Childhood Langerhans Cell Histiocytosis: Epidemiology, Clinical Presentations, Prognostic Factors, and Therapeutic Approaches

Childhood LCH is a rare disease, affecting 4–9 per 1,000,000 children below the age of 15 years. It is driven by somatic mutations in the MAPK pathway, arising in myeloid marrow progenitors. Both genders are affected by a slight male preponderance. The clinical spectrum of LCH varies from a single lesion affecting one organ system to severe multisystem disease with dysfunction of vital organs. Likewise, variable and unpredictable is its course, spanning from self-limiting course to progression with lethal outcome. Recognized unfavorable prognostic factors are the involvement of hematopoiesis, liver, and spleen, as well as non-response to systemic treatment. Recent studies suggest that patients carrying the BRAFV600E mutation may have a more severe clinical phenotype and less favorable prognosis. The combination of prednisolone and vinblastine is the standard first-line treatment for disseminated disease. Second-line options used in clinical practice are not well evidenced. Inhibitors of the MAPK pathway are a promising alternative option

Stem cell transplantation for children with hemophagocytic lymphohistiocytosis: results from the HLH-2004 study

We report the largest prospective study thus far on hematopoietic stem cell transplantation (HSCT) in hemophagocytic lymphohistiocytosis (HLH), a life-threatening hyperinflammatory syndrome comprising familial/genetic HLH (FHL) and secondary HLH. Although all patients with HLH typically need intensive anti-inflammatory therapy, patients with FHL also need HSCT to be cured. In the international HLH-2004 study, 187 children aged ,18 years fulfilling the study inclusion criteria (5 of 8 diagnostic criteria, affected sibling, or molecular diagnosis in FHL-causative genes) underwent 209 transplants (2004-2012), defined as indicated in patients with familial/genetic, relapsing, or severe/persistent disease. Five-year overall survival (OS) post-HSCT was 66% (95% confidence interval [CI], 59-72); event-free survival (EFS) was 60% (95% CI, 52-67). Five-year OS was 81% (95% CI, 65-90) for children with a complete response and 59% (95% CI, 48-69) for those with a partial response (hazard ratio [HR], 2.12; 95% CI, 1.06-4.27; P 5 .035). For children with verified FHL (family history/genetically verified, n 5 134), 5-year OS was 71% (95% CI, 62-78) and EFS was 62% (95% CI, 54-70); 5-year OS for children without verified FHL (n 5 53) was significantly lower (52%; 95% CI, 38-65) (P 5 .040; HR, 1.69; 95% CI, 1.03-2.77); they were also significantly older. Notably, 20 (38%) of 53 patients without verified FHL had natural killer cell activity reported as normal at diagnosis, after 2 months, or at HSCT, suggestive of secondary HLH; and in addition 14 (26%) of these 53 children had no evidence of biallelic mutations despite having 3 or 4 FHL genes analyzed (natural killer cell activity not analyzed after 2 months or at HSCT). We conclude that post-HSCT survival in FHL remains suboptimal, and that the FHL diagnosis should be carefully investigated before HSCT. Pretransplant complete remission is beneficial but not mandatory to achieve post-HSCT survival.Fil: Bergsten, Elisabet. Karolinska Huddinge Hospital. Karolinska Institutet; SueciaFil: Horne, AnnaCarin. Karolinska Huddinge Hospital. Karolinska Institutet; SueciaFil: Hed Myrberg, Ida. Karolinska Huddinge Hospital. Karolinska Institutet; SueciaFil: Aricó, Maurizio. Children Hospital Giovanni XXIII; ItaliaFil: Astigarraga, Itziar. Universidad del País Vasco; EspañaFil: Ishii, Eiichi. Ehime University; JapónFil: Janka, Gritta. Universitat Hamburg; AlemaniaFil: Ladisch, Stephan. Children’s National Medical Center; Estados UnidosFil: Lehmberg, Kai. Universitat Hamburg; AlemaniaFil: McClain, Kenneth L.. Baylor College of Medicine; Estados UnidosFil: Minkov, Milen. Universidad de Viena; AustriaFil: Nanduri, Vasanta. Watford General Hospital; Reino UnidoFil: Rosso, Diego. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños Pedro Elizalde (ex Casa Cuna); Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sieni, Elena. Universitaria A. Meyer Children Hospital; ItaliaFil: Winiarski, Jacek. Karolinska Huddinge Hospital. Karolinska Institutet; SueciaFil: Henter, Jan Inge. Karolinska Huddinge Hospital. Karolinska Institutet; Sueci

