Giovanni Amendola

Donor/recipient mixed chimerism does not predict graft failure in children with β-thalassemia given an allogeneic cord blood transplant from an HLA-identical sibling

This study indicates that mixed chimerism is a frequent event and does not predict the occurrence of graft failure in children with thalassemia major given a cord blood transplant from an HLA-identical sibling. See related perspective article on page 1780. Background Donor/recipient mixed chimerism has been reported to be associated with an increased risk of graft failure in patients with β-thalassemia given a bone marrow transplant. We investigated the relationship between the degree of mixed chimerism over time and clinical outcome of children undergoing cord blood transplantation for β-thalassemia. Design and Methods Twenty-seven consecutive children given a cord blood transplant from a related donor were analyzed by short tandem repeat polymerase chain reaction and their chimerism results were compared with those of 79 consecutive patients who received a bone marrow transplant from either a relative (RD-BMT, n=42) or an unrelated donor (UD-BMT, n=37). Cord blood and bone marrow recipients received comparable preparative regimens. Results All cord blood recipients engrafted and displayed mixed chimerism early after transplantation; 13/27 converted to full donor chimerism over time, while 14 maintained stable mixed chimerism; all patients are alive and transfusion-independent. Twenty-four of the 79 bone marrow-recipients (12 UD- and 12 RD-BMT) exhibited full donor chimerism at all time points examined, 4/79 (2 UD- and 2 RD-BMT) did not engraft and 51/79 (23 UD- and 28 RD-BMT) displayed mixed chimerism at the time of hematologic reconstitution. Forty of 51 bone marrow recipients with mixed chimerism converted to full donor chimerism (17 UD- and 23 RD-BMT), 3/51 maintained stable mixed chimerism (1 UD- and 2 RD-BMT), while 8/51 (5 UD- and 3 RD-BMT) progressively lost the graft, and became transfusion-dependent again. Conclusions Mixed chimerism is a frequent event and does not predict the occurrence of graft failure in children with β-thalassemia given a cord blood transplant from a relative.

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.

An Autosomal Dominant Thrombocytopenia Gene Maps to Chromosomal Region 10p

The increasing number of diagnosed cases of inherited thrombocytopenias, owing to the routine practice of including platelet counts in blood tests, suggests that this condition is not so rare as expected. In the majority of cases, the molecular basis of the disease is unknown, although the defect is likely to affect thrombocytopoiesis and regulation of the normal platelet count. Here we report a genomewide search in a large Italian family affected by autosomal dominant thrombocytopenia. Patients showed a moderate thrombocytopenia with minimal symptoms characterized by normocellular bone marrow, normal medium platelet volume, and positive aggregation tests. Microsatellite analysis demonstrated that the disease locus (THC2) is linked to chromosome 10p11.1-12, within a candidate region of 6 cM between markers D10S586 and D19S1639. A maximum LOD score of 8.12 at recombination fraction.00 was obtained with the microsatellite D10S588. These data localized the first locus of an autosomal dominant thrombocytopenia, and the subsequent identification of the gene will provide new insight into the basic mechanism of megakaryocytopoiesis disorders.

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.

Frequent de novo monoallelic expression of β-spectrin gene (SPTB) in children with hereditary spherocytosis and isolated spectrin deficiency

This report represents an attempt to define the rate of β‐spectrin de novo mutations affecting mRNA accumulation in patients with hereditary spherocytosis (HS). 19 HS children with haematologically normal parents and varying degrees of spectrin deficiency were studied. 13 of the 19 cases who were heterozygous at the genomic level for polymorphisms in the β‐spectrin coding region were further studied. However, in an analysis of reverse‐transcripted amplified cDNA from the regions of the polymorphisms, seven patients appeared to be homozygous, suggesting the occurrence of de novo mutational events affecting expression of one β‐spectrin allele. We conclude that in HS patients with isolated spectrin reduction and normal parents the apparently recessive pattern of inheritance may frequently be associated with de novo monoallelic expression of β‐spectrin.

Hepatocellular carcinoma in thalassaemia: an update of the Italian Registry.

The risk of developing hepatocellular carcinoma (HCC) in patients with thalassaemia is increased by transfusion‐transmitted infections and haemosiderosis. All Italian Thalassaemia Centres use an ad hoc form to report all diagnoses of HCC to the Italian Registry. Since our last report, in 2002, up to December 2012, 62 new cases were identified, 52% of whom were affected by thalassaemia major (TM) and 45% by thalassaemia intermedia (TI). Two had sickle‐thalassaemia (ST). The incidence of the tumour is increasing, possibly because of the longer survival of patients and consequent longer exposure to the noxious effects of the hepatotropic viruses and iron. Three patients were hepatitis B surface antigen‐positive, 36 patients showed evidence of past infection with hepatitis B virus (HBV). Fifty‐four patients had antibodies against hepatitis C virus (HCV), 43 of whom were HCV RNA positive. Only 4 had no evidence of exposure either to HCV or HBV. The mean liver iron concentration was 8 mg/g dry weight. Therapy included chemoembolization, thermoablation with radiofrequency and surgical excision. Three patients underwent liver transplant, 21 received palliative therapy. As of December 2012, 41 patients had died. The average survival time from HCC detection to death was 11·5 months (1·4–107·2 months). Ultrasonography is recommended every 6 months to enable early diagnosis of HCC, which is crucial to decrease mortality.

