Interleukin-2 as a marker for detecting asymptomatic individuals in areas where Leishmania infantum is endemic.
No field method exists for identifying asymptomatic individuals in areas where Leishmania infantum is endemic. This work reports that, 24 h after stimulating whole blood with soluble Leishmania antigen (SLA), plasma interferon-γ (IFN-γ) and interleukin-2 (IL-2) become significantly elevated in samples from asymptomatic individuals (n=47) compared with those from negative controls (n=50), all of them recruited from a blood bank. When compared with the reference test SLA-lymphoproliferative assay, IL-2 appears as a new, 100% sensitive and specific marker for asymptomatic individuals with a positive cellular response (compared with 100% and 84.78%, respectively, for IFN-γ). Further studies in other transmission areas and in other cohorts of exposed people need to be performed to confirm these results. Once validated, IFN-γ and IL-2 levels in SLA-stimulated whole blood could be reliably used in the field to estimate the prevalence of those asymptomatic individuals with Leishmania-specific cellular immune responses.
Instituto de Salud Carlos III, Centro Nacional de Microbiología, WHO Collaborating Centre for Leishmaniasis, Madrid, Spain.
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Ibarra-Meneses
Instituto de Salud Carlos III, Centro Nacional de Microbiología, WHO Collaborating Centre for Leishmaniasis, Madrid, Spain. Electronic address: ecarrillo@isciii.es.
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Carrillo
Instituto de Salud Carlos III, Centro Nacional de Microbiología, WHO Collaborating Centre for Leishmaniasis, Madrid, Spain.
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Sánchez
Hospital Universitario de Fuenlabrada, Blood Bank and Haemotherapy Department, Laboratory Medicine, Fuenlabrada, Madrid, Spain.
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García-Martínez
Hospital Universitario de Fuenlabrada, Blood Bank and Haemotherapy Department, Laboratory Medicine, Fuenlabrada, Madrid, Spain.
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López Lacomba
Hospital Universitario de Fuenlabrada, Department of Infectious Diseases, Internal Medicine, Fuenlabrada, Madrid, Spain.
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San Martin
Visceral Leishmaniasis Program, Drugs for Neglected Diseases Initiative (DNDi), Geneva, Switzerland.
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Alves
Visceral Leishmaniasis Program, Drugs for Neglected Diseases Initiative (DNDi), Geneva, Switzerland.
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Alvar
Instituto de Salud Carlos III, Centro Nacional de Microbiología, WHO Collaborating Centre for Leishmaniasis, Madrid, Spain.
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Moreno
D000328:Adult; D058070:Asymptomatic Diseases; D015415:Biomarkers; D016207:Cytokines / Q000097:blood; D005260:Female; D006801:Humans; D007376:Interleukin-2 / Q000097:blood*; D018314:Leishmania infantum; D007898:Leishmaniasis, Visceral / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology / Q000469:parasitology*; D008297:Male; D008875:Middle Aged; D055815:Young Adult
D015415:Biomarkers; D016207:Cytokines; D007376:Interleukin-2
Asymptomatic; Interferon-γ release assay; Interleukin-2; Leishmaniasis; Marker