Treatment failure in children in a randomized clinical trial with 10 and 20 days of meglumine antimonate for cutaneous leishmaniasis due to Leishmania viannia species

Innate biosignature of treatment failure in human cutaneous leishmaniasis

The quality and magnitude of the immune and inflammatory responses determine the clinical outcome of Leishmania infection, and contribute to the efficacy of antileishmanial treatments. However, the precise immune mechanisms involved in healing or in chronic immunopathology of human cutaneous leishmaniasis (CL) are not completely understood. Through sequential transcriptomic profiling of blood monocytes (Mo), neutrophils (Nφ), and eosinophils (Eφ) over the course of systemic treatment with meglumine antimoniate, we discovered that a heightened and sustained Type I interferon (IFN) response signature is a hallmark of treatment failure (TF) in CL patients. The transcriptomes of pre-treatment, mid-treatment and end-of-treatment samples were interrogated to identify predictive and prognostic biomarkers of TF. A composite score derived from the expression of 9 differentially expressed genes (common between Mo, Nφ and Eφ) was predictive of TF in this patient cohort for biomarker discovery. Similarly, machine learning models constructed using data from pre-treatment as well as post-treatment samples, accurately classified treatment outcome between cure and TF. Results from this study instigate the evaluation of Type-I IFN responses as new immunological targets for host-directed therapies for treatment of CL, and highlight the feasibility of using transcriptional signatures as predictive biomarkers of outcome for therapeutic decision making.

Natural resistance to meglumine antimoniate is associated with treatment failure in cutaneous leishmaniasis caused by Leishmania (Viannia) panamensis

The multifactorial basis of therapeutic response can obscure the relation between antimicrobial drug susceptibility and clinical outcome. To discern the relationship between parasite susceptibility to meglumine antimoniate (SbV) and therapeutic outcome of cutaneous leishmaniasis, risk factors for treatment failure were considered in evaluating this relationship in ninety-one cutaneous leishmaniasis patients and corresponding clinical strains of Leishmania (Viannia) panamensis. Parasite susceptibility to 32 μg SbV/mL (plasma Cmax) was evaluated in primary human macrophages, PBMCs, and U937 macrophages. Early parasitological response to treatment was determined in lesions of a subgroup of patients, and pathogenicity of Sb-resistant and sensitive clinical strains was compared in BALB/c mice. Parasite survival in cell models and patient lesions was determined by qRT-PCR of Leishmania 7SLRNA transcript. Parasite loads in BALB/c mice were quantified by limiting dilution analysis. The disparate Sb-susceptibility of parasite subpopulations distinguished by isoenzyme profiles (zymodemes) was manifest in all cell models. Notably, Sb-resistance defined by parasite survival, was most effectively discerned in U937 macrophages compared with primary human host cells, significantly higher among strains from patients who failed treatment than cured and, significantly associated with treatment failure. Each unit increase in transformed survival rate corresponded to a 10.6-fold rise in the odds of treatment failure. Furthermore, treatment failure was significantly associated with naturally Sb-resistant zymodeme 2.3 strains, which also produced larger lesions and parasite burdens in BALB/c mice than Sb-sensitive zymodeme 2.2 strains. The confounding effect of host risk factors for treatment failure in discerning this association was evidenced in comparing strains from patients with and without the defined risk factors for treatment failure. These results establish the association of natural resistance to meglumine antimoniate with treatment failure, the importance of host risk factors in evaluating drug susceptibility and treatment outcome, and the clinical and epidemiological relevance of natural Sb-resistance in L. (V.) panamensis subpopulations.

Cutaneous leishmaniasis treatment and therapeutic outcomes in special populations: A collaborative retrospective study

BACKGROUND

Treatment guidance for children and older adult patients affected by cutaneous leishmaniasis (CL) is unclear due to limited representation of these groups in clinical trials.

METHODS

We conducted a collaborative retrospective study to describe the effectiveness and safety of antileishmanial treatments in children ≤ 10 and adults ≥ 60 years of age, treated between 2014 and 2018 in ten CL referral centers in Latin America.

RESULTS

2,037 clinical records were assessed for eligibility. Of them, the main reason for non-inclusion was lack of data on treatment follow-up and therapeutic response (182/242, 75% of children and 179/468, 38% of adults). Data on 1,325 eligible CL patients (736 children and 589 older adults) were analyzed. In both age groups, disease presentation was mild, with a median number of lesions of one (IQR: 1-2) and median lesion diameter of less than 3 cm. Less than 50% of the patients had data for two or more follow-up visits post-treatment (being only 28% in pediatric patients). Systemic antimonials were the most common monotherapy regimen in both age groups (590/736, 80.2% of children and 308/589, 52.3% of older adults) with overall cure rates of 54.6% (95% CI: 50.5-58.6%) and 68.2% (95% CI: 62.6-73.4%), respectively. Other treatments used include miltefosine, amphotericin B, intralesional antimonials, and pentamidine. Adverse reactions related to the main treatment were experienced in 11.9% (86/722) of children versus 38.4% (206/537) of older adults. Most adverse reactions were of mild intensity.

CONCLUSION

Our findings support the need for greater availability and use of alternatives to systemic antimonials, particularly local therapies, and development of strategies to improve patient follow-up across the region, with special attention to pediatric populations.

Intralesional Meglumine Antimoniate: Safe, Feasible and Effective Therapy for Cutaneous Leishmaniasis in Bolivia

The standard of care for cutaneous leishmaniasis includes the intramuscular/intravenous administration of pentavalent antimonials that are toxic and poorly tolerated. Primary health care usually lacks trained health staff for the diagnosis and treatment of leishmaniasis in Cochabamba Bolivia. Taking these aspects into account, a Bolivian consortium set out to explore the intralesional administration of meglumine antimoniate to treat cutaneous leishmaniasis during primary care under programmatic conditions. A four-step strategy consisting of clinical training for intralesional treatment and the promotion and periodic follow-up of health staff was carried out. The training process was applied in situ to personnel of nine primary health care centres. The intralesional treatment was applied five times every other day. Clinical follow-up after six-months of treatment showed a 77% healing proportion and 5% of therapeutic failure among 152 enrolled patients. The drug volume used in the intralesional procedure was on average 1.7 mL/ulcer treated. In conclusion, the strategy used was successful and effective, accomplishing a healing proportion similar to the long standardized treatment with a reduced time of administration, no severe side effects, and it is feasible to conduct by trained health staff. Our study supports the current PAHO/WHO recommendation for the intralesional administration of pentavalent antimonials for the treatment of cutaneous leishmaniasis.

Sensitivity and Specificity of the Remote Evaluation of Therapeutic Response in Cutaneous Leishmaniasis Using Photographs from a Mobile Application

Cutaneous leishmaniasis (CL) primarily affects people in remote settings with limited access to health services. mHealth tools offer an opportunity to overcome knowledge gaps about clinical response to treatment. We evaluated the validity of the Guaral+ST mobile application for the remote assessment of therapeutic response in patients with CL, through photographs of lesions captured with the app by community health volunteers. Patients with confirmed CL were followed at weeks 13 and 26 after completion of treatment to assess therapeutic response in two clinical settings in southwest Colombia. Direct evaluation of lesions performed by an experienced physician was considered the reference standard. Photographs of lesions taken by CHV or nurse assistants with the mobile app, were independently evaluated by three physicians to define clinical response. A summary measure of clinical outcome defined by the three physicians was considered the index test. Sensitivity, specificity, and positive and negative predictive values were estimated. Interrater reliability (kappa) was calculated. Among 53 participants with CL who had at least one follow-up visit, the sensitivity of therapeutic response evaluation through photographs taken with the Guaral+ST app, compared with direct evaluation by an expert physician, had high validity with sensitivity of 100% (95% confidence interval: 80.5-100%) and specificity of 97.2% (95% confidence interval: 85.5-99.9%). The chance-adjusted agreement (κ) was > 0.8, which is conventionally characterized as almost perfect. The high accuracy of the remote evaluation of photographs for the assessment of therapeutic response supports the use of mHealth tools for improving access to treatment follow-up for CL.

