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Immunology. Jun 2010; 130(2): 193–201.
PMCID: PMC2878464

Evaluation of localized and systemic immune responses in cutaneous leishmaniasis caused by Leishmania tropica: interleukin-8, monocyte chemotactic protein-1 and nitric oxide are major regulatory factors

Abstract

We have established Leishmania tropica as the causative agent of cutaneous leishmaniasis (CL) in the region of India where the disease is endemic. The association between localized and circulating levels of immune-determinants in CL patients was evaluated. Reverse transcription–polymerase chain reaction analysis revealed up-regulation of interferon-γ (IFN-γ), interleukin (IL)-1β, IL-8, tumour necrosis factor-α (TNF-α), IL-10 and IL-4 in dermal lesions at the pretreatment stage (n = 31) compared with healthy controls (P<0·001) and a significant down-regulation after treatment (n = 14, P<0·05). The results indicated that an unfavourable clinical outcome in CL was not related to an inadequate T helper 1 (Th1) cell response, but rather to impairment in multiple immune functions. Comparative assessment of treatment regimes with rifampicin (RFM) or sodium antimony gluconate (SAG) revealed tissue cytokine levels to be significantly reduced after treatment with RFM (P < 0·005), while no significant decrease was evident in the levels of IFN-γ, TNF-α and IL-10 (P>0·05) as a result of treatment with SAG. Increased transcripts of monocyte chemoattractant protein-1 (MCP-1) (P<0·001) and inducible nitric oxide synthase (iNOS) (P<0·05) were evident before treatment in tissue lesions and remained high after treatment. Immunohistochemistry demonstrated strong expression of myeloperoxidase (MPO) and IL-8, and moderate expression of iNOS in dermal lesions. The expression levels of IL-8, MCP-1 and nitric oxide (NO) were high in patient sera before treatment, as determined using cytokine bead array and enzyme-linked immunosorbent assay (ELISA). At the post-treatment stage, the serum IL-8 levels had decreased; however, the levels of MCP-1 and NO remained high. These data suggest that IL-8 is an effector immune-determinant in the progression of CL, whereas NO facilitates the parasite killing by macrophages via MCP-1-mediated stimulation.

Keywords: cutaneous leishmaniasis, cytokine, interleukin, Leishmania, monocyte chemotactic protein-1, nitric oxide

Introduction

Leishmaniasis is a vector-borne parasitic disease, caused by protozoan parasites of the genus Leishmania, which affects 12 million people across 88 countries with 350 million more people at risk. The clinical picture of leishmaniasis is heterogeneous with a wide spectrum of human diseases, including diffuse cutaneous leishmaniasis (DCL), cutaneous leishmaniasis (CL), mucosal leishmaniasis (ML) and visceral leishmaniasis (VL). The annual incidence is estimated to be 1–1·5 million cases of CL and 500 000 cases of VL.1 In the Old World, (Asia, Africa and Mediterranean littorals), CL is caused by Leishmania major, Leishmania tropica and, rarely, by Leishmania infantum and Leishmania donovani. L. major and L. tropica are the prevalent species in semi-arid subtropical regions, important foci being the Middle East, mid-Asia, Transcaucasia and India.2 In India, CL is endemic in the western Thar region of Rajasthan, particularly in the Bikaner region, where we have recently established L. tropica as the causative agent of CL.3

