Infantile Disseminated Bacille Calmette-Guérin Disease with Hemophagocytosis and Mimicking Juvenile Myelomonocytic Leukemia: A Case Report with Concise Literature Review.

Bacille Calmette-Guérin (BCG) is a live-attenuated vaccine routinely administered to newborns to prevent severe forms of tuberculosis (TB) in TB-endemic countries. Disseminated BCG vaccine disease is a classic feature of children with human immunodeficiency virus (HIV) or primary immunodeficiency disorders (PIDs) and is associated with high mortality. We report a case of a 6-month-old infant with disseminated BCG disease and hemophagocytic lymphohistiocytosis mimicking juvenile myelomonocytic leukemia with no demonstrable features of HIV or PID even after extensive laboratory work-up and succumbed to progressive disease. Disseminated BCG disease is a rare and potentially fatal complication of BCG vaccine, and prompt immunological evaluation complemented by initiation of 4-drug antitubercular therapy and definitive treatment with antiretroviral therapy or hematopoietic stem cell transplant is warranted.

Droplet digital PCR: An effective method for monitoring and prognostic evaluation of minimal residual disease in JMML.

Juvenile myelomonocytic leukaemia (JMML) is a rare myeloproliferative neoplasm requiring haematopoietic stem cell transplantation (HSCT) for potential cure. Relapse poses a significant obstacle to JMML HSCT treatment, as the lack of effective minimal residual disease (MRD)-monitoring methods leads to delayed interventions. This retrospective study utilized the droplet digital PCR (ddPCR) technique, a highly sensitive nucleic acid detection and quantification technique, to monitor MRD in 32 JMML patients. The results demonstrated that ddPCR detected relapse manifestations earlier than traditional methods and uncovered molecular insights into JMML MRD dynamics. The findings emphasized a critical 1- to 3-month window post-HSCT for detecting molecular relapse, with 66.7% (8/12) of relapses occurring within this period. Slow MRD clearance post-HSCT was observed, as 65% (13/20) of non-relapse patients took over 6 months to achieve ddPCR-MRD negativity. Furthermore, bone marrow ddPCR-MRD levels at 1-month post-HSCT proved to be prognostically significant. Relapsed patients exhibited significantly elevated ddPCR-MRD levels at this time point (p = 0.026), with a cut-off of 0.465% effectively stratifying overall survival (p = 0.007), event-free survival (p = 0.035) and cumulative incidence of relapse (p = 0.035). In conclusion, this study underscored ddPCR's superiority in JMML MRD monitoring post-HSCT. It provided valuable insights into JMML MRD dynamics, offering guidance for the effective management of JMML.

A predictive classifier of poor prognosis in transplanted patients with juvenile myelomonocytic leukemia: a study on behalf of the Société Francophone de Greffe de Moelle et de Thérapie Cellulaire.

Juvenile myelomonocytic leukemia (JMML) is an aggressive pediatric myeloproliferative neoplasm requiring hematopoietic stem cell transplantation (HSCT) in most cases. We retrospectively analyzed 119 JMML patients who underwent first allogeneic HSCT between 2002 and 2021. The majority (97%) carried a RAS-pathway mutation, and 62% exhibited karyotypic alterations or additional mutations in SETBP1, ASXL1, JAK3 and/or the RAS pathway. Relapse was the primary cause of death, with a 5-year cumulative incidence of 24.6% (95% CI: 17.1-32.9). Toxic deaths occurred in 12 patients, resulting in treatment-related mortality (TRM) of 9.0% (95% CI: 4.6-15.3). The 5-year overall (OS) and event-free survival were 73.6% (95% CI: 65.7-82.4) and 66.4% (95% CI: 58.2-75.8), respectively. Four independent adverse prognostic factors for OS were identified: age at diagnosis >2 years, time from diagnosis to HSCT ≥6 months, monocyte count at diagnosis >7.2x109/L, and the presence of additional genetic alterations. Based on these factors, we proposed a predictive classifier. Patients with 3 or more predictors (21% of the cohort) had a 5-year OS of 34.2%, whereas those with none (7%) had a 5-year OS of 100%. Our study demonstrates improved transplant outcomes compared to prior published data, which can be attributed to the synergistic impacts of a low TRM and a reduced, yet still substantial, relapse incidence. By integrating genetic information with clinical and hematologic features, we have devised a predictive classifier. This classifier effectively identifies a subgroup of patients who are at a heightened risk of unfavorable post-transplant outcomes who would benefit from novel therapeutic agents and post-transplant strategies.