Treatment of Cutaneous Leishmaniasis in a Nonendemic Country: A Case Series of Children in Australia

We describe 4 cases of cutaneous leishmaniasis in children in Australia. Treatment is challenging given lack of firm guidelines and limited access to conventional modalities used in endemic countries. Topical paromomycin or oral fluconazole were effective outpatient-based first-line treatments, however, topical paromomycin use was limited by expense to import or compound locally.

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.

Insights from Leishmania (Viannia) guyanensis in vitro behavior and intercellular communication

BACKGROUND

Pentavalent antimonial-based chemotherapy is the first-line approach for leishmaniasis treatment and disease control. Nevertheless antimony-resistant parasites have been reported in some endemic regions. Treatment refractoriness is complex and is associated with patient- and parasite-related variables. Although amastigotes are the parasite stage in the vertebrate host and, thus, exposed to the drug, the stress caused by trivalent antimony in promastigotes has been shown to promote significant modification in expression of several genes involved in various biological processes, which will ultimately affect parasite behavior. Leishmania (Viannia) guyanensis is one of the main etiological agents in the Amazon Basin region, with a high relapse rate (approximately 25%).

METHODS

Herein, we conducted several in vitro analyses with L. (V.) guyanensis strains derived from cured and refractory patients after treatment with standardized antimonial therapeutic schemes, in addition to a drug-resistant in vitro-selected strain. Drug sensitivity assessed through Sb(III) half-maximal inhibitory concentration (IC₅₀) assays, growth patterns (with and without drug pressure) and metacyclic-like percentages were determined for all strains and compared to treatment outcomes. Finally, co-cultivation without intercellular contact was followed by parasitic density and Sb(III) IC₅₀ measurements.

RESULTS

Poor treatment response was correlated with increased Sb(III) IC₅₀ values. The decrease in drug sensitivity was associated with a reduced cell replication rate, increased in vitro growth ability, and higher metacyclic-like proportion. Additionally, in vitro co-cultivation assays demonstrated that intercellular communication enabled lower drug sensitivity and enhanced in vitro growth ability, regardless of direct cell contact.

CONCLUSIONS

Data concerning drug sensitivity in the Viannia subgenus are emerging, and L. (V.) guyanensis plays a pivotal epidemiological role in Latin America. Therefore, investigating the parasitic features potentially related to relapses is urgent. Altogether, the data presented here indicate that all tested strains of L. (V.) guyanensis displayed an association between treatment outcome and in vitro parameters, especially the drug sensitivity. Remarkably, sharing enhanced growth ability and decreased drug sensitivity, without intercellular communication, were demonstrated.

Neutrophil Activation: Influence of Antimony Tolerant and Susceptible Clinical Strains of L. (V.) panamensis and Meglumine Antimoniate

Emerging evidence indicates that innate host response contributes to the therapeutic effect of antimicrobial medications. Recent studies have shown that Leishmania parasites derived by in vitro selection for resistance to pentavalent antimony (SbV) as meglumine antimoniate (MA) modulate the activation of neutrophils. However, whether modulation of neutrophil activation extends to natural resistance to this antileishmanial drug has not been established. We have evaluated the influence of clinical strains of L. (V.) panamensis having intrinsic tolerance/resistance to SbV, on the inflammatory response of neutrophils during ex vivo exposure to MA. Accordingly, neutrophils obtained from healthy donors were infected with clinical strains that are sensitive (n = 10) or intrinsically tolerant/resistant to SbV (n = 10) and exposed to a concentration approximating the maximal plasma concentration (Cmax) of SbV (32 µg/ml). The activation profile of neutrophils was evaluated as the expression of the surface membrane markers CD66b, CD18, and CD62L by flow cytometry, measurement of reactive oxygen species (ROS) by luminometry, and NET formation using Picogreen to measure dsDNA release and quantification of NETs by confocal microscopy. These parameters of activation were analyzed in relation with parasite susceptibility to SbV and exposure to MA. Here, we show that clinical strains presenting intrinsic tolerance/resistance to SbV induced significantly lower ROS production compared to drug-sensitive clinical strains, both in the presence and in the absence of MA. Likewise, analyses of surface membrane activation markers revealed significantly higher expression of CD62L on cells infected with intrinsically SbV tolerant/resistant L. (V.) panamensis than cells infected with drug-sensitive strains. Expression of other activation markers (CD18 and CD66b) and NET formation were similar for neutrophils infected with SbV sensitive and tolerant clinical strains under the conditions evaluated. Exposure to MA broadly impacted the activation of neutrophils, diminishing NET formation and the expression of CD62L, while augmenting ROS production and CD66b expression, independently of the parasite susceptibility phenotype. These results demonstrated that activation of human neutrophils ex vivo is differentially modulated by infection with clinical strains of L. (V.) panamensis having intrinsic tolerance/resistance to SbV compared to sensitive strains, and by exposure to antimonial drug.

Immuno-pharmacokinetics of Meglumine Antimoniate in Patients With Cutaneous Leishmaniasis Caused by Leishmania (Viannia)

BACKGROUND

Control of cutaneous leishmaniasis (CL) relies on chemotherapy, yet gaps in our understanding of the determinants of therapeutic outcome impede optimization of antileishmanial drug regimens. Pharmacodynamic (PD) parameters of antimicrobials are based on the relationship between drug concentrations/exposure and microbial kill. However, viable Leishmania persist in a high proportion of individuals despite clinical resolution, indicating that determinants other than parasite clearance are involved in drug efficacy.

METHODS

In this study, the profiles of expression of neutrophils, monocytes, Th1 and Th17 gene signatures were characterized in peripheral blood mononuclear cells (PBMCs) during treatment with meglumine antimoniate (MA) and clinical cure of human CL caused by Leishmania (Viannia). We explored relationships of immune gene expression with plasma and intracellular antimony (Sb) concentrations.

RESULTS

Our findings show a rapid and orchestrated modulation of gene expression networks upon exposure to MA. We report nonlinear pharmacokinetic/pharmacodynamic (PK/PD) relationships of Sb and gene expression dynamics in PBMCs , concurring with a time lag in the detection of intracellular drug concentrations and with PK evidence of intracellular Sb accumulation.

CONCLUSIONS

Our results quantitatively portray the immune dynamics of therapeutic healing, and provide the knowledge base for optimization of antimonial drug treatments, guiding the selection and/or design of targeted drug delivery systems and strategies for targeted immunomodulation.

In Vitro and In Vivo Survey of Ethyl Acetate Extract of Acorus calamus (Sweet Flag) Rhizome on Toxoplasma gondii

Background

Toxoplasmosis is a zoonosis disease that can cause a variety range of manifestations in human specially fetus duration and immunodeficiency conditions. Due to toxicity and side effects of current treatment, we evaluated in vivo and in vitro effects of ethyl acetate extract of Acorus calamus rhizomes (rootstocks) on Toxoplasma gondii.

Methods

The plant, Acorus calamus, was collected from Sari, North of Iran in spring season. Ethyl acetate extract was provided from plant rhizomes using Soxhlet apparatus. The total phenolic and flavonoid contents of the extract were measured by the Folin-Ciocalteu method. The mortality effect of different concentrations (1-256 μg/ml) of the extract on Toxoplasma tachyzoites was assessed by flowcytometry and propidium iodide staining. For the therapeutic effect assessment, the tachyzoites were inoculated intraperitoneally to mice, and then these mice were orally and intraperitoneally administered different concentrations (32, 64, 128, and 256 mg/kg) of the extract. Also, an infected group received PBS including DMSO 1% as negative control, and an infected group administered sulfadiazine as positive control. For toxicity evaluation of this extract, a group only received dose 256 mg/kg.

