[Deferasirox and Complex Proximal Tubulopathy. Presentation of two clinical cases]

INTRODUCTION

Treatment with iron chelators is essential for patients with iron overload secondary to repeated trans fusions. Deferasirox is the first once-daily oral active iron chelator. As a result, therapeutic adherence has improved, reducing the complications of iron overload, especially heart failure. However, it is not exempt from possible side effects, such as kidney involvement, which is more frequent in children.

OBJECTIVE

To report 2 patients with Diamond-Blackfan anemia (DBA) who developed impaired renal function secondary to the administration of Deferasirox.

CLINICAL CASES

Case 1. A 15-year-old adolescent diagnosed with DBA undergoing treatment with periodic transfusions and Deferasirox. During an acute gastroenteritis, she developed acute renal failure along with complex proximal tubu- lopathy. Case 2. A 5-year-old boy diagnosed with DBA receiving periodic transfusions and treatment with Deferasirox. He presented polyuria with laboratory abnormalities compatible with acute renal failure and proximal tubular dysfunction. In both cases, they were adequately hydrated and Deferasi rox was temporarily suspended, improving renal function.

CONCLUSION

Based on these cases, close monitoring of renal and tubular function, as well as ferritin levels, is recommended in patients recei ving Deferasirox. In the presence of intercurrent processes, adequate hydration should be performed, and an early dose reduction or drug administration interruption should be considered in cases of kidney involvement.

Eltrombopag Improves Erythroid Differentiation in a Human Induced Pluripotent Stem Cell Model of Diamond Blackfan Anemia

Diamond Blackfan Anemia (DBA) is a congenital macrocytic anemia associated with ribosomal protein haploinsufficiency. Ribosomal dysfunction delays globin synthesis, resulting in excess toxic free heme in erythroid progenitors, early differentiation arrest, and pure red cell aplasia. In this study, DBA induced pluripotent stem cell (iPSC) lines were generated from blood mononuclear cells of DBA patients with inactivating mutations in RPS19 and subjected to hematopoietic differentiation to model disease phenotypes. In vitro differentiated hematopoietic cells were used to investigate whether eltrombopag, an FDA-approved mimetic of thrombopoietin with robust intracellular iron chelating properties, could rescue erythropoiesis in DBA by restricting the labile iron pool (LIP) derived from excessive free heme. DBA iPSCs exhibited RPS19 haploinsufficiency, reduction in the 40S/60S ribosomal subunit ratio and early erythroid differentiation arrest in the absence of eltrombopag, compared to control isogenic iPSCs established by CRISPR/Cas9-mediated correction of the RPS19 point mutation. Notably, differentiation of DBA iPSCs in the presence of eltrombopag markedly improved erythroid maturation. Consistent with a molecular mechanism based on intracellular iron chelation, we observed that deferasirox, a clinically licensed iron chelator able to permeate into cells, also enhanced erythropoiesis in our DBA iPSC model. In contrast, erythroid maturation did not improve substantially in DBA iPSC differentiation cultures supplemented with deferoxamine, a clinically available iron chelator that poorly accesses LIP within cellular compartments. These findings identify eltrombopag as a promising new therapeutic to improve anemia in DBA.

Identification of novel drug targets for diamond-blackfan anemia based on RPS19 gene mutation using protein-protein interaction network

BACKGROUND

Diamond-Blackfan anemia (DBA) is a congenital erythroid aplasia that usually presents in infancy. In order to explore the molecular mechanisms of wild and mutated samples from DBA patients were exposed to bioinformatics investigation. Biological network of differentially expressed genes was constructed. This study aimed to identify novel therapeutic signatures in DBA and uncovered their mechanisms. The gene expression dataset of GSE14335 was used, which consists of 6 normal and 4 diseased cases. The gene ontology (GO), as well as Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed, and then protein-protein interaction (PPI) network of the identified differentially expressed genes (DEGs) was constructed by Cytoscape software.

RESULTS

A total of 607 DEGs were identified in DBA, including 433 upregulated genes and 174 downregulated genes. GO analysis results showed that upregulated DEGs were significantly enriched in biological processes, negative regulation of transcription from RNA polymerase II promoter, chemotaxis, inflammatory response, immune response, positive regulation of cell proliferation, negative regulation of cell proliferation, response to mechanical stimulus, positive regulation of cell migration, response to lipopolysaccharide, and defence response. KEGG pathway analysis revealed the TNF signalling pathway, Osteoclast differentiation, Chemokine signalling pathway, Cytokine -cytokine receptor interaction, Rheumatoid arthritis, Biosynthesis of amino acids, Biosynthesis of antibiotics and Glycine, serine and threonine metabolism. The top 10 hub genes, AKT1, IL6, NFKB1, STAT3, STAT1, RAC1, EGR1, IL8, RELA, RAC3, mTOR and CCR2 were identified from the PPI network and sub-networks.

