Browsing by Author "Dvorak, Christopher C."

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    Criteria for evaluating response and outcome in clinical trials for children with juvenile myelomonocytic leukemia
    (Ferrata Storti Foundation, 2015-01) Niemeyer, Charlotte M.; Loh, Mignon L.; Cseh, Annamaria; Cooper, Todd; Dvorak, Christopher C.; Chan, Rebecca; Xicoy, Blanca; Germing, Ulrich; Kojima, Seiji; Manabe, Atsushi; Dworzak, Michael; De Moerloose, Barbara; Starý, Jan; Smith, Owen P.; Masetti, Riccardo; Catala, Albert; Bergstraesser, Eva; Ussowicz, Marek; Fabri, Oskana; Baruchel, André; Cavé, Hélène; Zwaan, Michel; Locatelli, Franco; Hasle, Henrik; van den Heuvel-Eibrink, Marry M.; Flotho, Christian; Yoshimi, Ayami; Department of Pediatrics, IU School of Medicine
    Juvenile myelomonocytic leukemia is a rare myeloproliferative disease in young children. While hematopoietic stem cell transplantation remains the only curative therapeutic option for most patients, children with juvenile myelomonocytic leukemia increasingly receive novel agents in phase I-II clinical trials as pre-transplant therapy or therapy for relapse after transplantation. However, response criteria or definitions of outcome for standardized evaluation of treatment effect in patients with juvenile myelomonocytic leukemia are currently lacking. Here we propose criteria to evaluate the response to the non-transplant therapy and definitions of remission status after hematopoietic stem cell transplantation. For the evaluation of non-transplant therapy, we defined 6 clinical variables (white blood cell count, platelet count, hematopoietic precursors and blasts in peripheral blood, bone marrow blast percentage, spleen size and extramedullary disease) and 3 genetic variables (cytogenetic, molecular and chimerism response) which serve to describe the heterogeneous picture of response to therapy in each individual case. It is hoped that these criteria will facilitate the comparison of results between clinical trials in juvenile myelomonocytic leukemia.
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    Outcome of domino hematopoietic stem cell transplantation in human subjects: An international case series
    (Elsevier, 2018) Belderbos, Mirjam E.; Gennery, Andrew R.; Dvorak, Christopher C.; Blok, Henric-Jan; Eikema, Dirk-Jan; Silva, Juliana M. F.; Veys, Paul; Neven, Bénédicte; Buckley, Rebecca; Cole, Theresa; Cowan, Morton J.; Goebel, W. Scott; Hoenig, Manfred; Kuo, Caroline Y.; Stiehm, E. Richard; Wynn, Robert; Bierings, Marc; Pediatrics, School of Medicine
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    Pulmonary Metagenomic Sequencing Suggests Missed Infections in Immunocompromised Children
    (Oxford University Press, 2019-05-17) Zinter, Matt S.; Dvorak, Christopher C.; Mayday, Madeline Y.; Iwanaga, Kensho; Ly, Ngoc P.; McGarry, Meghan E.; Church, Gwynne D.; Faricy, Lauren E.; Rowan, Courtney M.; Hume, Janet R.; Steiner, Marie E.; Crawford, Emily D.; Langelier, Charles; Kalantar, Katrina; Chow, Eric D.; Miller, Steve; Shimano, Kristen; Melton, Alexis; Yanik, Gregory A.; Sapru, Anil; DeRisi, Joseph L.; Pediatrics, School of Medicine
    BACKGROUND: Despite improved diagnostics, pulmonary pathogens in immunocompromised children frequently evade detection, leading to significant mortality. Therefore, we aimed to develop a highly sensitive metagenomic next-generation sequencing (mNGS) assay capable of evaluating the pulmonary microbiome and identifying diverse pathogens in the lungs of immunocompromised children. METHODS: We collected 41 lower respiratory specimens from 34 immunocompromised children undergoing evaluation for pulmonary disease at 3 children's hospitals from 2014-2016. Samples underwent mechanical homogenization, parallel RNA/DNA extraction, and metagenomic sequencing. Sequencing reads were aligned to the National Center for Biotechnology Information nucleotide reference database to determine taxonomic identities. Statistical outliers were determined based on abundance within each sample and relative to other samples in the cohort. RESULTS: We identified a rich cross-domain pulmonary microbiome that contained bacteria, fungi, RNA viruses, and DNA viruses in each patient. Potentially pathogenic bacteria were ubiquitous among samples but could be distinguished as possible causes of disease by parsing for outlier organisms. Samples with bacterial outliers had significantly depressed alpha-diversity (median, 0.61; interquartile range [IQR], 0.33-0.72 vs median, 0.96; IQR, 0.94-0.96; P < .001). Potential pathogens were detected in half of samples previously negative by clinical diagnostics, demonstrating increased sensitivity for missed pulmonary pathogens (P < .001). CONCLUSIONS: An optimized mNGS assay for pulmonary microbes demonstrates significant inoculation of the lower airways of immunocompromised children with diverse bacteria, fungi, and viruses. Potential pathogens can be identified based on absolute and relative abundance. Ongoing investigation is needed to determine the pathogenic significance of outlier microbes in the lungs of immunocompromised children with pulmonary disease.