title: Immune Defense in Upper Airways: A Single-Cell Study of Pathogen-Specific Plasmablasts and Their Migratory Potentials in Acute Sinusitis and Tonsillitis.
abstract: Despite the high frequency of upper respiratory tract (URT) infections and use of the nasal mucosa as route for vaccination, the local immune mechanism and dissemination of effector lymphocytes from the URT have been insufficiently characterized. To devise a single-cell approach for studying the mucosal immune response in the URT, we explored URT-originating B effector lymphocytes in the circulation of patients with one of two common respiratory infections, acute sinusitis or tonsillitis.
  
  
  
  Patients with acute sinusitis (n = 13) or tonsillitis (n = 11) were investigated by ELISPOT for circulating pathogen-specific antibody-secreting cells (ASCs) of IgA, IgG and IgM isotypes approximately one week after the onset of symptoms. These cells' potential to home into tissues was explored by assessing their expression of tissue-specific homing receptors α4β7, L-selectin, and cutaneous lymphocyte antigen (CLA).
  
  
  
  Pathogen-specific ASCs were detected in the circulation of all patients, with a geometric mean of 115 (95% CI 46-282) /106 PBMC in sinusitis, and 48 (27-88) in tonsillitis. These responses were mainly dominated by IgG. In sinusitis α4β7 integrin was expressed by 24% of the ASCs, L-selectin by 82%, and CLA by 21%. The proportions for tonsillitis were 15%, 80%, and 23%, respectively. Healthy individuals had no ASCs.
  
  
  
  URT infections-acute sinusitis and tonsillitis-both elicited a response of circulating pathogen-specific plasmablasts. The magnitude of the response was greater in sinusitis than tonsillitis, but the homing receptor profiles were similar. Human nasopharynx-associated lymphoid structures were found to disseminate immune effector cells with a distinct homing profile.
authors.affiliation: Department of Bacteriology and Immunology, University of Helsinki, Helsinki, Finland.|Department of Medicine, University of Helsinki, Helsinki, Finland.
authors.forename: Nina V
authors.initials: NV
authors.lastname: Palkola
authors.affiliation: Division of Otorhinolaryngology, Department of Medicine, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
authors.forename: Karin
authors.initials: K
authors.lastname: Blomgren
authors.affiliation: Department of Bacteriology and Immunology, University of Helsinki, Helsinki, Finland.
authors.forename: Sari H
authors.initials: SH
authors.lastname: Pakkanen
authors.affiliation: Helsinki University Hospital Laboratory (HUSLAB), University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
authors.forename: Ritvaleena
authors.initials: R
authors.lastname: Puohiniemi
authors.affiliation: Occupational Health and Environmental Medicine, Department of Public Health, University of Turku, Turku, Finland.
authors.forename: Jussi M
authors.initials: JM
authors.lastname: Kantele
authors.affiliation: Department of Medicine, University of Helsinki, Helsinki, Finland.|Inflammation Center, Clinic of Infectious Diseases, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.|Unit of Infectious Diseases, Department of Medicine/Solna, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Anu
authors.initials: A
authors.lastname: Kantele
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D000907:Antibodies, Bacterial / Q000096:biosynthesis; D000918:Antibody Specificity; D000921:Antibody-Producing Cells / Q000276:immunology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000378:metabolism; D001402:B-Lymphocytes / Q000276:immunology; D001424:Bacterial Infections / Q000276:immunology; D016022:Case-Control Studies; D002465:Cell Movement / Q000276:immunology; D005260:Female; D006801:Humans; D018928:Immunity, Mucosal; D016023:Integrins / Q000378:metabolism; D019041:L-Selectin / Q000378:metabolism; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D008875:Middle Aged; D010950:Plasma Cells / Q000276:immunology*; D016201:Receptors, Lymphocyte Homing / Q000276:immunology; D012852:Sinusitis / Q000276:immunology* / Q000382:microbiology; D014069:Tonsillitis / Q000276:immunology* / Q000382:microbiology; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial; D000945:Antigens, Differentiation, T-Lymphocyte; C063419:CTAGE1 protein, human; D016023:Integrins; D008562:Membrane Glycoproteins; D016201:Receptors, Lymphocyte Homing; C546935:SELL protein, human; C071777:integrin alpha4beta7; D019041:L-Selectin