Genetic and mechanistic diversity in pediatric hemophagocytic lymphohistiocytosis.

TitleGenetic and mechanistic diversity in pediatric hemophagocytic lymphohistiocytosis.
Publication TypeJournal Article
Year of Publication2018
AuthorsChinn, IK, Eckstein, OS, Peckham-Gregory, EC, Goldberg, BR, Forbes, LR, Nicholas, SK, Mace, EM, Vogel, TP, Abhyankar, HA, Diaz, MI, Heslop, HE, Krance, RA, Martinez, CA, Nguyen, TC, Bashir, DA, Goldman, JR, Stray-Pedersen, A, Pedroza, LA, M Poli, C, Aldave-Becerra, JC, McGhee, SA, Al-Herz, W, Chamdin, A, Coban-Akdemir, ZH, Jhangiani, SN, Muzny, DM, Cao, TN, Hong, DN, Gibbs, RA, Lupski, JR, Orange, JS, McClain, KL, Allen, CE
Date Published2018 Jul 05
KeywordsAdolescent, Child, Child, Preschool, Cohort Studies, Female, Genetic Testing, Genome, Human, Genome-Wide Association Study, High-Throughput Nucleotide Sequencing, Humans, Infant, Infant, Newborn, Lymphohistiocytosis, Hemophagocytic, Male, Multifactorial Inheritance

The HLH-2004 criteria are used to diagnose hemophagocytic lymphohistiocytosis (HLH), yet concern exists for their misapplication, resulting in suboptimal treatment of some patients. We sought to define the genomic spectrum and associated outcomes of a diverse cohort of children who met the HLH-2004 criteria. Genetic testing was performed clinically or through research-based whole-exome sequencing. Clinical metrics were analyzed with respect to genomic results. Of 122 subjects enrolled over the course of 17 years, 101 subjects received genetic testing. Biallelic familial HLH (fHLH) gene defects were identified in only 19 (19%) and correlated with presentation at younger than 1 year of age ( < .0001). Digenic fHLH variants were observed but lacked statistical support for disease association. In 28 (58%) of 48 subjects, research whole-exome sequencing analyses successfully identified likely molecular explanations, including underlying primary immunodeficiency diseases, dysregulated immune activation and proliferation disorders, and potentially novel genetic conditions. Two-thirds of patients identified by the HLH-2004 criteria had underlying etiologies for HLH, including genetic defects, autoimmunity, and malignancy. Overall survival was 45%, and increased mortality correlated with HLH triggered by infection or malignancy ( < .05). Differences in survival did not correlate with genetic profile or extent of therapy. HLH should be conceptualized as a phenotype of critical illness characterized by toxic activation of immune cells from different underlying mechanisms. In most patients with HLH, targeted sequencing of fHLH genes remains insufficient for identifying pathogenic mechanisms. Whole-exome sequencing, however, may identify specific therapeutic opportunities and affect hematopoietic stem cell transplantation options for these patients.

Alternate JournalBlood
PubMed ID29632024
PubMed Central IDPMC6034641
Grant ListR01 AI120989 / AI / NIAID NIH HHS / United States
R25 CA160078 / CA / NCI NIH HHS / United States
P50 CA126752 / CA / NCI NIH HHS / United States
K12 CA090433 / CA / NCI NIH HHS / United States
R01 NS058529 / NS / NINDS NIH HHS / United States
UM1 HG006542 / HG / NHGRI NIH HHS / United States
R01 AI067946 / AI / NIAID NIH HHS / United States

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