Dados do Trabalho

Título

Plasma cytokine profiles of human Leishmania (L.) infantum chagasi infection in an endemic area of visceral leishmaniasis in Amazonian Brazil

Introdução

American visceral leishmaniasis (AVL) represents the main clinical-immunological profile of human Leishmania infantum chagasi-infection. However, other subclinical/asymptomatic profiles of infection are also important to comprise the clinical-immunopathological spectrum. Based on species-specific and semi-quantitative DTH/IFAT-IgG assays and clinical evaluation of infected individuals this spectrum comprises five profiles: Asymptomatic Infection (AI), Subclinical Resistant Infection (SRI), and Indeterminate Initial Infection (III), Subclinical Oligosymptomatic Infection (SOI) and, Symptomatic Infection (SI= AVL).

Objetivo (s)

The study aimed to evaluate the plasma cytokine profile of the entire human Leishmania infantum chagasi-infection in an Amazonian endemic area.

Material e Métodos

Plasma concentrations of INF-γ, TNF-α, IL-2, IL-10, IL-6, and IL-17 cytokines were assessed by Flow Cytometry in these five infection profiles and a control group (IFAT-/DTH-): AI (14), SRI (9), III (18), SOI (4), SI (9) and CG (15) from a seroepidemiological survey in a rural endemic area in Bujaru municipality, in Pará State. Data were analyzed by the Student's t or Mann-Whitney test, P values less than 0.05 were considered statistically significant.

Resultados e Conclusão

For INF-Y, TNF-α, and IL-6, the mean plasma concentrations showed a statistically significant difference only between the CG (7.55, 8.33, and 9.56 pg/mL) and SI profile (25.81, 23.1, and 35.13 pg/mL). The IL-10 concentration in the SI profile was the highest among the profiles (49.77 pg/mL), evidencing the strong suppressive response in SI. The IL-2 concentration was statistically different between the CG (8.3 pg/mL) compared to AI (9.19 pg/mL), III (8.96 pg/mL), and SI profiles (10.21 pg/mL). Furthermore, the IL-17 concentrations of all five profiles were statistically significantly different AI (6.12 pg/mL), SRI (5.84 pg/mL), III (7.92 pg/mL), SOI (8.48 pg/mL) and SI profiles (28.28 pg/mL), compared to the CG (4.68 pg/mL). In the present study, a progressive increase in the IL-17 levels was shown from the asymptomatic/subclinical infection profiles (AI, SRI, and III) towards the symptomatic one (SI), which, in association with the high levels of IL-10 and IL-6 cytokines, seem to play a crucial role in the pathogenesis of AVL, even though significant levels of INF-Y, TNF-α, and IL-2 cytokines have also been observed, but in lower concentration than those of IL-17, IL-10 and IL-6 cytokines.

Palavras-chave

Cytokines profiles, Leishmania (L.) infantum chagasi, human-infection