Long-term remission of infantile Takayasu arteritis associated with germline CBL syndrome after allogeneic hematopoietic stem cell transplantation: A case report and literature review.

Takayasu arteritis (TA) is a large-vessel vasculitis that rarely presents in infancy. Casitas B-lineage lymphoma (CBL) syndrome is a rare genetic disorder due to heterozygous CBL gene germline pathogenic variants that is characterized by a predisposition to develop juvenile myelomonocytic leukemia (JMML). Vasculitis, including TA, has been reported in several patients. Herein, we describe a patient with CBL syndrome, JMML, and TA, developing long-term remission of this vasculitis after allogeneic hematopoietic stem cell transplant (HSCT), and perform a literature review of CBL syndrome with vasculitis or vasculopathy. We report a female patient with growth delay, developmental issues, and congenital heart disease who was admitted at 14 months of age with massive splenomegaly, lymphadenopathy, fever, and hypertension. Body imaging studies revealed arterial stenosis and wall inflammation of the aorta and multiple thoracic and abdominal branches. Whole exome sequencing revealed a pathogenic variant in CBL with loss of heterozygosity in blood cells, diagnosing CBL syndrome, complicated by JMML and TA. Allogeneic HSCT induced remission of JMML and TA, permitting discontinuation of immunosuppression after 12 months. Six years later, her TA is in complete remission off therapy. A literature review identified 18 additional cases of CBL syndrome with vasculitis or vasculopathy. The pathogenesis of vasculitis in CBL syndrome appears to involve dysregulated T cell function and possibly increased angiogenesis. This case advances the understanding of vascular involvement in CBL syndrome and of the genetic, immune, and vascular interplay in TA, offering insights for treating CBL syndrome and broader TA.

Allogeneic hematopoietic stem cell transplantation for juvenile myelomonocytic leukemia with intestinal Behçet's disease: A case report.

Behçet's disease (BD) is a rare condition that is seldom associated with hematological malignancies. In this case report, we present the unique case of a 7-year-old girl diagnosed with juvenile myelomonocytic leukemia (JMML) and intestinal BD. The patient received allogeneic hematopoietic stem cell transplantation (allo-HSCT), which resulted in complete remission of both JMML and BD. Our findings suggest that allo-HSCT may be a feasible treatment option for JMML patients with coexisting BD, and holds promise for achieving remission of both illnesses. However, further clinical investigations are needed to validate these findings.

Phenotypic profiling of CD34+ cells by advanced flow cytometry improves diagnosis of juvenile myelomonocytic leukemia.

Diagnostic criteria for juvenile myelomonocytic leukemia (JMML) are currently well defined, however in some patients diagnosis still remains a challenge. Flow cytometry is a well established tool for diagnosis and follow-up of hematological malignancies, nevertheless it is not routinely used for JMML diagnosis. Herewith, we characterized the CD34+ hematopoietic precursor cells collected from 31 children with JMML using a combination of standardized EuroFlow antibody panels to assess the ability to discriminate JMML cells from normal/reactive bone marrow cell as controls (n=29) or from cells of children with other hematological diseases mimicking JMML (n=9). CD34+ precursors in JMML showed markedly reduced B-cell and erythroid-committed precursors compared to controls, whereas monocytic and CD7+ lymphoid precursors were significantly expanded. Moreover, aberrant immunophenotypes were consistently present in CD34+ precursors in JMML, while they were virtually absent in controls. Multivariate logistic regression analysis showed that combined assessment of the number of CD34+CD7+ lymphoid precursors and CD34+ aberrant precursors or erythroid precursors had a great potential in discriminating JMMLs versus controls. Importantly our scoring model allowed highly efficient discrimination of truly JMML versus patients with JMML-like diseases. In conclusion, we show for the first time that CD34+ precursors from JMML patients display a unique immunophenotypic profile which might contribute to a fast and accurate diagnosis of JMML worldwide by applying an easy to standardize single eight-color antibody combination.

