{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,10]],"date-time":"2026-09-10T03:17:59Z","timestamp":1789010279669,"version":"build-2803163510"},"reference-count":42,"publisher":"American Society of Hematology","issue":"4","content-domain":{"domain":["ashpublications.org"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2020,2,25]]},"abstract":"<jats:title>Abstract<\/jats:title>\n               <jats:p>Langerhans cell histiocytosis (LCH) is a rare hematologic neoplasm characterized by a clonal proliferation of Langerhans-like cells. Genomic profiling has identified recurrent somatic activating mutations in the mitogen-activated protein kinase pathway, which are targetable by small-molecule inhibitors. However, key questions such as the curative potential of targeted therapy and the cell of origin remain unanswered. In this study, we describe clinical outcomes of a series of pediatric patients with multisystem BRAF V600E\u2013mutant LCH, as well as the results of accompanying murine xenograft experiments. Four infants with LCH (range, 7-11 months at diagnosis) and secondary hemophagocytic lymphohistiocytosis were referred to our institution and subsequently treated with the BRAF V600E\u2013specific inhibitor dabrafenib. All patients achieved complete clinical responses by 8 weeks of therapy, with remissions lasting a median of 36 months (range, 27-42 months). One infant successfully discontinued therapy long-term upon achieving a molecular response by real-time quantitative polymerase chain reaction (RT-qPCR). We further characterized the disease-propagating cell population in a subset of these patients by transplanting whole bone marrow into immunodeficient mice. Xenografted animals exhibited decreased survival with hematologic abnormalities, splenomegaly, and histiocytic infiltrates in the bone marrow resembling human disease. This process could also be secondarily transplanted, resulting in a comparable disease latency with similar histologic findings. These data further support the presence of a disease-initiating cell in the bone marrow compartment. We demonstrate that despite aggressive disease behavior in a xenograft model, these patients can achieve sustained clinical remissions with targeted monotherapy, with a select subset achieving molecular responses by RT-qPCR.<\/jats:p>","DOI":"10.1182\/bloodadvances.2019032367","type":"journal-article","created":{"date-parts":[[2020,2,24]],"date-time":"2020-02-24T11:40:26Z","timestamp":1582544426000},"page":"717-727","update-policy":"https:\/\/doi.org\/10.1182\/blood.2019cm0000","source":"Crossref","is-referenced-by-count":20,"title":["High-risk LCH in infants is serially transplantable in a xenograft model but responds durably to targeted therapy"],"prefix":"10.1182","volume":"4","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2898-6196","authenticated-orcid":false,"given":"Lynn H.","family":"Lee","sequence":"first","affiliation":[{"name":"Division of Oncology, Cincinnati Children\u2019s Hospital Medical Center, Cincinnati, OH;"},{"name":"Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH; and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christa","family":"Krupski","sequence":"first","affiliation":[{"name":"Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH; and"},{"name":"Division of Bone Marrow Transplant and Immune Deficiency,"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7812-4685","authenticated-orcid":false,"given":"Jason","family":"Clark","sequence":"first","affiliation":[{"name":"Division of Bone Marrow Transplant and Immune Deficiency,"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2166-5146","authenticated-orcid":false,"given":"Mark","family":"Wunderlich","sequence":"first","affiliation":[{"name":"Division of Experimental Hematology and Cancer Biology, Cancer and Blood Diseases Institute, and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Robert B.","family":"Lorsbach","sequence":"first","affiliation":[{"name":"Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH; and"},{"name":"Division of Pathology, Cincinnati Children\u2019s Hospital Medical Center, Cincinnati, OH"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Michael S.","family":"Grimley","sequence":"first","affiliation":[{"name":"Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH; and"},{"name":"Division of Bone Marrow Transplant and Immune Deficiency,"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Matthew","family":"Burwinkel","sequence":"first","affiliation":[{"name":"Division of Bone Marrow Transplant and Immune Deficiency,"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Adam","family":"Nelson","sequence":"first","affiliation":[{"name":"Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH; and"},{"name":"Division of Bone Marrow Transplant and Immune Deficiency,"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ashish R.","family":"Kumar","sequence":"first","affiliation":[{"name":"Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH; and"},{"name":"Division of Bone Marrow Transplant and Immune Deficiency,"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"234","published-online":{"date-parts":[[2020,2,24]]},"reference":[{"issue":"1","key":"2020022411393872800_B1","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1111\/bjh.13247","article-title":"Progress in understanding the pathogenesis of Langerhans cell histiocytosis: back to histiocytosis X?","volume":"169","author":"Berres","year":"2015","journal-title":"Br J 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