Oral Pentoxifylline Combined with Pentavalent Antimony: A Randomized Trial for Mucosal Leishmaniasis

Use of topical rSm29 in combination with intravenous meglumine antimoniate in the treatment of cutaneous leishmaniasis: A randomized controlled trial

BACKGROUND

Cutaneous leishmaniasis (CL) caused by Leishmania (Viannia) braziliensis is associated with an inflammatory response. Granzyme (GzmB) and IL-1β play a key role in the pathology. Meglumine antimoniate (MA) is the first-choice drug for the treatment of CL, but therapy failure is observed in up to 50% of the cases. The protein, rSm29 of Schistosoma mansoni, down-modulates pro-inflammatory cytokine production. We evaluate if the combination of topical rSm29 plus MA increases the cure rate of CL.

METHODS

In this randomized clinical trial, 91 CL patients were allocated in 3 groups. All cases received MA (20 mg/kg/weight) for 20 days. Group 1 used topical rSm29 (10 µg), group 2 a placebo topically applied, and group 3 received only MA.

RESULTS

The cure rate on day 90 was 71% in subjects treated with rSm29 plus MA, and 43% in patients who received MA plus placebo or MA alone (P < 0.05). There was a decrease in GzmB and an increase in IFN-γ (P < 0.05) in supernatants of skin biopsies of the lesions obtained on D7 of therapy (P < 0.05) in patients who received rSm29.

CONCLUSION

rSm29 associated with MA reduces GzmB levels, is more effective than MA alone, and decreases CL healing time.

CLINICAL TRIALS REGISTRATION

ClinicalTrial.gov under NCT06000514.

Behandlung der mukokutanen Leishmaniose – eine systematische Übersicht

Die mukokutane Leishmaniose ist eine schwere Infektionskrankheit, die überwiegend in Zentral‐ und Südamerika endemisch ist und sich klinisch mit granulomatösen, destruierenden Schleimhautläsionen im Mund‐Nasen‐Rachenraum manifestiert. Sie wird durch Protozoen, Leishmania spp., ausgelöst, die durch Sandmücken auf den Menschen übertragen werden. Sie tritt nach vorangegangener kutaner Leishmaniose auf, wenn diese nicht oder nur unzureichend behandelt wurde und kommt gehäuft bei immunsupprimierten Patienten vor. Das Ziel dieser systematischen Übersicht besteht darin, alle publizierten Behandlungsmöglichkeiten für die mukokutane Leishmaniose zusammenzufassen. Sie basiert auf allen englischen, deutschen, französischen, spanischen und portugiesischen Artikeln, die in den Datenbanken „PubMed“ und „Lilacs“ von 1995 bis 2020 veröffentlicht wurden. Die medizinische Literatur beschränkt sich auf Einzelfallberichte, kleine Fallserien, retrospektive Studien und nur wenige randomisierte kontrollierte Studien. Zu den Therapieoptionen gehören pentavalente Antimonverbindungen wie Megluminantimonat oder Natriumstibogluconat, Amphotericin B (liposomal, Desoxycholat, Lipidkomplex, kolloidale Dispersion), Miltefosin und Pentamidin. Weitere mögliche Therapien sind Itraconazol, Fluconazol, Ketoconazol, Aminosidinsulfat und Azithromycin. Die Wahl des geeigneten Medikaments richtet sich in erster Hinsicht nach der Verfügbarkeit im Endemiegebiet und den begleitenden Erkrankungen des Patienten.

Treatment of mucocutaneous leishmaniasis - A systematic review

Mucocutaneous leishmaniasis is a severe infectious disease, predominantly endemic in Central and South America and is characterized by granulomatous, destructive mucosal lesions in the oral, nasal, and pharyngeal cavities. It is caused by protozoa of the genus Leishmania spp. transmitted to humans by sandflies. Mucocutaneous leishmaniasis occurs after untreated or inadequately treated cutaneous leishmaniasis and is more common in immunocompromised patients. The aim of this systematic review is to summarize all reported treatment options for mucocutaneous leishmaniasis. This review is based on all English, German, French, Spanish and Portuguese articles published in the databases "PubMed" and "Lilacs" from 1995 to 2020. Most of the medical literature is limited to case reports, small case series, retrospective studies, and a few randomized controlled trials. Various treatment options include pentavalent antimonates such as meglumine antimonate or sodium stibogluconate, amphotericin B (liposomal, deoxycholate, lipid complex, colloidal dispersion), miltefosine, and pentamidine. Other therapeutic options include itraconazole, fluconazole, ketoconazole, aminosidine sulfate, and azithromycin. The choice of drug depends primarily on its availability in the endemic area and the patient's comorbidities.

Improved Treatment Outcome Following the Use of a Wound Dressings in Cutaneous Leishmaniasis Lesions

Leishmaniasis, caused by Leishmania parasites, is a neglected tropical disease and Cutaneous Leishmaniasis (CL) is the most common form. Despite the associated toxicity and adverse effects, Meglumine antimoniate (MA) remains the first-choice treatment for CL in Brazil, pressing the need for the development of better alternatives. Bacterial NanoCellulose (BNC), a biocompatible nanomaterial, has unique properties regarding wound healing. In a previous study, we showed that use of topical BNC + systemic MA significantly increased the cure rate of CL patients, compared to treatment with MA alone. Herein, we performed a study comparing the combination of a wound dressing (BNC or placebo) plus systemic MA versus systemic MA alone, in CL caused by Leishmania braziliensis. We show that patients treated with the combination treatment (BNC or placebo) + MA showed improved cure rates and decreased need for rescue treatment, although differences compared to controls (systemic MA alone) were not significant. However, the overall time-to-cure was significantly lower in groups treated with the combination treatment (BNC+ systemic MA or placebo + systemic MA) in comparison to controls (MA alone), indicating that the use of a wound dressing improves CL treatment outcome. Assessment of the immune response in peripheral blood showed an overall downmodulation in the inflammatory landscape and a significant decrease in the production of IL-1a (p < 0.05) in patients treated with topical BNC + systemic MA. Our results show that the application of wound dressings to CL lesions can improve chemotherapy outcome in CL caused by L. braziliensis.

Assessment of Immune and Clinical Response in Patients with Mucosal Leishmaniasis Treated with Pentavalent Antimony and Pentoxifylline

Mucosal leishmaniasis (ML) is a severe form of tegumentary leishmaniasis associated with a persistent inflammatory response. High levels of TNF, IFN-γ, CXCL9 and CXCL10 are found in ML patients, and the association of pentoxifylline with antimony is more effective in decreasing the healing time in ML patients when compared to antimony alone. The present study aimed to investigate the existence of a correlation between cytokine and chemokine production and ML severity and evaluate the potential value of cytokine and chemokine production as marker of therapeutic response in ML patients. This prospective study included 86 subjects in an area of endemic Leishmania braziliensis transmission. Patients diagnosed with ML were classified into clinical stages ranging from I to V according to disease severity. TNF, IFN-γ, CXCL9 and CXCL10 levels were quantified in the supernatant of the mononuclear cell cultures by ELISA before and after treatment with antimony alone or antimony plus pentoxifylline. The median TNF level in the group with mild disease (Stages I-II) was 1064 pg/mL (142-3738 pg/mL), while, in the group with moderate or severe disease (Stages III-V), it was 1941 pg/mL (529-5294 pg/mL) (p = 0.008). A direct correlation was observed between ML clinical severity and levels of TNF production (r = 0.44, p = 0.007). Patients who were treated with antimony and pentoxifylline healed significantly faster than those treated with antimony alone (52 vs. 77 days, hazard ratio = 0.60; 95% confidence interval = 0.38-0.95, p = 0.013). Therapeutic failure was higher in the group that received antimony alone (25% vs. 7%; p = 0.041). There was a significant decrease in CXCL9 after therapy of ML in both groups (p = 0.013; p = 0.043). TNF levels are associated with the severity of mucosal diseases, and pentoxifylline associated with antimony should be the recommended therapy for ML in countries where liposomal amphotericin B is not available.

