Pulmonary hypertension in a child with juvenile myelomonocytic leukemia secondary to pulmonary leukemic cell infiltration

A 4-year-old girl with juvenile myelomonocytic leukemia presented to the emergency room with dyspnea. Echocardiography was performed due to cardiomegaly and prominent main pulmonary artery on a chest X-ray film. On echocardiography the right ventricular pressure calculated from the velocity of tricuspid regurgitation jet was 55 mmHg with no pulmonary stenosis. Despite treatment for pulmonary hypertension and provision of respiratory support, the patient died. A postmortem lung biopsy specimen showed infiltration by tumor cells, which suggested that the pulmonary hypertension had been caused by leukemic infiltration. In conclusion, the findings suggest that leukemic infiltration into the lungs may occur in children with juvenile myelomonocytic leukemia. It should be recognized as a potentially treatable cause of pulmonary hypertension in patients with juvenile myelomonocytic leukemia.     

Biotinidase deficiency and juvenile myelomonocytic leukemia in a Turkish infant of consanguineous parents

Here, a case is presented with two rare genetic disorders, biotinidase deficiency and juvenile myelomonocytic leukemia, in a Turkish infant. This case may serve as a reminder that the diagnosis of a genetic disorder does not exclude the possibility of a second congenital but acquired disease.     

幼年型粒单核细胞白血病的临床和治疗

目的探索幼年型粒单核细胞白血病(JMML)的早期临床、实验室特点,以提高诊断水平和治疗的有效性。方法分析17例JMML患儿的临床特征、外周血常规、单核细胞计数、血涂片,骨髓活检和/或骨髓穿刺的形态学和分子生物学,胎儿血红蛋白(HbF)和病毒抗原检测,诊断及治疗问题。结果17例患儿的年龄分布:2个月～5岁4个月,中位年龄14个月。临床表现:88.2%出现发热、面色苍白、咳嗽,76.5%胸片示支气管肺炎,皮肤出现丘疹58.8%,所有病例肝脾均肿大,其中≥5 cm者占52.9%,淋巴结肿大(浅表和深部)占82.4%。实验室:17例患儿外周血白细胞数中位值32.9×109/L、单核细胞绝对值中位值3.9×109/L,14/17例外周血涂片见髓系前体细胞,中位值28%,7例红系有病态造血,血红蛋白中位值88 g/L,血小板计数中位值33×109/L。骨髓活检和/或骨髓穿刺:原始、早幼粒/原幼单细胞数在5%～20%;14例作骨髓细胞免疫学检测,12例的免疫表型为MPO 、CD117 及其他的髓系标记,2例免疫表型为MPO-、CD14 、CD33 ;14例进行细胞遗传分析,其中4例染色体单体改变依次为-8, 8q 、-6, 6q 、-20、-8;分子生物学检测bcr-abl基因阴性。HbF增高(中位值33%),病毒学检测EBV-IgM阳性7例、CMV-IgM阳性6例。结论JMML发病年龄以2岁以内多见,占60%。最初的诊断可类似ITP、病毒感染。JMML有效治疗很少,在缺乏相合供体情况下可选择联合化疗和诱导分化治疗。     

Juvenile xanthogranuloma in a child with previously unsuspected neurofibromatosis type 1 and juvenile myelomonocytic leukemia

The association of neurofibromatosis 1 (NF1), juvenile xanthogranulomas (JXG), and juvenile myelomonocytic leukemia (JMML) has been previously reported. We describe herein this triad in a Caucasian male infant with a pathogenic mutation in the NF1 gene (neurofibromin). The clinical course from initial presentation to final diagnosis is detailed; the physical features and hematologic characteristics are discussed. The patient underwent bone marrow transplantation and is currently in remission. Children with concurrent cutaneous café‐au‐lait and JXG lesions should be evaluated and monitored closely for the possible development of JMML. Pediatr Blood Cancer 2010; 54:173–175. © 2009 Wiley‐Liss, Inc.     

