title: Human herpesvirus 8 induces polyfunctional B lymphocytes that drive Kaposi's sarcoma.
abstract: Kaposi's sarcoma (KS) is an unusual neoplasia wherein the tumor consists primarily of endothelial cells infected with human herpesvirus 8 (HHV-8; Kaposi's sarcoma-associated herpesvirus) that are not fully transformed but are instead driven to excess proliferation by inflammatory and angiogenic factors. This oncogenic process has been postulated but unproven to depend on a paracrine effect of an abnormal excess of host cytokines and chemokines produced by HHV-8-infected B lymphocytes. Using newly developed measures for intracellular detection of lytic cycle proteins and expression of cytokines and chemokines, we show that HHV-8 targets a range of naive B cell, IgM memory B cell, and plasma cell-like populations for infection and induction of interleukin-6, tumor necrosis factor alpha, macrophage inhibitory protein 1α, macrophage inhibitory protein 1β, and interleukin-8 in vitro and in the blood of HHV-8/HIV-1-coinfected subjects with KS. These B cell lineage subsets that support HHV-8 infection are highly polyfunctional, producing combinations of 2 to 5 of these cytokines and chemokines, with greater numbers in the blood of subjects with KS than in those without KS. Our study provides a new paradigm of B cell polyfunctionality and supports a key role for B cell-derived cytokines and chemokines produced during HHV-8 infection in the development of KS.
  
  
  OBJECTIVE
  Kaposi's sarcoma (KS) is the most common cancer in HIV-1-infected persons and is caused by one of only 7 human cancer viruses, i.e., human herpesvirus 8 (HHV-8). It is unclear how this virus causes neoplastic transformation. Development and outgrowth of endothelial cell lesions characteristic of KS are hypothesized to be dependent on virus replication and multiple immune mediators produced by the KS cells and inflammatory cells, yet the roles of these viral and cell factors have not been defined. The present study advances our understanding of KS in that it supports a central role for HHV-8 infection of B cells inducing multiple cytokines and chemokines that can drive development of the cancer. Notably, HIV-1-infected individuals who developed KS had greater numbers of such HHV-8-infected, polyfunctional B cells across a range of B cell phenotypic lineages than did HHV-8-infected persons without KS. This intriguing production of polyfunctional immune mediators by B cells serves as a new paradigm for B cell function and classification.
authors.affiliation: Department of Infectious Diseases and Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Emilee R
authors.initials: ER
authors.lastname: Knowlton
authors.affiliation: Department of Infectious Diseases and Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Rappocciolo
authors.affiliation: Department of Infectious Diseases and Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Paolo
authors.initials: P
authors.lastname: Piazza
authors.affiliation: Department of Infectious Diseases and Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Lauren M
authors.initials: LM
authors.lastname: Lepone
authors.affiliation: Department of Infectious Diseases and Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Sagar V
authors.initials: SV
authors.lastname: Nadgir
authors.affiliation: Department of Pathology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Arlene
authors.initials: A
authors.lastname: Bullotta
authors.affiliation: Department of Infectious Diseases and Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Stella J
authors.initials: SJ
authors.lastname: Berendam
authors.affiliation: Department of Pathology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Infectious Diseases and Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Todd A
authors.initials: TA
authors.lastname: Reinhart
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Jenkins
authors.affiliation: rinaldo@pitt.edu.
authors.forename: Charles R
authors.initials: CR
authors.lastname: Rinaldo
mesh_terms: D001402:B-Lymphocytes / Q000166:cytology / Q000821:virology*; D002460:Cell Line; D049109:Cell Proliferation / Q000502:physiology; D018925:Chemokines / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D004279:DNA, Viral / Q000235:genetics; D019288:Herpesvirus 8, Human / Q000502:physiology*; D006801:Humans; D007075:Immunoglobulin M / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D016209:Interleukin-8 / Q000378:metabolism; D046228:Microarray Analysis; D012514:Sarcoma, Kaposi / Q000821:virology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D014779:Virus Replication
chemical_list: D018925:Chemokines; D016207:Cytokines; D004279:DNA, Viral; D007075:Immunoglobulin M; D015850:Interleukin-6; D016209:Interleukin-8; D014409:Tumor Necrosis Factor-alpha