Viable Leishmania parasites in the absence of an in vitro IFN-γ response in asymptomatic carriers

• Published in: Revista do Instituto de Medicina Tropical de São Paulo Vol. 66; pp. e13 - 7
• Main Authors: Loría-Cervera, Elsy Nalleli, Sosa-Bibiano, Erika Ivett, López-Ávila, Karina Beatriz, Oca-Aguilar, Ana Celia Montes de, Moreno-Nava, Marisol Sarahí, Torres-Castro, Jimmy Raymundo
• Format: Journal Article
• Language: English; Portuguese
• Published: Brazil Instituto de Medicina Tropical de Sao Paulo 01.01.2024; Instituto de Medicina Tropical de São Paulo
• Subjects: Animals; Asymptomatic Infections; Brief Communication; Humans; Leishmania; Leukocytes, Mononuclear; Mexico; Parasites; TROPICAL MEDICINE; Mexico; Cutaneous leishmaniasis; Asymptomatic infection; IFN-γ expression; Immune response; Leishmaniasis
• ISSN: 1678-9946; 0036-4665; 1678-9946
• DOI: 10.1590/S1678-9946202466013

Asymptomatic infection (the absence or inapparent signs and symptoms) has been observed in many endemic areas of leishmaniasis, however, little is known about the parasitological and immunological factors associated with this type of infection. This study aimed to identify the in vitro expression of IFN-γ in asymptomatic carriers of viable Leishmania parasites. Asymptomatic infection was identified using the Montenegro skin test in an at-risk population from Yucatan, Mexico. Parasite viability was evinced in the blood by 7SL RNA transcripts amplification. The expression of mRNA IFN-γ was analyzed in peripheral blood mononuclear cells stimulated with soluble Leishmania antigen, using RT-qPCR. Parasite viability was observed in 33.3 % (5/15) of asymptomatic subjects. No differences were found in the expression of IFN-γ between asymptomatic and healthy subjects, and no correlation was found between the presence of viable parasites and the expression of IFN-γ. This study demonstrates the persistence of Leishmania parasites in the absence of an in vitro IFN-γ response in asymptomatic carriers from Mexico.