Diagnosis and treatment of juvenile myelomonocytic leukemia

Juvenile myelomonocytic leukemia (JMML) is a rare myelodysplastic/myeloproliferative disorder that occurs during infancy and early childhood; this disorder is characterized by hypersensitivity of the myeloid progenitor cells to granulocyte–macrophage colony‐stimulating factor in vitro. JMML usually involves somatic and/or germline mutations in the genes of the RAS pathway, including PTPN11, NRAS, KRAS, NF1, and CBL, in the leukemic cells. Almost all patients with JMML experience an aggressive clinical course, and hematopoietic stem cell transplantation (HSCT) is the only curative treatment. A certain proportion of patients with somatic NRAS and germline mutations in CBL, however, have spontaneous resolution. A suitable treatment after diagnosis and conditioning regimen prior to HSCT are yet to be determined, but several clinical trials have been initiated throughout the world to develop suitable pre‐ or post‐allogeneic HSCT treatments and new targeted therapies that are less toxic, to improve patient outcome.     

Severe vitamin B-12 deficiency in a child mimicking thrombotic thrombocytopenic purpura

We report a case of severe vitamin B-12 deficiency in a child who had a clinical presentation of hemolysis and thrombocytopenia that suggested the diagnosis of thrombotic thrombocytopenic purpura (TTP) and was associated with decreased ADAMTS13 activity. In this report, we review vitamin B-12 deficiency in children, the relationship between ADAMTS13 activity and TTP and discuss other conditions associated with decreased ADAMTS13 activity.     

Non-hematopoietic stem cell transplantation treatment of juvenile myelomonocytic leukemia: a retrospective analysis and definition of response criteria

BACKGROUND: Juvenile myelomonocytic leukemia (JMML) is a rare myeloproliferative disease of infancy. Allogeneic hematopoietic stem cell transplantation (HSCT) is currently the only curative treatment modality, while the role of anti-leukemic therapy prior to HSCT is uncertain. A comparative evaluation of the efficacy of different clinical protocols and great variety of anti-neoplastic drugs applied pre-HSCT is hampered by the lack of uniform criteria of response. Classification schemas applied in other forms of leukemia are of little value, because in JMML therapy may result in divergent responses in solid organs compared to peripheral blood (PB). PROCEDURE: We therefore defined separate response criteria for white blood count (WBC), platelet count, liver size, and spleen size. We then retrospectively evaluated the efficacy of 129 treatment courses other than HSCT administered to 63 children with JMML. Treatment consisted of intensive therapy according to AML-type chemotherapy, maintenance-type combination therapy, and single agent therapy. To account for the variability observed in the natural course of disease, we also evaluated 32 episodes of "no therapy." RESULTS: Best responses within 3 months of initiation of therapy were highly variable for the four response criteria. In contrast to platelet count and liver size, there was a significant correlation between WBC or spleen size and therapy. Response rates for WBC and spleen size were best for purine analogs, etoposide, and cytarabine as single agents or for maintenance-type combination therapy. CONCLUSION: To rigorously test future therapeutic strategies in this rare disease an international consensus on the definition of response criteria will be helpful.     

幼年型粒单核细胞白血病的临床及实验室特征分析

目的 分析幼年型粒单核细胞白血病（JMML）的临床与实验室特征。方法 对10例初诊JMML患者的临床特征及实验室结果进行回顾性分析,并与同期确诊的28例骨髓增生异常综合征（MDS）、44例慢性粒细胞白血病（CML）患儿进行对比。结果 与CML及MDS患者相比,JMML患儿皮疹、瘀斑及淋巴结肿大的出现几率较高,而血清胆碱酯酶（ChE）最低。JMML患儿抗碱血红蛋白（HbF）最高,白细胞计数高于MDS组而低于CML组,粒红比与病态造血比例分别低于CML与MDS组;JMML组成熟单核细胞标记CD14表达较高,髓系标记CD33、CD11b、CD13及CD15的表达高于MDS组而低于CML组,差异均有统计学意义（P < 0.05）,CD7及CD2高于CML组而低于MDS组（P < 0.05）。结论 JMML患儿皮疹、瘀斑、淋巴结肿大以及ChE降低较为多见,骨髓病态造血现象较少,CD14表达明显增高。     

A conditioning regimen of busulfan, fludarabine, and melphalan for allogeneic stem cell transplantation in children with juvenile myelomonocytic leukemia

