Despite attempts to improve the definitions of ambiguous lineage leukemia (ALAL) during the last 2 decades, general therapy recommendations are missing. Herein, we report a large cohort of children with ALAL and propose a treatment strategy. A retrospective multinational study (International Berlin-Frankfurt-Münster Study of Leukemias of Ambiguous Lineage [iBFM-AMBI2012]) of 233 cases of pediatric ALAL patients is presented. Survival statistics were used to compare the prognosis of subsets and types of treatment. Five-year event-free survival (EFS) of patients with acute lymphoblastic leukemia (ALL)-type primary therapy (80% ± 4%) was superior to that of children who received acute myeloid leukemia (AML)-type or combined-type treatment (36% ± 7.2% and 50% ± 12%, respectively). When ALL- or AML-specific gene fusions were excluded, 5-year EFS of CD19 leukemia was 83% ± 5.3% on ALL-type primary treatment compared with 0% ± 0% and 28% ± 14% on AML-type and combined-type primary treatment, respectively. Superiority of ALL-type treatment was documented in single-population mixed phenotype ALAL (using World Health Organization and/or European Group for Immunophenotyping of Leukemia definitions) and bilineal ALAL. Treatment with ALL-type protocols is recommended for the majority of pediatric patients with ALAL, including cases with CD19 ALAL. AML-type treatment is preferred in a minority of ALAL cases with CD19 and no other lymphoid features. No overall benefit of transplantation was documented, and it could be introduced in some patients with a poor response to treatment. As no clear indicator was found for a change in treatment type, this is to be considered only in cases with ≥5% blasts after remission induction. The results provide a basis for a prospective trial.

Hepatosplenic candidiasis also known as chronic disseminated candidiasis is a rare manifestation of invasive fungal infection typically observed in patients with acute leukemia in prolonged, deep neutropenia. Immune reconstitution inflammatory syndrome (IRIS) is an inflammatory disorder triggered by rapid resolution of neutropenia. Diagnosis and treatment of IRIS are still challenging due to a variety of clinical symptoms, lack of certain diagnostic criteria, and no standards of treatment. The diagnosis of IRIS is even more difficult in patients with hematological malignancies complicated by “probable” invasive fungal infection, when fungal pathogen is still uncertain. We report a case of probable hepatic candidiasis in 4-year-old boy with acute lymphoblastic leukemia. Despite proper antifungal therapy, there was no clinical and radiological improvement, so diagnosis of Candida-related IRIS was made and corticosteroid therapy was added to antifungal treatment achieving prompt resolution of infection symptoms.

The names of the last five authors were mistakenly deleted during production. The full list of authors and their affiliations are given here.

The phenomenon of cellular drug resistance in childhood acute leukemias is multifactorial and plays an important role in response to therapy. Expression of MRP1, PGP and LRP proteins, as well as their co-expression play possible role in childhood relapsed ALL.

No abstract

The triple association between juvenile xanthogranuloma (JXG), juvenile myelomonocytic leukemia and neurofibromatosis was described in literature in about 20 cases. In this paper, the case of an 11-month-old infant boy with a disseminated JXG with unusual cytogenetic representation in the bone marrow was reported. Neurofibromatosis and juvenile myelomonocytic leukemia were excluded, just the same as other leukemias. Bone marrow and peripheral blood cytogenetic analysis revealed a karyotype with many rearrangements 46,XY,-6,der(12)t(6;12)(p21;p13),del(7)(p13p22),+9 once described in the literature as a B-acute lymphoblastic leukemia case. On the contrary, in our patient immunologic testing demonstrated a high activity of T lymphocytes, however, inflammation was excluded. To the best of our knowledge this is the first described case of systemic JXG with determined karyotype representing unusual chromosomal aberrations.

Combined ex vivo drug resistance profile to prednisolone, vincristine and L-asparaginase (PVA) has prognostic significance in childhood de novo ALL (Den Boer JCO 2003, Styczynski JCO 2004). So far, no data exist to support prognostic value of in vitro drug resistance profile in childhood acute myeloid leukemia (AML). The aim of this study was the analysis of prognostic value of ex vivo drug resistance profile in childhood AML. A total number of 90 children (46 male, 44 female) aged 0.1–17 yrs (median 10 yrs), with de novo AML were included into the study. All patients were recruited between 1999 and 2004 and were treated according to ANLL-98 protocol. Patients with early deaths were excluded from the study. Drug resistance profile was done by the MTT assay in one laboratory for 4–24 drugs. According to median cytotoxicity for each of tested drugs, all patients were scored as resistant or sensitive to this drug. Patients who received a HSC transplantation were censored at the time of transplantation. Drug resistance profile and other known prognostic parameters, were examined by Kaplan-Meier method and by multivariate analysis using the Cox regression proportional hazard model. Probability of overall survival was 0.57±0.05, p(LFS)=0.72±0.05, mean LFS 3.36 yrs (95%CI=2.95–3.77). Relapses occurred in 17/90 children; 40/90 children died during follow-up. Children who relapsed during follow-up showed median higher in vitro resistance of leukemic blasts to most of tested drugs, except for cytarabine, cladribine, vincristine, mercaptopurine and thioguanine. Better LFS was observed for patients with favourable cytogenetics (1.00 vs 0.74±0.09, p=0.055); early BM response by day 15 (0.76±0.07 vs 0.54±0.13, p=0.013); BM remission by day 28 of induction (0.74±0.07 vs 0.35±0.26, p=0.018); ex-vivo sensitive patients to cyclophosphamide (0.83±0.15 vs 0.65±0.09, p=0.12), doxorubicin (0.81±0.12 vs 0.64±0.09, p=0.18), epirubicin (0.72±0.13 vs 0.61±0.12, p=0.26), fludarabine (0.73±0.12 vs 0.62±0.11, p=0.22), mitoxantrone (0.77±0.12 vs 0.51±0.13, p=0.07), treosulphan (0.88±0.12 vs 0.62±0.11, p=0.29), etoposide (0.70±0.13 vs 0.63±0.09, p=0.4) and for patients with leukemic cells being sensitive to fludarabine, treosulphan and mitoxantrone ie. FTM score (0.73±0.12 vs 0.50±0.14, p=0.034). In multivariate analysis, two factors showed prognostic value: early BM response by day 15 (p=0.0021; HR=0.29, 95%CI=0.13–0.64) and combined ex vivo drug resistance profile to fludarabine, treosulphan and mitoxantrone (FTM score), p=0.0048; HR=0.38, 95%CI=0.19–0.77. Combined ex vivo drug resistance profile to fludarabine, treosulphan and mitoxantrone has prognostic significance in childhood acute myeloid leukaemia, however cytogenetics and early bone marrow response to therapy seems to have stronger prognostic value.