CONCLUSION

The present study flagged that the identified DEGs and hub genes enrich our understanding of the molecular mechanisms underlying the development of DBA, and might shine some lights on identifying molecular targets and diagnostic biomarkers for DBA.

[Successful long-term management with low-dose prednisolone in an adult patient with Diamond-Blackfan anemia]

Diamond-Blackfan anemia (DBA) is a rare congenital disease caused by mutations in ribosomal protein genes and is characterized by pure red cell aplasia. While the prognosis is relatively favorable, quality of life (QOL) among DBA patients is negatively impacted by the adverse effects of long-term prednisolone (PSL) therapy and blood transfusions. We describe a 43-year-old man who was diagnosed with DBA (Hb of 2.18 g/dl) at the age of two months. He was initially treated with PSL and blood transfusions, followed by cyclosporine and low-dose (6 mg/day) PSL, which resulted in a sustained hemoglobin level of 9 g/dl without severe adverse events or loss of QOL. High levels of eADA and GSH as well as a RPS19 gene mutation were confirmed. The only curative therapy is hematopoietic stem cell transplantation, which is associated with significant mortality. However, using low-dose PSL to maintain a stable hemoglobin level may improve QOL for patients who receive curative treatment.

Pure red cell aplasia

Pure red cell aplasia (PRCA) is a syndrome defined by a normocytic normochromic anemia with severe reticulocytopenia and marked reduction or absence of erythroid precursors from the bone marrow. Diamond-Blackfan anemia is a congenital form of PRCA. Acquired PRCA may be either a primary disorder or secondary to some other disorder or agent. Primary acquired PRCA is an autoimmune disorder that is frequently antibody-mediated. Myelodysplastic syndromes may also present with the morphologic appearance of PRCA. Secondary acquired PRCA may be associated with collagen vascular/autoimmune disorders such as systemic lupus erythematosus; lymphoproliferative disorders such as chronic lymphocytic leukemia or large granular lymphocyte leukemia; infections, particularly B19 parvovirus; thymoma and other solid tumors; or a variety of other disorders, drugs, or toxic agents. The therapeutic approach to PRCA typically involves immunosuppression, but specific pathogenic subtypes are associated with specific therapeutic approaches. Cyclosporine A, with or without concurrent corticosteroids, appears to be the single most effective immunosuppressive agent.

Diamond-Blackfan anemia: Clinical features and treatment results in 4 cases

Diamond-Blackfan anemia is a rare hematological disease characterized by selective marrow erythroid hypoplasia. We present the clinical and hematological profile and results of treatment in four children. The median age at presentation was 14 months with a median age of onset of pallor at 7.5 months. Mean Hb at presentation was 2.9 g/dl. All children were started on prednisolone with response in one child. One child was switched to dexamethasone and responded transiently relapsing in 4 months but responded to further dexamethasone. Two children required cyclosporin for 3 and 8 weeks for response. With median follow-up of 59 months, all four children continue in complete hematological remission with no further relapses.

Dexamethasone and lenalidomide have distinct functional effects on erythropoiesis

Corticosteroids and lenalidomide decrease red blood cell transfusion dependence in patients with Diamond-Blackfan anemia (DBA) and myelodysplastic syndrome (MDS), respectively. We explored the effects of dexamethasone and lenalidomide, individually and in combination, on the differentiation of primary human bone marrow progenitor cells in vitro. Both agents promote erythropoiesis, increasing the absolute number of erythroid cells produced from normal CD34(+) cells and from CD34(+) cells with the types of ribosome dysfunction found in DBA and del(5q) MDS. However, the drugs had distinct effects on the production of erythroid progenitor colonies; dexamethasone selectively increased the number of burst-forming units-erythroid (BFU-E), whereas lenalidomide specifically increased colony-forming unit-erythroid (CFU-E). Use of the drugs in combination demonstrated that their effects are not redundant. In addition, dexamethasone and lenalidomide induced distinct gene-expression profiles. In coculture experiments, we examined the role of the microenvironment in response to both drugs and found that the presence of macrophages, the central cells in erythroblastic islands, accentuated the effects of both agents. Our findings indicate that dexamethasone and lenalidomide promote different stages of erythropoiesis and support the potential clinical utility of combination therapy for patients with bone marrow failure.