The cure rate after different treatments for mucosal leishmaniasis in the Americas: A systematic review

BACKGROUND

Mucosal or mucocutaneous leishmaniasis is the most severe form of tegumentary leishmaniasis due to its destructive character and potential damage to respiratory and digestive tracts. The current treatment recommendations are based on low or very low-quality evidence, and pentavalent antimonial derivatives remain strongly recommended. The aim of this review was to update the evidence and estimate the cure rate and safety profile of the therapeutic options available for mucosal leishmaniasis (ML) in the Americas.

METHODOLOGY

A systematic review was conducted in four different databases and by different reviewers, independently, to evaluate the therapeutic efficacy and toxicity associated with different treatments for ML. All original studies reporting cure rates in more than 10 patients from American regions were included, without restriction of design, language, or publication date. The risk of bias was assessed by two reviewers, using different tools according to the study design. The pooled cure rate based on the latest cure assessment reported in the original studies was calculated grouping all study arms addressing the same intervention. The protocol for this review was registered at the International Prospective Register of Systematic Reviews, PROSPERO: CRD42019130708.

PRINCIPAL FINDINGS

Twenty-seven original studies from four databases fulfilled the selection criteria. A total of 1,666 patients with ML were treated predominantly with pentavalent antimonials in Brazil. Other interventions, such as pentamidine, miltefosine, imidazoles, aminosidine sulfate, deoxycholate and lipidic formulations of amphotericin B (liposomal, lipid complex, colloidal dispersion), in addition to combinations with pentoxifylline, allopurinol or sulfa were also considered. In general, at least one domain with a high risk of bias was identified in the included studies, suggesting low methodological quality. The pooled cure rate based on the latest cure assessment reported in the original studies was calculated grouping all study arms addressing the same intervention. It was confirmed that antimony is still the most used treatment for ML, with only moderate efficacy (possibly increased by combining with pentoxifylline). There is already evidence for the use of miltefosine for ML, with a cure rate similar to antimony, as observed in the only direct meta-analysis including 57 patients (OR: 1.2; 0.43-3.49, I2 = 0). It was possible to gather all descriptions available about adverse events reported during ML treatment, and the toxicity reflected the pattern informed in the manufacturers' technical information.

CONCLUSIONS

This study provides an overview of the clinical experience in the Americas related to ML treatment and points out interventions and possible combinations that are eligible to be explored in future well-designed studies.

Pioglitazone, a Peroxisome Proliferator-Activated Receptor-γ Agonist, Downregulates the Inflammatory Response in Cutaneous Leishmaniasis Patients Without Interfering in Leishmania braziliensis Killing by Monocytes

Patients with cutaneous leishmaniasis (CL) due to Leishmania braziliensis infection have an exacerbated inflammatory response associated with tissue damage and ulcer development. An increase in the rate of patients who fail therapy with pentavalent antimony has been documented. An adjuvant therapy with an anti-inflammatory drug with the potential of Leishmania killing would benefit CL patients. The aim of the present study was to investigate the contribution of peroxisome proliferator-activated receptor-γ (PPAR-γ) activation by pioglitazone in the regulation of the inflammatory response and L. braziliensis killing by monocytes. Pioglitazone is an oral drug used in the treatment of diabetes, and its main mechanism of action is through the activation of PPAR-γ, which is expressed in many cell types of the immune response. We found that activation of PPAR-γ by pioglitazone decreases the inflammatory response in CL patients without affecting L. braziliensis killing by monocytes. Our data suggest that pioglitazone may serve as an adjunctive treatment for CL caused by L. braziliensis.

Pentoxifylline in the Treatment of Cutaneous Leishmaniasis: A Randomized Clinical Trial in Colombia

Addition of the immunomodulator pentoxifylline (PTX) to antimonial treatment of mucosal leishmaniasis has shown increased efficacy. This randomized, double-blind, placebo-controlled trial evaluated whether addition of pentoxifylline to meglumine antimoniate (MA) treatment improves therapeutic response in cutaneous leishmaniasis (CL) patients. Seventy-three patients aged 18−65 years, having multiple lesions or a single lesion ≥ 3 cm were randomized to receive: intramuscular MA (20 mg/kg/day × 20 days) plus oral PTX 400 mg thrice daily (intervention arm, n = 36) or MA plus placebo (control arm, n = 37), between 2012 and 2015. Inflammatory gene expression was evaluated by RT-qPCR in peripheral blood mononuclear cells from trial patients, before and after treatment. Intention-to-treat failure rate was 35% for intervention vs. 25% for control (OR: 0.61, 95% CI: 0.21−1.71). Per-protocol failure rate was 32% for PTX, and 24% for placebo (OR: 0.50, 95% CI: 0.13−1.97). No differences in frequency or severity of adverse events were found (PTX = 142 vs. placebo = 140). Expression of inflammatory mediators was unaltered by addition of PTX to MA. However, therapeutic failure was associated with significant overexpression of il1β and ptgs2 (p < 0.05), irrespective of study group. No clinical benefit of addition of PTX to standard treatment was detected in early mild to moderate CL caused by Leishmania (V.) panamensis.

Host-directed antileishmanial interventions: Harvesting unripe fruits to reach fruition

Leishmaniasis is an exemplary paradigm of immune evasion, fraught with the perils of limited clinical assistance, escalating costs of treatment and made worse with the lack of suitable vaccine. While drugs remain central to large-scale disease control, the growing emergence of parasite resistance necessitates the need for combination therapy involving host-directed immunological agents. Also, since prolonged disease progression is associated with strong immune suppression of the host, augmentation of host immunity via restoration of the immunoregulatory circuit involving antigen-presenting cells and T-cells, activation of macrophage function and/or CD4⁺ T helper 1 cell differentiation may serve as an ideal approach to resolve severe cases of leishmaniasis. As such, therapies that embody a synergistic approach that involve direct killing of the parasite in addition to elevating host immunity are likely to pave the way for widespread elimination of leishmaniasis in the future. With this review, we aim to recapitulate the various immunotherapeutic agents found to hold promise in antileishmanial treatment both in vitro and in vivo. These include parasite-specific antigens, dendritic cell-targeted therapy, recombinant inhibitors of various components intrinsic to immune cell signaling and agonists or antagonists to immune cells and cytokines. We also summarize their abilities to direct therapeutic skewing of the host cell-immune response and review their potential to combat the disease either alone, or as adjunct modalities.

Modulation of miR-145-5p and miR-146b-5p levels is linked to reduced parasite load in H9C2 Trypanosoma cruzi infected cardiomyoblasts

In the heart tissue of acutely Trypanosoma cruzi-infected mice miR-145-5p and miR-146b-5p are, respectively, downregulated and upregulated. Here, we used the H9C2 rat cardiomyoblast cell line infected with the Colombian T. cruzi strain to investigate the parasite-host cell interplay, focusing on the regulation of miR-145-5p and miR-146b-5p expression. Next, we explored the effects of interventions with the trypanosomicidal drug Benznidazole (Bz) alone or combined with Pentoxifylline (PTX), a methylxanthine derivative shown to modulate immunological and cardiac abnormalities in a model of chronic chagasic cardiomyopathy, on parasite load and expression of miR-145-5p and miR-146b-5p. The infection of H9C2 cells with trypomastigote forms allowed parasite cycle with intracellular forms multiplication and trypomastigote release. After 48 and 144 h of infection, upregulation of miR-145-5p (24 h: 2.38 ± 0.26; 48 h: 3.15 ± 0.9-fold change) and miR-146b-5b (24 h: 2.60 ± 0.46; 48 h: 2.97 ± 0.23-fold change) was detected. The peak of both miRNA levels paralleled with release of trypomastigote forms. Addition of 3 µM and 10 µM of Bz 48 h after infection reduced parasite load but did not interfere with miR-145-5p and miR-146b-5p levels. Addition of PTX did not interfere with Bz-induced parasite control efficacy. Conversely, combined Bz + PTX treatment decreased the levels of both microRNAs, resembling the expression levels detected in non-infected H9C2 cells. Moreover, the use of miR-145-5p and miR-146b-5p mimic/inhibitor systems before infection of H9C2 cells decreased parasite load, 72 h postinfection. When H9C2 cells were treated with miR-145-5p and miR-146b-5p mimic/inhibitor 48 h after infection, all the used systems, except the miR-146b-5p inhibitor, reduced parasite load. Altogether, our data indicate that these microRNAs putatively control signaling pathways crucial for parasite–host cell interaction. Thus, miR-145-5p and miR-146b-5p deserve to be further investigated as biomarkers of parasite control and tools to identify therapeutic adjuvants to etiological treatment in Chagas disease.

