Kumar et al. characterized the transcriptome and proteome of the DC compartment in both pediatric and adult ALL, and demonstrated that DC maturation into functional lineages was disrupted. Proliferation, antigen presentation, and cytokine production were impaired across all residual DC subsets, except progenitor/DC4 fractions, leading to a semi-mature, potentially tolerogenic phenotype with defective T cell priming. MYC overexpression in malignant lymphoblasts partly drove the disruption of DC homeostasis. A stimulated DC transcriptional signature at ALL diagnosis correlated with favorable outcomes in B-ALL, but adverse outcomes in T-ALL.

Contributed by Shishir Pant

ABSTRACT: Perturbations in dendritic cells (DCs) in B/T cell acute lymphoblastic leukemia (ALL), their cause(s) and consequence(s) on antileukemia immunity, and patient outcomes remain poorly explored. We find that maturation of DC1-6 subsets is disrupted in children and adults with ALL. Conventional DC1 and DC2 subpopulations are reduced at the expense of the progenitors and the DC4 fractions in ALL. The potential to mature, present antigens, and produce cytokines for initiating T cell surveillance appears to be impaired in every ALL DC subset. Such DC subsets are accordingly unable to induce T cell proliferation compared to DCs from healthy donors. MYC overexpression in ALL cells disrupts DC homeostasis and reduces the ability of DCs to induce T cell proliferation. Predominance of cells with transcriptional signatures typical of "stimulated DCs" predicts favorable clinical outcomes in B-ALL, while it is associated with unfavorable outcomes in T-ALL. Phenotyping DC subsets at ALL diagnosis could thus be valuable in informing treatment outcomes.

Author Info: (1) Department of Systems Biology, Beckman Research Institute of City of Hope, Monrovia, CA 91016, USA. (2) Department of Systems Biology, Beckman Research Institute of City of Hop e, Monrovia, CA 91016, USA. (3) The Human Immune Monitoring Center (HIMC), Institute for Immunity, Transplantation and Infection, Stanford University School of Medicine, Stanford, CA 94305, USA. (4) Department of Systems Biology, Beckman Research Institute of City of Hope, Monrovia, CA 91016, USA. (5) Department of Systems Biology, Beckman Research Institute of City of Hope, Monrovia, CA 91016, USA. (6) Department of Molecular and Cellular Biology, City of Hope National Medical Center, Duarte, CA 91010, USA. (7) The Hematopoietic Tissue Biorepository/Research Pathology Shared Resources, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA. (8) Department of Pediatrics (Hematology and Oncology), Stanford University School of Medicine, Stanford, CA 94305, USA. (9) Department of Systems Biology, Beckman Research Institute of City of Hope, Monrovia, CA 91016, USA. (10) Department of Systems Biology, Beckman Research Institute of City of Hope, Monrovia, CA 91016, USA. (11) Department of Systems Biology, Beckman Research Institute of City of Hope, Monrovia, CA 91016, USA. (12) The Hematopoietic Tissue Biorepository/Research Pathology Shared Resources, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA. (13) The Hematopoietic Tissue Biorepository/Research Pathology Shared Resources, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA; The Department of Hematological Malignancies Translational Science, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA. (14) Department of Pediatrics (Hematology and Oncology), Stanford University School of Medicine, Stanford, CA 94305, USA. (15) Department of Pediatrics (Hematology and Oncology), Stanford University School of Medicine, Stanford, CA 94305, USA. (16) Department of Basic Science, Division of Cancer Sciences, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA. (17) Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA. (18) Division of Oncology and Center for Childhood Cancer Research, Department of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Department of Pediatrics and Abramson Cancer Center, University of Pennsylvania School of Medicine, Philadelphia, PA, USA. (19) Department of Laboratory Medicine, University of California, San Francisco, San Francisco, CA 94143, USA. (20) Department of Clinical Population and Public Health Sciences, University of Southern California, Los Angeles, CA 91016, USA. (21) Department of Pediatrics, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA. (22) Schneider Children's Medical Center, Tel Aviv University, Felsenstein Research Institute, Tel Aviv, Israel. (23) Department of Molecular and Cellular Biology, City of Hope National Medical Center, Duarte, CA 91010, USA. (24) The Human Immune Monitoring Center (HIMC), Institute for Immunity, Transplantation and Infection, Stanford University School of Medicine, Stanford, CA 94305, USA. (25) Department of Systems Biology, Beckman Research Institute of City of Hope, Monrovia, CA 91016, USA; Department of Pediatrics, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA; Center for RNA Biology and Therapeutics, Beckman Research Institute of City of Hope, Monrovia, CA 91016, USA. Electronic address: sswaminathan@coh.org.