Domenico De Mattia

Hereditary deficiency of gp91(phox) is associated with enhanced arterial dilatation: results of a multicenter study.

Background— NADPH oxidase is believed to modulate arterial tone, but its role in humans is still unclear. The objective of this study was to evaluate whether NADPH oxidase is involved in flow-mediated arterial dilation (FMD). Methods and Results— Twenty-five patients with hereditary deficiency of gp91phox, the catalytic core of NADPH oxidase, (X-CGD), 25 healthy subjects, and 25 obese patients matched for sex and age were recruited. FMD, platelet gp91phox, serum levels of nitrite and nitrate as markers of nitric oxide generation, oxidized low-density lipoprotein, and urinary excretion of isoprostanes as markers of oxidative stress were determined. Platelet gp91phox expression was downregulated in X-CGD patients (1.0±0.8 mean fluorescence; P<0.001) and upregulated in obese patients (4.1±2.2 mean fluorescence; P=0.01) compared with healthy subjects (2.9±1.7 mean fluorescence). Urinary excretion of isoprostanes was reduced in X-CGD patients (41.7±33.3 pg/mg creatinine; P=0.04) and increased in obese patients (154.4±91 pg/mg creatinine; P<0.001) compared with healthy subjects (69.5±52.4 pg/mg creatinine). Obese patients had higher serum oxidized low-density lipoprotein than healthy subjects (35.3±6.7 versus 24.8±9.8 U/L; P<0.001) and X-CGD patients (28.5±7.2 U/L; P<0.001). X-CGD patients had significantly higher FMD (14.7±5.9%) compared with healthy subjects (7.9±2.5%; P<0.001); obese patients had lower FMD (5.3±3.0%; P=0.028) compared with healthy subjects. Serum nitrite and nitrate levels were significantly higher in patients with X-CGD (36.0±10.8 μmol/L; P=0.016) and lower in obese patients (9.3±11.0 μmol/L; P=0.001) compared with healthy subjects (27.1±19.1 μmol/L). Serum nitrite and nitrate levels significantly correlated with FMD (Rs=0.403, P<0.001) and platelet gp91phox (Rs=−0.515, P<0.001). FMD inversely correlated with platelet gp91phox (Rs=−0.502, P<0.001) and isoprostanes (Rs=−0.513, P<0.001). Conclusion— This study provides the first evidence that, in humans, gp91phox is implicated in the modulation of arterial tone.

Metabolic, inflammatory, endothelial and haemostatic markers in a group of Italian obese children and adolescents.

Childhood obesity and its related comorbidities are increasingly recognised in children, predisposing them to early cardiovascular disease and metabolic syndrome. The objective of the study was to investigate markers of metabolism, inflammation and haemostasis in a group of Italian obese children and adolescents. Fifty-nine obese and 40 non-obese subjects were recruited. Fasting glucose and insulin, total cholesterol, HDL and LDL cholesterol, triglycerides, high-sensitivity C-reactive protein (hsCRP), tumour necrosis factor alpha (TNF-α), and adiponectin were measured. Hypercoagulability was assessed by measuring the circulating levels of thrombin-antithrombin complex (TAT), D-dimer, fibrinogen, plasminogen activator inhibitor 1 (PAI-1) and von Willebrand Factor (vWF). A significant degree of insulin resistance was present in obese subjects compared with controls (p < 0.0001). The obese showed higher levels of total cholesterol, LDL cholesterol and triglycerides, and lower levels of HDL cholesterol than controls (p < 0.0001). Circulating levels of hsCRP and TNF-α were significantly higher in obese than in controls while serum adiponectin levels were significantly lower in obese than non-obese subjects (p < 0.001; p = 0.031; p < 0.0001, respectively). vWF, TAT, D-dimer, fibrinogen and PAI-1 levels were significant higher in obese subjects compared with control group (p = 0.02; p < 0.0001; p = 0.0037; p < 0.0001; p = 0.017, respectively). In conclusion, our results suggest that childhood obesity per se is associated with a proinflammatory and prothrombotic state.

