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...

In idiopathic thrombocytopenic purpura (ITP), corticosteroids have been widely recognized as the most appropriate firstline treatment, even if the best therapeutic approach is still a matter of debate. Recently, a single high-dose dexamethasone (HD-DXM) course was administered as first-line therapy in adult patients with ITP. In this paper we show the results of 2 prospective pilot studies (monocentric and multicentric, respectively) concerning the use of repeated pulses of HD-DXM in untreated ITP patients. In the monocenter study, 37 patients with severe ITP, age at least 20 years and no more than 65 years, were enrolled. HD-DXM was given in 4-day pulses every 28 days, for 6 cycles. Response rate was 89.2%; relapse-free survival (RFS) was 90% at 15 months; long-term responses, lasting for a median time of 26 months (range 6-77 months) were 25 of 37 (67.6%). In the multicenter study, 95 patients with severe ITP, age at least 2 years and no more than 70 years, were enrolled. HD-DXM was given in 4-day pulses every 14 days, for 4 cycles; 90 patients completed 4 cycles. Response rate (85.6%) was similar in patients classified by age (< 18 years, 36 of 42 ‫؍‬ 85.7%; > 18 years, 41 of 48 ‫؍‬ 85.4%, P ‫؍‬ not significant), with a statistically significant difference between the second and third cycle (75.8% vs 89%, P ‫؍‬ .018). RFS at 15 months 81%; long-term responses, lasting for a median time of 8 months (range 4-24 months) were 67 of 90 (74.4%). In both studies, therapy was well tolerated. A schedule of 3 cycles of HD-DXM pulses will be compared with standard prednisone therapy (eg, 1 mg/kg per day) in the next randomized Gruppo Italiano Malattie EMatologiche dell'Adulto (GIMEMA) trial. (Blood.

This study demonstrates that familial and sporadic ET recognize different pathogenetic mechanisms. Myeloproliferative markers are specific tests for the diagnosis of ET in children with sporadic forms, while a significant proportion of children with PV can prove negative.

Sixty-four patients < 20 years of age, investigated for a suspicion of Philadelphianegative myeloproliferative disease (MPD), were retrospectively evaluated to characterize the different forms and to examine the treatments used and longterm outcome. JAK2 mutations, endogenous erythroid colony growth, and clonality were investigated in 51 children. After a median follow-up of 124 months, no patient had developed leukemia or myelofibrosis and 5% had thrombosis; the miscarriage rate in thrombocythemic patients was 14%. The low complication rate in our population suggests that children with MPD may be managed by tailored approaches.

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