Unrelated cord blood transplantation in children with severe congenital neutropenia

Abstract:  SCN is an inherited hematological disorder with severe neutropenia and recurrent infections. Although there are some reports that recombinant rhG-CSF improves clinical outcome, allogeneic HSCT appears to be the only curative treatment for these patients. We report here two children with SCN successfully treated by CBT from unrelated donors. They were refractory to rhG-CSF treatment and have no identical family donor. Bu + CY were given as conditioning. Case 1 and Case 2 received 6/6 and 5/6 HLA-matched unrelated umbilical cord blood, respectively. The number of infused nucleated cells was 6, 18 × 10⁷/kg and CD34⁺  cell number was 3, 74 × 10⁵/kg in Case 1. Those cell numbers were 8, 8 × 10⁷/kg and 5, 34 × 10⁵/kg for Case 2, respectively. Neutrophil/platelet engraftments were 45/49 days in Case 1 and 24/36 days in Case 2. Grade II cutaneous acute GVHD was seen in Case 2 that was treated successfully with prednisolone. Both patients are well with normal hematological findings and full donor chimerism for post-transplant 20 and 24 months, respectively. We conclude that UCB can be considered as a safe source of stem cell in patients with SCN who need urgent HSCT.     

Strong evidence for autosomal dominant inheritance of severe congenital neutropenia associated with ELA2 mutations

OBJECTIVE: To investigate cases of severe congenital neutropenia (SCN) to ascertain SCN inheritance after determining that the same sperm donor was used by 4 different families to impregnate mothers. STUDY DESIGN: Because the donor sperm was not available, alternative methods were used to determine whether the sperm donor transmitted SCN. DNA isolated from leukocytes was used to sequence the ELA2 gene in the affected children and their mothers. ELA2 was amplified by polymerase chain reaction (PCR), and the product was sequenced. PCR was also performed with genomic DNA from the mothers and affected children using a set of 22 microsatellite PCR primers on chromosomes 14 and 19 to establish linkage to the paternal allele. RESULTS: None of the mothers had a mutation in ELA2, but all 5 affected children had the same mutation affecting the fourth exon at site S97L. Linkage mapping analysis confirmed that all affected children had the same paternal allele on chromosome 19, which contains ELA2. CONCLUSIONS: Our findings indicate that the father provided consistent haplotypes leading to the expression of SCN in all affected children, supporting an autosomal dominant inheritance in which ELA2 mutations occur.     

Hematopoietic stem cell transplantation in patients with severe congenital neutropenia: An analysis of 18 Japanese cases

Oshima K, Hanada R, Kobayashi R, Kato K, Nagatoshi Y, Tabuchi K, Kato S; for the Hematopoietic Stem Cell Transplantation Committee of the Japanese Society of Pediatric Hematology. Hematopoietic stem cell transplantation in patients with severe congenital neutropenia: An analysis of 18 Japanese cases.
Pediatr Transplantation 2010: 14:657–663. © 2010 John Wiley & Sons A/S. Abstract: We studied the outcome of allogeneic HSCT in patients with SCN. Between 1989 and 2005, 18 patients with SCN in Japan received HSCT for reasons other than malignant transformation, i.e., because of the lack of or a partial response to treatment with r‐HuG‐CSF. The median age of the patients at the first HSCT was three and a half yr (range 0.2–16.7 yr). Nine patients received stem cells from an HLA‐identical sibling donor and nine from an alternative donor. Twelve and six patients received myeloablative and non‐myeloablative conditioning regimens, respectively. Engraftment occurred at the first HSCT in 12 patients, four patients received a second HSCT for graft failure, and two patients died. The cause of death was renal failure and graft failure at the first and second HSCT, respectively. The cumulative incidence of grade II–IV acute GVHD and TRM at the first transplantation was 11% and 5.6%, respectively. Of our patients, 16 are alive and in complete remission, with a median follow‐up of six and a half yr. Our results suggest that HSCT is beneficial for patients with SCN refractory to r‐HuG‐CSF treatment.     

Successful second hematopoietic cell transplantation in severe congenital neutropenia

Allogeneic HCT is curative for SCN; however, a standard conditioning regimen or intensity has not been established. We describe a patient with SCN associated with c.1A>G (M1V) mutation in ELANE gene resulting in refractoriness to G‐CSF, who received reduced‐intensity HCT and developed secondary graft failure requiring a second myeloablative HCT. This case suggests that M1V mutation confers a poor G‐CSF response and HCT using the best available donor is beneficial.     