Results

The plant extract was rich of phenolic compounds (41.27 ± 0.21 mg/g), whereas it contained fewer amounts of flavonoids (4.79 ± 0.01 mg/g). Results of in vitro experiments showed that there is an inverse relationship between the concentrations and the mortality of the parasites (IC₅₀ = 200.01 ± 7.74 μg/ml). The highest percentage (62%) of dead tachyzoites was seen at maximum concentration of the extract. A significant longevity (8.9 days) was belonged to mice orally administered extract dose (256 mg/kg/day).

Conclusion

The ethyl acetate extract of A. calamus rhizomes had significant anti-Toxoplasma activities either in vitro or in vivo. It may be connected to high amount of phenolic compounds. We suggest that the effects of different fractions and the admin types of the extract will be evaluated on the parasite.

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.

Leishmania naiffi and lainsoni in French Guiana: Clinical features and phylogenetic variability

In French Guiana, five species are associated with Cutaneous Leishmaniasis (CL). Though infections with Leishmania guyanensis, L. (V.) braziliensis and L. (L.) amazonensis have been extensively described, there are few available clinical and genetic data on L. (V.) lainsoni and L. (V.) naiffi. We determined the clinical and epidemiological features of all cases of CL due to L. (V.) naiffi and L. (V.) lainsoni diagnosed in French Guiana between 2003 and 2019. Phylogenetic analysis was performed by sequencing a portion of HSP70 and cyt b genes. Five cases of L. naiffi and 25 cases of L. lainsoni were reported. Patients infected by L. (V.) lainsoni were usually infected on gold camps, mostly along the Maroni river (60%), while L. naiffi was observed in French patients infected on the coast (100%). A high number of pediatric cases (n = 5; 20%) was observed for L. (V.) lainsoni. A mild clinical course was observed for all cases of L. (V.) naiffi. HSP70 and cyt b partial nucleotide sequence analysis revealed different geographical clusters within L. (V.) naiffi and L. (V.) lainsoni but no association were found between phylogenetic and clinical features. Our data suggest distinct socio-epidemiological features for these two Leishmania species. Patients seem to get infected with L. (V.) naiffi during leisure activities in anthropized coastal areas, while L. (V.) lainsoni shares common features with L. (V.) guyanensis and braziliensis and seems to be acquired during professional activities in primary forest regions. Phylogenetic analysis has provided information on the intraspecific genetic variability of L. (V.) naiffi and L. (V.) lainsoni and how these genotypes are distributed at the geographic level.

Clinical Presentation and Response to Therapy in Children with Cutaneous Leishmaniasis

Cutaneous leishmaniasis (CL) caused by Leishmania braziliensis occurs predominantly in adult males. Herein, we compare the clinical presentation and the response to antimony therapy of CL in children versus adults. Participants included 571 patients with CL; of these, 129 were children (age ≤ 12 years). Cure was defined as the complete healing of ulcer in the absence of raised borders at day 90 after initiation of therapy. Failure was defined by the presence of an active ulcer or a scar with elevated borders at day 90. In comparison with adults, children had shorter duration of illness, more lesions in the head, and smaller ulcers. Risk factors for therapeutic failure were younger age, shorter duration of disease, higher number of lesions, and larger size of the biggest ulcer. When age was categorized in ≤ 12-year-olds (children versus adults), it predicted therapeutic failure with statistical significance at day 60 but not at day 90. In conclusion, our data indicate that there are significant differences in the clinical presentation of CL between children and adults. Physicians caring for children with CL should be aware that lesions may take longer to heal and remain alert for the possibility of higher odds of therapeutic failure in this group.

Efficacy of Topical Treatment with (-)-Epigallocatechin Gallate, A Green Tea Catechin, in Mice with Cutaneous Leishmaniasis

The treatment of leishmaniasis includes pentavalent antimony drugs but, because of the side effects, toxicity and cases of treatment failure or resistance, the search of new antileishmanial compounds are necessary. The aims of this study were to evaluate and compare the in vitro antileishmanial activity of four green tea catechins, and to assess the efficacy of topical (−)-epigallocatechin gallate in a cutaneous leishmaniasis model. The antileishmanial activity of green tea catechins was evaluated against intracellular amastigotes, and cytotoxicity was performed with human monocytic cell line. BALB/c mice were infected in the ear dermis with Leishmania (Leishmania) amazonensis and treated with topical 15% (−)-epigallocatechin gallate, intraperitoneal Glucantime, and control group. The efficacy of treatments was evaluated by quantifying the parasite burden and by measuring the lesions size. (−)-Epigallocatechin gallate and (−)-epigallocatechin were the most active compounds with IC₅₀ values <59.6 µg/mL and with a selectivity index >1. Topical treatment with (−)-epigallocatechin gallate decreased significantly both lesion size and parasite burden (80.4% inhibition) compared to control group (p < 0.05), and moreover (−)-epigallocatechin gallate showed a similar efficacy to Glucantime (85.1% inhibition), the reference drug for leishmaniasis treatment.

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 Clinicoepidemiological Study of Pediatric Cutaneous Leishmaniasis in Sinjar Province, Iraq

Cutaneous leishmaniasis (CL) is a major health problem worldwide. Although CL is a common disease among children, treatment regimens for the pediatric age group are based on extrapolation of efficacy data in adults. The present study aimed to evaluate the treatment outcome of CL in preschool-age children and the factors influencing the outcome. Two hundred ninety-four children were diagnosed with CL between December 2018 and March 2019 in Sinjar Province, Iraq. All patients were treated with intralesional injections of sodium stibogluconate and followed up for 3 months after the completion of treatment. The treatment success rate was 99% (291/294). A statistically significant association was found between the number of doses per lesion and the number of lesions (P = 0.002; CI = 0.066-0.2875). No association was found between the number of lesions, age, gender, or the presence of livestock and the treatment outcome. In conclusion, treatment success rate was high with the use of intralesional injection of sodium stibogluconate. A significant association was found between the number of lesions and the number of doses. Further studies are required to assess the treatment outcome indicators, including the genotype of leishmania.

Proteomics and Leishmaniasis: Potential Clinical Applications

Leishmaniases are diseases caused by protozoan parasites of the genus Leishmania. They are endemic in 98 countries, affect around 12 million people worldwide and may present several distinct clinical forms. Unfortunately, there are only a few drugs available for treatment of leishmaniasis, which are toxic and not always effective. Different parasite species and different clinical forms require optimization of the treatment or more specific therapies, which are not available. The emergence of resistance is also a matter of concern. Besides, diagnosis can sometimes be complicated due to atypical manifestations and associations with other pathologies. In this review, proteomic data are presented and discussed in terms of their application in important issues in leishmaniasis such as parasite resistance to chemotherapy, diagnosis of active disease in patients and dogs, markers for different clinical forms, identification of virulence factors, and their potential use in vaccination. It is shown that proteomics has contributed to the discovery of potential biomarkers for prognosis, diagnosis, therapeutics, monitoring of disease progression, treatment follow-up and identification of vaccine candidates for specific diseases. However, the authors believe its capabilities have not yet been fully explored for routine clinical analysis for several reasons, which will be presented in this review.

Pharmacometabolomics of Meglumine Antimoniate in Patients With Cutaneous Leishmaniasis

Control of cutaneous leishmaniasis (CL) in the Americas is dependent on chemotherapy with parenteral pentavalent antimonials. High rates of treatment failure urge the search for predictive and prognostic markers of therapeutic responsiveness. In this study, we aimed to identify biomarkers of therapeutic response during treatment with meglumine antimoniate (MA). We conducted untargeted metabolomic profiling of plasma samples from CL patients (n = 39; 25 who cured and 14 who did not cure), obtained before and at the end of treatment. Exposure to MA induced metabolic perturbations primarily reflecting alteration in long-chain fatty acid β-oxidation and energy production. Allantoin, N-acetylglutamine, taurine, and pyruvate were significantly more abundant in samples from patients who responded to treatment, and were predictive and prognostic of treatment outcome in this patient cohort (AUC > 0.7). In an ex vivo model of infection, allantoin but not taurine enhanced the MA-dependent killing of intracellular Leishmania (Viannia) panamensis. Our results support the participation of metabolites mediating antioxidant and wound healing responses in clinical cure of CL, revealing relationships between metabolism and immune responses in the outcome of antileishmanial treatment.

