RESUMO
Leishmaniasis remains a serious health problem. The outcome of Leishmania infection depends on the early innate response. In this study, whole blood samples of 40 patients with visceral leishmaniasis (VL), 10 leishmanin skin test-negative (LST-ve) controls and 10 leishmanin skin test-positive (LST+ve) controls were stimulated by live L. donovani promastigotes. Also, THP1 human cell line was infected with L. donovani. The production of interleukin 10 (IL-10), tumour necrosis factor alpha (TNF) and interferon gamma (IFNG) cytokines was measured, and the expression of Toll-like receptors (TLR2, TLR4 and TLR9) was done in the blood samples and also in the THP1 cell line. IL-10 was found to be higher in LST+ve controls compared with VL patients. TNF was moderately produced with no variation between patients, controls and THP1 cells. IFNG was higher in LST+ve controls also in THP1 cells. TLR4 and TLR9 were found to be highly expressed in patients with VL. L. donovani increases the expression of TLR4 and TLR9 in patients with VL and TLR2 in THP1 cells, suggesting a TLRs relation in induction of a mixed cytokine response. TLR9 was markedly recognized by L. donovani DNA.