Extensive studies with experimental models have shown that the outcome of Leishmania infection is critically dependent on the activation of one of the two subsets of CD4 T cells, namely T helper 1 (Th1) and T helper 2 (Th2). Interferon-γ (IFN-γ), secreted by Th1 cells, leads to host resistance to infection with Leishmania parasites,4 whereas interleukin (IL)-4, secreted by Th2 cells, is associated with the down-modulation of IFN-γ-mediated macrophage activation.5 However, in human CL, a clear functional dichotomy in CD4 T cells has not definitely been documented. In this context, a few studies have analyzed the intralesional cytokine gene expression in various forms of CL. In CL caused by Leishmania braziliensis, IFN-γ was preferentially expressed in localized lesions, whereas IL-4, IL-5 and IL-10 were detected in mucosal and diffuse forms of the disease;6,7 however, in patients infected with Leishmania mexicana, high levels of IL-10 and IFN-γ were expressed.8 In recent years, chemokines have been identified in the host response against Leishmania and have different roles in Leishmania infection; the most obvious is the recruitment of immune cells to the site of parasite delivery. In humans, polymorphonuclear cells (PMNs) containing Leishmania start secreting chemokines, such as IL-8 (also known as CXCL8),9 which are essential in attracting PMNs to the site of infection. Upon experimental infection with L. major, macrophage inflammatory protein (MIP)-2 and keratinocyte-derived cytokine (KC; also known as CXCL1), the functional murine homologues of human IL-8, are rapidly produced in the skin.10 Lesions in CL patients contain high levels of CC chemokine ligand 2 (CCL2)/monocyte chemotactic protein-1 (MCP-1), CX chemokine ligand 9 (CXCL9)/MIG and CXCL10/IFN-γ-inducible protein 10 (IP-10), whereas patients with DCL express CCL3/MIP-1α.11 Thus, the levels of cytokines/chemokines are modulated differently depending on the clinical forms of the disease and the causative species of Leishmania.

There are limited studies reporting the cellular immune responses in CL caused by L. tropica.12,13 Comprehensive studies in human CL caused by infection with L. tropica are lacking and an open field awaits the intrepid investigator. In the present study, we examined the profile of circulating and localized immune response in patients with CL. The study was further extended in subjects from the region where CL is endemic to investigate the outcome of the immune response in patients cured of CL upon treatment with different drugs. This study led to the identification of key cytokines that determine the clinical outcome of the disease and helped in understanding the immunological pathways that may be involved in the pathogenesis of CL caused by L. tropica.

Patients, materials and methods

Patients with suspected CL were recruited between April 2006 and April 2008 in the Department of Skin, STD & Leprosy, S. P. Medical College, Bikaner (Rajasthan), India, and the study was approved by the Ethical committee. Of the 31 patients with CL who were included in this study, 23 (74·19%) were male and 8 (25·81%) were female. The majority of patients were in the age range of 5–50 years, with the mean age being 33·48 ± 3·47 [standard error (SE)] years. The history of CL cases was 1–7 months of onset of lesions at the time of diagnosis. The clinical diagnosis was confirmed by laboratory demonstration of the parasite by direct microscopy of a tissue smear. The causative organism was established as L. tropica, as described previously.3 Patients were given treatment with sodium antimony gluconate (SAG) intralesionally, 0·5 ml/cm2 of lesion, twice a week for 5–7 injections, depending on the lesion and its response to treatment. Alternatively, in patients with multiple lesions, and in paediatric patients, rifampicin (RFM) (20 mg/kg body weight) was given for 3 months orally. Skin biopsies were taken before starting the treatment and in 14 patients 2–4 weeks after the last dose of treatment, in clinically cured patients. Six normal skin biopsy samples were collected as controls from healthy volunteers.

RNA extraction and reverse transcription–polymerase chain reaction analysis

Skin biopsies of 5–10 mm were taken from the border of the ulcers in RNAlater® (Ambion, Austin, TX), total RNA was isolated using Trizol reagent and complementary DNA (cDNA) was prepared using a SuperScript RNase H-Reverse Transcriptase kit (Invitrogen, Carlsbad, CA). Published sequences for hypoxanthine phosphoribosyltransferase (HPRT) and cytokine genes were used in the study.1417 cDNAs were normalized on the basis of the expression of HPRT. The reaction mixture (20 μl) contained normalized cDNA, 200 mmol/l of each deoxyribonucleotide triphosphate (dNTP), 1·5 mmol/l of MgCl2, 25 pmol of each primer and 0·5 U of Thermus aquaticus (Taq) DNA polymerase in polymerase chain reaction (PCR) buffer (Invitrogen). PCR was performed and the products were analyzed as described previously.1416,18 The PCR products were scanned using a gel documentation system (Alpha-Innotech Corporation, San Leandro, CA), and the intensity of PCR products present in each lane was measured densitometrically using alphaimager (software version 5.5; Alpha-Innotech Corporation, Santa Clara, CA).

Isolation of serum

Whole blood (1 ml) was collected into sterile tubes at pretreatment and post-treatment stages, and from healthy volunteers. Blood was allowed to coagulate for 2–3 hr at 4° before centrifugation. Sera were preserved at −70° until use. Sera were collected 2–4 weeks after the last dose of treatment in clinically cured patients.