The Leishmania antigen-specific pro-inflammatory response in cutaneous leishmaniasis is linked to disease progression but not to the therapeutic failure of pentavalent antimonials

High levels of pro-inflammatory cytokines in cutaneous leishmaniasis patients are associated with tissue damage and ulcer development. We found higher levels of TNF and IL-1β in peripheral blood mononuclear cell supernatants in response to soluble Leishmania antigen in individuals with a longer duration of disease. In addition, L. braziliensis-infected patients with a longer disease progression before treatment presented a shorter time to cure after treatment onset. No associations were found between the levels of the pro-inflammatory cytokines IL-6, TNF and IL-1-β and patients' response to pentavalent antimony treatment. Our data suggest that while the Leishmania antigen-specific pro-inflammatory cytokines investigated may lead to ulcer development, they do not influence therapeutic failure in cutaneous leishmaniasis patients.

Mechanisms of Immunopathogenesis in Cutaneous Leishmaniasis And Post Kala-azar Dermal Leishmaniasis (PKDL)

Leishmaniasis is a neglected tropical disease that affects 12 million people worldwide. The disease has high morbidity and mortality rates and is prevalent in over 80 countries, leaving more than 300 million people at risk of infection. Of all of the manifestations of this disease, cutaneous leishmaniasis (CL) is the most common form and it presents as ulcerating skin lesions that can self-heal or become chronic, leading to disfiguring scars. This review focuses on the different pathologies and disease manifestations of CL, as well as their varying degrees of severity. In particular, this review will discuss self-healing localized cutaneous leishmaniasis (LCL), leishmaniasis recidivans (LR), mucocutaneous leishmaniasis (MCL), anergic diffuse cutaneous leishmaniasis (ADCL), disseminated leishmaniasis (DL), and Post Kala-azar Dermal Leishmaniasis (PKDL), which is a cutaneous manifestation observed in some visceral leishmaniasis (VL) patients after successful treatment. The different clinical manifestations of CL are determined by a variety of factors including the species of the parasites and the host's immune response. Specifically, the balance between the pro and anti-inflammatory mediators plays a vital role in the clinical presentation and outcome of the disease. Depending upon the immune response, Leishmania infection can also transition from one form of the disease to another. In this review, different forms of cutaneous Leishmania infections and their immunology are described.

Recent advancements in anti-leishmanial research: Synthetic strategies and structural activity relationships

Leishmaniasis is a parasitic neglected tropical disease caused by various species of Leishmania parasite. Despite tremendous advancements in the therapeutic sector and drug development strategies, still the existing anti-leishmanial agents are associated with some clinical issues like drug resistance, toxicity and selectivity. Therefore, several research groups are continuously working towards the development of new therapeutic candidates to overcome these issues. Many potential heterocyclic moieties have been explored for this purpose including triazoles, chalcones, chromone, thiazoles, thiosemicarbazones, indole, quinolines, etc. It is evident from the literature that the majority of anti-leishmanial agents act by interacting with key regulators including PTR-I, DHFR, LdMetAP1, MAPK, 14 α-demethylase and pteridine reductase-I, etc. Also, these tend to induce the production of ROS which causes damage to parasites. In the present compilation, authors have summarized various significant synthetic procedures for anti-leishmanial agents reported in recent years. A brief description of the pharmacological potentials of synthesized compounds along with important aspects related to structural activity relationship has been provided. Important docking outcomes highlighting the possible mode of interaction for the reported compounds have also been included. This review would be helpful to the scientific community to design newer strategies and also to develop novel therapeutic candidates against leishmaniasis.

High Anti-Leishmania IgG Antibody Levels Are Associated With Severity of Mucosal Leishmaniasis

Background

Mucosal leishmaniasis (ML), the most inflammatory form of tegumentary leishmaniasis, is predominantly caused by Leishmania braziliensis. The disease is characterized by the development of lesions, mainly in the nasal mucosa. An exacerbated inflammatory response has been associated with the presence of destructive and disfiguring lesions, with stages of severity ranging from small nodulations to the complete destruction of the nasal pyramid architecture. As Leishmania is an intracellular parasite, most immunological studies have emphasized the cell-mediated immune response, while relatively few studies aimed to investigate the role antibodies in protection against, or the pathology of ML.

Methods

Patients with a confirmed diagnosis of ML were classified according to clinical staging criteria. Serum levels of Leishmania-specific IgG, IgG1 and IgG2 antibodies were determined by ELISA before and after treatment with antimony or antimony plus pentoxifylline.

Results

Patients in stages IV and V produced higher concentrations of IgG and IgG1 antibodies when compared to those in stage I and II. Significant reductions were seen in the concentrations of IgG and IgG2 antibodies in most patients who responded well to treatment.

Conclusions

Our data demonstrate an association between IgG antibody titers and the severity of mucosal disease. The observed reduction in antibody production after successful treatment in most patients preliminarily indicates that these tests can be used to aid in the assessment of therapeutic response.

Host-Directed Therapies for Cutaneous Leishmaniasis

Cutaneous leishmaniasis exhibits a wide spectrum of clinical presentations from self-resolving infections to severe chronic disease. Anti-parasitic drugs are often ineffective in the most severe forms of the disease, and in some cases the magnitude of the disease can result from an uncontrolled inflammatory response rather than unrestrained parasite replication. In these patients, host-directed therapies offer a novel approach to improve clinical outcome. Importantly, there are many anti-inflammatory drugs with known safety and efficacy profiles that are currently used for other inflammatory diseases and are readily available to be used for leishmaniasis. However, since leishmaniasis consists of a wide range of clinical entities, mediated by a diverse group of leishmanial species, host-directed therapies will need to be tailored for specific types of leishmaniasis. There is now substantial evidence that host-directed therapies are likely to be beneficial beyond autoimmune diseases and cancer and thus should be an important component in the armamentarium to modulate the severity of cutaneous leishmaniasis.

Anti-Leishmania IgG is a marker of disseminated leishmaniasis caused by Leishmania braziliensis

BACKGROUND

In this study, we determined the accuracy of anti-Leishmania IgG and IgG subclasses to distinguish clinical forms of American tegumentary leishmaniasis (ATL) and and determined the relationship between antibodies levels with cytokine production and severity of ATL.

METHODS

Participants were 40 patients with cutaneous leishmaniasis (CL), 20 patients with mucosal leishmaniasis (ML), 20 patients with disseminated leishmaniasis (DL), and 20 individuals with subclinical Leishmania braziliensis infection (SC). Diagnosis was performed by DNA of L. braziliensis or IFN-γ production in SC. IgG and subclasses of IgG to soluble Leishmania antigen and cytokine levels in supernatants of mononuclear cells were detected by ELISA.