[Diamond-Blackfan anemia. Case report]

Diamond-blakfan anemia (DBA) is a rare condition in pediatric pathology, with more than 500 cases described in literature. It is a congenital eritroblastopenia, with AD/AR/ X-linkage inheritance, 90% were diagnosed by one year of age. Physical appearances were abnormal only in 29%. The current recommendations are corticosteroids, with suportive treatment and bone marrow transplantation. In general, DBA remains a single cytopenia. Long term prognosis remains uncertain, DBA is a preleukemia condition. We present two cases that we took care of in our clinics.

Hematopoietic growth factors for the treatment of inherited cytopenias

The clinical availability of recombinant hematopoietic growth factors was initially thought to be breakthrough in the treatment of bone marrow failure syndromes. However, in most disorders of hematopoeisis, the clinical use was rather disappointing. Only in congenital neutropenias (CNs) has the long-term administration of granulocyte colony-stimulating factor (G-CSF) led to a maintained increase in absolute neutrophil count (ANC) and a reduction of severe bacterial infections. In other disorders of hematopoiesis, the use of lineage-specific growth factors is either not possible due to mutations in the growth factor receptor or leads to a transient benefit only. Initial clinical trials with multilineage hematopoietic growth factors, such as stem cell factor (SCF; c-kit ligand) were discontinued due to adverse events. It is well known that bone marrow failure syndromes are pre-leukemic disorders. So far, there is no evidence for induction of leukemia by hematopoietic growth factors. However, it has been shown in patients with CN and Fanconi anemia that hematopoietic growth factors might induce preferential outgrowth of already transformed cells. Thus, it is strongly recommended to monitor patients for clonal aberrations prior to and during long-term treatment with hematopoietic growth factors.

Fatal agranulocytosis after deferiprone therapy in a child with Diamond-Blackfan anemia

A 10-year-old girl with steroid-resistent Diamond-Blackfan anemia (DBA) developed agranulocytosis 9 weeks after chelation with deferiprone was initiated (45 mg/kg daily, 60% of recommended dose) in addition to her ordinary deferoxamine therapy. The blood counts, checked weekly, dropped markedly between weeks 8 and 9. She rapidly developed a septicemia and was admitted with high fever (40.9°C), white blood cell count 0.4 × 109/L, absolute neutrophil count 0.1 × 109/L and platelets 114 × 109/L. She was administered broad spectrum antibiotics, G-CSF (10 microgram/kg daily) and corticosteroids but remained neutropenic and died 6 weeks after admission. Bone marrow examination day 23 revealed areas with low cellularity (around 30%), but also areas with infiltrates of T cells; granulopoiesis and erythropoiesis were scarce. We conclude that weekly neutrophil monitoring is not sufficient to avoid fatal agranulocytosis. We suggest that deferiprone not be prescribed to DBA patients unless the clinical indications are particularly strong, and that the risk of agranulocytosis in thalassemia patients be carefully considered.

High-risk pregnancies in Diamond-Blackfan anemia: a survey of 64 pregnancies from the French and German registries

We reviewed 64 pregnancies in 26 women with Diamond-Blackfan anemia (DBA) included in the French and German DBA registries. Complications were seen in 42 pregnancies (66%) and included abortion, pre-eclampsia, in utero fetal death, intrauterine growth retardation, retroplacental hematoma, pre-term delivery and fetal malformations. Of the 34 children (53%) born alive, 13 had DBA. No correlations were found between pregnancy outcome and features of either maternal or child DBA. Pregnancies in DBA-affected women are at high risk, especially for complications likely to be of vascular-placental origin. Careful monitoring with prevention of severe anemia and early introduction of aspirin is suggested.

Allogeneic peripheral blood stem cell transplant (PBSCT) using anti-IL2 receptor antibody Daclizumab for the prevention of acute graft versus host disease in steroid refractory Diamond Blackfan anaemia: a case report

The case report of a 2 year old boy with steroid refractory DBA, treated with allogeneic PBSCT from an HLA matched sibling is presented. Anti-IL2 receptor antibody Daclizumab was used as a prophylaxis for graft versus host disease (GvHD). Complete recovery without any evidence of GvHD ensued.