Measurement of circulating cytokines

Cytokine levels in serum were determined by flow cytometry utilizing the inflammatory cytokine bead array (CBA) kit (BD Biosciences, San Jose, CA). Briefly, 50 μl of bead populations with discrete fluorescence intensities, coated with cytokine-specific capture antibodies, were added to 50-μl samples of patient sera and 50 μl of phycoerythrin (PE)-conjugated anti-human inflammatory cytokine antibodies. Simultaneously, standards for each cytokine (0–5000 pg/ml) were mixed with cytokine capture beads. The vortexed mixtures were allowed to incubate for 1·5 hr in the dark. After washing the beads, 50 μl of the human inflammation PE detection reagent was added and incubated for 1·5 hr in dark. Beads were washed and analyzed using flow cytometry (FACS Calibur; BD Biosciences). The quantity (pg/ml) of respective cytokine was calculated using CBA software. Standard curves were derived from the cytokine standards supplied with the kit.

Enzyme-linked immunosorbent assay for analysis of IL-8 and MCP-1

The BD OptEIA™ (BD Biosciences) human IL-8 and MCP-1 enzyme-linked immunosorbent assay (ELISA) kit was used for quantitative determination, as per the manufacturer’s instructions. The absorbance was measured at 450 nm within 30 min of stopping the reaction.

Determination of serum nitric oxide

Nitric oxide (NO) is degraded quickly into nitrite and nitrate, and therefore the serum nitrite concentration was determined using the Griess reaction as an indicator of NO. The Griess reagent (Sigma, St Louis, MO) was dissolved in 250 ml of nitrite-free water, and then 50 μl of reagent and an equal volume of the sample was added in an ELISA plate (Griener, Monroe, NC) and mixed immediately. After 30 min of incubation at room temperature, the absorbance was read at 540 nm.

Immunohistochemistry

The EnVision TM G/2 system/AP (DakoCytomation, Glostrup, Denmark) procedure for light microscopic immunohistochemistry (IHC) in dermal lesions and control tissues was performed. In brief, the tissue sections were deparaffinized and rehydrated followed by heat-induced epitope retrieval in 10 mm citrate buffer, pH 6, at 350 W for 15 min in a microwave oven. Endogenous peroxidase activity was quenched by immersion of the sections in methanol containing 2% H2O2 for 30 min, and non-specific binding was blocked by immersion of the sections in Tris buffered saline (TBS) containing 2% BSA. Single antigen staining was carried out with antibodies against myeloperoxidase (MPO; DakoCytomation) and IL-8 (Invitrogen), at dilutions of 1 : 600, and with antibody against inducible nitric oxide synthase (iNOS) (R&D systems, Minneapolis, MN), at a dilution of 1 : 300, in TBS for 45 min. All steps of the procedure were preceded by washes with TBS containing 0·05% Tween-20. After colour development with permanent red chromogen, the sections were counterstained with haematoxylin, dehydrated and mounted. Negative controls comprised omission of the primary antibody and its replacement with TBS.

Statistical analysis

The differences between experimental groups were analyzed using the Student’s paired and unpaired t-tests. All data are presented as mean ± SE and a difference in mean values was considered significant when the P-value was < 0·05. Correlations between continuous variables were evaluated using Spearman’s correlation test. To avoid the potential dependency between variables related to multiple lesions from the same individual, only one lesion (randomly selected) per patient was included in the statistical analysis.

Results

Intralesional expression of cytokines in patients with CL

Intralesional expression of messenger RNA (mRNA) for IFN-γ, tumour necrosis factor-α (TNF-α), IL-1β, IL-8, IL-10 and IL-4 was analyzed by reverse transcription–polymerase chain reaction in patients with CL (n = 31) and in healthy controls (n = 6). Transcripts of IFN-γ, TNF-α, IL-1β, IL-8 and IL-10 were expressed in lesions of all the CL patients, while IL-4 was detected in 77·4% (24/31) of biopsies. The levels of expression of all cytokines were significantly elevated in CL lesions, compared with those in control tissues (P<0·001 for all cytokines) (Fig. 1). IL-1β was expressed at a very high level compared with other cytokines in all the samples. A strong correlation was found in the expression of IFN-γ with IL-8 (r > 0·7) and IL-10 (r > 0·8), and between TNF-α and IL-8 (r > 0·8). The strongest correlation was observed in the expression of IL-10 with TNF-α and IL-8 and between IFN-γ with TNF-α (r > 0·9, Table 1).

