title: Immune markers characteristic for asymptomatically infected and diseased Entamoeba histolytica individuals and their relation to sex.
abstract: BACKGROUND
  The protozoan parasite Entamoeba histolytica (E. histolytica) usually asymptomatically colonizes the human intestine. In the minority of the cases, the parasite evades from the gut and can induce severe symptoms like colitis or amebic liver abscess (ALA). Interestingly, ALA predominates in adult men despite a higher prevalence of the parasite in women. The present study aimed to identify characteristic serum markers in a unique cohort of clearly defined asymptomatically infected E. histolytica individuals in comparison to patients with an E. histolytica liver manifestation of both sex.
  
  
  METHODS
  The following study groups were investigated: ALA patients (n = 38), healthy asymptomatic E. histolytica carriers (AC) (n = 44), and healthy E. dispar-infected controls (n = 24) out of an amebiasis endemic area. E. histolytica-specific immunoglobulin G (IgG) and the IgG subclasses against proteinaceous and non-proteinaceous amebic antigens were measured by ELISA. Serum cytokine and chemokine levels were investigated using a flow cytometry bead-based multiplex immunoassay.
  
  
  RESULTS
  The IgG results revealed that not only ALA patients, but also AC, developed high E. histolytica-specific titers of IgG and all IgG subclasses as well as IgA. IgG and IgG2 titers against the glycolipid E. histolytica lipophosphoglycan were highest in ALA patients. As in ALA patients, high cytokine levels of interleukin (IL-) 4 were detected in AC compared to E. dispar infected individuals, while IL-6 was exclusively elevated in ALA patients. IL-10 was lower in AC compared to ALA patients. Equal serum levels of CCL2 were found in all study groups but ALA patients showed decreased levels of CCL3. Sex dependent analysis of the data indicated significantly higher IgG and IgG1 titers in female AC compared to male AC. CCL2, the chemokine involved in immunopathology in the mouse model for the disease, was higher in male AC compared to female AC.
  
  
  CONCLUSIONS
  In this study we characterize for the first time an asymptomatic carrier stage in amebiasis that is associated with a significant immune reaction and provide immunological markers that might give first hints towards an understanding of immune mechanisms underlying the control or development of invasive amebiasis.
authors.forename: Hannah
authors.initials: H
authors.lastname: Bernin
authors.forename: Claudia
authors.initials: C
authors.lastname: Marggraff
authors.forename: Thomas
authors.initials: T
authors.lastname: Jacobs
authors.forename: Norbert
authors.initials: N
authors.lastname: Brattig
authors.forename: Van An
authors.initials: VA
authors.lastname: Le
authors.forename: Jörg
authors.initials: J
authors.lastname: Blessmann
authors.forename: Hannelore
authors.initials: H
authors.lastname: Lotter
mesh_terms: D000328:Adult; D000913:Antibodies, Protozoan / Q000276:immunology*; D058345:Asymptomatic Infections; D015415:Biomarkers; D002353:Carrier State / Q000276:immunology; D016022:Case-Control Studies; D018932:Chemokine CCL2 / Q000276:immunology; D054405:Chemokine CCL3 / Q000276:immunology; D004748:Entamoeba histolytica / Q000276:immunology*; D004749:Entamoebiasis / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D016753:Interleukin-10 / Q000276:immunology; D015847:Interleukin-4 / Q000276:immunology; D015850:Interleukin-6 / Q000276:immunology; D008101:Liver Abscess, Amebic / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D012737:Sex Factors
chemical_list: D000913:Antibodies, Protozoan; D015415:Biomarkers; D018932:Chemokine CCL2; D054405:Chemokine CCL3; D007074:Immunoglobulin G; D015850:Interleukin-6; D016753:Interleukin-10; D015847:Interleukin-4