In paroxysmal nocturnal hemoglobinuria (PNH) hemolytic anemia is due mainly to deficiency of the complement regulator CD59 on the surface of red blood cells (RBCs). Eculizumab, an antibody that targets complement fraction 5 (C5), has proven highly effective in abolishing complement-mediated intravascular hemolysis in PNH; however, the hematologic benefit varies considerably among patients. In the aim to understand the basis for this variable response, we have IntroductionParoxysmal nocturnal hemoglobinuria (PNH) is a hematologic disorder characterized by the clonal expansion of one or a few hematopoietic stem cells that are incapable of glycosylphosphatidylinositol (GPI)-anchor biosynthesis, due to an acquired somatic mutation in the phosphatidylinositol glycan class A (PIG-A) gene. [1][2][3][4][5][6] Affected progeny cells are deficient in all GPI-anchored surface proteins, including the complement regulators CD55 and CD59. 7-9 Thus, PNH red blood cells (RBCs) are exquisitely vulnerable to activated complement, and particularly to the membrane attack complex (MAC), 10,11 resulting in chronic intravascular hemolysis with recurrent exacerbations, and consequent anemia.Eculizumab (Soliris; Alexion Pharmaceuticals, Cheshire, CT) is a humanized monoclonal antibody against complement fraction 5 (C5), which inhibits MAC formation. 12 Eculizumab has proven highly beneficial in the treatment of transfusion-dependent PNH patients. [13][14][15] In a placebo-controlled phase 3 trial, eculizumab led to a marked decrease in transfusion requirement, and improvement in anemia, fatigue, pain, shortness of breath, and QoL measures. 15 These data were confirmed in 2 subsequent studies, 16,17 the last one also suggesting that eculizumab may reduce the occurrence of thromboembolic events. 17 In the face of such gratifying clinical results, it is clear that not all patients respond equally to the treatment. In some patients there is only little improvement of anemia, and some still require blood transfusion at times, with signs of persistent hemolysis (reticulocytosis, elevated unconjugated bilirubin). 15,16 In this work, we have investigated the notion that in patients with suboptimal hematologic response to eculizumab there may be extravascular hemolysis mediated by complement effector mechanisms other than MAC. 15 Based on flow cytometry analysis of complement fraction 3 (C3) on RBCs, we provide evidence of selective C3 opsonization of GPI-negative red cells, the extent of which tends to correlate with the clinical response to eculizumab, and may be the manifestation of a novel phenomenon in the pathophysiology of PNH. Methods PatientsThe study was conducted in 56 Italian PNH patients (Table 1); biologic samples were collected by venipuncture according to standard procedures, after informed consent was obtained in accordance with the Declaration of Helsinki as approved within the study protocol by the Institutional Review Board at the Federico II University of Naples. Twenty-eight patients were studied at diagnosis, before any t...

Aberrant signal transduction contributes substantially to leukemogenesis. The Janus kinase 1 (JAK1) gene encodes a cytoplasmic tyrosine kinase that noncovalently associates with a variety of cytokine receptors and plays a nonredundant role in lymphoid cell precursor proliferation, survival, and differentiation. We report that somatic mutations in JAK1 occur in individuals with acute lymphoblastic leukemia (ALL). JAK1 mutations were more prevalent among adult subjects with the T cell precursor ALL, where they accounted for 18% of cases, and were associated with advanced age at diagnosis, poor response to therapy, and overall prognosis. All mutations were missense, and some were predicted to destabilize interdomain interactions controlling the activity of the kinase. Three mutations that were studied promoted JAK1 gain of function and conferred interleukin (IL)-3–independent growth in Ba/F3 cells and/or IL-9–independent resistance to dexamethasone-induced apoptosis in T cell lymphoma BW5147 cells. Such effects were associated with variably enhanced activation of multiple downstream signaling pathways. Leukemic cells with mutated JAK1 alleles shared a gene expression signature characterized by transcriptional up-regulation of genes positively controlled by JAK signaling. Our findings implicate dysregulated JAK1 function in ALL, particularly of T cell origin, and point to this kinase as a target for the development of novel antileukemic drugs.

The GIMEMA ALL 0288 trial was designed to evaluate the impact of a 7-day prednisone (PDN) pretreatment on complete remission (CR) achievement and length, the influence of the addition of cyclophosphamide (random I) to a conventional 4-drug induction on CR rate and duration, and whether an early post-CR intensification (random II) by an 8-drug consolidation could improve CR duration. Median follow-up of this study was 7.3 years. From January 1988 to April 1994, among 794 adult (> 12 but < 60 years) patients registered, 778 were eligible. Their median age was 27.5 years; 73% had Blineage acute lymphoblastic leukemia (ALL) and 22% had T-lineage disease; 18% showed associated myeloid markers; 47 of 216 analyzed patients (22%) had Philadelphia chromosome-positive ALL. Response to PDN pretreatment was observed in 65% of cases. CR was achieved in 627 patients (82%). Resistant patients and induction death rates were 11% and 7%, respectively. Random II was applied to 388 patients with CR; 201 had maintenance alone and 187 had consolidation followed by maintenance. The relapse rate was 60%; isolated central nervous system relapses were 8% of all

Purpose Cytarabine plays a pivotal role in the treatment of patients with acute myeloid leukemia (AML). Most centers use 7 to 10 days of cytarabine at a daily dose of 100 to 200 mg/m2 for remission induction. Consensus has not been reached on the benefit of higher dosages of cytarabine. Patients and Methods The European Organisation for Research and Treatment of Cancer (EORTC) and Gruppo Italiano Malattie Ematologiche dell' Adulto (GIMEMA) Leukemia Groups conducted a randomized trial (AML-12; Combination Chemotherapy, Stem Cell Transplant and Interleukin-2 in Treating Patients With Acute Myeloid Leukemia) in 1,942 newly diagnosed patients with AML, age 15 to 60 years, comparing remission induction treatment containing daunorubicin, etoposide, and either standard-dose (SD) cytarabine (100 mg/m2 per day by continuous infusion for 10 days) or high-dose (HD) cytarabine (3,000 mg/m2 every 12 hours by 3-hour infusion on days 1, 3, 5, and 7). Patients in complete remission (CR) received a single consolidation cycle containing daunorubicin and intermediate-dose cytarabine (500 mg/m2 every 12 hours for 6 days). Subsequently, a stem-cell transplantation was planned. The primary end point was survival. Results At a median follow-up of 6 years, overall survival was 38.7% for patients randomly assigned to SD cytarabine and 42.5% for those randomly assigned to HD cytarabine (log-rank test P = .06; multivariable analysis P = .009). For patients younger than age 46 years, survival was 43.3% and 51.9%, respectively (P = .009; multivariable analysis P = .003), and for patients age 46 to 60 years, survival was 33.9% and 32.9%, respectively (P = .91). CR rates were 72.0% and 78.7%, respectively (P < .001) and were 75.6% and 82.4% for patients younger than age 46 years (P = .01) and 68.3% and 74.8% for patients age 46 years and older (P = .03). Patients of all ages with very-bad-risk cytogenetic abnormalities and/or FLT3-ITD (internal tandem duplication) mutation, or with secondary AML benefitted from HD cytarabine. Conclusion HD cytarabine produces higher remission and survival rates than SD cytarabine, especially in patients younger than age 46 years.