ALBERT

Description: Congenital amegakaryocytic thrombocytopenia (CAMT) is a rare disease presenting with isolated thrombocytopenia in infancy and developing into a pancytopenia in later childhood. Thrombopoietin (TPO) is the main regulator of thrombocytopoiesis and has also been demonstrated to be an important factor in early hematopoiesis. We analyzed 9 patients with CAMT for defects in TPO production and reactivity. We found high levels of TPO in the sera of all patients. However, platelets and hematopoietic progenitor cells of patients with CAMT did not show any reactivity to TPO, as measured by testing TPO-synergism to adenosine diphosphate in platelet activation or by megakaryocyte colony assays. Flow cytometric analysis revealed absent surface expression of the TPO receptor c-Mpl in 3 of 3 patients. Sequence analysis of the c-mpl gene revealed point mutations in 8 of 8 patients: We found frameshift or nonsense mutations that are predicted to result in a complete loss of c-Mpl function in 5 patients. Heterozygous or homozygous missense mutations predicted to lead to amino acid exchanges in the extracellular domain of the receptor were found in 3 other patients. The type of mutations correlated with the clinical course of the disease. We propose a defective c-Mpl expression due to c-mpl mutations as the cause for thrombocytopenia and progression into pancytopenia seen in patients with CAMT.

Description: CAMT is a rare disease characterized by thrombocytopenia in infancy due to ineffective megakaryopoiesis. We retrospectively analyzed clinical parameters of 21 patients diagnosed with CAMT, characterized by severe thrombocytopenia at birth, normal bone marrow cellularity and severely reduced numbers of megakaryocytes. 18 children developed postnatal bleeding symptoms with a median platelet count of 21/nl. 2 children suffered from a postnatal cerebral bleeding and intrauterine cerebral bleeding was suspected in 4 more children. We observed differences in the course of disease: 12 children formed a homogeneous group regarding the hematological parameters. Their platelet counts remained on a very low level, bone marrow cellularity decreased during the first year of life and they developed severe aplastic anemia in early infancy (2 to 53 months). 7 children also presented with physical anomalies like strabismus (2), nystagmus (2), motor and mental retardation (2), growth retardation (2) and cardiac defects (2). In 5 of 7 patients the parents were cousins of first degree. Sequence analysis of the c-mpl gene in 5 children revealed nonsense mutations with a complete loss of the thrombopoietin receptor. This group we classified as CAMT Type I. In contrast, 6 children formed a more heterogeneous group with delayed bone marrow failure. Their platelet counts at birth were slightly increased compared to those of type I patients (median 35/nl). In all children the number of platelets rose during early infancy and achieved a median maximum of 132/nl. At a median age of 4 9/12 years (range 3 to 6 10/12years) 4 children developed aplastic anemia. In one girl bone marrow morphology revealed refractory anemia with excess blasts at the age of 7 1/12 years. She received two bone marrow transplantations (BMT) and finally died from acute myeloid leukemia. Another girl feels well at the age of 14 years without signs of pancytopenia. One girl presented with growth retardation and a second with a small apical ventricular septal defect. Sequence analysis in 3 children revealed different forms of amino acid exchanges in the extracellular domain of c-Mpl. This might correspond to a residual function of c-Mpl. This group we classified as CAMT Type II. Altogether 18 children received BMT. 3 patients with type II CAMT required a second BMT due to primary graft failure, secondary graft failure and relapse of MDS. BMT with a matched unrelated donor (MUD) was performed in 5 patients, all with a fatal outcome. 8 children died at a mean age of 4 2/12 years: 2 due to bleeding complications and 6 following BMT. We conclude, that c-Mpl deficiency is the main reason for CAMT and can be associated with described physical anomalies. As exemplified the prognosis for patients is poor. Clinical differences can be seen between a total lack and a residual function of the c-Mpl receptor. Besides CAMT due to c-Mpl deficiency the incidence of congenital forms of ineffective megakaryopoiesis was described for other diseases with no defects in the c-mpl gene. (e.g. CAMT with radio-ulnar synostosis, Hoyeraal-Hreidarsson-Syndrome). This heterogeneous group of diseases with normal c-Mpl function we classified as CAMT Type III. Further clinical studies have to be performed to understand the relationship between genotype and clinical phenotype in terms of bone marrow failure, leukemia development and overall survival to better predict the clinical outcome.