Topical paromomycin for New World cutaneous leishmaniasis

Background

Paromomycin-based topical treatments were shown to be effective in curing cutaneous leishmaniasis (CL) lesions caused by Leishmania major in Tunisia. Cure rates of an index lesion were approximately 80%. As a follow on, we conducted a similar Phase 3 trial in Panama to demonstrate the efficacy of these treatments against New World species. The primary objective was to determine if a combination topical cream (paromomycin-gentamicin) resulted in statistically superior final clinical cure rates of an index lesion compared to a paromomycin alone topical cream for the treatment of CL, primarily caused by Leishmania panamensis.

Methods

We conducted a randomized, double blind, Phase 3 trial of topical creams for the treatment of CL caused by Leishmania spp. Three hundred ninety nine patients with one to ten CL lesions were treated by topical application once daily for 20 days. The primary efficacy endpoint was percentage of subjects with clinical cure of an index lesion confirmed to contain Leishmania with no relapse.

Results

The clinical cure of the index lesion for paromomycin-gentamicin was 79% (95% CI; 72 to 84) and for paromomycin alone was 78% (95% CI; 74 to 87) (p = 0.84). The most common adverse events considered related to study cream application were mild to moderate dermatitis, pain, and pruritus.

Conclusions

Superiority of paromomycin-gentamicin was not demonstrated. However, the approximately 80% cure rates for both topical creams were similar to those demonstrated in Tunisia and previously reported with parenteral antimonials.

Leishmaniasis, a neglected parasitic infection transmitted by the bite of a female sand fly, is endemic in 98 countries or territories with approximately 0.7 to 1.2 million cutaneous leishmaniasis (CL) cases occurring each year. In Panama, most of the CL cases are caused by L. panamensis and, the first line of treatment is pentavalent antimony, given parenterally for 20 days. These systemic regimen is associated with toxicities that can limit the patient from receiving a full course of treatment. Alternative therapies are needed particularly for patients with mild disease, no mucosal involvement, no immunosuppression, and for patients living in areas with scarce infrastructure. Therefore, less toxic, non-parenteral new therapies against CL are urgently needed. We conducted a comparative clinical study that evaluated Paromomycin topical creams (Paromomycin alone versus Paromomycin+Gentamicin) for the treatment of cutaneous leishmaniasis (n = 399) in three sites of country. Our study demonstrated the efficacy of these preparations against New World leishmanial species (mostly L. panamensis) with a cure rate close to 80%.

Our trial supports Paromomycin as a viable alternative treatment for CL caused for the New World Leishmania species.

Interventions to treat cutaneous leishmaniasis in children: A systematic review

BACKGROUND

Case management in children with cutaneous leishmaniasis (CL) is mainly based on studies performed in adults. We aimed to determine the efficacy and harms of interventions to treat CL in children.

METHODS

We conducted a systematic review of clinical trials and cohort studies, assessing treatments of CL in children (≤12 years old). We performed structured searches in PubMed, CENTRAL, LILACS, SciELO, Scopus, the International Clinical Trials Registry Platform (ICTRP), clinicaltrials.gov and Google Scholar. No restrictions regarding ethnicity, country, sex or year of publication were applied. Languages were limited to English, Spanish and Portuguese. Two reviewers screened articles, completed the data extraction and assessment of risk of bias. A qualitative summary of the included studies was performed.

RESULTS

We identified 1092 records, and included 8 manuscripts (6 Randomized Clinical Trials [RCT] and 2 non-randomized studies). Most of the articles excluded in full-text review did not report outcomes separately for children. In American CL (ACL), 5 studies evaluated miltefosine and/or meglumine antimoniate (MA). Their efficacy varied from 68-83% and 17-69%, respectively. In Old-World CL (OWCL), two studies evaluated systemic therapies: rifampicin and MA; and one study assessed efficacy of cryotherapy (42%, Per Protocol [PP]) vs intralesional MA (72%, PP). Few studies (4) provided information on adverse events (AEs) for children, and no serious AEs were reported in participants. Risk of bias was generally low to unclear in ACL studies, and unclear to high in OWCL studies.

CONCLUSION

Information on efficacy of treatment for CL in children is scarce. There is an unmet need to develop specific formulations, surveillance of AEs, and guidelines both for the management of CL and clinical trials involving the pediatric population.

REGISTRATION

The protocol of this review was registered in the PROSPERO International register of systematic reviews, number CRD42017062164.

Intraspecies susceptibility of Leishmania (Viannia) braziliensis to antileishmanial drugs: Antimony resistance in human isolates from atypical lesions

Leishmania (Viannia) braziliensis is the most common etiological agent of cutaneous and mucocutaneous leishmaniasis (MCL) in Latin America. An interesting aspect of the disease outcome caused by this species is the appearance of non-ulcerated atypical cutaneous leishmaniasis. Atypical (AT) lesions are often associated with therapeutic failure when treated with antimony(Sb)-based drugs. Refractory cases are not necessarily due to intrinsic parasite drug resistance. The status of in vitro drug susceptibility from L. braziliensis field isolates is less assessed than patient treatment outcome. In this work, L. braziliensis isolated from typical CL (6), MCL (1) and AT (3) lesions and vector (1) were tested for their susceptibility to amphotericin B (AmB), miltefosine (MIL), glucantime (GLU) and non-comercial meglumine antimoniate (MA). Overall, intracellular amastigotes of all isolates were sensitive to the tested antileishmanial drugs except AT lesions-derived strains 316, 330 and 340 that presented in vitro resistance against Sb^V-based drugs. Although susceptible to miltefosine - based on phenotypic screening - intramacrophagic quiescent amastigotes could restore infection. L. braziliensis promastigotes isolated from AT lesions also displayed 29% reduced capacity to infect human monocyte-derived macrophages when compared with parasites obtained from patients with typical lesions, MCL or from sand-fly. These data indicate differences in drug susceptibility and infectiveness among L. braziliensis isolated from patients exhibiting different types of lesions and highlight the importance of its characterization for drug response prediction outcome in clinical practice.

Eligibility criteria and outcome measures adopted in clinical trials of treatments of cutaneous leishmaniasis: systematic literature review covering the period 1991-2015

OBJECTIVE

To document the sources of heterogeneity in outcomes and shortcomings in trial designs reported by previous systematic reviews.

METHODS

Systematic review of clinical trials of CL treatments published since 1991, to assess and compare eligibility criteria and outcome measures in trials (any type of treatment) of CL (any form) reported before and after the publication of the CONSORT statement.

RESULTS

We identified 106 eligible trials published between 1991 and 2015, 74% after the 2001 CONSORT statement; 58% (n = 63) were on Old-World CL and 37% (n = 40) in New-World CL; overall, 11 531 patients enrolled in 243 treatment groups on 30 different treatments. Both requirements and definitions for eligibility and outcome criteria varied. Compliance with CONSORT requirements increased for studies published after the 2010 update. As for entry criteria, 94% of studies had a requirement for sex (74% of those enrolling also women excluded those who were pregnant or lactating), 69% for age (variable age ranges), 99% parasitological confirmation, 43% prior duration of illness (14% excluded cases with previous episodes), 46% defined the number, 28% the size and 13% the type of lesions (27% with restrictions as to their anatomical location). Follow-up ranged 1-24 months, with 14% and 91% of studies, respectively, having defined initial and final cure.

CONCLUSIONS

This review documents changes in reporting before and after the publication of the CONSORT statement. Lack of standardisation, compounded with the small number of trials relative to the magnitude of the disease in its multiple forms, and with the range of treatments tested explains why evidence to inform treatment guidelines is generally weak for CL. Adopting standardised methodologies will improve the quality and consistency of clinical trials, and ultimately yield better treatments for CL.