Table 1
Spearman’s rank correlation between intralesional cytokine gene expression
Figure 1
Analysis of intralesional cytokines in cutaneous leishmaniasis (CL) patients at the pretreatment stage. Levels of expression of messenger RNA (mRNA) for interleukin (IL)-1β, -4, -8 and -10, tumour necrosis factor-α (TNF-α) and ...

Analysis of intralesional cytokines in patients with CL before and after treatment

Paired samples were collected from nine patients at post-treatment stage for comparative analysis of cytokine mRNA levels. A significant decrease in the levels of expression of mRNA for IFN-γ, TNF-α, IL-1β, IL-8, IL-10 and IL-4 was noticed after treatment (P<0·05 for levels of all cytokines) (Fig. 2a). IL-8 is a chemoattractant and recruits the accumulation of PMNs at inflammatory sites,17 whereas MCP-1, also a chemoattractant, contributes not only to the recruitment of macrophage into Leishmania-infected skin but also to macrophage activation via the production of NO.12 Therefore, analysis of MCP-1 and iNOS was also considered in this study, and both were detected in all the patients. The expression of mRNA for MCP-1 and iNOS was significantly up-regulated at the pretreatment stage compared with healthy controls (P<0·001 and P<0·05 respectively), but remained high at the post-treatment stage (P > 0·05) (Fig. 2a). Furthermore, the levels of expression of mRNA for IFN-γ, TNF-α, IL-1β, IL-8, IL-10 and IL-4 were analyzed comparatively in lesions of patients treated with SAG or RFM (Fig. 2b). Three patients treated with SAG and five patients treated with RFM could be followed in this study. To compare the outcome of different treatment regimens in patients with CL, an additional three patients treated with SAG and two treated with RFM (for whom tissue lesions at the pretreatment stage were not available), were also included in the study. There was a significant decrease in the levels of cytokine gene expression in the CL lesions treated with RFM (P<0·05), whereas no significant decrease was noticed in the levels of IFN-γ, TNF-α and IL-10 (P>0·05) in lesions treated with SAG.

Figure 2
Comparative analysis of intralesional immunodeterminants in cutaneous leishmaniasis (CL) patients at pretreatment and post-treatment stages. (a) Levels of expression of messenger RNA (mRNA) for interleukin (IL)-1β, -4, -8 and -10, tumour necrosis ...

Cytokine levels in sera of CL patients, analyzed using CBA

In order to understand the in vivo circulating cytokine profile, serum cytokine levels were analyzed at pretreatment and post-treatment stages in patients with CL and compared with healthy controls. The level of IL-8 was found to be significantly higher in CL samples at the pretreatment stage (1022·4 ± 313·78 pg/ml) compared with the post-treatment stage (10·11 ± 6·97 pg/ml) or the control (10·48 ± 3·9 pg/ml). The level of IL-8 was restored to normal levels after treatment (Fig. 3). The levels of other circulating inflammatory cytokines examined, including IL-1β, IL-6, IL-10, TNF and IL-12p70, were not detectable in sera.

Figure 3
Quantitative estimation of interleukin-8 (IL-8) in the sera of cutaneous leishmaniasis (CL) patients using cytokine bead array analysis (CBA). Analysis of IL-8 at the protein level was carried out at pretreatment (n = 15) and post-treatment (n = 9) stages, ...