A child with severe form of dyskeratosis congenita and TINF2 mutation of shelterin complex

A 26-month-old male presented with bone marrow failure and dystrophic nail lesions mimicking onychomycosis. There was no skin finding. Treatment with androgen and methylprednisolone was started due to unavailability of a matched-related hematopoietic stem cell donor. After 30 months, transfusion support was required. TINF2 mutation was identified at the age of five and dyskeratosis congenita (DC) was confirmed. TIN2 mutation analysis must be carried out in patients younger than 10 years presenting with bone marrow failure even if characteristic physical anomalies of DC is missing. Genetic confirmation of DC prevents ineffective immunotherapy with misdiagnosis of acquired aplastic anemia.     

Mosaic tetraploidy and transient GFI1 mutation in a patient with severe chronic neutropenia

This report presents the case of a 15-year-old male with severe chronic neutropenia, leukopenia, and persistent tetraploid mosaicism in the bone marrow and peripheral blood. His father had mild neutropenia and bone marrow tetraploidy. Flow cytometric analysis of DNA content peripheral blood showed tetraploidy in 20% of granulocytes and 15% of monocytes. Sequence analysis of the ELA2 gene was normal, but the GFI1 gene exhibited transient appearance of single base changes the coding region and promoter. We speculate that an underlying genetic defect, inherited in an autosomal dominant pattern, leads to both disordered mitosis and neutropenia in this kindred.     

A novel homozygous VPS45 p.P468L mutation leading to severe congenital neutropenia with myelofibrosis

VPS45‐associated severe congenital neutropenia (SCN) is a rare disorder characterized by life‐threating infections, neutropenia, neutrophil and platelet dysfunction, poor response to filgrastim, and myelofibrosis with extramedullary hematopoiesis. We present a patient with SCN due to a homozygous c.1403C>T (p.P468L) mutation in VPS45, critical regulator of SNARE‐dependent membrane fusion. Structural modeling indicates that P468, like the T224 and E238 residues affected by previously reported mutations, cluster in a VPS45 “hinge” region, indicating its critical role in membrane fusion and VPS45‐associated SCN. Bone marrow transplantation, complicated by early graft failure rescued with stem cell boost, led to resolution of the hematopoietic phenotype.     

A novel phenotype variant of severe congenital neutropenia caused by G6PC3 deficiency

Severe congenital neutropenia type 4 (SCN4) is associated with mutations in the G6PC3 gene. To date, all patients bearing the p.Gly260Arg variant of the G6PC3 gene show heart defects. Here, we present a case of the p.Gly260Arg variant in a patient who did not have structural or functional heart anomalies. Treatment with granulocyte colony‐stimulating factor recovered the absolute neutrophil count and neutrophil functional competence. Pediatr Blood Cancer 2013; 60: E29–E31. © 2013 Wiley Periodicals, Inc.     

Unrelated cord blood transplantation for severe congenital neutropenia: report of two cases with very different transplant courses

SCN is characterized by neutropenia, life-threatening infections, and progression to myelodysplastic syndrome/acute myelogenous leukemia. The only curative option is SCT, but few reports using UCB as a stem cell source exist. Here, we report two SCN patients transplanted with UCB. Patient 1 was transplanted at seven yr of age due to increasingly large injections of G-CSF (>100 microg/kg/day) and the risk of developing leukemia. He engrafted promptly and is clinically well and immune reconstituted >2 yr post-transplant. Patient 2 underwent UCB SCT at nine months of age for recurrent severe infections, despite high doses of G-CSF. He rejected his first graft, having 100% host cells on day +35, and immediately underwent a second UCB SCT. He engrafted but experienced late graft rejection six months after the second transplant. He received a third UCB SCT following a more immunosuppressive conditioning regimen. His course was complicated by HHV-6 viremia and gut GVHD, but he is now clinically well and has 99% donor engraftment >20 months post-transplant. We conclude that UCB is an acceptable stem cell source for SCN patients, but conditioning must be adequately immunosuppressive to ensure engraftment in patients without prior chemotherapy.     

Compound heterozygous HAX1 mutations in a Swedish patient with severe congenital neutropenia and no neurodevelopmental abnormalities

Kostmann disease or severe congenital neutropenia (SCN) is an autosomal recessive disorder of neutrophil production. Homozygous HAX1 mutations were recently identified in SCN patients belonging to the original family in northern Sweden described by Kostmann. Moreover, recent studies have suggested an association between neurological dysfunction and HAX1 deficiency. Here we describe a patient with a compound heterozygous HAX1 mutation consisting of a nonsense mutation (c.568C > T, p.Glu190X) and a frame‐shift mutation (c.91delG, p.Glu31LysfsX54) resulting in a premature stop codon. The patient has a history of neutropenia and a propensity for infections, but has shown no signs of neurodevelopmental abnormalities. Pediatr Blood Cancer 2009;53:1143–1146. © 2009 Wiley‐Liss, Inc.     