Noonan Syndrome-related Myeloproliferative Disorder Occurring in the Neonatal Period: Case Report and Literature Review.

Noonan syndrome-related myeloproliferative disorder (NS/MPD) and juvenile myelomonocytic leukemia (JMML) are rare MPDs that occur in young children. We herein report a case of NS/MPD with neonatal onset. The patient had a characteristic appearance and high monocyte count in the peripheral blood and bone marrow. Genetic testing showed the E139D mutation in PTPN11 ; however, the patient did not meet all the diagnostic criteria for JMML, and we thus diagnosed him with NS/MPD. Eight other cases of NS/MPD with neonatal onset are also summarized. The initial presentation varied, and the prognosis was considered poor compared with previous reports of NS/MPD.

Too many white cells-TAM, JMML, or something else?

Leukocytosis is a common finding in pediatric patients, and the differential diagnosis can be broad, including benign reactive leukocytosis and malignant myeloproliferative disorders. Transient abnormal myelopoiesis is a myeloproliferative disorder that occurs in young infants with constitutional trisomy 21 and somatic GATA1 mutations. Most patients are observed, but outcomes span the spectrum from spontaneous resolution to life-threatening complications. Juvenile myelomonocytic leukemia is a highly aggressive myeloproliferative disorder associated with altered RAS-pathway signaling that occurs in infants and young children. Treatment typically involves hematopoietic stem cell transplantation, but certain patients can be observed. Early recognition of these and other myeloproliferative disorders is important and requires a clinician to be aware of these diagnoses and have a clear understanding of their presentations. This paper discusses the presentation and evaluation of leukocytosis when myeloproliferative disorders are part of the differential and reviews different concepts regarding treatment strategies.

Tretinoin Enhances the Effects of Chemotherapy in Juvenile Myelomonocytic Leukemia Using an Ex Vivo Drug Sensitivity Assay.

PURPOSE: Juvenile myelomonocytic leukemia (JMML) is an aggressive pediatric malignancy with myelodysplastic and myeloproliferative features. Curative treatment is restricted to hematopoietic stem-cell transplantation. Fludarabine combined with cytarabine (FLA) and 5-azacitidine (AZA) monotherapy are commonly used pre-transplant therapies. Here, we present a drug screening strategy using a flow cytometry-based precision medicine platform to identify potential additional therapeutic vulnerabilities. METHODS: We screened 120 dual- and 10 triple-drug combinations (DCs) on peripheral blood (n = 21) or bone marrow (n = 6) samples from 27 children with JMML to identify DCs more effectively reducing leukemic cells than the DCs' components on their own. If fewer leukemic cells survived a DC ex vivo treatment compared with that DC's most effective component alone, the drug effect was referred to as cooperative. The difference between the two resistant fractions is the effect size. RESULTS: We identified 26 dual- and one triple-DC more effective than their components. The differentiation agent tretinoin (TRET; all-trans retinoic acid) reduced the resistant fraction of FLA in 19/21 (90%) samples (decrease from 15% [2%-61%] to 11% [2%-50%] with a mean effect size of 3.8% [0.5%-11%]), and of AZA in 19/25 (76%) samples (decrease from 69% [34%-100+%] to 47% [17%-83%] with a mean effect size of 16% [0.3%-40%]). Among the resistant fractions, the mean proportion of CD38+ cells increased from 7% (0.03%-25%; FLA) to 17% (0.3%-38%; FLA + TRET) or from 10% (0.2%-31%; AZA) to 51% (0.8%-88%; AZA + TRET). CONCLUSION: TRET enhanced the effects of FLA and AZA in ex vivo assays with primary JMML samples.