Measurement of IL-8, MCP-1 and NO by ELISA in sera

To establish the association between the circulating and localized response of IL-8 and MCP-1, quantitative analysis of IL-8 and MCP-1 was carried out at pretreatment and post-treatment stages in the sera of patients and controls using the more sensitive ELISA method (Fig. 4a). The level of IL-8 determined in the sera (1 : 20 dilution) was found to be significantly higher (P<0·001) in CL patients (20/20) at the pretreatment stage (89·04 ± 18·8 pg/ml) than in CL patients post-treatment (13·12 ± 5·16 pg/ml) or in controls (5·16 ± 1·45 pg/ml). Similarly, an elevated level of MCP-1 was observed in all 20 CL patients at the pretreatment stage (39·25 ± 5·29 pg/ml) compared with the controls (21·1 ± 2·6 pg/ml, P<0·01), but the level of MCP-1 remained high at the post-treatment stage (47·77 ± 3·03 pg/ml, P>0·05). The circulating nitrite level was analyzed at the pretreatment stage in CL patients (n = 32) and in healthy controls (n = 10), followed by evaluation post-treatment (n = 10) (Fig. 4b). The level of nitrite was significantly higher in CL samples pretreatment (61·37 ± 2·46 μm) than in healthy controls (15·4 ± 0·99 μm, P<0·001), but the level of nitrite was not significantly down-regulated after treatment (41·1 ± 10·11 μm, P>0·05).

Figure 4
Quantitative enzyme-linked immunosorbent assay (ELISA) analysis of (a) interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) and (b) nitric oxide (NO) in the sera of patients. (a) Levels (pg/ml) of IL-8 and MCP-1, in a 1 : 20 dilution of ...

In vivo evaluation of MPO, IL-8 and iNOS by IHC

In vivo analysis of MPO (a marker for PMNs), IL-8 and iNOS was carried out by IHC in CL lesions (n = 5) and in healthy controls (n = 2). IHC revealed the presence of an inflammatory infiltrate consisting predominantly of neutrophils, which presented a heterogeneous pattern of distribution. A difference in cell morphology was also observed: in sections with fewer neutrophils these cells were well compacted, whereas in sections presenting larger numbers this cell type was characterized by a larger size and cytoplasmic content (Fig. 5a). IL-8 was strongly expressed (Fig. 5c) and iNOS was moderately expressed (Fig. 5e) in all the lesions examined. Infiltrate neutrophils, IL-8 and iNOS were not detected in controls (Fig. 5b,d,f ).

Figure 5
Immunohistochemical analysis of tissue biopsies from cutaneous leishmaniasis (CL) patients for myeloperoxidase (a), interleukin-8 (IL-8) (c) and inducible nitric oxide synthase (iNOS) (e), and in the respective controls (b, d, f ). Immunostaining ...

Discussion

The outcome of Leishmania infection is determined by the delicate balance that exists among a large array of cytokines expressed by the cellular infiltrate at the site of infection. In this study, we observed concomitant expression of both macrophage-activating and de-activating cytokines within cutaneous lesions caused by L. tropica infection. Analysis of cytokine gene expression in the CL lesions revealed elevated levels of IFN-γ, IL-10, TNF-α, IL-1β, IL-8, IL-4, MCP-1 and iNOS, suggesting that CL results from an exacerbated and improperly modulated Th1 immune response. Although IFN-γ, TNF-α and NO are products that are necessary to kill Leishmania,19 they are also implicated in the inflammation leading to tissue damage in other infections.20,21 IFN-γ and TNF-α are important in defence mechanisms against parasites; however, overproduction of these cytokines does not necessarily lead to parasite clearance and may even be harmful to the host.

IFN-γ and IL-10 mRNAs were co-expressed in 100% of the lesions, and a significant correlation (0·84) was observed; this extends previous observations of concomitant expression of these cytokines in patients with CL22 and in VL.18 These two cross-regulatory cytokines have contrasting effects on the host response against intracellular pathogens.23 IL-10 expression has previously been described to be significantly higher in the more slowly healing lesions in patients with CL caused by L. major22 and is a promoter of persistent disease in patients infected with L. mexicana.8 In our study, IL-10 expression correlated strongly with both TNF-α and IL-8 (0·95), while the expression of TNF-α and IL-8 also correlated (0·89). IL-8, also known as monocyte-derived neutrophil chemotactic factor, is a strong neutrophil chemotactic and activating cytokine.24 The potential importance of IL-8 in the pathogenesis of inflammatory diseases has been suggested by findings of increased synthesis in adult respiratory distress syndrome, rheumatoid arthritis, idiopathic pulmonary fibrosis and central nervous diseases.2426 A positive correlation of TNF-α and IFN-γ with IL-8 indicated that both may synergistically induce IL-8 production, as reported in earlier studies.27 We have also demonstrated that lesions from CL patients exhibited an inflammatory infiltrate consisting mainly of PMN together with a strong expression of IL-8. 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 as delaying their apoptosis,28,29 which is beneficial for the survival of parasites.3032 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 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 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.42 An in vitro study in the human Jurkat T-cell line has shown that rifamide analogues, including RFM, inhibited TNF-α and phorbol 12-myristate 13-acetate-induced activation of the transcription nuclear factor B, which is involved in immunostimulation, thereby explaining the mechanism of the immunosuppressive effect of RFM.43 RFM also enhances the production of NO, which might be responsible for parasite killing.44