Clinical and laboratory profiles of patients with early spontaneous healing in cutaneous localized leishmaniasis: a historical cohort study

BACKGROUND

Skin ulcers in American cutaneous leishmaniasis (ACL) may heal spontaneously after months/years. However, few cases may present quick heal even during diagnosis procedure (early spontaneous healing- ESH). The main objective of this study was to compare ESH patients with cases requiring specific treatment [non-ESH (NESH)].

METHODS

A historical cohort study of ACL patients (n = 445) were divided into 2 groups: ESH - spontaneously healed patients (n = 13; 2.90%), and NESH- treated patients (n = 432; 97.10%). We compared clinical and laboratorial findings at diagnosis, including the lesion healing process.

RESULTS

ESH patients had a higher percentage of single lesions (p = 0.027), epithelialized lesion on initial examination (p = 0.001), lesions located in the dorsal trunk (p = 0.017), besides earlier healing (p < 0.001). NESH presents higher frequency of ulcerated lesions (p = 0.002), amastigotes identified in histopathology exams (p = 0.005), positive cultures (p = 0.001), and higher positivity in ≥3 parasitological exams (p = 0.030). All ESH cases were positive in only a single exam, especially in PCR.

CONCLUSIONS

ESH group apparently presented a lower parasitic load evidenced by the difficulty of parasitological confirmation and its positivity only by PCR method. The absence or deficiency of specific treatment is commonly identified as predisposing factors for recurrence and metastasis in ACL. However, due to the drugs toxicity, the treatment of cases which progress to early spontaneous healing is controversial. ESH patients were followed for up to 5 years after cure, with no evidence of recrudescence, therefore suggesting that not treating these patients is justifiable, but periodic dermatological and otorhinolaryngological examinations are advisable to detect a possible relapse.

American cutaneous leishmaniasis in infancy and childhood

Infant and young child skin diseases are among the most common features of morbidity throughout the tropics. Because the skin is directly exposed to the environment, it is considerably affected by climatic and local conditions such as vectors and microorganisms, as in the case of leishmaniasis. In America the observed magnitude of cutaneous leishmaniasis in children has led to the study of increased risk of exposure of this group due to the possibility of peri- and intradomiciliary transmission. The present review pretends to make a concrete approach all through the broad and main figures of this parasitic disease, including the clinical, physiopathological, epidemiological, diagnostic, and therapeutic aspects, in order to be used as a practical source of reference for pediatricians leading with tropical cutaneous pathology in the region.

Risk factors for therapeutic failure to meglumine antimoniate and miltefosine in adults and children with cutaneous leishmaniasis in Colombia: A cohort study

Introduction

Reports of therapeutic failure to meglumine antimoniate (MA) and miltefosine in cutaneous leishmaniasis (CL) varies between species, populations and geographic regions. This study aimed to determine the clinical, drug-related factors, and Leishmania species associated with treatment failure in children and adults with cutaneous leishmaniasis.

Methods

A cohort study was performed with children (2–12 years old) and adults (18–65 years old) with CL, who have participated in clinical studies at CIDEIM Cali, Tumaco and Chaparral. Incidence of therapeutic failure was estimated by treatment and age groups. Descriptive, bivariate, and multiple logistic regression analyses were performed for the complete cohort and pediatric patients.

Results

Two hundred and thirty patients were included (miltefosine: 112; MA: 118), of which 60.4% were children and 83.9% were infected with L.V. panamensis. Overall incidence of therapeutic failure was 15.65% (95%CI: 10.92–20.38), and was lower for miltefosine than for MA (8.92%, 95%CI: 3.59–14.26 versus 22.03%, 95%CI:14.48–29.58, p = 0.006). Treatment failure was associated with age ≤8 years (OR: 3.29; 95%CI: 1.37–7.89), disease duration ≤1 month (OR: 3.29; 95%CI: 1.37–7.89), regional lymphadenopathy (OR: 2.72; 95%CI: 1.10–6.70), treatment with MA (OR: 3.98; 95%CI: 1.66–9.50), and adherence <90% (OR: 3.59; 95%CI: 1.06–12.11). In children, higher Z-score of height/age was a protective factor (OR: 0.58; 95%CI: 0.36–0.93), while treatment with MA was a risk factor (OR: 40.82; 95%CI: 2.45–677.85), demonstrating significant interaction with age (p = 0.03).

Conclusions

Clinical and drug-related factors determine therapeutic failure in CL. High risk of failure in children treated with MA indicates the need to reconsider this drug as first line treatment in this population.

Trial registration

Clinical trial registration: NCT00487253

Clinical trial registration: NCT01462500

Clinical trial registration: NCT01464242

Cutaneous leishmaniasis (CL) is a parasitic disease that causes chronic, often ulcerated, skin lesions. Treatment require administration of systemic and poorly tolerated drugs, of which, the most commonly used is meglumine antimoniate (MA) injections during 20 days. Although children and adults might have different responses to these drugs, Colombian treatment guidelines recommends meglumine antimoniate for all age groups. In this study, we explored the factors that influence the therapeutic response in children and adults with CL treated with MA and miltefosine. We included 230 children and adults in the analysis, and we found that young age (≤8 years old), presence of regional lymphadenopathy, disease duration ≤1 month, poor adherence to treatment (<90%) were associated with increased odds of treatment failure. Additionally, being treated with MA was a risk factor for therapeutic failure, especially for children. A better nutritional status (higher Z-score of height/age) was a protector factor in pediatric patients. These results highlight the urgent need to reconsider MA as first line treatment in children in Colombia and to evaluate better treatment options for this population.

Cost-effectiveness of meglumine antimoniate versus miltefosine caregiver DOT for the treatment of pediatric cutaneous leishmaniasis

BACKGROUND

Oral miltefosine has been shown to be non-inferior to first-line, injectable meglumine antimoniate (MA) for the treatment of cutaneous leishmaniasis (CL) in children. Miltefosine may be administered via in-home caregiver Directly Observed Therapy (cDOT), while patients must travel to clinics to receive MA. We performed a cost-effectiveness analysis comparing miltefosine by cDOT versus MA for pediatric CL in southwest Colombia.

METHODOLOGY/PRINCIPLE FINDINGS

We developed a Monte Carlo model comparing the cost-per-cure of miltefosine by cDOT compared to MA from patient, government payer, and societal perspectives (societal = sum of patient and government payer perspective costs). Drug effectiveness and adverse events were estimated from clinical trials. Healthcare utilization and costs of travel were obtained from surveys of providers and published sources. The primary outcome was cost-per-cure reported in 2015 USD. Treatment efficacy, costs, and adherence were varied in sensitivity analysis to assess robustness of results. Treatment with miltefosine resulted in substantially lower cost-per-cure from a societal and patient perspective, and slightly higher cost-per-cure from a government payer perspective compared to MA. Mean societal cost-per-cure were $531 (SD±$239) for MA and $188 (SD±$100) for miltefosine, a mean cost-per-cure difference of +$343. Mean cost-per-cure from a patient perspective were $442 (SD ±$233) for MA and $30 (SD±$16) for miltefosine, a mean difference of +$412. Mean cost-per-cure from a government perspective were $89 (SD±$55) for MA and $158 (SD±$98) for miltefosine, with a mean difference of -$69. Results were robust across a variety of assumptions in univariate and multi-way analysis.

CONCLUSIONS/SIGNIFICANCE

Treatment of pediatric cutaneous leishmaniasis with miltefosine via cDOT is cost saving from patient and societal perspectives, and moderately more costly from the government payer perspective compared to treatment with MA. Results were robust over a range of sensitivity analyses. Lower drug price for miltefosine could result in cost saving from a government perspective.