RESULTS

IgG was detected in 95%, 95%, and 100% of patients with CL, ML, and DL, respectively. Higher levels of anti-Leishmania IgG and IgG2 were seen in DL compared to CL, ML, and SC. ROC analysis confirmed the ability of IgG to distinguish DL from the other clinical forms. A direct correlation was observed between IgG titers and levels of IFN-γ and CXCL10 in CL and DL, and IgG2 antibodies were correlated with the number of lesions in DL.

CONCLUSIONS

High anti-Leishmania IgG and IgG2 levels are characteristic of DL, and while IgG was correlated with pro-inflammatory cytokines, IgG2 was direct correlated with the number of lesions.

Pharmacokinetics and pharmacodynamics in the treatment of cutaneous leishmaniasis - challenges and opportunities

Pharmacological efficacy is obtained when adequate concentrations of a potent drug reach the target site. In cutaneous leishmaniasis, a heterogeneous disease characterised by a variety of skin manifestations from simple nodules, skin discoloration, plaques to extensive disseminated forms, the parasites are found in the dermal layers of the skin. Treatment thus involves the release of the active compound from the formulation (administered either topically or systemically), it's permeation into the skin, accumulation by the local macrophages and further transport into the phagolysosome of the macrophage. The pharmacodynamic activity of a drug against the parasite is relatively straight forward to evaluate both in vivo and in vitro. The pharmacokinetic processes taking place inside the skin are more complex to elucidate due to the multi-lamellar structure of the skin, heterogeneous distribution of drugs within the tissue, the difficulty of accessing the site of infection complicating sampling and the lack of surrogate markers reflecting the activity of a drug in the skin. This review will discuss the difficulties encountered when investigating drug distribution, PK PD relationships and efficacy in the skin with a focus on cutaneous leishmaniasis treatment.

Case Report: Unusual Presentation of Pharyngeal Mucosal Leishmaniasis due to Leishmania (Viannia) braziliensis

Mucosal leishmaniasis (ML) affects predominantly the nose and occurs usually weeks or months after the cure of the primary cutaneous lesion. The pathology of ML is characterized by an exaggerated inflammatory reaction with infiltration of lymphocytes, macrophages, and plasma cells. There is also a paucity of parasites and a strong delayed-type hypersensitivity reaction. Herein, we report a case of a young man who had a large ulcer in his left leg and complained of dysphagia. In nasofibrolaryngoscopy, there were nodular lesions in the oropharynx and rhinopharynx. The skin lesion biopsy showed a chronic inflammation with amastigotes inside macrophages, and DNA of Leishmania braziliensis confirmed the diagnosis of ML in tissue biopsied from the pharynx. The leishmaniasis skin test was negative. Cytokine evaluation showed lack of production of interferon (IFN)-γ, interleukin (IL)-1β, and IL-17 with enhancement of these cytokine levels after cure.

Evaluation of the Ability of Miltefosine Associated with Topical GM-CSF in Modulating the Immune Response of Patients with Cutaneous Leishmaniasis

Cutaneous leishmaniasis (CL) due to L. braziliensis is associated with an exaggerated inflammatory response and tissue damage. Miltefosine is more effective than pentavalent antimony (Sb^v) in the treatment of CL, and here, we evaluate the ability of Sb^v, miltefosine, and GM-CSF administered intravenously, orally, or topically, respectively, to modify the immune response. Patients were treated with miltefosine plus GM-CSF, miltefosine plus placebo, or Sb^v. Mononuclear cells were stimulated with soluble Leishmania antigen (SLA) on day 0 and day 15 of therapy, and cytokine levels were determined in supernatants by ELISA. The lymphocyte proliferation and oxidative burst were evaluated by flow cytometry, and the degree of infection and Leishmania killing by optical microscopy. Proliferation of CD4⁺ T cells were enhanced in patients using miltefosine and in CD8⁺ T cells when GM-CSF was associated. Enhancement in the oxidative burst occurred in the miltefosine plus GM-CSF group on day 15 of therapy. Moreover, the number of L. braziliensis in infected monocytes on day 15 as well as the percentage of infected cells was lower after 48- and 72-hour culture in cells from patients treated with miltefosine plus GM-CSF. In addition to the ability of miltefosine to kill Leishmania, the changes in the immune response caused by miltefosine and GM-CSF may increase the cure rate of CL patients using these drugs.

Interventions for American cutaneous and mucocutaneous leishmaniasis

BACKGROUND

On the American continent, cutaneous and mucocutaneous leishmaniasis (CL and MCL) are diseases associated with infection by several species of Leishmania parasites. Pentavalent antimonials remain the first-choice treatment. There are alternative interventions, but reviewing their effectiveness and safety is important as availability is limited. This is an update of a Cochrane Review first published in 2009.

OBJECTIVES

To assess the effects of interventions for all immuno-competent people who have American cutaneous and mucocutaneous leishmaniasis (ACML).

SEARCH METHODS

We updated our database searches of the Cochrane Skin Group Specialised Register, CENTRAL, MEDLINE, Embase, LILACS and CINAHL to August 2019. We searched five trials registers.

SELECTION CRITERIA

Randomised controlled trials (RCTs) assessing either single or combination treatments for ACML in immuno-competent people, diagnosed by clinical presentation and Leishmania infection confirmed by smear, culture, histology, or polymerase chain reaction on a biopsy specimen. The comparators were either no treatment, placebo only, or another active compound.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Our key outcomes were the percentage of participants 'cured' at least three months after the end of treatment, adverse effects, and recurrence. We used GRADE to assess evidence certainty for each outcome.

MAIN RESULTS

We included 75 studies (37 were new), totalling 6533 randomised participants with ATL. The studies were mainly conducted in Central and South America at regional hospitals, local healthcare clinics, and research centres. More male participants were included (mean age: roughly 28.9 years (SD: 7.0)). The most common confirmed species were L. braziliensis, L. panamensis, and L. mexicana. The most assessed interventions and comparators were non-antimonial systemics (particularly oral miltefosine) and antimonials (particularly meglumine antimoniate (MA), which was also a common intervention), respectively. Three studies included moderate-to-severe cases of mucosal leishmaniasis but none included cases with diffuse cutaneous or disseminated CL, considered the severe cutaneous form. Lesions were mainly ulcerative and located in the extremities and limbs. The follow-up (FU) period ranged from 28 days to 7 years. All studies had high or unclear risk of bias in at least one domain (especially performance bias). None of the studies reported the degree of functional or aesthetic impairment, scarring, or quality of life. Compared to placebo, at one-year FU, intramuscular (IM) MA given for 20 days to treat L. braziliensis and L. panamensis infections in ACML may increase the likelihood of complete cure (risk ratio (RR) 4.23, 95% confidence interval (CI) 0.84 to 21.38; 2 RCTs, 157 participants; moderate-certainty evidence), but may also make little to no difference, since the 95% CI includes the possibility of both increased and reduced healing (cure rates), and IMMA probably increases severe adverse effects such as myalgias and arthralgias (RR 1.51, 95% CI 1.17 to 1.96; 1 RCT, 134 participants; moderate-certainty evidence). IMMA may make little to no difference to the recurrence risk, but the 95% CI includes the possibility of both increased and reduced risk (RR 1.79, 95% CI 0.17 to 19.26; 1 RCT, 127 participants; low-certainty evidence). Compared to placebo, at six-month FU, oral miltefosine given for 28 days to treat L. mexicana, L. panamensis and L. braziliensis infections in American cutaneous leishmaniasis (ACL) probably improves the likelihood of complete cure (RR 2.25, 95% CI 1.42 to 3.38), and probably increases nausea rates (RR 3.96, 95% CI 1.49 to 10.48) and vomiting (RR 6.92, 95% CI 2.68 to 17.86) (moderate-certainty evidence). Oral miltefosine may make little to no difference to the recurrence risk (RR 2.97, 95% CI 0.37 to 23.89; low-certainty evidence), but the 95% CI includes the possibility of both increased and reduced risk (all based on 1 RCT, 133 participants). Compared to IMMA, at 6 to 12 months FU, oral miltefosine given for 28 days to treat L. braziliensis, L. panamensis, L. guyanensis and L. amazonensis infections in ACML may make little to no difference to the likelihood of complete cure (RR 1.05, 95% CI 0.90 to 1.23; 7 RCTs, 676 participants; low-certainty evidence). Based on moderate-certainty evidence (3 RCTs, 464 participants), miltefosine probably increases nausea rates (RR 2.45, 95% CI 1.72 to 3.49) and vomiting (RR 4.76, 95% CI 1.82 to 12.46) compared to IMMA. Recurrence risk was not reported. For the rest of the key comparisons, recurrence risk was not reported, and risk of adverse events could not be estimated. Compared to IMMA, at 6 to 12 months FU, oral azithromycin given for 20 to 28 days to treat L. braziliensis infections in ACML probably reduces the likelihood of complete cure (RR 0.51, 95% CI 0.34 to 0.76; 2 RCTs, 93 participants; moderate-certainty evidence). Compared to intravenous MA (IVMA) and placebo, at 12 month FU, adding topical imiquimod to IVMA, given for 20 days to treat L. braziliensis, L. guyanensis and L. peruviana infections in ACL probably makes little to no difference to the likelihood of complete cure (RR 1.30, 95% CI 0.95 to 1.80; 1 RCT, 80 participants; moderate-certainty evidence). Compared to MA, at 6 months FU, one session of local thermotherapy to treat L. panamensis and L. braziliensis infections in ACL reduces the likelihood of complete cure (RR 0.80, 95% CI 0.68 to 0.95; 1 RCT, 292 participants; high-certainty evidence). Compared to IMMA and placebo, at 26 weeks FU, adding oral pentoxifylline to IMMA to treat CL (species not stated) probably makes little to no difference to the likelihood of complete cure (RR 0.86, 95% CI 0.63 to 1.18; 1 RCT, 70 participants; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

