Jean-Hugues Dalle

Characterization of cord blood natural killer cells : Implications for transplantation and neonatal infections

The role of natural killer (NK) cells in hematopoietic stem cell transplantation and in the control of neonatal infections is not yet clear. Donor-versus-recipient NK cell alloreactivity was found to improve outcome in some settings of hematopoietic stem cell transplantation. We hypothesized that the role of NK cells in cord blood (CB) transplantation and neonatal infections may depend on CB NK cell maturation stage. We therefore analyzed the expression of NK cell differentiation/phenotypic markers in human CB, as well as functional properties of purified CB NK cells. CD8 and CD57 expression was lower in CB than in adult NK cells. However, the expression of other differentiation markers was similar, as was cell surface density of CD56, the percentage of late NK cell precursors, interferon-γ production, and the proliferative response of purified NK cells to IL-2. Spontaneous cytotoxic activity of purified CB NK cells against NK-sensitive targets was low but reached adult levels after treatment with IL-15. Expression of perforin and granzyme B was higher in CB NK cells (90 versus 58% and 86 versus 69%, respectively). intercellular adhesion molecule-1 and CD161 expression was lower in CB. Surprising, fewer CB NK cells expressed L-selectin, a marker of immature NK cells. Taken together, our results suggest that CB NK cells are phenotypically and functionally mature.

Myelodysplasia and leukemia of Fanconi anemia are associated with a specific pattern of genomic abnormalities that includes cryptic RUNX1/AML1 lesions

Fanconi anemia (FA) is a genetic condition associated with bone marrow (BM) failure, myelodysplasia (MDS), and acute myeloid leukemia (AML). We studied 57 FA patients with hypoplastic or aplastic anemia (n = 20), MDS (n = 18), AML (n = 11), or no BM abnormality (n = 8). BM samples were analyzed by karyotype, high-density DNA arrays with respect to paired fibroblasts, and by selected oncogene sequencing. A specific pattern of chromosomal abnormalities was found in MDS/AML, which included 1q+ (44.8%), 3q+ (41.4%), -7/7q (17.2%), and 11q- (13.8%). Moreover, cryptic RUNX1/AML1 lesions (translocations, deletions, or mutations) were observed for the first time in FA (20.7%). Rare mutations of NRAS, FLT3-ITD, MLL-PTD, ERG amplification, and ZFP36L2-PRDM16 translocation, but no TP53, TET2, CBL, NPM1, and CEBPα mutations were found. Frequent homozygosity regions were related not to somatic copy-neutral loss of heterozygosity but to consanguinity, suggesting that homologous recombination is not a common progression mechanism in FA. Importantly, the RUNX1 and other chromosomal/genomic lesions were found at the MDS/AML stages, except for 1q+, which was found at all stages. These data have implications for staging and therapeutic managing in FA patients, and also to analyze the mechanisms of clonal evolution and oncogenesis in a background of genomic instability and BM failure.

Impact of Addition of Maintenance Therapy to Intensive Induction and Consolidation Chemotherapy for Childhood Acute Myeloblastic Leukemia: Results of a Prospective Randomized Trial, LAME 89/91

PURPOSE To determine whether the use of maintenance therapy (MT) delivered after intensive induction and consolidation therapy confers any advantage in childhood acute myeloid leukemia (AML). PATIENTS AND METHODS A total of 268 children with AML were registered in the Leucámie Aiquë Myéloïde Enfant (LAME) 89/91 protocol. This regimen included an intensive induction phase (mitoxantrone plus cytarabine) and, for patients without allograft, two consolidation courses, one containing timed-sequential high-dose cytarabine, asparaginase, and amsacrine. In the LAME 89 pilot study, patients were given an additional MT consisting of mercaptopurine and cytarabine for 18 months. In the LAME 91 trial, patients were randomized to receive or not receive MT. RESULTS A total of 241 (90%) of 268 patients achieved a complete remission. The overall survival and event-free survival at 6 years were 60% +/- 6% and 48% +/- 6%, respectively. For the complete responders after consolidation therapy, the 5-year disease-free survival was not significantly different in MT-negative and in MT-positive randomized patients (respectively, 60% +/- 19% v 50% +/- 15%; P =.25), whereas the 5-year overall survival was significantly better in MT-negative randomized patients (81% +/- 13% v 58% +/- 15%; P =.04) due to a higher salvage rate after relapse. CONCLUSION More than 50% of patients can be cured of AML in childhood. Either drug intensity or each of the induction and postremission phases may have contributed to the outstanding improvement in outcome. Low-dose MT is not recommended. Exposure to this low-dose MT may contribute to clinical drug resistance and treatment failure in patients who experience relapse.