In Vitro Sensitivity of Cutaneous Leishmania Promastigote Isolates Circulating in French Guiana to a Set of Drugs

AbstractAnti-leishmaniasis drug resistance is a common problem worldwide. The aim of this study was to inventory the general in vitro level of sensitivity of Leishmania isolates circulating in French Guiana and to highlight potential in vitro pentamidine-resistant isolates. This sensitivity study was conducted on 36 patient-promastigote isolates for seven drugs (amphotericin B, azithromycin, fluconazole, meglumine antimoniate, miltefosine, paromomycin, and pentamidine) using the Cell Counting Kit-8 viability test. The IC₅₀ values obtained were heterogeneous. One isolate exhibited high IC₅₀ values for almost all drugs tested. Pentamidine, which is the first-line treatment in French Guiana, showed efficacy at very low doses (mean of 0.0038 μg/mL). The concordance of the in vitro pentamidine results with the patients' clinical outcomes was 94% (K = 0.82).

Ornithine decarboxylase or gamma-glutamylcysteine synthetase overexpression protects Leishmania (Vianna) guyanensis against antimony

Trypanosomatids present a unique mechanism for detoxification of peroxides that is dependent on trypanothione (bisglutathionylspermidine). Ornithine decarboxylase (ODC) and γ-glutamylcysteine synthetase (GSH1) produce molecules that are direct precursors of trypanothione. In this study, Leishmania guyanensis odc and gsh1 overexpressor cell lines were generated to investigate the contribution of these genes to the trivalent antimony (Sb^III)-resistance phenotype. The ODC- or GSH1-overexpressors parasites presented an increase of two and four-fold in Sb^III-resistance index, respectively, when compared with the wild-type line. Pharmacological inhibition of ODC and GSH1 with the specific inhibitors α-difluoromethylornithine (DFMO) and buthionine sulfoximine (BSO), respectively, increased the antileishmanial effect of Sb^III in all cell lines. However, the ODC- and GSH1-overexpressor were still more resistant to Sb^III than the parental cell line. Together, our data shows that modulation of ODC and GSH1 levels and activity is sufficient to affect L. guyanensis susceptibility to Sb^III, and confirms a role of these genes in the Sb^III-resistance phenotype.

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.

Insights into the structural patterns of the antileishmanial activity of bi- and tricyclic N-heterocycles

The influence of various structural patterns in a series of novel bi- and tricyclic N-heterocycles on the activity against Leishmania major and Leishmania panamensis has been studied and compounds that are active in the low micromolar region have been identified. Both quinolines and tetrahydrooxazinoindoles (TOI) proved to have significant antileishmanial activities, while substituted indoles were inactive. We have also showed that a chloroquine analogue induces Leishmania killing by modulating macrophage activation.

In vitro characterization of Leishmania (Viannia) braziliensis isolates from patients with different responses to Glucantime(®) treatment from Northwest Paraná, Brazil

Leishmaniasis is a group of diseases that presents various clinical manifestations. Many studies have shown that the parasite plays an important role in the clinical manifestations and prognosis of this disease. The cutaneous and mucosal forms of American tegumentary leishmaniasis (ATL) are associated with Leishmania (Viannia) braziliensis, which exhibits intraspecific genetic polymorphisms and various clinical manifestations. The present study focused on four different L. braziliensis strains that were isolated from patients with distinct Glucantime(®) treatment responses. The isolates were described based on their molecular, biological, and infective characteristics. Growth patterns in culture medium and different grow phases were analyzed, MID-Logarithimic (Mid-LOG), Logarithimic (LOG) and Stationary (STAT) phases. Complement resistance was evaluated using guinea pig serum. Infection to murine peritoneal macrophages, cytokine and nitric oxide were analyzed. Ultrastructural features were determined by transmission electron microscopy, and molecular characteristics were determined based on random amplified polymorphic DNA (RAPD). All of the L. braziliensis isolates showed typical growth and similar complement sensitivity patterns. Markedly lower infectivity indexes were observed for all strains in the LOG phase, with different cytokine profiles. The ultrastructure analysis revealed distinct differences between the MID-LOG, LOG, and STAT phases. The RAPD results showed a divergence between the isolates of the L. braziliensis. The in vitro characterization of L. braziliensis isolates from humans with different treatment responses using various parameters enabled us to observe differences among the isolates. Molecular and in vivo characterizations are currently under study to improve understanding of the parasite-host interaction that can imply in the clinical manifestation differences.

AMERICAN CUTANEOUS LEISHMANIASIS WITH UNUSUAL CLINICAL PRESENTATION AND RESPONSE TO TREATMENT

The clinical manifestations and prognosis of cutaneous leishmaniasis (CL) can be influenced by the immune response of the patient and the species of the parasite. A case of atypical clinical presentation of CL, with development of non-characteristic lesions, poor response to therapy, and a long time to resolution is reported. Confirmatory laboratory tests included parasite detection, indirect immunofluorescence, Montenegro skin test, polymerase chain reaction, and parasite identification by multilocus enzyme electrophoresis. The parasite was identified as Leishmaniabraziliensis. The lesion was unresponsive to three complete courses of N-methylglucamine antimoniate intramuscular, and to treatment with pentamidine. The patient did not tolerate amphotericin B. The lesion finally receded after treatment with intravenous N-methylglucamine antimoniate. It is essential to ensure the accuracy of diagnosis and the appropriate treatment, which can include the use a second choice drug or a different route of administration.

Association of the Endobiont Double-Stranded RNA Virus LRV1 With Treatment Failure for Human Leishmaniasis Caused by Leishmania braziliensis in Peru and Bolivia

Cutaneous and mucosal leishmaniasis, caused in South America by Leishmania braziliensis, is difficult to cure by chemotherapy (primarily pentavalent antimonials [Sb(V)]). Treatment failure does not correlate well with resistance in vitro, and the factors responsible for treatment failure in patients are not well understood. Many isolates of L. braziliensis (>25%) contain a double-stranded RNA virus named Leishmaniavirus 1 (LRV1), which has also been reported in Leishmania guyanensis, for which an association with increased pathology, metastasis, and parasite replication was found in murine models. Here we probed the relationship of LRV1 to drug treatment success and disease in 97 L. braziliensis-infected patients from Peru and Bolivia. In vitro cultures were established, parasites were typed as L. braziliensis, and the presence of LRV1 was determined by reverse transcription-polymerase chain reaction, followed by sequence analysis. LRV1 was associated significantly with an increased risk of treatment failure (odds ratio, 3.99; P = .04). There was no significant association with intrinsic Sb(V) resistance among parasites, suggesting that treatment failure arises from LRV1-mediated effects on host metabolism and/or parasite survival. The association of LRV1 with clinical drug treatment failure could serve to guide more-effective treatment of tegumentary disease caused by L. braziliensis.

Intrachromosomal amplification, locus deletion and point mutation in the aquaglyceroporin AQP1 gene in antimony resistant Leishmania (Viannia) guyanensis

BACKGROUND

Antimony resistance complicates the treatment of infections caused by the parasite Leishmania.

METHODOLOGY/PRINCIPAL FINDINGS

Using next generation sequencing, we sequenced the genome of four independent Leishmania guyanensis antimony-resistant (SbR) mutants and found different chromosomal alterations including aneuploidy, intrachromosomal gene amplification and gene deletion. A segment covering 30 genes on chromosome 19 was amplified intrachromosomally in three of the four mutants. The gene coding for the multidrug resistance associated protein A involved in antimony resistance was also amplified in the four mutants, most likely through chromosomal translocation. All mutants also displayed a reduced accumulation of antimony mainly due to genomic alterations at the level of the subtelomeric region of chromosome 31 harboring the gene coding for the aquaglyceroporin 1 (LgAQP1). Resistance involved the loss of LgAQP1 through subtelomeric deletions in three mutants. Interestingly, the fourth mutant harbored a single G133D point mutation in LgAQP1 whose role in resistance was functionality confirmed through drug sensitivity and antimony accumulation assays. In contrast to the Leishmania subspecies that resort to extrachromosomal amplification, the Viannia strains studied here used intrachromosomal amplification and locus deletion.

CONCLUSIONS/SIGNIFICANCE

This is the first report of a naturally occurred point mutation in AQP1 in antimony resistant parasites.