Evidence certainty was mostly moderate or low, due to methodological shortcomings, which precluded conclusive results. Overall, both IMMA and oral miltefosine probably result in an increase in cure rates, and nausea and vomiting are probably more common with miltefosine than with IMMA. Future trials should investigate interventions for mucosal leishmaniasis and evaluate recurrence rates of cutaneous leishmaniasis and its progression to mucosal disease.

Leishmaniasis immunopathology-impact on design and use of vaccines, diagnostics and drugs

Leishmaniasis is a disease complex caused by 20 species of protozoan parasites belonging to the genus Leishmania. In humans, it has two main clinical forms, visceral leishmaniasis (VL) and cutaneous or tegumentary leishmaniasis (CL), as well as several other cutaneous manifestations in a minority of cases. In the mammalian host Leishmania parasites infect different populations of macrophages where they multiply and survive in the phagolysosomal compartment. The progression of both VL and CL depends on the maintenance of a parasite-specific immunosuppressive state based around this host macrophage infection. The complexity and variation of immune responses and immunopathology in humans and the different host interactions of the different Leishmania species has an impact upon the effectiveness of vaccines, diagnostics and drugs.

Autochthonous Cases of Mucosal Leishmaniasis in Northeastern Italy: Clinical Management and Novel Treatment Approaches

Mucosal leishmaniasis (ML) is a rare clinical variant of tegumentary leishmaniasis in Mediterranean Europe. Here we report on three autochthonous cases of head and neck ML in patients living in Northeastern Italy. Patients presented with non-specific, long-standing symptoms of upper respiratory tract involvement, mimicking other diseases. Parasitological diagnosis was reached by histopathology, immunohistochemistry and molecular biology on tissue specimens. Leishmania infantum was identified by molecular typing in all three cases. All patients reached a complete remission with protracted multivalent antileishmanial drugs; in one case, a novel approach of combined medical and endoscopic surgical treatment was carried out. High clinical suspicion led to a prompt diagnosis and deployment of a multivalent treatment. ML should be considered in the differential diagnosis of nasal, oral, and pharyngolaryngeal lesions in endemic areas. A prompt diagnosis is mandatory to establish a correct management; different antileishmanial medications as well as endoscopic surgical options may be required to reach a complete remission.

In Situ Cellular Response Underlying Successful Treatment of Mucosal Leishmaniasis with a Combination of Pentavalent Antimonial and Pentoxifylline

Mucosal leishmaniasis (ML) is characterized by high production of inflammatory cytokines. Administration of pentoxifylline (PTX), an inhibitor of TNF-alpha, with pentavalent antimony (Sb^v), has been successfully used as alternative treatment for refractory ML. Our study aims to investigate the in situ cellular response underlying the effectiveness of this therapy, by evaluating the intensity of the inflammatory infiltrate, cellular composition, and expression of cytokines and granzyme A in lesions from ML before and after treatment with Sb^v alone or in combination with PTX. Our data showed no differences in the intensity of inflammatory infiltrate comparing before and after treatment, and comparing between different treatments. However, although the number and frequency of CD4⁺ and CD8⁺ cells were not different before and after treatments or comparing different treatments, frequency of CD68⁺ cells decreased after treatment with Sb^v + PTX, but not with Sb^v. This was due to a reduction in CD68⁺ TNF-alpha⁺ and not in CD68⁺ IL-10⁺ cells. The frequency of TNF-alpha⁺ cells was correlated with the intensity of the inflammatory infiltrate before treatment, but this correlation was lost after treatment with Sb^v + PTX. Although the total expression of granzyme A did not significantly change after treatments, a clear trend of decrease was observed after treatment with Sb^v + PTX. Interestingly, patients who took longer to heal, regardless of the treatment, displayed a higher frequency of granzyme A⁺ cells. Our data suggest that treatment with Sb^v + PTX acts in CD68⁺ cells reducing the expression of TNF-alpha but not IL-10, resulting in more efficient modulation of the inflammatory response, accelerating the healing process.

Synthesis of quinoline derivatives as potential cysteine protease inhibitors

Aim: Cysteine proteases are important molecular targets involved in the replication, virulence and survival of parasitic organisms, including Trypanosoma and Leishmania species. Methodology & results: Analogs of the 7-chloro-N-[3-(morpholin-4-yl)propyl]quinolin-4-amine were synthesized and their inhibitory activity against the enzymes cruzain and rhodesain as well as against promastigotes forms of Leishmania species and epimastigotes forms of Trypanosoma cruzi were evaluated. Five compounds showed activity against both enzymes with half maximal inhibitory concentration (IC₅₀) values ranging from 23 to 123 μM. Among these, compounds 3 and 4 displayed leishmanicidal activity; compound 4 was the most promising with IC₅₀ values <10 μM and no cytotoxicity for uninfected cells. Conclusion: The results obtained indicate that cysteine proteases are likely to be the molecular target of compounds 3 and 4.

Profiles of Local and Systemic Inflammation in the Outcome of Treatment of Human Cutaneous Leishmaniasis Caused by Leishmania (Viannia)

The immune mechanisms that contribute to the efficacy of treatment of cutaneous leishmaniasis (CL) are not fully understood. The aim of this study was to define immune correlates of the outcome of treatment of CL caused by Leishmania (Viannia) species during standard of care treatment with pentavalent antimonials. We conducted a comparative expression profiling of immune response genes in peripheral blood mononuclear cells (PBMCs) and lesion biopsy specimens obtained from CL patients before and at the end of treatment (EoT) with meglumine antimoniate. The ex vivo response of PBMCs to L (V) panamensis partially reflected that of lesion microenvironments. Significant downregulation of gene expression profiles consistent with local innate immune responses (monocyte and neutrophil activation and chemoattractant molecules) was observed at EoT in biopsy specimens of patients who cured (n = 8), compared to those from patients with treatment failure (n = 8). Among differentially expressed genes, pretreatment expression of CCL2 was significantly predictive of the therapeutic response (receiver operating characteristic [ROC] curve, area under the curve [AUC] = 0.82, P = 0.02). Polymorphisms in regulatory regions of the CCL2 promoter were analyzed in a pilot cohort of DNA samples from CL patients (cures, n = 20, and treatment failure, n = 20), showing putative association of polymorphisms rs13900(C/T) and rs2857656(G/C) with treatment outcome. Our data indicate that dampening gene expression profiles of monocyte and neutrophil activation characterize clinical cure after treatment of CL, supporting participation of parasite-sustained inflammation or deregulated innate immune responses in treatment failure.