Juvenile myelomonocytic leukemia displays mutations in components of the RAS pathway and the PRC2 network

Juvenile myelomonocytic leukemia (JMML) is a rare and severe myelodysplastic and myeloproliferative neoplasm of early childhood initiated by germline or somatic RAS-activating mutations. Genetic profiling and whole-exome sequencing of a large JMML cohort (118 and 30 cases, respectively) uncovered additional genetic abnormalities in 56 cases (47%). Somatic events were rare (0.38 events/Mb/case) and restricted to sporadic (49/78; 63%) or neurofibromatosis type 1 (NF1)-associated (8/8; 100%) JMML cases. Multiple concomitant genetic hits targeting the RAS pathway were identified in 13 of 78 cases (17%), disproving the concept of mutually exclusive RAS pathway mutations and defining new pathways activated in JMML involving phosphoinositide 3-kinase (PI3K) and the mTORC2 complex through RAC2 mutation. Furthermore, this study highlights PRC2 loss (26/78; 33% of sporadic JMML cases) that switches the methylation/acetylation status of lysine 27 of histone H3 in JMML cases with altered RAS and PRC2 pathways. Finally, the association between JMML outcome and mutational profile suggests a dose-dependent effect for RAS pathway activation, distinguishing very aggressive JMML rapidly progressing to acute myeloid leukemia.

Interaction between methotrexate and ciprofloxacin.

High-dose methotrexate is used in malignant hemopathies and solid tumors in children. Methotrexate serum concentrations must be monitored because of the possible toxicity of drug elimination delay. Several drugs (e.g., penicillin, probenecid) can alter the elimination of methotrexate. The authors report two cases of delayed elimination of methotrexate in patients receiving ciprofloxacin, with severe toxicity.

Efficacy of fractionated gemtuzumab ozogamicin combined with cytarabine in advanced childhood myeloid leukaemia

Gemtuzumab ozogamicin (GO) monotherapy is reported to yield a 20–30% response rate in advanced acute myeloid leukaemia (AML). This study examined the efficacy and tolerability of GO combined with cytarabine (GOCYT) in children with refractory/relapsed CD33+ AML. Seventeen children received GO 3 mg/m2 on days 1, 4 and 7 plus cytarabine 100 mg/m2/d for 7 d on a compassionate‐use basis. Seven patients then received GO‐based consolidation. At the outset of GOCYT, two patients were refractory; eight patients were in refractory first relapse; six patients had relapsed after stem cell transplantation (SCT); and one patient [del(5q) therapy‐related AML (t‐AML)] had not yet been treated. Mean follow‐up was 17 months (8–33 months). Ten responses were obtained after GOCYT induction, including complete remission (CR) or CR without complete recovery of platelets (CRp) in six patients (35%). The responses improved in three children who received GOCYT consolidation, increasing the CR + CRp rate to 53%. SCT was subsequently performed in eight responders. Grade 3–4 adverse events consisted of haematological disorders (n = 17, 100%) and documented infections (n = 5, 29%). No cases of sinusoidal obstructive syndrome occurred. Three patients were alive at the cut‐off date for this analysis, all of whom had responded to GOCYT. GOCYT combination therapy yielded a high response rate (53%) and showed acceptable toxicity in heavily pretreated children with refractory/relapsed AML. These results warrant a larger prospective study.

Multicenter randomized trial of chewing gum for preventing oral mucositis in children receiving chemotherapy.

