title: Giardia-specific cellular immune responses in post-giardiasis chronic fatigue syndrome.
abstract: The role of pathogen specific cellular immune responses against the eliciting pathogen in development of post-infectious chronic fatigue syndrome (PI-CFS) is not known and such studies are difficult to perform. The aim of this study was to evaluate specific anti-Giardia cellular immunity in cases that developed CFS after Giardia infection compared to cases that recovered well. Patients reporting chronic fatigue in a questionnaire study three years after a Giardia outbreak were clinically evaluated five years after the outbreak and grouped according to Fukuda criteria for CFS and idiopathic chronic fatigue. Giardia specific immune responses were evaluated in 39 of these patients by proliferation assay, T cell activation and cytokine release analysis. 20 Giardia exposed non-fatigued individuals and 10 healthy unexposed individuals were recruited as controls.
  
  
  
  Patients were clinically classified into CFS (n = 15), idiopathic chronic fatigue (n = 5), fatigue from other causes (n = 9) and recovered from fatigue (n = 10). There were statistically significant antigen specific differences between these Giardia exposed groups and unexposed controls. However, we did not find differences between the Giardia exposed fatigue classification groups with regard to CD4 T cell activation, proliferation or cytokine levels in 6 days cultured PBMCs. Interestingly, sCD40L was increased in patients with PI-CFS and other persons with fatigue after Giardia infection compared to the non-fatigued group, and correlated well with fatigue levels at the time of sampling.
  
  
  
  Our data show antigen specific cellular immune responses in the groups previously exposed to Giardia and increased sCD40L in fatigued patients.
authors.affiliation: Department of Clinical Science, Lab-building 8.floor, University of Bergen, N-5021, Bergen, Norway. kurt.hanevik@med.uib.no.|Center for Tropical Infectious Diseases, Haukeland University Hospital, Bergen, Norway. kurt.hanevik@med.uib.no.
authors.forename: Kurt
authors.identifier: 0000-0002-1466-2326
authors.initials: K
authors.lastname: Hanevik
authors.affiliation: Department of Clinical Science, Lab-building 8.floor, University of Bergen, N-5021, Bergen, Norway.|Department of immunology and transfusion medicine, Haukeland University Hospital, Bergen, Norway.
authors.forename: Einar
authors.initials: E
authors.lastname: Kristoffersen
authors.affiliation: Department of Clinical Science, Lab-building 8.floor, University of Bergen, N-5021, Bergen, Norway.|Center for Tropical Infectious Diseases, Haukeland University Hospital, Bergen, Norway.
authors.forename: Kristine
authors.initials: K
authors.lastname: Mørch
authors.affiliation: Department of Clinical Science, Lab-building 8.floor, University of Bergen, N-5021, Bergen, Norway.
authors.forename: Kristin Paulsen
authors.initials: KP
authors.lastname: Rye
authors.affiliation: Department of Clinical Science, Lab-building 8.floor, University of Bergen, N-5021, Bergen, Norway.
authors.forename: Steinar
authors.initials: S
authors.lastname: Sørnes
authors.affiliation: Department of Cell and Molecular biology, Uppsala University, Uppsala, Sweden.
authors.forename: Staffan
authors.initials: S
authors.lastname: Svärd
authors.affiliation: Department of Clinical Science, Lab-building 8.floor, University of Bergen, N-5021, Bergen, Norway.
authors.forename: Øystein
authors.initials: Ø
authors.lastname: Bruserud
authors.affiliation: Department of Clinical Science, Lab-building 8.floor, University of Bergen, N-5021, Bergen, Norway.|Center for Tropical Infectious Diseases, Haukeland University Hospital, Bergen, Norway.
authors.forename: Nina
authors.initials: N
authors.lastname: Langeland
mesh_terms: D000328:Adult; D000368:Aged; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000469:parasitology; D023201:CD40 Ligand / Q000378:metabolism; D049109:Cell Proliferation; D016207:Cytokines / Q000378:metabolism; D015673:Fatigue Syndrome, Chronic / Q000209:etiology / Q000276:immunology*; D005260:Female; D005500:Follow-Up Studies; D005872:Giardia / Q000276:immunology*; D005873:Giardiasis / Q000150:complications / Q000276:immunology*; D006801:Humans; D007111:Immunity, Cellular; D008297:Male; D008875:Middle Aged; D009664:Norway; D055815:Young Adult
chemical_list: D016207:Cytokines; D023201:CD40 Ligand
keywords: Antigen-specific; Chronic fatigue syndrome; Giardia; Immune response; T cell; sCD40L