This was a comprehensive study carried out to investigate the abundance of localized and circulating cytokines in patients with CL caused by L. tropica. Furthermore, the study carried out a comparative assessment of different treatment regimens on the host immune response, which will help to explore the action of chemotherapy. The higher production of IL-8 in CL patients, leading to excessive inflammatory cell activation, predominantly PMNs that provide shelter to parasites, may allow the parasite to survive and multiply, leading to the development of disease. The observation of high levels of NO and MCP-1 following treatment suggests that MCP-1 orchestrates the induction of leishmanicidal activities in human macrophages via the generation of NO.

Acknowledgments

Financial assistance by the Indian Council of Medical Research is gratefully acknowledged.

Disclosures

None of the authors of this paper have conflict of interest to disclose.

References

1. Gramiccia M, Gradoni L. The current status of zoonotic leishmaniasis and approaches to disease control. Int J Parasitol. 2005;35:1169–80. [PubMed]
2. Schwenkenbecher JM, Wirth T, Schnur LF, et al. Microsatellite analysis reveals genetic structure of Leishmania tropica. Int J Parasitol. 2006;36:237–46. [PubMed]
3. Kumar R, Bumb RA, Ansari NA, Mehta RD, Salotra P. Cutaneous leishmaniasis caused by Leishmania tropica in Bikaner, India: parasite identification and characterization using molecular and immunological tools. Am J Trop Med Hyg. 2007;76:896–901. [PubMed]
4. Swihart K, Fruth U, Messmer N, et al. Mice from genetically resistant background lacking IFN-γ receptor are susceptible to infection with Leishmania major but mount a polarized T helper cell type-1 CD4+ T cell response. J Exp Med. 1995;181:961–71. [PMC free article] [PubMed]
5. Louis J, Himmelrich H, Parra-Lopez C, Tacchini-Cottier F, Launois P. Regulation of protective immunity against Leishmania major in mice. Curr Opin Immunol. 1998;10:459–64. [PubMed]
6. Cáceres-Dittmar G, Tapia FJ, Sánchez MA, et al. Determination of the cytokine profile in American cutaneous leishmaniasis using the polymerase chain reaction. Clin Exp Immunol. 1993;91:500–5. [PMC free article] [PubMed]
7. Pirmez C, Cooper C, Paes-Oliveira M, Schubach A, Torigian VK, Modlin RL. Immunologic responsiveness in American cutaneous leishmaniasis lesions. J Immunol. 1990;145:3100–4. [PubMed]
8. Melby PC, Andrade-Narvaez F, Darnell BJ, Valencia-Pacheco G. In situ expression of interleukin-10 and interleukin-12 in active human cutaneous leishmaniasis. FEMS Immunol Med Microbiol. 1996;15:101–7. [PubMed]
9. Laufs H, Müller K, Fleischer J, et al. Intracellular survival of Leishmania major in neutrophil granulocytes after uptake in the absence of heat-labile serum factors. Infect Immun. 2002;70:826–35. [PMC free article] [PubMed]
10. Muller K, Zandbergen GV, Hansen B, et al. Chemokines, NK cells and granulocytes in the early course of Leishmania major infecton in mice. Med Microbiol Immunol. 2001;190:73–6. [PubMed]
11. Ritter U, Korner H. Divergent expression of inflammatory dermal chemokines in cutaneous leishmaniasis. Parasite Immunol. 2002;24:295–301. [PubMed]
12. Sadick MD, Locksley RM, Raff HV. Development of cellular immunity in cutaneous leishmaniasis due to Leishmania tropica. J Infect Dis. 1984;150:135–8. [PubMed]
13. Anderson CF, Lira R, Kamhawi S, Belkaid Y, Wynn TA, Sacks D. IL-10 and TGF-β control the establishment of persistent and transmissible infections produced by Leishmania tropica in C57BL/6 mice. J Immunol. 2008;180:4090–7. [PubMed]