Lupus anticoagulant, anticardiolipin antibodies and hepatitis C virus infection in thalassaemia

Anticardiolipin antibodies (ACA) and lupus anticoagulant (LA) have been detected in patients with hepatitis C virus (HCV) infection and have been associated in autoimmune diseases (i.e. systemic lupus erythematosus) with an increased risk of thromboembolic events. Because of the high prevalence of HCV infection and the thrombotic risk described in thalassaemia we decided to investigate the prevalence of ACA and LA in a cohort of 68 thalassaemia patients. We found a high prevalence (34%) of β2‐glycoprotein I independent ACA in our thalassaemia patients which was related to HCV infection. None of patients developed any complications related to antiphospholipid antibodies (APL); therefore the clinical significance of positivity for APL in patients with HCV infection is at present unclear. In conclusion, the results of our study indicate that ACA in the serum of HCV‐infected thalassaemic patients exhibit the characteristics of natural autoantibodies rather than those of the pathogenic autoantibodies that are found in patients with systemic lupus erythematosus.

Prospective study of hemostatic alterations in children with acute lymphoblastic leukemia

In a group of newly diagnosed acute lymphocytic leukemia (ALL) children we evaluated a number of hemostatic and inflammatory markers at diagnosis and at different time points during chemotherapy for the remission induction to identify alterations in the plasma levels of prothrombotic markers before and during the course of chemotherapy. The following plasma markers were evaluated: thrombin‐antithrombin complex (TAT), D‐Dimer, plasminogen activator inhibitor 1 (PAI‐1), antithrombin, fibrinogen, von Willebrand factor (VWF) antigen and high molecular weight VWF (HMW‐VWF) multimers, P‐selectin, tumor necrosis factor alpha (TNF‐α), and interleukin 6 (IL‐6). Plasma samples were collected at the following time points: at T0 (baseline) and T1 (+24 days of therapy), T2 (+36 days therapy), and T3 (+64 days therapy). The results show that, at diagnosis, ALL children presented with laboratory signs of increased thrombin generation and fibrin formation (i.e. high TAT and D‐dimer levels), fibrinolysis inhibition (i.e. high PAI‐1 level), endothelial activation (i.e., high HMW‐VWF and soluble P‐selectin levels) and inflammation (i.e. high TNF‐alpha and IL‐6 levels). After starting induction therapy, the thrombin generation markers and inflammatory cytokines significantly decreased. To the opposite, PAI‐1 and P‐selectin significantly increased, suggesting an insult by chemotherapy on the vascular endothelium. These effects were more evident during steroid administration. Symptomatic venous thromboembolism (VTE) episodes developed in two cases during induction therapy, which did not allow the evaluation of the predictive value for VTE of laboratory markers. Am. J. Hematol., 2010.

Dyserythropoietic Anemia and Thrombocytopenia due to a Novel Mutation in GATA-1

Hematopoiesis is a complex process regulated by nuclear proteins that coordinate lineage-specific patterns of gene expression. Targeted mutagenesis has revealed critical roles for the X-linked transcription factor GATA-1 in erythrocyte and megakaryocyte differentiation. GATA-1 has two zinc fingers essential for normal function. The C-terminal finger is necessary for DNA binding. The N-terminal finger mediates interaction with FOG-1, a cofactor for GATA-1. Mutations in the N-terminal zinc finger of GATA-1 result in abnormal hematopoiesis. Here we report a family with a novel single base mutation that results in an amino acid substitution (Gly208Arg) within the highly conserved portion of the GATA-1 N-terminal finger domain, leading to dyserythropoietic anemia and macrothrombocytopenia. Another mutation described at the same codon (208) has been found to be associated with thrombocytopenia only. Our data support and extend the effect of the amino acid substitution at codon 208 on GATA-1 function not only regarding megakaryocyte but also regarding erythroid development.

Effect of eradication of Helicobacter pylori in children with chronic immune thrombocytopenia: A prospective, controlled, multicenter study†

The eradication of Helicobacter pylori has been associated with remission of immune thrombocytopenia (ITP) in approximately half of eradicated patients. Data on children are limited to small case series.