A Th2-Type Response Is Associated With Exuberant Lesions in Pregnant Women Infected With Leishmania braziliensis

Background

Cutaneous leishmaniasis (CL) is characterized by an exaggerated inflammatory response. During pregnancy there is a decreased inflammatory response, and we have shown that pregnant women with CL develop exuberant lesions.

Methods

Cytokine production by peripheral blood mononuclear cells and the frequency of cells expressing cytokines in lesions from pregnant and nonpregnant women with CL were evaluated.

Results

We observed that CL lesions from pregnant women displayed a more intense cellular infiltrate, associated with an increase in neutrophils and CD4+ cells. While no difference was observed regarding the number of interferon-gamma (IFN-γ)+ cells in lesions from pregnant compared to nonpregnant women with CL, interleukin-10 (IL-10) and IL-4 expression were approximately 3-times higher in lesions in pregnant women. Main sources of IL-4 and IL-10 were CD4+ and CD68+ cells, respectively. Expression of IL-4, but not IFN-γ or IL-10, was positively correlated with the intensity of inflammatory infiltrate in lesions from pregnant women.

Conclusions

These results provide evidence of an IL-4-mediated pathology in Leishmania braziliensis-infected pregnant women. These differences in lesion pathogenesis in pregnant and nonpregnant women may open possibilities for new therapies for CL treatment during pregnancy, which are currently lacking.

How to master the host immune system? Leishmania parasites have the solutions!

Infection by protozoan parasites of the genus Leishmania results in the development of leishmaniasis, an increasingly prevalent group of diseases affecting over 12 million people worldwide. Leishmaniasis can have very different outcomes ranging from cutaneous lesions, mucosal lesions to visceralization depending on the species of the infecting parasite and on the immune response developed by the host. As an obligate intracellular parasite, residing within macrophages, Leishmania evolved in strict contact with the host immune system, developing different mechanisms to evade or modulate the immune response. Various types of immune responses are observed during different Leishmania spp. infections, resulting in parasite clearance but also contributing to the pathogenesis, thus increasing the complexity of the course of the disease. Interestingly, depending on the type of leishmaniasis developed, opposite treatment strategies, which either boost or inhibit the inflammatory response, have shown efficacy. In this review, we summarize the contribution of different immune cell types to the development of the anti-leishmanial immune response and the parasite strategies to evade and modulate host immunity. Further, we discuss the involvement of co-infecting pathogens in the determination of the outcome of leishmaniasis and on the effectiveness of treatment and the implication of the immune response for treatment and vaccine development.

A randomized, open-label clinical trial comparing the long-term effects of miltefosine and meglumine antimoniate for mucosal leishmaniasis

INTRODUCTION

The treatment of mucosal leishmaniasis (ML) is difficult due to the toxicity and route of administration of standard drugs. Miltefosine is an oral agent used for leishmaniasis treatment; however, no data exist regarding its use for ML in Brazil. In this study, we aimed to evaluate the efficacy of miltefosine for ML treatment compared to that of pentavalent antimonial in a pilot study.

METHODS

We performed a randomized clinical trial with two parallel groups. The tested intervention consisted of miltefosine 1.3-2 mg/kg/day (two capsules) for 28 days or intravenous 20 mg SbV/kg/day of meglumine antimoniate (N-MA) for 30 days. The final endpoint was defined as complete healing of the lesion four years after treatment. We also analyzed an early endpoint at 90 days after treatment.

RESULTS

Forty patients were included in this study: each experimental group comprised 20 patients. Applying a multivariate model in an intention-to-treat analysis, we observed that patients treated with miltefosine had a cure probability 2.08 times greater (95% confidence interval [CI] = 1.03-4.18) than those treated with N-MA at 90 days after treatment. At the final endpoint, we observed no differences in cure probability between miltefosine and N-MA (relative risk = 0.66; 95% CI = 0.33-1.32). With respect to adverse reactions, significant differences between groups were related to gastrointestinal effects, which were more frequent in the miltefosine group.

CONCLUSIONS

Miltefosine may be an interesting alternative for treating ML because of its oral administration and cure rate after long-term follow-up.

Pentavalent Antimonials Combined with Other Therapeutic Alternatives for the Treatment of Cutaneous and Mucocutaneous Leishmaniasis: A Systematic Review

The first choice drugs for the treatment of cutaneous and mucocutaneous leishmaniasis are pentavalent antimonials, sodium stibogluconate, or meglumine antimoniate. However, the treatment with these drugs is expensive, can cause serious adverse effects, and is not always effective. The combination of two drugs by different routes or the combination of an alternative therapy with systemic therapy can increase the efficacy and decrease the collateral effects caused by the reference drugs. In this systematic review we investigated publications that described a combination of nonconventional treatment for cutaneous and mucocutaneous with pentavalent antimonials. A literature review was performed in the databases Web of Knowledge and PubMed in the period from 01st of December 2004 to 01st of June 2017, according to Prisma statement. Only clinical trials involving the treatment for cutaneous or mucocutaneous leishmaniasis, in English, and with available abstract were added. Other types of publications, such as reviews, case reports, comments to the editor, letters, interviews, guidelines, and errata, were excluded. Sixteen articles were selected and the pentavalent antimonials were administered in combination with pentoxifylline, granulocyte macrophage colony-stimulating factor, imiquimod, intralesional sodium stibogluconate, ketoconazole, silver-containing polyester dressing, lyophilized LEISH-F1 protein, cryotherapy, topical honey, and omeprazole. In general, the combined therapy resulted in high rates of clinical cure and when relapse or recurrence was reported, it was higher in the groups treated with pentavalent antimonials alone. The majority of the articles included in this review showed that cure rate ranged from 70 to 100% in patients treated with the combinations. Serious adverse effects were not observed in patients treated with drugs combination. The combination of other drugs or treatment modalities with pentavalent antimonials has proved to be effective for cutaneous and mucocutaneous leishmaniasis and for most seemed to be safe. However, new randomized, controlled, and multicentric clinical trials with more robust samples should be performed, especially the combination with immunomodulators.

Case Report: Mucosal Leishmaniasis Presenting with Nasal Septum Perforation after Almost Thirty Years

Mucosal leishmaniasis (ML) is associated with progressive tissue destruction and granuloma formation, often after a considerable period of latency from an initial cutaneous infection. We report a case of recurrent epistaxis of 3 years duration and nasopharyngeal obstruction in a woman with treated cutaneous leishmaniasis nearly 30 years before and with no further exposure to Leishmania. Computed tomography revealed nasal septal perforation and histopathology demonstrated chronic inflammation. Microscopy was negative for amastigotes, but molecular testing of nasal mucosa biopsy detected Leishmania (Viannia) braziliensis. The patient underwent 28 days of treatment with IV sodium stibogluconate and her symptoms improved significantly. Sixteen months after treatment, she continues to have episodic epistaxis and detectable parasite load in her nasal lesion. Although ML is known to take years to decades to develop, there are few reported cases in the literature of such a long latency period. This report highlights the importance of considering ML in the differential diagnosis of chronic epistaxis in countries where leishmaniasis is endemic or in immigrants from these countries, even when presentation occurs decades after leaving an endemic region.