Use of rituximab to treat refractory Diamond-Blackfan anemia

We report here the first case with Diamond-Blackfan anemia (DBA) who responded to rituximab. The patient is an 8-yr-old Japanese girl with refractory DBA accompanied by complex congenital heart disease. She received two doses of rituximab, 375 mg/m(2)/wk. She became transfusion independent 6 months after the treatment without any serious side effect. However, after 8 months of transfusion-free period, her condition returned to the pretreatment level with recovery of peripheral B cells. Rituximab may be a successful therapy for refractory DBA where B cells play a crucial role in the pathogenesis of the severe anemia.

Successful treatment of Diamond-Blackfan anemia with metoclopramide

Diamond-Blackfan anemia (DBA) is a congenital anemia characterized by a low reticulocyte count, the absence or severe reduction of hemoglobin-containing cells in the bone marrow, and normal megakaryocytic and granulocytic differentiation. Although the anemia may initially respond to corticosteroid therapy, many patients require lifelong red blood cell (RBC) transfusion, leading to infectious complications and iron overload. Metoclopramide has recently been used to treat DBA. Treatment with metoclopramide induces the release of prolactin from the pituitary and stimulates erythropoiesis. For these reasons, we used metoclopramide to treat a 20-year-old man with DBA refractory to low and high doses of corticosteroids, cyclosporin A, and tacrolimus (FK506). The hemoglobin and hematocrit slowly increased, and he has remained asymptomatic and transfusion-independent for 8 months. Metoclopramide therapy should be considered in patients with refractory DBA before treatment-related complications develop.

Diamond-Blackfan anemia in Japan: clinical outcomes of prednisolone therapy and hematopoietic stem cell transplantation

The epidemiology and treatment outcomes for Diamond-Blackfan anemia (DBA) were surveyed in a cohort of 54 children (M/F = 26:28) registered in Japan from 1988 to 1998. The annual incidence was 4.02 cases per million births, the median age at diagnosis was 60 days, and 59% of the cases presented by 3 months of age. Three patients had a familial occurrence. All patients received prednisolone (PSL), and cyclosporin A (CsA) was added to the therapy in 17 patients. Forty-seven patients received transfusions, and 13 underwent hematopoietic stem cell transplantation (HSCT). The cumulative probabilities of a medication-free or a transfusion-free state prior to HSCT were 36% and 69%, respectively, at more than 5 years after diagnosis. Thirteen patients were weaned from PSL therapy without HSCT, and CsA was not associated with weaning from therapy. Transfusion and medication were stopped at 249 days and 933 days after diagnosis in 34 and 13 patients, respectively, who achieved a state of independence. No initial findings predicted the treatment dependence. More than 20% of patients experienced sustained hemosiderosis and/or adverse effects of PSL. The ages and reticulocyte counts at diagnosis of the patients who underwent HSCT were lower than in the patients who did not. HSCT led to the highest success (85%) of all previous reports, even though 5 alternative donors were included in our study. Two cord blood transplants from unrelated donors failed. These findings suggest the need for developing an integral treatment strategy including selective HSCT for refractory DBA.

Nomimmune hydrops fetalis due to Diamond-Blackfan anemia

We describe case report of a baby with Diamond-Blackfan anemia, who presented as non-immune hydrops fetalis. The diagnosis was confirmed by measurement of red cell adenosine deaminase activity which is increased in Diamond-Blackfan anemia. At 2 years of age he is dependent on small dose of alternate day steroid to maintain his hemoglobin.

Sustained cyclosporine-induced erythropoietic response in identical male twins with diamond-blackfan anemia

After failing a trial of corticosteroid therapy, molecularly proven identical twins were treated for transfusion-dependent Diamond-Blackfan anemia with cyclosporine A, resulting in a robust erythropoietic response and a reversal of anemia. Clonogenic assays of marrow hematopoietic progenitors from both patients showed exuberant growth of BFU-E colonies but absent CFU-E. Clinically, the response has been sustained, and both patients have continued cyclosporine therapy and have been transfusion-independent for more than 27 months.

Diamond-Blackfan anemia: report of 6 cases

Diamond-Blackfan anemia is a rare congenital hypoplastic anemia. We report 6 children diagnosed as Diamond-Blackfan anemia at our clinic. All had severe pallor at presentation, with mild hepatomegaly and just palpable spleen in one child. Thumb anomaly was present in one of them. All of them had macrocytic or normocytic anemia with reticulocytopenia, and bone marrow examination revealed marked erythroid hypoplasia. All of them were treated with oral steroids with a good response.