Description: Background HD is a B-lineage lymphoma characterized, depending on subtype, by a prominent inflammatory infiltrate and fibrosis. Clinically, inflammatory symptoms like fever, weight loss and night sweats (B-symptoms) and increased blood biomarkers of inflammation, including ESR and CRP, are characteristic of more advanced disease. The clinical trial EURONET-PHL-C2 (Second International Inter-Group Study for Classical Hodgkin's Lymphoma in Children and Adolescents) is a randomized, prospective trial that compares chemo- and radiotherapy treatment concepts of different intensities in patients with intermediate and advanced HD. Patients are stratified by risk into 3 therapy groups (TL-1 to TL-3). An ESR〉 30mm/h had been a risk factor for relapse in previous studies and leads to upstaging from the lowest (TL-1, Ann Arbor stage I and IIa without additional risk factors) to the intermediate risk group TL-2 in the current study. This addon pilot study tested urine proteomic patterns from pediatric patients with HD at diagnosis and compared them to the patterns of normal children. The questions were: Is there a HD-specific pattern, a pattern that identifies high risk or a pattern that correlates with inflammatory markers? Patients and methods Capillary electrophoresis coupled to mass spectrometry (CE-MS) was used to compare the peptide profiles in the mass range of 0.8 to 20 kDa of urine samples (N=34) from 16 children with pediatric Hodgkin lymphoma (PHL) as case and 32 age-matched children with no evidence of a disease (N=28) or with urinary tract infection (N=4) as control groups. Marker selection was based on a two-step strategy. First, a group-wise comparison of rank sum differences was performed on a set of 2418 annotated peptides with distribution frequencies above 30% in at least one of the groups with subsequent adjustment for multiple testing by the method of Bonferroni. In the second step marker candidates were further restricted to those demonstrating a significant positive or negative Spearman rho correlation coefficient (≥0.34 or ≤-0.34) to the Ann-Arbor classification criteria. From the resulting peptides a multivariate peptide marker classifier was established by support vector machine modeling and applied to an independent confirmation set of PHL (N=16, 31 urine samples) and control (N=18, 18 urine samples) patients to determine classification accuracy in receiver operating characteristics (ROC) analysis. Peptides included in the PHL classifier were resolved in their amino acid sequence by tandem mass spectrometry to identify the proteins from which the peptide markers are derived. Results The established multivariate peptide marker model consisting of 40 naturally occurring urinary peptides enabled absolute differentiation between PHL patients and children without signs of disease or urinary tract infection in independent validation as revealed by an area under the ROC curve value of 1.0 (95% confidence interval: 0.93 to 1.00, p

Description: Complex immune dysregulation is a hallmark of sepsis. The occurring phases of immunosuppression and hyperinflammation require rapid detection and close monitoring. Reliable tools to monitor patient’s immune status are yet missing. Currently, microRNAs are being discussed as promising new biomarkers in sepsis. However, no suitable internal control for normalization of miRNA expression by qPCR has been validated so far, thus hampering their potential benefit. We here present the first evaluation of endogenous controls for miRNA analysis in human sepsis. Novel candidate reference miRNAs were identified via miRNA microArray. TaqMan qPCR assays were performed to evaluate these microRNAs in T-cells and whole blood cells of sepsis patients and healthy controls in two independent cohorts. In T-cells, U48 and miR-320 proved suitable as endogenous controls, while in whole blood cells, U44 and miR-942 provided best stability values for normalization of miRNA quantification. Commonly used snRNA U6 exhibited worst stability in all sample groups. The identified internal controls have been prospectively validated in independent cohorts. The critical importance of housekeeping gene selection is emphasized by exemplary quantification of imuno-miR-150 in sepsis patients. Use of appropriate internal controls could facilitate research on miRNA-based biomarker-use and might even improve treatment strategies in the future.

Description: Purpose Results of the prospective trial "CML-PAED-II" assessing treatment efficacy and side effects in children and adolescents with newly diagnosed chronic myeloid leukemia (CML) are reported. Patients and Methods 156 patients (age range 1.3-18.0 years, 91 male) with newly diagnosed CML (N= 146 chronic phase (CML-CP), N= 3 accelerated phase (CML-AP), N= 7 blastic phase (CML-BP)) received imatinib upfront (300 mg/m², 400 mg/m², 500 mg/m², respectively). Therapy response, progression-free survival, causes of treatment failure and proportion of patients undergoing stem cell transplantation were analyzed in 148 patients with complete data. Results Event-free survival rate at 18 months for pediatric patients diagnosed in CML-CP (median follow-up time 25 months, range: 0.1-120) was 97% (95% CI, 94.2%-99.9%). According to the 2006 ELN-criteria complete hematologic response at month 3, complete cytogenetic response (CCyR) at month 12, and molecular response (MR3.0) at month 18 were achieved in 98%, in 63%, and 59% of the patients, respectively. At month 36 on continuous first line imatinib or 2nd generation tyrosine kinase inhibitor treatment, 86% of the patients achieved CCyR and 74% achieved MR3.0. 66% of the patients experienced at least one side effect. Imatinib-related anemia was the most frequent toxicity observed if all grades were considered (N=98; 66%) while neutropenia was the most frequently reported grade 3/4 hematologic adverse effect (N=22; 15%). Among non-hematologic toxicities, all grades of gastrointestinal toxicity were observed most frequently (N=57, 38%), however, it occurred at lower grades 1/2 in all but one patient. Higher grade 3/4 musculoskeletal pain was also frequent (N=53, 36%). Twenty-seven patients (18%) had to discontinue treatment temporarily while nine patients permanently terminated imatinib due to non-tolerable side effects (neutropenia N= 4, muscle cramps N= 3, skin N= 1, liver N= 1). Thirty-eight patients (27%) experienced imatinib failure because of unsatisfactory response (N= 27) or intolerance (N= 9). 28/148 patients (19%) underwent stem cell transplantation (SCT). In the SCT sub-cohort 2/23 patients diagnosed in CML-CP, 0/1 in CML-AP, and 2/4 in CML-BP, respectively, died of relapse (N=3) or SCT-related complications (N=2). Conclusion This large pediatric trial provides evidence confirming that first line imatinib in children is highly effective. Observed adverse effects are acceptable and mainly comprise hematological side effects. Long term outcome and effects of a potentially life-long TKI treatment have to be registered in cooperation with adult hematologists in extended surveillance follow-up studies. Disclosures Suttorp: Novartis: Research Funding. Schrappe: JAZZ Pharma: Consultancy, Research Funding; Baxalta: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; SigmaTau: Consultancy, Research Funding; Medac: Consultancy, Research Funding. Thiede: Novartis: Consultancy, Speakers Bureau; Bayer: Consultancy, Speakers Bureau; Roche: Consultancy; Agendix: Employment.