A pilot study was undertaken using a myeloablative conditioning with fludarabine, busulfan, and melphalan to improve the outcome of HSCT in 10 children, aged six months to six yr, with JMML. All patients were conditioned with oral busulfan (560 mg/m(2)), fludarabine (120 mg/m(2)), and melphalan (180-210 mg/m(2)) prior to HSCT, and received stem cells from bone marrow in seven cases, and from cord blood in three cases. Engraftment was documented in eight patients, whereas graft failure occurred in two, one of whom had received HLA-mismatched cord blood and other had received bone marrow from HLA-mismatched mother. Three patients, including two in who graft failure had occurred, relapsed. Five patients developed acute GVHD and two developed chronic GVHD. Seven patients are alive and in remission 27-69 months after transplantation. Thus, our study showed that HSCT following conditioning with fludarabine, busulfan, and melphalan was well tolerated and appeared to be effective for JMML.     

The strange case of the lost NRAS mutation in a child with juvenile myelomonocytic leukemia

Juvenile myelomonocytic leukemia (JMML) is a rare myelodysplastic/myeloproliferative disorder of early childhood characterized by mutations of the RAS-RAF-MAP kinase signaling pathway. We report the case of a child with a diagnosis of JMML carrying two mutations of NRAS gene (c.37G>C and c.38G>A) independently occurring in long-term culture initiating cells. However, only the former was consistently found in more mature hematopoietic cells, suggesting that cancer transformation may lead to the loss of a mutation. This case also indicates that molecular analysis on cell types other than peripheral blood leukocytes may be useful to obtain relevant biological information on JMML pathogenesis.     

幼年粒单细胞白血病造血干细胞移植疗效初探

目的探讨造血干细胞移植治疗幼年粒单细胞白血病(JMML)的疗效。方法 5例JMML患儿接受无关供者脐血造血干细胞移植治疗。预处理均采用Bu/Cy+Mel+ATG方案:马利兰(0.8～1.0)mg/kg,每6小时1次共用16次(-8d～-5d);环磷酰胺60mg/(kg·d)用2d(-4～-3d);马法兰140mg/m2用1次(-2d):抗胸腺细胞球蛋白2.5mg/(kg·d)连用4d(-4～-1d)。GVHD预防采用CsA+MP±MMF。结果 5例成功植入,3例复发,1例复发后死于卡氏肺囊虫肺炎,1例死于CMV感染相关间质性肺炎,1例长期无病存活。结论 5例JMML移植初步治疗结果不满意,移植失败主要原因为白血病复发。为减少复发,今后需进一步改进移植方法 ,包括选择其他供体、改进GVHD预防方案。     

Outcomes of juvenile myelomonocytic leukemia patients after sequential therapy with cytarabine and 6-mercaptopurine

Abstract

Juvenile myelomonocytic leukemia(JMML) is a pediatric myeloproliferative disorder. Allogeneic hematopoietic stem cell transplant (HSCT) is the only curative treatment for JMML. Pre-transplant therapy is a matter of controversy, and there are no firm recommendations. Whether chemotherapy is effective in achieving durable remission is questionable. Patients diagnosed as JMML at our center from January-2014 to December-2019 were retrospectively analyzed. All patients treated with at least one cycle of sequential therapy with subcutaneous cytarabine and oral 6-mercaptopurine were further assessed. The total number of patients diagnosed during the study period was 33. Patients were divided into two groups: patients who did not get any chemotherapy (n?=?13) and ones who received at least one cycle of chemotherapy(n?=?20). Age, total leukocyte count (TLC), monocyte percent, platelet count and spleen size were comparable between the two groups. There was no difference in the overall survival between the two groups, but 6 out of 20 patients showed a response to chemotherapy (2 complete remission, 4 partial remission). Two patients out of 20 underwent hematopoietic stem cell transplant (HSCT). The patients who achieved complete remission received 12 cycles of chemotherapy and have been in follow up for 28?months and 50?months respectively. Our results showed that sequential therapy with 6-mercaptopurine and cytarabine may be offered to patients in whom HSCT is not feasible or as a bridge therapy in those awaiting HSCT. The advantages of this approach include low cost, out-patient management and decreased requirement of blood components. In a subset of patients it may achieve remission.