A novel mutation in a family with DNA ligase IV deficiency syndrome

DNA ligase IV deficiency syndrome (LIG4 syndrome) is a rare autosomal recessive disorder characterized by microcephaly, growth retardation, low birth weight, dysmorphic facial findings, immunodeficiency, pancytopenia, and radiosensitivity due to impaired repair of DNA double‐strand breaks by non‐homologous end‐joining. Herein, we report two siblings with LIG4 syndrome with a novel mutation. One of the siblings, who had normocellular marrow, had autologous reconstitution after initial non‐myeloablative conditioning and underwent successful second hematopoietic stem cell transplantation after conditioning with busulfan, cyclophosphamide, and anti‐thymocyte globulin. Our findings indicate that transplantation with myeloablative conditioning can be used successfully in LIG4 syndrome patients. Pediatr Blood Cancer 2009;53:482–484. © 2009 Wiley‐Liss, Inc.     

Macrothrombocytopenia associated with a rare GFI1B missense variant confounding the presentation of immune thrombocytopenia

Growth factor‐independent 1B (GFI1B) variants are a rare cause of thrombocytopenia. We report on a male child who was initially diagnosed with immune thrombocytopenia. However, subtle clinical signs led to suspicion of a genetic cause of thrombocytopenia. Gene panel sequencing revealed a rare variant in GFI1B (C168F), which has recently been reported in several families with thrombocytopenia. We demonstrate that this variant significantly alters platelet parameters in population studies. This case highlights how diagnoses of exclusion, such as immune thrombocytopenia, can be confounded by genetic variation. Our understanding of blood disorders will undoubtedly evolve from an increased knowledge of human genetic variation.     

Clinical phenotype associated with TANGO2 gene mutation

The clinical picture associated with a Transport and Golgi Organization 2 (TANGO2) gene bi-allelic mutation is represented by encephalopathy and rhabdomyolysis marked by cardiac rhythm disorders and neurological regression. The presentation of encephalopathy is diverse and can range from isolated language delay and cognitive impairment in a child to multiple disabilities and spastic quadriparesis. Hypothyroidism has also been frequently reported. This article presents the clinical phenotype of seven children with a TANGO2 bi-allelic mutation. The mutation was found by sequencing a panel of genes associated with rhabdomyolysis. While the clinical picture represents generalized cases, there is phenotypic variability in, for example, the degree of disability for each patient. A TANGO2 gene mutation, nevertheless, represents a serious illness with a limited life expectancy due to an unpredictable risk of cardiac rhythm disorder and death, particularly during rhabdomyolysis. Although the natural history of the disease presents an evolution of rhabdomyolysis triggered by infections or effort, an early diagnosis is difficult due in part to the fact that there is a lack of specific biochemical marker or identifying symptoms in the early presentation of the disease. Clinicians must therefore consider the TANGO2 gene when confronted with rhabdomyolysis in a patient suffering from an early developmental disorder. In the meantime, management of the disease remains purely symptomatic.     

Lymphadenopathy as the primary manifestation of malignant transformation in two patients with severe congenital neutropenia

We present the cases of two patients with severe congenital neutropenia (SCN) who both developed generalized adenopathy. Although both had recent histories that placed infection high on the differential of causes for the adenopathy, biopsies demonstrated acute myeloid leukemia (AML) as the etiology. The risk of malignant transformation in SCN is known to be significantly elevated, and these cases illustrate the need for physicians of such patients to keep myelodysplastic syndrome (MDS) and AML high on the differential when patients manifest atypical symptoms.     

造血干细胞移植治疗重型先天性中性粒细胞缺乏症的临床研究

目的探讨造血干细胞移植对重型先天性中性粒细胞缺乏症（SCN）的治疗效果。方法1例2岁7个月SCN患儿,经粒细胞集落刺激因子（G．CSF）治疗7个月无效后行HLA不全相合无关脐血移植,预处理采用BU／CY＋Flud方案[马利兰（BU）1．2mg／kg·次,每6h一次,连用4d;环磷酰胺（CY）60mg／（kg·d）,连用2d;氟达拉滨（Flud）30mg／（m^2·d）,连用4d。输入脐血有核细胞11．24×10^7／kg,CD34＋细胞6．41×10^5／kg。移植物抗宿主病（GVHD）的预防采用抗胸腺球蛋白＋环胞菌素A＋吗替麦考酚酯。移植后应用G．CSF加速造血重建。结果＋17d粒细胞植入,＋21d血小板植入,＋20d取患儿骨髓经STR基因位点检测证实为完全供者型嵌合状态,此后嵌合稳定。＋24d出现Ⅱ度GVHD;无肝静脉闭塞病、间质性肺炎、出血性膀胱炎等并发症,未出现慢性GVHD。随访14个月,前囟闭合,身高增加3cm,复查颅骨及膝关节x线片,骨质疏松明显好转,免疫球蛋白及补体正常,T细胞、B细胞亚群及NK细胞基本正常。结论本例为我国首例采用造血干细胞移植治疗SCN成功,为今后SCN的治疗积累了初步的经验。