THE PARTICIPATION OF THE CHEMOKINE TARC/CCL17 IN CUTANEUS LEISHMANIASIS

PIMENTEL SOLÁ, J; GARCÍA BUSTOS, MF; MESIAS, A; MARCO, JD; BARROSO, PA; BRACAMONTE, E; PERÉZ-BRANDÁN C; PARODI,C

Congreso; SAI; 2019

Chemokines play an important role in pathogenesis and inflammation. Cutaneousleishmaniasis (CL), the most common clinical form of tegumentary leishmaniasis is generally characterized by skin ulcers. The aim of this work was to determine the role of CCL17, implicated in lymphocyte recruitment to normal and inflamed cutaneous sites during CL. Using enzyme-linked immunosorbent assays (ELISA) we found decreased levels of plasma CCL17 in CL patients (n=12) comparing with healthy subjects (HS, n=6) (234,7±104,10 pg/ml vs. 445,5±180,40 pg/ml respectively; p=0,0048), with similar interleukin 10 (IL-10; CL:39,19±14,49 pg/ml; HS:29,57±14,49 pg/ml; p=0,1870) and interferon-γ (IFN-γ; CL: 39,53±38,72 pg/ml; HS:72,25±78,31 pg/ml; p=0,3627) concentrations among both groups. CCL17 levels positively correlated with IL-10 (p=0,043, r=0,647) while no correlation was found between CCL17 and IFN-γ (p= 0,314, r= - 0,335). Next we performed peripheral blood mononuclear cells (PBMC) cultures (1x106 cells/ml, 7 days of culture) and determined by ELISA that the spontaneous production of CCL17 was similar in both CL (249,70±227,10 pg/ml) and HS (415,90±425,30 pg/ml) groups. Then, we analyzed the influence of soluble leishmania antigen (SLA, 20µg/ml) on PBMCs from CL patients and found a significant decrease in the spontaneous secretion of CCL17 (80,53±43,64 pg/ml; p=0,0313). Media±DS; Unpaired t test; Wilcoxon test; Pearson correlation. The diminished plasma concentration of CCL17 found in CL, together with its in vitro decrease after the addition of SLA, suggest a possible pathogenic strategy of the parasite to avoid CCL17 action. Besides, the correlation of CCL17 with IL-10 might represent an attempt to regulate the excessive inflammatory response produced during cutaneousinfection.