A Web Application for Text Document Classification Based on K-Nearest Neighbor Algorithm

The paper gives insight on how the text document categorization problem can be solved and implemented in a software product. On that score, it specifies how input data are provided, processed and transformed into output data. The goal of the paper is not only to suggest a simple theoretical solution to the text document categorization problem but to provide a real-life implementation as part of a software system. ACM Computing Classication System (1998): H.3.3, H.3.5, I.7.5.*The research presented in this paper was partially supported by the project FNI-SU- 2017/80 10-128 (St. Kliment Ohridski University of Sofia, Bulgaria) Secure and re-usable software architectures for Technology-enhanced learning

Polycythaemia-inducing mutations in the erythropoietin receptor (EPOR):mechanism and function as elucidated by epidermal growth factor receptor-EPOR chimeras

Primary familial and congenital polycythaemia (PFCP) is a disease characterized by increased red blood cell mass, and can be associated with mutations in the intracellular region of the erythropoietin (EPO) receptor (EPOR). Here we explore the mechanisms by which EPOR mutations induce PFCP, using an experimental system based on chimeric receptors between epidermal growth factor receptor (EGFR) and EPOR. The design of the chimeras enabled EPOR signalling to be triggered by EGF binding. Using this system we analysed three novel EPOR mutations discovered in PFCP patients: a deletion mutation (Del1377-1411), a nonsense mutation (C1370A) and a missense mutation (G1445A). Three different chimeras, bearing these mutations in the cytosolic, EPOR region were generated; Hence, the differences in the chimera-related effects are specifically attributed to the mutations. The results show that the different mutations affect various aspects related to the signalling and metabolism of the chimeric receptors. These include slower degradation rate, higher levels of glycan-mature chimeric receptors, increased sensitivity to low levels of EGF (replacing EPO in this system) and extended signalling cascades. This study provides a novel experimental system to study polycythaemia-inducing mutations in the EPOR, and sheds new light on underlying mechanisms of EPOR over-activation in PFCP patients

Transcobalamin II deficiency at birth

Transcobalamin II deficiency (# MIM 275350) is a rare, recessively inherited disorder of cobalamin transport that leads to intracellular cobalamin depletion with secondary impairment of methionine synthetase and methyl-malonyl CoA mutase activities. Affected individuals may suffer from long-term neurological sequelae if therapy with intramuscular hydroxocobalamin is not initiated promptly. We report two sisters with complete absence of transcobalamin due to homozygosity for a novel mutation (c.insC110) in the TCN2 gene that leads to a premature stop codon and non-functional protein. The older sister, now 4.5 years old, presented at 6 weeks of age with pancytopenia, protein losing enteropathy and a rapidly declining clinical course. Prompt therapy with 1mg hydroxocobalamin/day led to full recovery within days. Her now 1.5 year old sister was diagnosed shortly after birth and was started on hydroxocobalamin prior to onset of clinical symptoms. Interestingly, urinary methylmalonic acid excretion was increased significantly during the first days of life suggesting that functional cobalamin deficiency is present also during fetal life, although not giving rise to clinical symptoms until well after birth

Additive prognostic impact of gastrointestinal involvement in severe multisystem Langerhans cell histiocytosis

Objective: To evaluate the prognostic impact of gastrointestinal involvement on the survival of children with Langerhans cell histiocytosis (GI-LCH) registered with the international clinical trials of the Histiocyte Society. Study design: This was a retrospective analysis of 2414 pediatric patients registered onto the consecutive trials DAL-HX 83, DAL-HX 90, LCH-I, LCH-II, and LCH-III. Results: Among the 1289 patients with single-system LCH, there was no single case confined to the GI tract; 114 of 1125 (10%) patients with multisystem LCH (MS-LCH) had GI-LCH at initial presentation. GI-LCH was significantly more common in children aged 2 years; P < .001) and in those with risk organ involvement (15% vs 6% in those without risk organ involvement; P < .001). The 5-year overall survival (OS) in patients without risk organ involvement was excellent irrespective of GI disease (98% vs 97% in patients with GI-LCH; P = .789). In patients with risk organ involvement, the 5-year OS was 51% in 70 patients with GI-LCH vs 72% in 394 patients without GI-LCH (P < .001). Conclusions: GI-LCH has an additive unfavorable prognostic impact in children with MS-LCH and risk organ involvement. The emerding need for more intensive or alternative treatments mandates prospective evaluation

Notch is active in Langerhans Cell Histiocytosis and confers pathognomonic features on dendritic cells