Up to 5% of patients with acute leukemia (AL) are diagnosed as AL of ambiguous lineage. The ambiguous lineage ALs consist of mixed phenotype AL (MPAL, or biphenotypic AL, BAL), bilineal AL, switching AL and rare, undifferentiated ALs. From a molecular genetic point of view, they overlap with several molecular genetic subsets such as AL with MLL rearrangements or early T precursor AL. As no general treatment strategy exists, these patients have been variably treated with lymphoblastic (ALL)- , myeloid (AML)- or combined (hybrid) therapy, with or without stem cell transplant. They are often unreported as they are excluded from standard protocols. So far, attempts to shed more light on these patients has largely focused on definitions of ambiguous lineage AL. Only limited therapeutic observations have been possible in studies on this AL subset, usually reporting 50 or fewer pediatric/adult patients. In order to facilitate more detailed analyses, we have created an international study "iBFM AMBI2012 Study/Registry". In this study, patients under 18 years at diagnosis are eligible. Each center/country was asked to report all consecutive patients with ambiguous lineage AL, from a 2- to 13-year period ending May 31, 2015. The definitions included those with WHO and EGIL criteria and remained unchanged throughout the study. Complete information on type of treatment, follow up and immunophenotype was requested. Where available (n=101 at the time of this abstract uploading), raw cytometric FCS data files were stored centrally for review. Apart from the study itself, the central database served also as a basis for consulting individual patients during the diagnostic workup. Furthermore, data on fusion genes, cytogenetics, treatment response and availability of specimens for collateral studies were also collected. In total, 247 patients from Australia, Austria, Brazil, Czechia, Germany, Greece, Israel, Netherlands, NOPHO (Denmark, Estonia, Finland, Norway, Sweden, Iceland and Lithuania), PINDA (Chile), Poland, SAHOP (Argentina), Slovakia, St. Jude Children's Research Hospital (USA), Ukraine and United Kingdom are reported. Among those, 222 fulfilled the definitions of MPAL/BAL, partially overlapping with cases in whom two clones had been identified (n=47) and 14 cases presented with undifferentiated AL. Most of them, consistent with our general treatment guideline (Figure 1), started their treatment with an ALL type of protocol (n=150), 60 patients started on AML therapy, 8 patients received a combined regimen including the Interfant protocols, 2 patients were not treated, 13 received other treatment, and this information is missing in 9 patients (additional 5 pts. started on ALL treatment but their follow up information is incomplete). The 5 year event free survival of the entire cohort was 55±4% and its separation by first type of treatment is shown in Figure 2. In a collateral study, we set up a qPCR array on 90 genes that are characteristic of the lymphoid or myeloid lineages and/or are thought to be involved in their regulation. Using this array, sorted cells of granulocytic, monocytic, T, and B lineages at various stages of development (17 stages total) were analyzed and compared to samples of AL including 6 samples of MPAL of precursor B/myeloid phenotype. Although this array did not show a general deregulation in the MPAL genome compared to that in AL or healthy cells, subtle changes were seen such as decrease of CEBPE and LILRA2 gene expression, in comparison to classical B precursor ALL. Overall, our data shows that the general treatment guideline (Figure 1), which favors ALL treatment is justified by the outcome. However, although this study is larger than those published, caution is needed during its interpretation due to variations in diagnostics and treatment among the participating countries. Therefore, our data should be viewed as a basis for non-ambiguous treatment guidelines that will direct each patient to either ALL or AML treatment. These guidelines will be tested prospectively. In addition, the framework of this study is being used as a basis of consulting new AL cases with diagnostic uncertainties. Furthermore, it serves as a data resource for biologic studies. Supported by AZV 15-28525A, UNCE 204012, NT/14534-3, NT/13462-4, P302/12/G101. Disclosures Kattamis: Novartis: Research Funding, Speakers Bureau; ApoPharma: Speakers Bureau.