg twice a day for 14 days) and in 14 patients oral ATRA (45 mg/sqm in the same days) was added to LDAC; the courses were repeated every 4 weeks from diagnosis to relapse. The treatment was well tolerated and the patients could self-administer sc LDAC and oral ATRA at home. No statistically significant differences were observed in complete remission rate (21% vs. 50%, respectively) and resistant rate (57% vs. 29%), but the patients treated with the combination of the 2 drugs had a better time to treatment failure (15 weeks vs. 30 weeks, respectively) (P = 0.045) and a longer survival (37 weeks vs. 66 weeks) (P = 0.019). Our experience, although with a low number of patients, confirms the efficacy of ATRA in combination with sc LDAC in the treatment of AML in elderly patients.

Summary A genome‐wide association study of chronic lymphocytic leukaemia (CLL) suggested that common variants at 15q25.2 (rs783540) and 18q21.1 (rs1036935) influence CLL. To validate these associations and explore their relationship with CLL risk we genotyped case‐control datasets from Poland, UK and Italy totalling 1428 cases and 1920 controls. Combined data from these and previously genotyped series (2503 cases and 5789 controls) provided evidence for an association between 15q25.2 and 18q21.1 loci and CLL risk (Pcombined = 1·10 × 10−7 and 1·30 × 10−5 respectively). These data provide further evidence for the involvement of common genetic variants in CLL risk and insight into the biological basis of disease development.