14. Dasgupta B, Roychoudhury K, Ganguly S, Akbar MA, Das P, Roy S. Infection of human mononuclear phagocytes and macrophage-like THP1 cells with Leishmania donovani results in modulation of expression of a subset of chemokines and a chemokine receptor. Scand J Immunol. 2003;57:366–74. [PubMed]
15. Yoshida A, Elner SG, Bian ZM, Kunkel SL, Lukacs NW, Elner VM. Differential chemokine regulation by Th2 cytokines during human RPE–monocyte coculture. Invest Ophth Vis Sci. 2001;42:1631–8. [PubMed]
16. Coste SC, Heldwein KA, Stevens SL, Tobar-Dupres E, Stenzel-Poore MP. IL-1 and TNF down-Regulate CRH Receptor-2 mRNA expression in the mouse heart. Endocrinology. 2001;42:3537–45. [PubMed]
17. Yu CL, Sun KH, Shei SC, et al. Interleukin 8 modulates interleukin-1 beta, interleukin-6 and tumor necrosis factor-alpha release from normal human mononuclear cells. Immunopharmacology. 1994;27:207–14. [PubMed]
18. Ansari NA, Ramesh V, Salotra P. Interferon (IFN)-gamma, tumor necrosis factor-alpha, interleukin-6, and IFN-gamma receptor 1 are the major immunological determinants associated with post-kala azar dermal leishmaniasis. J Infect Dis. 2006;194:958–65. [PubMed]
19. Liew FY, Li Y, Millott S. Tumor necrosis factor-alpha synergizes with IFN-gamma in mediating killing of Leishmania major through the induction of nitric oxide. J Immunol. 1990;145:4306–10. [PubMed]
20. Grau GE, Piguet PF, Vassalli P, Lambert PH. Tumor necrosis factor and other cytokines in cerebral malaria: experimental and clinical data. Immunol Rev. 1989;112:49–70. [PubMed]
21. Sarno EN, Grau GE, Vieira LM, Nery JA. Serum levels of tumour necrosis factor-alpha and interleukin-1 beta during leprosy reactional states. Clin Exp Immunol. 1991;84:103–8. [PMC free article] [PubMed]
22. Louzir H, Melby PC, Salah A, et al. Immunologic determinants of disease evolution in localized cutaneous leishmaniasis due to L. major. J Infect Dis. 1998;177:1687–95. [PubMed]
23. Heinzel FP, Sadick MD, Mutha SS, Locksley RM. Production of interferon gamma, interleukin 2, interleukin 4, and interleukin 10 by CD4+ lymphocytes in vivo during healing and progressive murine leishmaniasis. Proc Natl Acad Sci USA. 1991;88:7011–115. [PMC free article] [PubMed]
24. Donnelly S, Strieter R, Kunkel SL, Carter DC, Haslett C. Interleukin-8 and development of adult respiratory distress syndrome at risk patient group. Lancet. 1993;341:643–7. [PubMed]
25. Brennan FM, Zachariae C, Chantry D, et al. Detection of interleukin-8: biological activity in synovial fluid from patients with rheumatoid arthritis. Eur J Immunol. 1990;20:2141–4. [PubMed]
26. Van Mier E, Ceska M, Effenberger F, et al. Interleukin-8 is produced in neoplastic and infectious diseases of the human central nervous system. Cancer Res. 1992;52:4297–305. [PubMed]
27. Yasumoto K, Okamoto S, Mukaida N, Murakami S, Mai M, Matsushima K. Tumor necrosis factor alpha and interferon gamma synergistically induce interleukin 8 production in a human gastric cancer cell line through acting concurrently on AP-1 and NF-κB-like binding sites of the interleukin 8 gene. J Biol Chem. 1992;267:22506–11. [PubMed]
28. Aga E, Katschinski DM, Zandbergen GV, et al. Inhibition of the spontaneous apoptosis of neutrophil granulocytes by the intracellular parasite Leishmania major. J Immunol. 2002;169:898–905. [PubMed]