The properties of saliva led us to hypothesize that the salivary flow increase induced by gum chewing might protect the oral mucosa from lesions due to cancer chemotherapy. We conducted a multicenter randomized trial to evaluate the efficacy of chewing gum in preventing oral mucositis in 145 children receiving chemotherapy regimens expected to induce WHO grade 3-4 oral mucositis in at least 30% of patients. Patients were allocated at random to standard oral care with or without 5 gum pieces per day. No overall reduction in severe oral mucositis occurred in the gum arm (51%) compared with the standard arm (44%). VIDE, COPADM, and multidrug intensive chemotherapy caused severe oral mucositis in 75% of patients in both arms. In patients receiving less toxic regimens, a decrease in WHO grade 1-4 oral mucositis was noted in the gum arm compared with the standard arm (49% vs. 72%, P=0.03). In the multivariate analysis, the risk of oral mucositis was related only to the type of chemotherapy regimen, suggesting that further strategies for preventing oral mucositis could be mainly based on these criteria.

Limited efficacy and tolerance of imatinib mesylate in steroid-refractory sclerodermatous chronic GVHD

To the editor: Imatinib mesylate (IM), a tyrosine kinase inhibitor, has shown efficacy for the treatment of chronic GVHD (cGVHD),[1][1][⇓][2]–[3][3] with overall response rates of fibrotic skin symptoms evaluated in 2 open-label studies ranging from 50%[1][1] to 79%.[2][2] To assess the global

Testicular Disease in Childhood B-Cell Non-Hodgkin’s Lymphoma: The French Society of Pediatric Oncology Experience

PURPOSE To investigate whether testicular disease in childhood B-cell lymphoma should continue to be considered a sanctuary site, as it is with other lymphoid malignancies such as acute lymphoblastic leukemia. PATIENTS AND METHODS Seven hundred forty-two children with B-cell non-Hodgkins lymphoma were included in the LMB protocols of the French Society of Pediatric Oncology from February 1981 to May 1994. Thirty patients (5.3%) had testicular involvement at diagnosis. We describe the clinical presentation and outcome of these 30 patients, who were treated without local radiation therapy. RESULTS Five patients underwent diagnostic orchidectomy. The median patient age was 8.5 years (range, 2 to 14 years), and their cancers were stage III (18 patients), stage IV (five patients), and B-cell acute lymphoblastic leukemia (seven patients). Five patients had central nervous system involvement. Twenty-eight patients (95%) achieved complete remission. Twenty-six patients are alive without progressive disease (median follow-up, 6.5 years). CONCLUSION Testicular disease does not seem to confer a poor prognosis, and it is curable with intensive combination chemotherapy alone. Local treatment (surgery or radiation) is avoidable; therefore, gonadal function can be preserved.

Malignant and benign thyroid nodules after total body irradiation preceding hematopoietic cell transplantation during childhood

BACKGROUND The risk of radiation-induced benign and malignant thyroid nodules is well known. OBJECTIVE The aim of this study was to determine the occurrence of thyroid nodules and carcinomas after fractionated total body irradiation (TBI) preceding hematopoietic stem cell transplantation (HSCT) for malignant hematological disease during childhood. METHODS We conducted a retrospective university hospital-based observational study. The participants were 76 patients receiving fractionated TBI between 1989 and 2009 as part of the conditioning regimen for HSCT to treat malignant hematological disease, with a median age of 8.2 (5.7-11.4) years, for whom the last ultrasound examination was performed at a median age of 14.2 (11.2-17) years. The main outcome measure was cumulative incidence of thyroid nodules detected by ultrasound scans followed by biopsy if necessary. RESULTS Thyroid nodules were examined in 21 (28%) patients, six (29%) of whom were diagnosed with thyroid carcinoma at the age of 2.2-18.6 years after TBI. The cumulative incidence of nodule occurrence increased with increasing time from diagnosis. The 10-year cumulative incidence of benign and malignant thyroid nodules was 16% (95% confidence interval (CI) 4-27%) and 8% (95% CI 0-16%) respectively. Seventeen (22%) patients had hypothyroidism (compensated n=12, in five patients it was transient). No significant independent risk factors were identified in the multivariable competing risk model as a function of nodule occurrence. CONCLUSION Short-term and life-long monitoring, with screening for nodules of the thyroid gland using ultrasound scans, is recommended for survivors subjected to TBI for HSCT during childhood.