title: Enterobacterial infection modulates major histocompatibility complex class I expression on mononuclear cells.
abstract: Major histocompatibility complex (MHC) class I expression is reduced in several viral infections, but it is not known whether the same happens during infections caused by intracellular enterobacteria. In this study, the expression of MHC class I antigens on peripheral blood mononuclear cells (PBMC) from 16 patients with Salmonella, Yersinia, or Klebsiella infection was investigated. During or after the acute infection, the expression of MHC class I antigens was markedly decreased in eight patients, all with genotype HLA-B27, and six out of eight with reactive arthritis (ReA). A significant decrease of monomorphic MHC class I was found in three patients, of HLA-B27 in eight (P<0.05) and of HLA-A2 in two. However, patients negative for the HLA-B27 genotype, or healthy HLA-B27-positive individuals, did not have a significant decrease of MHC class I antigens. During the decreased expression on the cell surface, intracellular retention of MHC class I antigens was observed, whereas HLA-B27 mRNA levels did not vary significantly. This is the first evidence that enterobacterial infection may down-regulate expression of MHC class I molecules in vivo and that down-regulation is predominant in patients with the HLA-B27 genotype.
authors.affiliation: National Public Health Institute, Department in Turku, Department of Pediatrics, Turku University Central Hospital, Turku, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Kirveskari
authors.forename: Q
authors.initials: Q
authors.lastname: He
authors.forename: M
authors.initials: M
authors.lastname: Leirisalo-Repo
authors.forename: O
authors.initials: O
authors.lastname: Mäki-Ikola
authors.forename: M
authors.initials: M
authors.lastname: Wuorela
authors.forename: A
authors.initials: A
authors.lastname: Putto-Laurila
authors.forename: K
authors.initials: K
authors.lastname: Granfors
mesh_terms: D000293:Adolescent; D000328:Adult; D000954:Antigens, Surface / Q000097:blood; D016918:Arthritis, Reactive / Q000276:immunology*; D015536:Down-Regulation; D004756:Enterobacteriaceae Infections / Q000276:immunology*; D005260:Female; D005500:Follow-Up Studies; D015789:HLA-A2 Antigen / Q000097:blood; D015796:HLA-B27 Antigen / Q000097:blood; D015395:Histocompatibility Antigens Class I / Q000097:blood*; D006801:Humans; D007710:Klebsiella Infections / Q000276:immunology; D007963:Leukocytes, Mononuclear / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000276:immunology; D000091402:Prohibitins; D012480:Salmonella Infections / Q000276:immunology; D012486:Salmonella typhimurium; D015009:Yersinia Infections / Q000276:immunology; D015008:Yersinia enterocolitica
chemical_list: D000954:Antigens, Surface; D015789:HLA-A2 Antigen; D015796:HLA-B27 Antigen; D015395:Histocompatibility Antigens Class I; C000717331:PHB2 protein, human; D000091402:Prohibitins