title: Interferon-gamma release assay (modified QuantiFERON) as a potential marker of infection for Leishmania donovani, a proof of concept study.
abstract: BACKGROUND
  In areas endemic for visceral leishmaniasis (VL), a large number of infected individuals mount a protective cellular immune response and remain asymptomatic carriers. We propose an interferon-gamma release assay (IFN-γRA) as a novel marker for latent L. donovani infection.
  
  
  RESULTS
  We modified a commercial kit (QuantiFERON) evaluating five different leishmania-specific antigens; H2B, H2B-PSA2, H2B-Lepp12, crude soluble antigen (CSA) and soluble leishmania antigen (SLA) from L. donovani with the aim to detect the cell-mediated immune response in VL. We evaluated the assay on venous blood samples of active VL patients (n = 13), cured VL patients (n = 15), non-endemic healthy controls (n = 11) and healthy endemic controls (n = 19). The assay based on SLA had a sensitivity of 80% (95% CI = 54.81-92.95) and specificity of 100% (95% CI = 74.12-100).
  
  
  CONCLUSIONS
  Our findings suggest that a whole-blood SLA-based QuantiFERON assay can be used to measure the cell-mediated immune response in L. donovani infection. The positive IFN-γ response to stimulation with leishmania antigen in patients with active VL was contradictory to the conventional finding of a non-proliferative antigen-specific response of peripheral blood mononuclear cells and needs further research.
authors.affiliation: Banaras Hindu University, Varanasi, India.
authors.forename: Kamlesh
authors.initials: K
authors.lastname: Gidwani
authors.forename: Stephen
authors.initials: S
authors.lastname: Jones
authors.forename: Rajiv
authors.initials: R
authors.lastname: Kumar
authors.forename: Marleen
authors.initials: M
authors.lastname: Boelaert
authors.forename: Shyam
authors.initials: S
authors.lastname: Sundar
mesh_terms: D000953:Antigens, Protozoan; D001769:Blood / Q000276:immunology; D019411:Clinical Laboratory Techniques / Q000379:methods*; D006801:Humans; D007111:Immunity, Cellular; D007118:Immunoassay / Q000379:methods; D007371:Interferon-gamma / Q000378:metabolism*; D007893:Leishmania donovani / Q000276:immunology*; D007898:Leishmaniasis, Visceral / Q000175:diagnosis*; D007963:Leukocytes, Mononuclear / Q000276:immunology; D012680:Sensitivity and Specificity
chemical_list: D000953:Antigens, Protozoan; D007371:Interferon-gamma