Therapeutic options for old world cutaneous leishmaniasis and new world cutaneous and mucocutaneous leishmaniasis

Estimated worldwide incidence of tegumentary leishmaniasis (cutaneous leishmaniasis [CL] and mucocutaneous leishmaniasis [MCL]) is over 1.5 million cases per year in 82 countries, with 90 % of cases occurring in Afghanistan, Brazil, Iran, Peru, Saudi Arabia and Syria. Current treatments of CL are poorly justified and have sub-optimal effectiveness. Treatment can be based on topical or systemic regimens. These different options must be based on Leishmania species, geographic regions, and clinical presentations. In certain cases of Old World CL (OWCL), lesions can spontaneously heal without any need for therapeutic intervention. Local therapies (thermotherapy, cryotherapy, paromomycin ointment, local infiltration with antimonials) are good options with less systemic toxicity, reserving systemic treatments (azole drugs, miltefosine, antimonials, amphotericin B formulations) mainly for complex cases. The majority of New World CL (NWCL) types require systemic treatment (mainly with pentavalent antimonials), either to speed the healing or to prevent dissemination to oral-nasal mucosa as MCL (NWMCL). These types of lesions are potentially serious and always require systemic-based regimens, mainly antimonials and pentamidine; however, the associated immunotherapy is promising. This paper is an exhaustive review of the published literature on the treatment of OWCL, NWCL and NWMCL, and provides treatment recommendations stratified according to their level of evidence regarding the species of Leishmania implicated and the geographical location of the infection.

Species-directed therapy for leishmaniasis in returning travellers: a comprehensive guide

Background

Leishmaniasis is increasingly reported among travellers. Leishmania species vary in sensitivity to available therapies. Fast and reliable molecular techniques have made species-directed treatment feasible. Many treatment trials have been designed poorly, thus developing evidence-based guidelines for species-directed treatment is difficult. Published guidelines on leishmaniasis in travellers do not aim to be comprehensive or do not quantify overall treatment success for available therapies. We aimed at providing comprehensive species-directed treatment guidelines.

Methodology/Principal Findings

English literature was searched using PubMed. Trials and observational studies were included if all cases were parasitologically confirmed, the Leishmania species was known, clear clinical end-points and time points for evaluation of treatment success were defined, duration of follow-up was adequate and loss to follow-up was acceptable. The proportion of successful treatment responses was pooled using mixed effects methods to estimate the efficacy of specific therapies. Final ranking of treatment options was done by an expert panel based on pooled efficacy estimates and practical considerations. 168 studies were included, with 287 treatment arms. Based on Leishmania species, symptoms and geography, 25 clinical categories were defined and therapy options ranked. In 12/25 categories, proposed treatment agreed with highest efficacy data from literature. For 5/25 categories no literature was found, and in 8/25 categories treatment advise differed from literature evidence. For uncomplicated cutaneous leishmaniasis, combination of intralesional antimony with cryotherapy is advised, except for L. guyanensis and L. braziliensis infections, for which systemic treatment is preferred. Treatment of complicated (muco)cutaneous leishmaniasis differs per species. For visceral leishmaniasis, liposomal amphotericin B is treatment of choice.

Conclusions/Significance

Our study highlights current knowledge about species-directed therapy of leishmaniasis in returning travellers and also demonstrates lack of evidence for treatment of several clinical categories. New data can easily be incorporated in the presented overview. Updates will be of use for clinical decision making and for defining further research.

Human leishmaniasis is caused by unicellular parasites that are injected into the skin by sand-flies, small, flying insects. Many different Leishmania species cause various manifestations of disease, both of the skin and internal organs. Leishmaniasis is a curable disease but clear guidelines on the best available treatment are lacking. Leishmania species differ in sensitivity to available drugs. Until recently, identification of the infecting Leishmania parasite was laborious, thus therapy could not precisely be targeted to the infecting species, in contrast to many other infectious diseases. Nowadays, Leishmania parasites can be identified relatively easily with new DNA techniques. We studied efficacy of therapies for diseases due to different Leishmania species, limited to the English literature. Efficacy was summarized and presented in an easy to read format. Because of difficulties with identification of parasite species in earlier studies, quality of evidence was often limited. Our findings are a major help for clinicians to easily find optimal treatment for specific patients. Moreover, our results demonstrate where additional research is needed to further improve treatment of leishmaniasis.

Pharmacokinetics of experimental pentavalent antimony after intramuscular administration in adult volunteers

BACKGROUND

Pentavalent antimony (SbV) has demonstrated therapeuticeffectiveness against clinical manifestations of leishmaniasis, an infection caused by Leishmania, a genus of flagellate protozoa comprising parasites of worldwide distribution. Approximately 1.8 million new cases are reported annually.

OBJECTIVE

The aim of this study was to assess the pharmacokinetics of the investigational generic SbV, Ulamina (pentachloride of antimony + N-methylglucamine), in healthy adult volunteers.

METHODS

In this study, SbV was administered IM as a single 5-mg/kg dose.Blood samples were collected at 0.25, 0.75, 1, 2, 4, 8, 12, and 24 hours after administration; urine samples were collected at 6-hour intervals during the 24-hour postadministration period. Determination of trivalent antimony, SbV, and total antimony concentrations in blood and urine samples was carried out using atomic absorption spectrometry. Clinical history was reviewed and the subjects were monitored before and after administration of SbV using physical examination, weight, and hepatic- and renal-function studies. The pharmacokinetic parameters calculated were Cmax, Tmax, absorption constant (Ka), elimination constant (Kel), AUC2-24h, AUC0-∞, elimination phase (t½β), volume of distribution (Vd), and urinary excretion rate.

RESULTS

Five subjects (3 men, 2 women; mean age, 28 years [range, 18-34 years]) were included in the study. One hour after drug administration the following values were obtained: Cmax, 1.1 μg/mL; Tmax, 1.3 hours; Ka, 1.87 hours; Kel, 0.043 hours; AUC0-24h, 12.26 μg/mL · h; AUC0-∞, 19.84 μg/mL · h; t½β, 17.45 hours; Vd, 6.6 L/kg; and urinary excretion rate, 2.8 μg/h; these were mean values for the entire study group. The single dose was well tolerated by all subjects.

CONCLUSIONS

The investigational generic SbV, Ulamina, was associated with linearelimination after IM administration of a single 5-mg/kg dose. A 2-compartment pharmacokinetic model was observed in these volunteers; the mean t½β, was 17.45 hours and the mean Vd was 6.6 L/kg.

Proteomics advances in the study of Leishmania parasites and leishmaniasis

Leishmania spp. are digenetic parasites which cause a broad spectrum of fatal diseases in humans. These parasites, as well as the other trypanosomatid, regulate gene expression at the post-transcriptional and post-translational levels, so that a poor correlation is observed between mRNA content and translated proteins. The completion of the genomic sequencing of several Leishmania species has enormous relevance to the study of the leishmaniasis pathogenesis. The combination of the available genomic resources of these parasites with powerful high-throughput proteomic analysis has shed light on various aspects of Leishmania biology as well as on the mechanisms underlying the disease. Diverse proteomic approaches have been used to describe and catalogue global protein profiles of Leishmania spp., reveal changes in protein expression during development, determine the subcellular localization of gene products, evaluate host-parasite interactions and elucidate drug resistance mechanisms. The characterization of these proteins has advanced, although many fundamental questions remain unanswered. Here, we present a historic review summarizing the different proteomic technologies applied to the study of Leishmania parasites during the last decades and we discuss the proteomic discoveries that have contributed to the understanding of Leishmania parasites biology and leishmaniasis.

