title: Re-evaluation of hepatitis B virus clinical phases by systems biology identifies unappreciated roles for the innate immune response and B cells.
abstract: To identify immunological mechanisms that govern distinct clinical phases of a chronic hepatitis B virus (HBV) infection-immune tolerant (IT), immune active (IA), inactive carrier (IC), and hepatitis B e antigen (HBeAg)-negative (ENEG) hepatitis phases-we performed a systems biology study. Serum samples from untreated chronic HBV patients (n = 71) were used for multiplex cytokine measurements, quantitative hepatitis B surface antigen (HBsAg), HBeAg levels, HBV genotype, and mutant analysis. Leukocytes were phenotyped using multicolor flow cytometry, and whole-blood transcriptome profiles were generated. The latter were compared with liver biopsy transcriptomes from IA (n = 16) and IT (n = 3) patients. HBV viral load as well as HBeAg and HBsAg levels (P < 0.001), but not leukocyte composition, differed significantly between distinct phases. Serum macrophage chemotactic protein 1, interleukin-12p40, interferon (IFN)-gamma-inducible protein 10, and macrophage inflammatory protein 1 beta levels were different between two or more clinical phases (P < 0.05). Comparison of blood transcriptomes identified 64 differentially expressed genes. The gene signature distinguishing IA from IT and IC patients was predominantly composed of highly up-regulated immunoglobulin-encoding genes. Modular repertoire analysis using gene sets clustered according to similar expression patterns corroborated the abundant expression of B-cell function-related genes in IA patients and pointed toward increased (ISG) transcript levels in IT patients, compared to subsequent phases. Natural killer cell activities were clustered in clinical phases with biochemical liver damage (IA and ENEG phases), whereas T-cell activities were higher in all phases, compared to IT patients. B-cell-related transcripts proved to be higher in biopsies from IA versus IT patients.
  
  
  CONCLUSIONS
  HBV clinical phases are characterized by distinct blood gene signatures. Innate IFN and B-cell responses are highly active during the IT and IA phases, respectively. This suggests that the presumed immune tolerance in chronic HBV infections needs to be redefined.
authors: Department of Gastroenterology and Hepatology, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors: Thomas
authors: T
authors: Vanwolleghem
authors: Department of Gastroenterology and Hepatology, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors: Jun
authors: J
authors: Hou
authors: Department of Gastroenterology and Hepatology, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors: Gertine
authors: G
authors: van Oord
authors: Department of Viroscience, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors: Arno C
authors: AC
authors: Andeweg
authors: Department of Viroscience, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors: A D M E
authors: AD
authors: Osterhaus
authors: Department of Viroscience, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors: Suzan D
authors: SD
authors: Pas
authors: Department of Gastroenterology and Hepatology, Erasmus University Medical Center, Rotterdam, The Netherlands.|Liver Clinic, University Health Network, Toronto, Ontario, Canada.
authors: Harry L A
authors: HL
authors: Janssen
authors: Department of Gastroenterology and Hepatology, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors: Andre
authors: A
authors: Boonstra
mesh_terms: D000328:Adult; D016207:Cytokines / Q000097:blood; D005260:Female; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D006509:Hepatitis B / Q000235:genetics; D019694:Hepatitis B, Chronic / Q000097:blood* / Q000276:immunology*; D006801:Humans; D007113:Immunity, Innate; D016130:Immunophenotyping; D008297:Male; D008875:Middle Aged; D049490:Systems Biology; D059467:Transcriptome; D014758:Viral Core Proteins / Q000235:genetics; D055815:Young Adult
chemical_list: D016207:Cytokines; D014758:Viral Core Proteins