A patient with extensive stem cell factor-induced hyperpigmentation

Stem cell factor (SCF) is a cytokine that stimulates development of erythroid precursors and, consequently, may have potential importance in the treatment of certain anemias. We report a case of a young woman with Diamond-Blackfan anemia who received SCF treatment. One effect of SCF treatment is cutaneous hyperpigmentation at the injection site. In contrast to previously reported cases of patients who had fewer SCF injections, her hyperpigmentation was extensive and of major cosmetic concern. SCF may play a role in a number of disease processes. This case demonstrates the need to consider the potential pigmentary side effects of SCF therapy and to make careful selection of the injection sites.

Response of Diamond-Blackfan anemia to metoclopramide: evidence for a role for prolactin in erythropoiesis

A 47-year-old woman with severe macrocytic anemia markedly improved during the second and third trimesters of 3 pregnancies and when breast-feeding her 2 children. Because the serum prolactin level is elevated at these times, we later treated her with metoclopramide (10 mg orally 3 times daily), a medication known to induce prolactin release. Her serum prolactin levels increased from 7 to 133 ng/mL (normal < 20 ng/mL) and hematocrit from 17% to 22% to 35%. With continued therapy (now 10 mg orally daily), her hematocrit has ranged from 30% to 40% for 6 years, although the macrocytosis persists (mean corpuscular volume, 100-112 fL). On the basis of this observation, a pilot study was undertaken of metoclopramide therapy in patients with Diamond-Blackfan anemia who were refractory to low doses of corticosteroids. Fifteen patients were enrolled and 9 completed the planned 16 weeks of therapy. Three individuals responded, suggesting that this therapeutic approach may benefit others. As with the index case, the anemia did not improve until 12 to 15 weeks of therapy had been completed.

Study of 22 Egyptian patients with Diamond-Blackfan anemia, corticosteroids, and cyclosporin therapy results

OBJECTIVE

Diamond-Blackfan anemia is a rare congenital hypoproliferative anemia of infancy and early childhood. Treatment with corticosteroids is commonly used, but with limited success. Trials with cyclosporin-A (CSA) are not frequently reported. Therefore, in this study we analyzed our results in the management of this rare disease by different medical treatments.

DESIGN

The results of 22 patients diagnosed at our Hematology Center in the New Cairo University Children's Hospital during the period 1991-2001 were retrospectively analyzed. Our patients first received prednisolone (2 mg/kg/d) for different courses according to their response. Since the year 2000, the steroid nonresponders received CSA (3-12 mg/kg/d) for 6 months unless treatment complications developed.

RESULTS

The age at the onset of the disease ranged from 1 to 24 months (median: 2.5 months). The mean values of the hemoglobin, the reticulocyte count, and the myeloid/erythroid ratio at the onset of the disease were 4.75 +/- 1.79 g/dL, 0.14 +/- 0.16, and 39.4 +/- 27.08, respectively. Patients received prednisolone from 0.25 to 10 years (median: 2 years). Ten patients were nonresponders (45.5%), and 5 patients (22.7%) responded to corticosteroid therapy. Two of 5 responders are off treatment with a hemoglobin level of >9 g/dL, and 3 of 5 are currently corticosteroid-dependent. Of 10 patients not responding to steroids, 8 received CSA for 6 months. Four patients (50%) responded to CSA therapy. A significant positive association was found between CSA dose and response.

CONCLUSION

CSA therapy should be tried in steroid-resistant Diamond-Blackfan anemia patients before blood transfusion or corticosteroid therapy complications are instituted.

Pneumocystis carinii pneumonia in patients with Diamond-Blackfan anemia receiving high-dose corticosteroids

The authors describe three infants with Diamond-Blackfan anemia receiving corticosteroids who were diagnosed with Pneumocystis carinii pneumonia. Two patients exhibited intermittent neutropenia as well. Each child had been receiving relatively high doses of corticosteroids for at least 2 months, and two were having prednisone tapered when pneumonia developed. One child responded to trimethoprim/sulfamethoxazole and pentamidine, but the other two patients died. Infants with Diamond-Blackfan anemia receiving prolonged corticosteroid therapy should receive P. carinii pneumonia prophylaxis, such as trimethoprim/sulfamethoxazole, and prophylaxis should continue during corticosteroid tapering.