The Elderly Respond to Antimony Therapy for Cutaneous Leishmaniasis Similarly to Young Patients but Have Severe Adverse Reactions

There is evidence that elderly patients with cutaneous leishmaniasis (CL) have more mucosal and disseminated diseases than young patients and their cells produce less antigen-induced interferon (IFN)-γ. Herein, we compared the roles of interleukin (IL)-10 and IL-15 as modulators of antigen-induced immune responses and the incidence of adverse reaction and response to therapy in young versus elderly patients with CL. Study participants included 35 senior (60-85 years) and 35 young (18-40 years) patients who had a diagnosis of CL documented by typical cutaneous lesions containing Leishmania braziliensis DNA. Elderly patients had less lymph node enlargement. Antigen-induced blood cell cytokine responses were studied in the absence or presence of IL-10 antibody or exogenously added recombinant IL-15. The ratio of IFN-γ/IL-10 was lower in elderly patients, and IFN-γ production was enhanced by either neutralization of IL-10 or exogenous recombinant IL-15 in blood cells from elderly but not young patients. Patients were treated three times weekly with antimony at 20 mg/kg/day for 20 doses. Although there was no difference in response to therapy between the two groups, two young patients needed rescue therapy with amphotericin B. Ventricular arrhythmias and ventricular overload were more frequent in elderly patients. We conclude that elderly patients have alterations in the immune response that may influence clinical manifestations, but we did not find that they had a higher failure rate than young subjects to antimony therapy. However, because of the high rate of electrocardiographic abnormalities during therapy, antimony should not be used in elderly patients with CL.

Safety and efficacy of miltefosine monotherapy and pentoxifylline associated with pentavalent antimony in treating mucosal leishmaniasis

INTRODUCTION

Mucosal Leishmaniasis (ML) is a difficult to treat and severe form of Leishmaniasis. In general, more than 40% of subjects with ML have therapeutic failure upon the use of pentavalent antimony (Sb^v) at 20mg/kg/day during 30 days. Additionally, Sb^v is a toxic drug that requires parenteral administration, and many patients will need several courses to be cured. In cases that cannot be treated or cured by Sb^v, the alternative is amphotericin B, another toxic and parenteral drug. As a consequence, many ML patients will be cured only after years of disease and may present several morbidities due to the aggressiveness of the disease or toxicity related to the treatment. Areas covered: We aimed to review clinical trials with Miltefosine or Sb^v associated with pentoxifylline in the treatment of ML. Expert commentary: There are few studies to define more effective and safer therapy in mucosal disease caused by Leishmania, with an urgent need to supporting and funding well designed trials. Miltefosine monotherapy, as well as pentoxifylline combined with Sb^v are promising therapeutic approaches to increase the cure rate of this neglected disease.

Repurposing as a strategy for the discovery of new anti-leishmanials: the-state-of-the-art

Leishmaniasis is a vector-borne neglected tropical disease caused by protozoan parasites of the genus Leishmania for which there is a paucity of effective viable non-toxic drugs. There are 1·3 million new cases each year causing considerable socio-economic hardship, best measured in 2·4 million disability adjusted life years, with greatest impact on the poorest communities, which means that desperately needed new antileishmanial treatments have to be both affordable and accessible. Established medicines with cheaper and faster development times may hold the cure for this neglected tropical disease. This concept of using old drugs for new diseases may not be novel but, with the ambitious target of controlling or eradicating tropical diseases by 2020, this strategy is still an important one. In this review, we will explore the current state-of-the-art of drug repurposing strategies in the search for new treatments for leishmaniasis.

Molecular epidemiology and in vitro evidence suggest that Leishmania braziliensis strain helps determine antimony response among American tegumenary leishmaniasis patients

Antimony is the first line drug for treating American tegumentary leishmaniasis (ATL) in Brazil. In this country, Leishmania braziliensis causes at least three distinct forms of disease: localized cutaneous (CL), mucosal (ML) and disseminated leishmaniasis (DL). All forms can be found in Corte de Pedra, Northeast Brazil. ML and DL respond poorly to antimony, in contrast to CL. The L. braziliensis population causing ATL in Corte de Pedra is genetically very diverse, with strains of the parasite associating with the clinical form of leishmaniasis. We tested the hypotheses that antimony refractoriness is associated with L. braziliensis genotypes, and that parasites from ML and DL present greater in vitro resistance to antimony than L. braziliensis from CL. Comparison of geographic coordinates of living sites between antimony responders and non-responders by Cusick and Edward́s test showed that refractoriness and responsiveness to the drug were similarly wide spread in the region (p>0.05). Parasites were then genotyped by sequencing a locus starting at position 425,451 on chromosome 28, which is polymorphic among L. braziliensis of Corte de Pedra. Haplotype CC- in CHR28/425,451 was associated with risk of treatment failure among CL patients (Fisheŕs exact test, p=0.03, odds ratio=4.65). This haplotype could not be found among parasites from ML or DL. Finally, sensitivity to antimony was evaluated exposing L. braziliensis promastigotes to increasing concentrations of meglumine antimoniate in vitro. Parasites from ML and DL were more resistant to antimony at doses of 2mg/100μL and beyond than those isolated from CL (Fisher's exact test, p=0.02 and p=0.004, respectively). The intrinsically lower susceptibility of L. brazliensis from ML and DL to antimony parallels what is observed for patients' responsiveness in the field. This finding reinforces that ML and DL patients would benefit from initiating treatment with drugs currently considered as second line, like amphotericin B.

In Vitro Immunomodulatory Activity of a Transition-State Analog Inhibitor of Human Purine Nucleoside Phosphorylase in Cutaneous Leishmaniasis

Cutaneous leishmaniasis (CL) is the most common clinical form of American tegumentary leishmaniasis caused by Leishmania (Viannia) braziliensis. CL is associated with a strong Th1 immune response. This exacerbated inflammatory response is correlated with severity of disease and delays the healing time of the ulcer. The fourth-generation immucillin derivative (DI4G), a potent inhibitor of purine nucleoside phosphorylase, has been proposed as a promising agent in the treatment of diseases associated with T cell activation. Herein, we evaluated the in vitro immunomodulatory activity of DI4G in cells of patients presenting with CL. Peripheral blood mononuclear cells (PBMC) from CL patients were stimulated with soluble leishmania antigen (SLA), in the presence or absence of DI4G, and IFN-γ, TNF, CXCL9, and CXCL10 levels were determined by ELISA. Lymphocyte proliferation in the presence or absence of DI4G was also evaluated, using flow cytometry. DI4G was able to decrease (p < 0.05) IFN-γ production but did not change the TNF, CXCL9, and CXCL10 levels. DI4G decreased (p < 0.05) the lymphoproliferative response mediated by CD8⁺ T cells, but not that by CD4⁺ T cells. DI4G is able to attenuate the exaggerated immune response in CL, exhibiting immunomodulatory activity in IFN-γ production and in CD8⁺ T cell proliferation.

Mucosal leishmaniasis: A Retrospective Study of 327 Cases from an Endemic Area of Leishmania (Viannia) braziliensis

Mucosal leishmaniasis (ML) is observed only in about 3% of patients with American tegumentary leishmaniasis (ATL) but has a high potential for destructive, disfiguring, and disabling sequelae. Prior reports of clinical and epidemiologic features of ML are limited by small numbers of cases. In this study, we evaluated changes in the demographic features and clinical presentation of ML in an endemic area of Leishmania braziliensis transmission over a period of 20 years. The charts of 327 patients with ML diagnosed between 1995 and 2014 were reviewed. The majority of patients (67%) were male. Age ranged from 8 months to 103 years, with a median age of 38.5 years (interquartile range: 22-58 years). The greatest number of patients was between 19 and 39 years (31%). Over the study period, there was an increase in patients with ML more than 60 years of age, an increase in ML with concomitant cutaneous lesions, a decrease in the period of time between the documentation of cutaneous lesions and the diagnosis of mucosal disease, and an increase in the frequency of patients presenting with stage I and V of ML. Moreover, there was a positive correlation between severity of mucosal disease and both age and the period of time between cutaneous lesion and mucosal disease. Response to therapy of ML remained similar over a period of 20 years. Despite the improvement in medical care during the study period, the prevalence of ML did not change and severe disease continues to be a major challenge for the management of these patients.