Generic sodium stibogluconate is as safe and effective as branded meglumine antimoniate, for the treatment of tegumentary leishmaniasis in Isiboro Secure Park, Bolivia

Human cutaneous leishmaniasis (CL) and mucous leishmaniasis (ML) are highly endemic in Isiboro Secure Park, which lies in the Bolivian department of Cochabamba--an area where branded meglumine antimoniate (Glucantime) is expensive and poorly distributed. The safety and efficacy of generic sodium stibogluconate (SSG), from Albert David Ltd, was therefore explored, in CL and ML cases from the park, who were treated with 20 mg/kg.day for 20 and 30 days, respectively. A questionnaire recording adverse effects was completed by a physician in each treatment centre. Efficacy of treatment was assessed at the end of treatment and at follow-ups 1 month and 3, 6 and 12 months later. Overall, 146 patients completed treatment with SSG in 2003-2004. No fatalities or severe adverse effects were reported but mild to moderate adverse effects were noted in 41 (28%) of the patients. The incidence of adverse effects was significantly higher among the cases of ML than among the cases of CL. Of the 86 patients with CL who completed 6 months of follow-up, 81 (94.2%) were considered to have been clinically cured; a comparable cohort of 69 CL cases who had been treated with Glucantime in 2001-2002 showed a similar frequency of clinical cure (90%). Generic SSG was shown to be safe and efficacious for the treatment of tegumentary leishmaniasis in Bolivia. Being several times cheaper than Glucantime, it could contribute to improving the access of CL and ML patients to treatment, not only in Bolivia but also in other countries of Latin America.

Clinical and epidemiologic profile of cutaneous leishmaniasis in Colombian children: considerations for local treatment

Treatment alternatives have seldom been evaluated in children with cutaneous leishmaniasis (CL). We examine the clinical/epidemiological profile of children with CL considering international guidelines for local treatment. Descriptive analyses were conducted using International Center for Medical Research and Training (CIDEIM) case reports of parasitologically diagnosed patients ≤ 14 years of age from 2004 to 2010. Eligibility for local treatment based on World Health Organization/Pan American Health Organization (WHO/PAHO) criteria was determined. Among 380 children, 90% presented lesions of < 3 months duration, 54% presented single lesions < 30 mm in diameter, and 45% were ≤ 5 years old. Lesions on the head and neck were more frequent among children 0-5 years, and lesions below the head/neck were more frequent among 11- to 14-year-old children (P = 0.004). Using PAHO and WHO criteria, 26% and 53% of children, respectively, were eligible for local treatment. Recommended local treatments for New World CL have potential but limited applicability in children. Individual risk-benefit assessment and effectiveness data in children may increase eligibility.

Interventions for American cutaneous and mucocutaneous leishmaniasis: a systematic review update

Introduction

Leishmaniasis is an important public health problem in the Americas. A Cochrane review published in 2009 analyzed 38 randomized controlled trials (RCT). We conducted a systematic review to evaluate the effects of therapeutic interventions for American cutaneous and mucocutaneous leishmaniasis.

Methods

All studies were extracted from PubMed, Embase, Lilacs (2009 to July, 2012 respectively), the Cochrane Central Register of Controlled Trials (6-2012) and references of identified publications. RCTs’ risk of bias was assessed.

Results

We identified 1865 references of interest; we finally included 10 new RCTs. The risk of bias scored low or unclear for most domains. Miltefosine was not significantly different from meglumine antimoniate in the complete cure rate at 6 months (4 RCT; 584 participants; ITT; RR: 1.12; 95%CI: 0.85 to 1.47; I2 78%). However a significant difference in the rate of complete cure favoring miltefosine at 6 months was found in L. panamensis and L. guyanensis (2 RCTs, 206 participants; ITT; RR: 1.22; 95%CI: 1.02 to 1.46; I2 0%). One RCT found that meglumine antimoniate was superior to pentamidine in the rate of complete cure for L. braziliensis (80 participants, ITT; RR: 2.21; 95%CI: 1.41 to 3.49), while another RCT assessing L. guyanensis did not find any significant difference. Although meta-analysis of three studies found a significant difference in the rate of complete cure at 3 months favoring imiquimod versus placebo (134 participants; ITT; RR: 1.45; 95%CI: 1.12 to 1.88; I2 0%), no significant differences were found at 6 and 12 months. Thermotherapy and nitric oxide were not superior to meglumine antimoniate.

Conclusion

Therapeutic interventions for American cutaneous and mucocutaneous leishmaniasis are varied and should be decided according to the context. Since mucosal disease is the more neglected form of leishmaniasis a multicentric trial should be urgently considered.

IL-17 mediates immunopathology in the absence of IL-10 following Leishmania major infection

Leishmaniasis, resulting from infection with the protozoan parasite Leishmania, consists of a wide spectrum of clinical manifestations, from healing cutaneous lesions to fatal visceral infections. A particularly severe form of cutaneous leishmaniasis, termed mucosal leishmaniasis, exhibits decreased IL-10 levels and an exaggerated inflammatory response that perpetuates the disease. Using a mouse model of leishmaniasis, we investigated what cytokines contribute to increased pathology when IL-10-mediated regulation is absent. Leishmania major infected C57BL/6 mice lacking IL-10 regulation developed larger lesions than controls, but fewer parasites. Both IFN-γ and IL-17 levels were substantially elevated in mice lacking the capacity to respond to IL-10. IFN-γ promoted an increased infiltration of monocytes, while IL-17 contributed to an increase in neutrophils. Surprisingly, however, we found that IFN-γ did not contribute to increased pathology, but instead regulated the IL-17 response. Thus, blocking IFN-γ led to a significant increase in IL-17, neutrophils and disease. Similarly, the production of IL-17 by cells from leishmaniasis patients was also regulated by IL-10 and IFN-γ. Additional studies found that the IL-1 receptor was required for both the IL-17 response and increased pathology. Therefore, we propose that regulating IL-17, possibly by downregulating IL-1β, may be a useful approach for controlling immunopathology in leishmaniasis.

Leishmaniasis is a tropical disease transmitted by sand flies that causes visceral and cutaneous lesions. In humans, the most severe form of cutaneous leishmaniasis is the mucosal form, causing disfiguring lesions in the nasal and oral mucosa. Why these patients develop severe disease is not clear. It is known, however, that the severe disease is not due to an overwhelming number of parasites, but rather appears to be due to an uncontrolled inflammatory response that includes elevated production of IFN-γ and IL-17. Here, we used a murine model of leishmaniasis to identify the factors involved in this pathology, and found that mice infected with Leishmania major developed severe lesions in the absence of IL-10 or IL-10 signaling, and similar to patients, contained high levels of IFN-γ and IL-17. While both of these cytokines have the potential to induce pathology, we found that IL-17 was responsible for the severe pathology seen in the absence of IL-10 regulation, and furthermore that IL-17 levels were higher and pathology greater in the absence of IFN-γ. Thus, our study suggests that IL-17, but not the IFN-γ, is a strong candidate to be targeted in strategies to control the severe immunopathology observed in mucosal leishmaniasis patients.

Methodology of clinical trials aimed at assessing interventions for cutaneous leishmaniasis

The current evidence-base for recommendations on the treatment of cutaneous leishmaniasis (CL) is generally weak. Systematic reviews have pointed to a general lack of standardization of methods for the conduct and analysis of clinical trials of CL, compounded with poor overall quality of several trials. For CL, there is a specific need for methodologies which can be applied generally, while allowing the flexibility needed to cover the diverse forms of the disease. This paper intends to provide clinical investigators with guidance for the design, conduct, analysis and report of clinical trials of treatments for CL, including the definition of measurable, reproducible and clinically-meaningful outcomes. Having unified criteria will help strengthen evidence, optimize investments, and enhance the capacity for high-quality trials. The limited resources available for CL have to be concentrated in clinical studies of excellence that meet international quality standards.

Solid evidence is needed to decide how to treat conditions. In the case of cutaneous leishmaniasis, the diversity of clinical conditions, combined with the heterogeneity and weaknesses of the methodologies used in clinical trials, make it difficult to derive robust conclusions as to which treatments should be used. There also other imperatives - ethical (not exposing patients to treatments that cannot be assessed adequately) and financial (optimize use of limited resources for a neglected condition). This paper is meant to provide clinical investigators with guidance for the design, conduct, analysis and report of clinical trials to assess the efficacy and safety of treatments of this condition.