[Juvenile myelomonocytic leukemia and pediatric myelodysplastic syndromes]. / Leucémies myélo-monocytaires juvéniles et syndromes myélodysplasiques de l'enfant.

Juvenile myelomonocytic leukemia (JMML) and myelodysplastic syndromes (MDS) of children are rare and aggressive diseases. They both have the particularity of being very frequently associated with an underlying predisposition syndrome, which must be systematically investigated by meticulous clinical exam completed by molecular analysis on fibroblasts, in order to guarantee the best therapeutic management. New generation sequencing techniques have made it possible to better define the landscape of constitutional predisposing pathologies, to understand the clonal evolution that leads to the development of hematological malignancies and to identify new prognostic markers. In these two diseases, the only curative treatment is allogeneic hematopoietic stem cell transplantation, for which the appropriate timeframe, the type of donor and the conditioning must be decided in consultation with the expert teams in each entity.

Response to chemotherapy in juvenile myelomonocytic leukemia and its clinical implications for survival: A retrospective registry-based study of the Korean Pediatric Hematology-Oncology Group.

Juvenile myelomonocytic leukemia (JMML) is a life-threatening myeloproliferative neoplasm. The chemotherapeutic effect on survival remains unclear, and feasible standardized response criteria are yet to be established. We aimed to evaluate the chemotherapeutic response and its effect on survival in patients with JMML. A retrospective registry was reviewed for children diagnosed with JMML between 2000 and 2019. Response was assessed according to the criteria proposed by the International JMML Symposium in 2007 (criteria I) and the updated version in 2013 with its modifications (criteria II). A total of 73 patients were included in this study. Complete response (CR) rates were 46.6% and 28.8% using the criteria I and criteria II, respectively. A platelet count ≥ 40 × 109/L at diagnosis was associated with higher CR rates using the criteria II. Patients with criteria I-based CR had a better overall survival (OS) than those without CR (81.1% vs. 49.1% at 5 years). Patients with criteria II-based CR showed better OS (85.7% vs. 55.5% at 5 years) and event-free survival (EFS) (71.1% vs. 44.7% at 5 years) than those without CR. Additionally, a trend toward better EFS was observed in patients with criteria II-based CR than in those with criteria I-based CR but without criteria II-based CR (71.1% vs. 53.8% at 5 years). Chemotherapeutic response is associated with better survival outcomes. Along with splenomegaly, the addition of platelet count recovery, existence of extramedullary leukemic infiltration, and more stringent leukocyte counts to the response criteria allows for a more sensitive prediction of survival outcomes.

[Clinical features and prognosis of juvenile myelomonocytic leukemia: an analysis of 63 cases]. / 63ä¾‹å¹¼å¹´åž‹ç²’å•æ ¸ç»†èƒžç™½è¡€ç— çš„ä¸´åºŠç‰¹å¾ä¸Žé¢„åŽåˆ†æž.