Oral Pentoxifylline Associated with Pentavalent Antimony: A Randomized Trial for Cutaneous Leishmaniasis

AbstractCutaneous leishmaniasis (CL) by Leishmania braziliensis is associated with decreasing cure rates in Brazil. Standard treatment with pentavalent antimony (Sb^v) cures only 50-60% of the cases. The immunopathogenesis of CL ulcer is associated with high interferon-γ and tumor necrosis factor (TNF) production. Pentoxifylline, a TNF inhibitor, has been successfully used in association with Sb^v in mucosal and cutaneous leishmaniasis. This randomized, double-blind, and placebo-controlled trial aimed to evaluate the efficacy and safety of oral pentoxifylline plus Sb^v versus placebo plus Sb^v in patients with CL in Bahia, Brazil. A total of 164 patients were randomized in two groups to receive the combination or the monotherapy. Cure rate 6 months after treatment was 45% in the pentoxifylline group and 43% in the control group. There was also no difference between the groups regarding the healing time (99.7 ± 66.2 days and 98.1 ± 72.7 days, respectively). Adverse events were more common in the pentoxifylline group (37.8%), versus 23% in the placebo group. This trial shows that Sb^v combined therapy with pentoxifylline is not more effective than Sb^v monotherapy in the treatment of CL caused by L. braziliensis.

Meglumine antımoniate-TiO2@Ag nanoparticle combinations reduce toxicity of the drug while enhancing its antileishmanial effect

Currently, the treatment of leishmaniasis is increasingly insufficient as current antileishmanial drugs have many disadvantages such as toxic side effects, high cost, and growing drug resistance. In order to overcome these disadvantages, researchers have recently focused on combination therapy by using pentavalent antimonials in conjunction with other antileihmanial compounds. Our previous study found that TiO2@Ag nanoparticles (TiAgNps) demonstrated significant antileishmanial effects. However, a lethal dose of TiAgNps on L. topica promastigotes was found to be toxic for macrophage cells. Moreover, non-toxic concentrations of TiAgNps were ineffective in inhibiting L. topica promastigotes and amastigotes. Thus, we propose the use of TiAgNps in combination with other antileishmanial compounds like meglumine antimoniate (MA) at non-toxic concentrations, which may increase the efficacies of both agents and decrease their toxicities. Therefore, the aim of this study was to determine in vitro and in vivo antileishmanial efficacies of TiAgNps-MA combinations at non-toxic concentrations and develop a new approach for treatment that lowers the toxicities of pentavalent antimonials to minimal levels and enhances their effectiveness. In vitro screening was performed on L. topica promastigote and amastigote-macropage culture by using MTT assay to determine proliferation, perform infection index analysis, and to conduct a Griess reaction for nitric oxide production, while in vivo antileishmanial assays were applied on Balb/c mice with CL models. The results demonstrated that combinations including TiAgNps and MA at non-toxic concentrations were highly efficacious against both promastigotes and amastigotes, while MA application alone did not show any inhibitory effects. It was determined that combination applications decreased the proliferation of L. topica promastigotes 2- to 5-fold in contrast to use of MA alone, and was dependent on concentrations. Moreover, the use of combinations led to inhibition of L. topica amastigotes at rates ranging between 80% and 95%. Additionally, combinations were found to decrease metabolic activities of each form of the parasite at ranges between 7- to 20-fold, causing programmed-cell death and stimulation of macrophages for intensive production of nitric oxide, which is accepted as an important antileishmanial agent (p<0.05). Furthermore, Σ FIC analysis demonstrated that the tested combinations composed little additive, but mostly synergistic effects for inhibition of promastigotes and amastigotes. According to in vivo screening results, the combinations displayed high antileishmanial activities by successfully healing lesions and significantly reducing parasite burdens. Combined, these results show that TiAgNps-MA combinations were much more effective than use of MA alone at non-toxic concentrations and they possess high potential for development of new antileishmanial drugs to fight against leishmaniasis.

Wound healing in cutaneous leishmaniasis: A double edged sword of IL-10 and TGF-β

Immune responses have a crucial role during the wound healing process in cutaneous leishmaniasis (CL). However, there are several paradoxes in immunity against CL. On the one hand, regulatory cytokines interleukin (IL)-10 and transforming growth factor beta (TGF-β) increase susceptibility to CL through suppression of several proinflammatory cytokines that require for defense against CL. On the other hand, these cytokines play a pivotal role in the acceleration of wound healing process. This review discusses about the dual role of IL-10 and TGF-β during the wound healing process and immunity against CL to offer a new insight about wound healing in CL.

Chemotherapy of leishmaniasis: present challenges

Cutaneous and visceral leishmaniasis are amongst the most devastating infectious diseases of our time, affecting millions of people worldwide. The treatment of these serious diseases rely on a few chemotherapeutic agents, most of which are of parenteral use and induce severe side-effects. Furthermore, rates of treatment failure are high and have been linked to drug resistance in some areas. Here, we reviewed data on current chemotherapy practice in leishmaniasis. Drug resistance and mechanisms of resistance are described as well as the prospects for applying drug combinations for leishmaniasis chemotherapy. It is clear that efforts for discovering new drugs applicable to leishmaniasis chemotherapy are essential. The main aspects on the various steps of drug discovery in the field are discussed.

Diagnosis and Treatment of Leishmaniasis: Clinical Practice Guidelines by the Infectious Diseases Society of America (IDSA) and the American Society of Tropical Medicine and Hygiene (ASTMH)

It is important to realize that leishmaniasis guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. The IDSA and ASTMH consider adherence to these guidelines to be voluntary, with the ultimate determinations regarding their application to be made by the physician in the light of each patient's individual circumstances.

Fluconazole in the Treatment of Cutaneous Leishmaniasis Caused by Leishmania braziliensis: A Randomized Controlled Trial

BACKGROUND

 The treatment of cutaneous leishmaniasis (CL) caused by Leishmania braziliensis in Brazil with pentavalent antimony (Sb^v) is associated with a high rate of failure, up to 45% of cases. In addition, Sb^v can only administered parenterally and has important toxic effect. An effective, safe, and oral treatment for CL is required.

METHODS

 A randomized controlled clinical trial was conducted to compare the efficacy and safety of high-dosage oral fluconazole (6.5-8.0 mg/kg/d for 28 days) versus a standard Sb^v protocol (20 mg/kg/d for 20 days) for the treatment of CL in Bahia, Brazil.

RESULTS

 A total of 53 subjects were included in the trial; 26 were treated with Sb^v, and 27 with fluconazole. Intention-to-treat analysis showed initial cure rates (2 months after treatment) of 22.2% (6 of 27) in the fluconazole and 53.8% (14 of 26) in the Sb^v group (P = .04). Six months after treatment, the final cure rate remained the same in both groups, without any relapses. The frequencies of adverse effects in the Sb^v and fluconazole groups were similar, 34.6% versus 37% respectively. One patient treated with fluconazole discontinued treatment owing to malaise, headache, and moderate dizziness (Common Terminology Criteria for Adverse Events grade 2).

CONCLUSIONS

 Oral fluconazole at a dosage of 6.5-8 mg/kg/d for 28 days should not be considered an effective treatment for CL caused by L. braziliensisClinical Trials Registration. NCT01953744.