IL-8 effectively stimulates the release of potent inflammatory cytokines,

such as IL-1, IL-6 and TNF-α, from mononuclear cells near the inflammatory site.17 The IL-1β and TNF-α in CL lesions may further activate mononuclear cells to increase the production of IL-8.17 It has been reported that IL-8 promotes the rapid recruitment of PMNs as well learn more as delaying their apoptosis,28,29 which is beneficial for the survival of parasites.30–32 Furthermore, TNF-α has also been reported to inhibit the apoptosis of macrophages in L. donovani infection.33 Thus, IL-8, with the support of TNF-α, emerges as an immunomodulator in the pathogenesis of CL. MCP-1 activates macrophages, leading to a Th1 response, but is antagonized by IL-4, which predominates during a Th2 response.34 Furthermore, IL-4 strongly impairs the production of MCP-1 by

Leishmania-infected monocytes. The association of IL-4 with the non-healing skin lesions of DCL patients6 provides an explanation for the very low level of MCP-1 in DCL lesions, despite the massive load of parasitized macrophages.35 In a parallel study, a high IL-4 level was observed in early SB203580 chemical structure lesions (≤ 2 months) and was associated with a higher parasite load, while other cytokine levels did not correlate with the parasite load,36 similarly to the observation in a mouse model.37 Furthermore, in the current study, expression of MCP-1 and nitric oxide molecules (iNOS and NO) remained high, after therapy, in both tissue lesions and sera of CL patients, while the levels of the cytokines IFN-γ, TNF-α, IL-1β, IL-8, IL-10 and IL-4 decreased rapidly following treatment. In vitro studies with SDHB murine macrophages revealed that soluble factors secreted by activated T cells

mediate activation of macrophages to produce NO, resulting in killing or control of L. major.38 A continued production of IL-12 and NO by resident macrophages in mice treated with SAG and recombinant IFN-γ (rIFN-γ) is associated with successful therapy of chronic CL.39 MCP-1 stimulates the killing of L. major by human monocytes, acts synergistically with IFN-γ and is antagonized by IL-4.35 IL-4 and IL-10 inhibit the production of NO by down-regulating iNOS.40 It has been demonstrated that MCP-1 orchestrates the induction of leishmanicidal activities in murine macrophages via the generation of nitric oxide.41 Thus, our results are consistent with these observations in a murine model, suggesting that MCP-1 and NO play an important role in the resolution of CL in humans infected with L. tropica. In the present study, the levels of all cytokines studied (IFN-γ, TNF-α, IL-1β, IL-8, IL-10 and IL-4) decreased significantly in CL lesions after treatment with RFM, while the cytokines IFN-γ, TNF-α and IL-10 remained high upon treatment with SAG. Pentavalent antimonial compounds may have immune-stimulating effects responsible for their antimicrobial activity.