Langerhans cell histiocytosis (LCH) is an enigmatic disease defined by the accumulation of Langerhans-cell-like dendritic cells (DC). Here we demonstrate that LCH cells exhibit a unique transcription profile that separates them not only from plasmacytoid and myeloid DC but also from epidermal Langerhans cells, indicating a distinct DC entity. Molecular analysis revealed that isolated as well as tissue bound LCH-cells selectively express Notch ligand Jagged 2 (JAG2) and are the only DC that express both Notch ligand and its receptor. We further show that JAG2 signaling induces key LCH-cell markers in monocyte-derived DC, suggesting a functional role of Notch signaling in LCH ontogenesis. Notably, JAG2 also induced matrix-metalloproteinases 1 and 12, which are highly expressed in LCH and may account for tissue destruction in LCH lesions. This induction was selective for DC and not recapitulated in monocytes. Together these findings suggest that JAG2 mediated Notch activation confers phenotypic and functional aspects of LCH to DC. Thus, interference with Notch signaling may prove an attractive strategy to combat this disease

Confirmed efficacy of etoposide and dexamethasone in HLH treatment: Long term results of the cooperative HLH-2004 study.

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory syndrome comprising familial/genetic HLH (FHL) and secondary HLH. In the HLH-94 study, with an estimated 5-year probability of survival (pSu) of 54% (95% confidence interval, 48%-60%), systemic therapy included etoposide, dexamethasone, and, from week 9, cyclosporine A (CSA). Hematopoietic stem cell transplantation (HSCT) was indicated in patients with familial/genetic, relapsing, or severe/persistent disease. In HLH-2004, CSA was instead administered upfront, aiming to reduce pre-HSCT mortality and morbidity. From 2004 to 2011, 369 children aged <18 years fulfilled HLH-2004 inclusion criteria (5 of 8 diagnostic criteria, affected siblings, and/or molecular diagnosis in FHL-causative genes). At median follow-up of 5.2 years, 230 of 369 patients (62%) were alive (5-year pSu, 61%; 56%-67%). Five-year pSu in children with (n = 168) and without (n = 201) family history/genetically verified FHL was 59% (52%-67%) and 64% (57%-71%), respectively (familial occurrence [n = 47], 58% [45%-75%]). Comparing with historical data (HLH-94), using HLH-94 inclusion criteria, pre-HSCT mortality was nonsignificantly reduced from 27% to 19% (P = .064 adjusted for age and sex). Time from start of therapy to HSCT was shorter compared with HLH-94 (P = .020 adjusted for age and sex) and reported neurological alterations at HSCT were 22% in HLH-94 and 17% in HLH-2004 (using HLH-94 inclusion criteria). Five-year pSu post-HSCT overall was 66% (verified FHL, 70% [63%-78%]). Additional analyses provided specific suggestions on potential pre-HSCT treatment improvements. HLH-2004 confirms that a majority of patients may be rescued by the etoposide/dexamethasone combination but intensification with CSA upfront, adding corticosteroids to intrathecal therapy, and reduced time to HSCT did not improve outcome significantly.Fil: Bergsten, Elisabet. Karolinska Huddinge Hospital. Karolinska Institutet; SueciaFil: Horne, AnnaCarin. Karolinska Huddinge Hospital. Karolinska Institutet; SueciaFil: Aricó, Maurizio. No especifica;Fil: Astigarraga, Itziar. Universidad del País Vasco; EspañaFil: Egeler, R. Maarten. University Of Toronto. Hospital For Sick Children; CanadáFil: Filipovich, Alexandra H.. Cincinnati Children’s Hospital Medical Center; Estados UnidosFil: Ishii, Eiichi. Ehime University; JapónFil: Janka, Gritta. University Medical Center Hamburg; AlemaniaFil: Ladisch, Stephan. Children’s National Medical Center; Estados UnidosFil: Lehmberg, Kai. University Medical Center Hamburg; AlemaniaFil: McClain, Kenneth L.. Baylor College of Medicine; Estados UnidosFil: Minkov, Milen. Medical University of Vienna; AustriaFil: Montgomery, Scott. Karolinska Huddinge Hospital. Karolinska Institutet; Suecia. University College London; Reino Unido. Orebro University; SueciaFil: Nanduri, Vasanta. Watford General Hospital; Reino UnidoFil: Rosso, Diego. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños Pedro Elizalde (ex Casa Cuna); Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; Argentina. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Henter, Jan Inge. Karolinska Huddinge Hospital. Karolinska Institutet; Sueci