title: Viridans streptococcal septicaemia in neutropenic patients: role of proinflammatory cytokines.
abstract: The immunostimulatory activity of viridans streptococcal strains isolated from neutropenic patients with severe sepsis (n=9) or uncomplicated bacteraemia (n=10) was compared. Peripheral blood mononuclear cells from healthy individuals were stimulated with heat-killed bacteria or culture supernatants, and cytokine production assessed. All strains were potent inducers of IL1beta, IL8, and TNFalpha production. Heat-killed bacteria induced consistently higher IL1beta and TNFalpha production than did the cell-free bacterial supernatants (P<0.01). The strains did not induce any proliferative response, nor any significant TNFbeta or IFNgamma production. No difference in cytokine-inducing capacity could be detected between the cohorts of severe and nonsevere isolates. Comparison of strains causing severe and nonsevere episodes in the same patient (n=2) revealed a significantly higher induction of IL1beta by the severe episodes associated isolates as compared to the nonsevere (P<0.04). The study underscores the importance of the host-pathogen interplay in determining the level of inflammation, and hence the severity of disease.
authors.affiliation: Department of Medicine, Center for Infectious Medicine, Karolinska Institutet, Huddinge University Hospital, Stockholm, Sweden.
authors.forename: N
authors.initials: N
authors.lastname: Ihendyane
authors.forename: E
authors.initials: E
authors.lastname: Sparrelid
authors.forename: B
authors.initials: B
authors.lastname: Wretlind
authors.forename: M
authors.initials: M
authors.lastname: Remberger
authors.forename: J
authors.initials: J
authors.lastname: Andersson
authors.forename: P
authors.initials: P
authors.lastname: Ljungman
authors.forename: O
authors.initials: O
authors.lastname: Ringdén
authors.forename: B Henriques
authors.initials: BH
authors.lastname: Normark
authors.forename: U
authors.initials: U
authors.lastname: Allen
authors.forename: D E
authors.initials: DE
authors.lastname: Low
authors.forename: A
authors.initials: A
authors.lastname: Norrby-Teglund
mesh_terms: D016470:Bacteremia / Q000276:immunology; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis* / Q000276:immunology; D006801:Humans; D007249:Inflammation / Q000209:etiology* / Q000276:immunology; D007375:Interleukin-1 / Q000032:analysis; D016209:Interleukin-8 / Q000032:analysis; D007963:Leukocytes, Mononuclear / Q000276:immunology / Q000382:microbiology; D009503:Neutropenia / Q000276:immunology*; D018805:Sepsis / Q000276:immunology* / Q000473:pathology; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis; D034363:Viridans Streptococci
chemical_list: D016207:Cytokines; D007375:Interleukin-1; D016209:Interleukin-8; D014409:Tumor Necrosis Factor-alpha