29. Zandbergen GV, Hermann N, Laufs H, Solbach W, Laskay T. Leishmania promastigotes release a granulocyte chemotactic factor and induce interleukin-8 release but inhibit gamma interferon-inducible protein 10 production by neutrophil granulocytes. Infect Immun. 2002;70:4177–84. [PMC free article] [PubMed]
30. Tacchini-Cottier F, Zweifel C, Belkaid Y, et al. An immunomodulatory function for neutrophils during the induction of a CD4+ Th2 response in BALB/c mice infected with Leishmania major. J Immunol. 2000;165:2628–36. [PubMed]
31. Brandonisio O, Panunzio M, Faliero SM, et al. Evaluation of polymorphonuclear cell and monocyte functions in Leishmania infantum-infected dogs. Vet Immunol Immunopathol. 1996;53:95–103. [PubMed]
32. Belkaid Y, Mendez S, Lira R, Kadambi N, Milon G, Sacks D. A natural model of Leishmania major infection reveals a prolonged “silent” phase of parasite amplification in the skin before the onset of lesion formation and immunity. J Immunol. 2000;165:969–77. [PubMed]
33. Moore KJ, Matlashewski G. Intracellular infection by Leishmania donovani inhibits macrophage apoptosis. J Immunol. 1994;152:2930–7. [PubMed]
34. Ritter U, Moll H. Monocyte chemotactic protein-1 stimulates the killing of Leishmania major by human monocytes, acts synergistically with IFN-γ and is antagonised by IL-4. Eur J Immunol. 2000;30:3111–20. [PubMed]
35. Ritter U, Moll H, Laskay T, et al. Differential expression of chemokines patients with localized and diffuse cutaneous American leishmaniasis. J Infect Dis. 1996;173:699–709. [PubMed]
36. Kumar R, Bumb RA, Salotra P. Correlation of parasitic load with Interleukin-4 response in patients with cutaneous leishmaniasis due to Leishmania tropica. FEMS Immunol Med Microbiol. 2009;57:239–46. [PubMed]
37. Launois P, Maillard I, Pingel S, et al. IL-4 rapidly produced by V beta 4 V alpha 8 CD4+ T cells in BALB/c mice infected with Leishmania major instructs Th2 cell development and susceptibility to infection. Immunity. 1997;6:541–9. [PubMed]
38. Belosevic M, Davis CE, Meltzer MS, Nacy CA. Regulation of activated macrophage antimicrobial activities. Identification of lymphokines that cooprate with IFN-gamma for induction of resistance to infection. J Immunol. 1988;141:890–6. [PubMed]
39. Li J, Sutterwala S, Farrell JP. Successful therapy of chronic, non-healing murine cutaneous leishmaniasis with sodium stibogluconate and gamma interferon depends on continued interleukin-12 production. Infect Immun. 1997;65:3225–30. [PMC free article] [PubMed]
40. Haung FP, Xu D, Esfandiari EO, et al. Mice defective in Fas are highly susceptible to Leishmania major infection despite elevated IL-12 synthesis, strong Th1 responses, and enhanced nitric oxide production. J Immunol. 1998;160:4143–7. [PubMed]
41. Bhattacharya S, Ghosh S, Dasgupta B, Mazumdar D, Roy S, Majumdar S. Chemokine-induced leishmanicidal activity in murine macrophages via generation of nitric oxide. J Infect Dis. 2002;185:1704–8. [PubMed]
42. Kocyigit A, Gur S, Gurel MS, Bulut V, Ulukanligil M. Antimonial therapy Induces circulating proinflammatory cytokines in patients with cutaneous leishmaniasis. Infect Immun. 2002;70:6589–91. [PMC free article] [PubMed]
43. Pahlevan AA, Wright DJM, Bradley L, Smith C, Foxwell BMJ. Potential of rifamides to inhibit TNF-induced NF- κB activation. J Antimicrob Chemother. 2001;49:531–4. [PubMed]
44. Yuhas Y, Berent E, Ovadiah H, et al. Rifampin augments cytokine-induced nitric oxide production in human alveolar epithelial cells. Antimicrob Agents Chemother. 2006;50:396–8. [PMC free article] [PubMed]

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