Long‐term follow‐up analysis after rituximab therapy in children with refractory symptomatic ITP: identification of factors predictive of a sustained response

We report the long‐term follow‐up (median 39·5 months) of 49 paediatric patients (33 females and 16 males) with refractory symptomatic immune thrombocytopenic purpura (ITP) treated with rituximab. The overall response rate was 69% (34/49 patients). Twenty‐one responders had a platelet count >50 × 109/l at a median 20·2 months from treatment. Kaplan–Meier analysis showed a probability of relapse‐free survival (RFS) of 60% at 36 months from the first rituximab infusion. The number of infusions and a previous splenectomy did not influence overall response rate. Patients who achieved complete response were significantly older at diagnosis and first rituximab infusion than partial responders (P = 0·027). Older children displayed a significantly greater probability of sustained response (RFS) at 36 months than younger children (88·9% vs. 56·7%, P = 0·037). Earlier responses (within 20 d from treatment) were significantly associated with both complete (P = 0·004) and sustained response (P = 0·002). Only mild and transient side‐effects were observed in 9/49 children; no major infections nor delayed toxicities were recorded during the follow‐up.

Mutational screening of thrombopoietin receptor gene (c-mpl) in patients with congenital thrombocytopenia and absent radii (TAR)

Thrombocytopenia with absent radii (TAR) is a rare autosomal recessive disease characterized by hypomegakaryocytic thrombocytopenia and bilateral radial aplasia. We performed mutational screening of coding and promoter regions of the c‐mpl gene, encoding thrombopoietin (TPO) receptor, by sequence analysis in four unrelated patients affected by TAR syndrome. Our results indicate that c‐mpl gene mutations are not a common cause of thrombocytopenia in TAR syndrome.

Rituximab (anti-cd20 monoclonal antibody) in children with chronic refractory symptomatic immune thrombocytopenic purpura: efficacy and safety of treatment

This retrospective study investigated the effects of rituximab in 19 pediatric patients (15 girls and 4 boys) with chronic refractory symptomatic immune thrombocytopenic purpura (ITP). Patients received from 2 to 5 weekly infusions of rituximab (375 mg/m2); 15 patients were younger than 12 years when treated. The median follow-up time was 30 months (range, 9–43 months). The overall response rate was 68% (13/19 patients). Six responders relapsed at a median of 4.5 months (range, 3–8 months). Seven patients still displayed a platelet count >150,000/μL at a median of 33 months (range, 14-43 months) after rituximab treatment. Six of 15 patients treated with 4 or 5 weekly infusions and 1 of 4 patients treated with 2 or 3 infusions are still in remission. No difference was detected between splenectomized and nonsplenectomized patients. The duration of ITP disease at the time of treatment did not influence the response rate. Patients still in remission showed significantly lower levels of CD19+ cells after 4 and 6 months than nonresponding or relapsed patients (P < .05). No major infections were reported during follow-up. Our data show the efficacy and tolerability of rituximab in young children with refractory symptomatic ITP. Nonrelapsed patients showed a more prolonged B-cell depletion.

Impact of influenza-like illness and effectiveness of influenza vaccination in oncohematological children who have completed cancer therapy

Abstract In order to evaluate the impact of influenza-like illness and the effectiveness of influenza vaccination in children with oncohematological disease who have completed cancer therapy, 182 children with a diagnosis of oncohematological disease were divided into two subgroups on the basis of the length of time off therapy (<6 months or 6–24 months) and randomised 1:1 to receive influenza vaccination or not. The controls were 91 otherwise healthy children unvaccinated against influenza. The results show that the clinical and socioeconomic impact of influenza-like illnesses and the effectiveness of influenza vaccination in oncohematological children who have completed cancer therapy are related to the length of the off therapy period, and seem to be significantly greater in those who have been off therapy for less than 6 months in comparison with healthy controls. This suggests that the administration of influenza vaccination should be strongly recommended only among oncohematological children who have been off therapy for less than 6 months.