Endocrine function and bone disease during long-term chelation therapy with deferasirox in patients with β-thalassemia major

Iron overload in β‐thalassemia major (TM) typically results in iron‐induced cardiomyopathy, liver disease, and endocrine complications. We examined the incidence and progression of endocrine disorders (hypothyroidism, diabetes, hypoparathyroidism, hypogonadism), growth and pubertal delay, and bone metabolism disease during long‐term deferasirox chelation therapy in a real clinical practice setting. We report a multicenter retrospective cohort study of 86 transfusion‐dependent patients with TM treated with once daily deferasirox for a median duration of 6.5 years, up to 10 years. No deaths or new cases of hypothyroidism or diabetes occurred. The incidence of new endocrine complications was 7% (P = 0.338, for change of prevalence from baseline to end of study) and included hypogonadism (n = 5) and hypoparathyroidism (n = 1). Among patients with hypothyroidism or diabetes at baseline, no significant change in thyroid parameters or insulin requirements were observed, respectively. Mean lumbar spine bone mineral density increased significantly (P < 0.001) and the number of patients with lumbar spine osteoporosis significantly decreased (P = 0.022) irrespective of bisphosphonate therapy, hormonal replacement therapy, and calcium or vitamin D supplementation. There were no significant differences in the number of pediatric patients below the 5th centile for height between baseline and study completion. Six pregnancies occurred successfully, and four of them were spontaneous without ovarian stimulation. This is the first study evaluating endocrine function during the newest oral chelation therapy with deferasirox. A low rate of new endocrine disorders and a stabilization of those pre‐exisisting was observed in a real clinical practice setting. Am. J. Hematol. 89:1102–1106, 2014.

Treatment with short‐term, high‐dose cyclosporin A in children with refractory chronic idiopathic thrombocytopenic purpura

Summary. We report on 14 children (seven boys, seven girls) with chronic idiopathic thrombocytopenic purpura (ITP) refractory to multiple treatments, who were given a short‐term therapy (range between 6 and 10 weeks) with high doses of cyclosporin A (CyA) (median, 10 mg/kg/d). Six patients experienced adverse events and one developed severe systemic mycosis during therapy. A complete response (CR) was observed in four patients and a partial response (PR) in three patients. Only the four CR patients, who were all girls, had a sustained response. These data suggest that CyA may be effective in some children with chronic symptomatic ITP.

EPO Receptor Gain-of-Function Causes Hereditary Polycythemia, Alters CD34+ Cell Differentiation and Increases Circulating Endothelial Precursors

Background Gain-of-function of erythropoietin receptor (EPOR) mutations represent the major cause of primary hereditary polycythemia. EPOR is also found in non-erythroid tissues, although its physiological role is still undefined. Methodology/Principal Findings We describe a family with polycythemia due to a heterozygous mutation of the EPOR gene that causes a G→T change at nucleotide 1251 of exon 8. The novel EPOR G1251T mutation results in the replacement of a glutamate residue by a stop codon at amino acid 393. Differently from polycythemia vera, EPOR G1251T CD34+ cells proliferate and differentiate towards the erythroid phenotype in the presence of minimal amounts of EPO. Moreover, the affected individuals show a 20-fold increase of circulating endothelial precursors. The analysis of erythroid precursor membranes demonstrates a heretofore undescribed accumulation of the truncated EPOR, probably due to the absence of residues involved in the EPO-dependent receptor internalization and degradation. Mutated receptor expression in EPOR-negative cells results in EPOR and Stat5 phosphorylation. Moreover, patient erythroid precursors present an increased activation of EPOR and its effectors, including Stat5 and Erk1/2 pathway. Conclusions/Significance Our data provide an unanticipated mechanism for autosomal dominant inherited polycythemia due to a heterozygous EPOR mutation and suggest a regulatory role of EPO/EPOR pathway in human circulating endothelial precursors homeostasis.

A mutation in the acyl-coenzyme A binding domain-containing protein 5 gene (ACBD5 ) identified in autosomal dominant thrombocytopenia

*Department of Clinical Genetics, Erasmus Medical Centre, Rotterdam, the Netherlands; Department of Paediatrics, Second University ofNaples, Naples; Ematologia-Oncologia Pediatrica, Ospedale di Nocera Inferiore, Salerno, Italy; and §CBG-Department of Clinical Genetics,Erasmus Medical Centre, Rotterdam, the NetherlandsTo cite this article: Punzo F, Mientjes EJ, Rohe CF, Scianguetta S, Amendola G, Oostra BA, Bertoli-Avella AM, Perrotta S. A mutation in the acyl-coenzyme A binding domain-containing protein 5 gene (ACBD5) identified in autosomal dominant thrombocytopenia. J Thromb Haemost 2010; 8:2085–7.