OBJECTIVES: To investigate the clinical features of juvenile myelomonocytic leukemia (JMML) and their association with prognosis. METHODS: Clinical and prognosis data were collected from the children with JMML who were admitted from January 2008 to December 2016, and the influencing factors for prognosis were analyzed. RESULTS: A total of 63 children with JMML were included, with a median age of onset of 25 months and a male/female ratio of 3.2∶1. JMML genetic testing was performed for 54 children, and PTPN11 mutation was the most common mutation and was observed in 23 children (43%), among whom 19 had PTPN11 mutation alone and 4 had compound PTPN11 mutation, followed by NRAS mutation observed in 14 children (26%), among whom 12 had NRAS mutation alone and 2 had compound NRAS mutation. The 5-year overall survival (OS) rate was only 22%±10% in these children with JMML. Of the 63 children, 13 (21%) underwent hematopoietic stem cell transplantation (HSCT). The HSCT group had a significantly higher 5-year OS rate than the non-HSCT group (46%±14% vs 29%±7%, P<0.05). There was no significant difference in the 5-year OS rate between the children without PTPN11 gene mutation and those with PTPN11 gene mutation (30%±14% vs 27%±10%, P>0.05). The Cox proportional-hazards regression model analysis showed that platelet count <40×109/L at diagnosis was an influencing factor for 5-year OS rate in children with JMML (P<0.05). CONCLUSIONS: The PTPN11 gene was the most common mutant gene in JMML. Platelet count at diagnosis is associated with the prognosis in children with JMML. HSCT can improve the prognosis of children with JMML.

Short-term efficacy of decitabine-based therapy in JMML: a retrospective study from a single center in China.

Juvenile myelomonocytic leukemia (JMML) is an aggressive pediatric myeloproliferative disease, and newly diagnosed patients frequently cannot tolerate hematopoietic stem cell transplantation (HSCT) at diagnosis due to their poor condition. This retrospective analysis aimed to explore the short-term effect of decitabine-dominant therapy on improving the condition of JMML patients before HSCT. The subjects were 10 JMML patients. All patients were treated with decitabine after low-dose chemotherapy with an interval of 4 weeks before bridging to HSCT. The median treatment course was 3 cycles, and the overall response rate (ORR) was 70.0% after one cycle and 71.4% after three cycles. White blood cell (WBC) and monocyte counts were significantly lower after treatment, and spleen volume was also lower, though not significantly lower. The 12 month progression-free survival rate (PFS) was 80.0 ± 12.6%. Decitabine-dominant therapy was beneficial for reducing tumor burden and improving clinical condition.

High serum cystatin C levels in juvenile myelomonocytic leukemia patients without abnormal kidney function.

BACKGROUND: In pediatric cancer patients, the estimated glomerular filtration rate based on serum cystatin C (CysC) was reported to be suitable for estimating kidney function because of low serum creatinine (Cr) and high serum ß2-microglobulin. Recently, however, serum CysC levels have been reported to be elevated in some cancer patients other than those with juvenile myelomonocytic leukemia (JMML), regardless of normal kidney function. CASE REPORTS: We describe two pediatric cases of JMML with an elevated serum CysC level. Urinalysis tests showed no abnormalities and no evidence of nephritis or nephropathy, and there were no findings indicating abnormal kidney function, such as Cr clearance in one case or the estimated glomerular filtration rate based on serum Cr in both cases, except for the serum CysC levels. There were no other causes of a high serum CysC level, including hyperthyroidism and steroid administration. The patients were treated with a conventional dosage of drugs, and their serum CysC levels decreased to the normal range when they were in complete remission after treatment. CONCLUSION: An elevated serum CysC level may reflect tumor burden independent of kidney function in JMML patients. Therefore, creatinine or inulin clearance should be determined to more accurately estimate kidney function for administering an optimal dose of anticancer drugs. In addition, a high serum CysC level may be a potential biomarker of cancer progression.

Therapy-related myeloid neoplasms resembling juvenile myelomonocytic leukemia: a case series and review of the literature.

Therapy-related myeloid neoplasms (t-MN) are a distinct subgroup of myeloid malignancies with a poor prognosis that include cases of therapy-related myelodysplastic syndrome (t-MDS), therapy-related myeloproliferative neoplasms (t-MPN) and therapy-related acute myeloid leukemia (t-AML). Here, we report a series of patients with clinical features consistent with juvenile myelomonocytic leukemia (JMML), an overlap syndrome of MDS and myeloproliferative neoplasms that developed after treatment for another malignancy.