Immunochemotherapy for cutaneous leishmaniasis: a controlled trial using killed Leishmania (Leishmania) amazonensis vaccine plus antimonial

Immunotherapeutic Strategies as Potential Treatment Options for Cutaneous Leishmaniasis

Cutaneous leishmaniasis (CL), caused by protozoan parasites of the Leishmania genus, is prevalent in tropical and subtropical regions, with important morbidity, particularly in low- to middle-income countries. Current systemic treatments, including pentavalent antimonials and miltefosine, are associated with significant toxicity, reduced efficacy, and are frequently ineffective in cases of severe or chronic CL. Immunotherapies leverage the immune system to combat microbial infection and offer a promising adjunct or alternative approach to the current standard of care for CL. However, the heterogeneous clinical presentation of CL, which is dependent on parasite species and host immunity, may require informed clinical intervention with immunotherapies. This review explores the clinical and immunological characteristics of CL, emphasising the current landscape of immunotherapies in in vivo models and clinical studies. Such immune-based interventions aim to modulate immune responses against Leishmania, with additive therapeutic effects enabling the efficacy of lower drug doses and decreasing the associated toxicity. Understanding the mechanisms that underlie immunotherapy for CL provides critical insights into developing safer and more effective treatments for this neglected tropical disease. Identifying suitable therapeutic candidates and establishing their safety and efficacy are essential steps in this process. However, the feasibility and utility of these treatments in resource-limited settings must also be considered, taking into account factors such as cost of production, temperature stability, and overall patient access.

Immunoregulatory effects of soluble antigens of Leishmania sp. in human lymphocytes in vitro

The clinical manifestations of cutaneous leishmaniasis (CL) depend not only on the infecting species involved, but also on the immune response of the individual. Although not yet well understood in humans, parasite survival and persistence are related to the cytokine profile and T cell proliferation, with the Th1 profile being related to cure, and the Th2 profile to disease progression. Considering the need for studies focused on the species with the highest circulation in the state of Amazonas, this study aimed to analyze the immunoregulation stimulated by soluble antigens (SLAs) of Leishmania (L.) amazonensis and Leishmania (V.) guyanensis in human lymphocytes in vitro, in order to understand the immune response of patients with CL. Lymphoproliferation was evaluated against stimuli of SLAs from L. amazonensis (100 µg/mL), SLAs from L. guyanensis (100 µg/mL) and phytohemagglutinin (10 µg/mL) using a BrdU Cell Proliferation ELISA kit after 72 h of incubation. Quantification of the cytokines IL-1b, IL-6, IL-8, IL-10, IL-12 and TNF was performed using the BD™ cytometric bead array human Th1/Th2/Th17 cytokine kit. Our results demonstrated that soluble antigens from L. amazonensis and L. guyanensis stimulated the lymphoproliferation of PBMCs from patients primo-infected with CL. Among the cytokines dosed, the highest concentrations were of IL-6 and IL-8, thus demonstrating that the soluble antigens evaluated are capable of inducing regulatory mechanisms.

Field-Deployable Treatments For Leishmaniasis: Intrinsic Challenges, Recent Developments and Next Steps

Leishmaniasis is a neglected tropical disease endemic primarily to low- and middle-income countries, for which there has been inadequate development of affordable, safe, and efficacious therapies. Clinical manifestations of leishmaniasis range from self-healing skin lesions to lethal visceral infection with chances of relapse. Although treatments are available, secondary effects limit their use outside the clinic and negatively impact the quality of life of patients in endemic areas. Other non-medicinal treatments, such as thermotherapies, are limited to use in patients with cutaneous leishmaniasis but not with visceral infection. Recent studies shed light to mechanisms through which Leishmania can persist by hiding in cellular safe havens, even after chemotherapies. This review focuses on exploring the cellular niches that Leishmania parasites may be leveraging to persist within the host. Also, the cellular, metabolic, and molecular implications of Leishmania infection and how those could be targeted for therapeutic purposes are discussed. Other therapies, such as those developed against cancer or for manipulation of the ferroptosis pathway, are proposed as possible treatments against leishmaniasis due to their mechanisms of action. In particular, treatments that target hematopoietic stem cells and monocytes, which have recently been found to be necessary components to sustain the infection and provide a safe niche for the parasites are discussed in this review as potential field-deployable treatments against leishmaniasis.

Vaccination in Leishmaniasis: A Review Article

Leishmaniasis is caused by protozoan Leishmania parasites that are transmitted through female sandfly bites. The disease is predominantly endemic to the tropics and semi-tropics and has been reported in more than 98 countries. Due to the side effects of anti-Leishmania drugs and the emergence of drug-resistant isolates, there is currently no encouraging prospect of introducing an effective therapy for the disease. Hence, it seems that the key to disease control management is the introduction of an effective vaccine, particularly against its cutaneous form. Advances in understanding underlying immune mechanisms are feasibale using a variety of candidate antigens, including attenuated live parasites, crude antigens, pure or recombinant Leishmania proteins, Leishmania genes encoding protective proteins, as well as immune system activators from the saliva of parasite vectors. However, there is still no vaccine against different types of human leishmaniasis. In this study, we review the works conducted or being performed in this field.

Comparative assessment of interventions for treating cutaneous leishmaniasis: A network meta-analysis of randomized clinical trials

INTRODUCTION

Various interventions including laser therapy, heat therapy, and several drugs have been trialed in patients with cutaneous leishmaniasis. Due to the lack of an evidence-based comparison of all these interventions, we carried out the present network meta-analysis.

METHODS

Electronic databases were searched for randomized clinical trials evaluating the efficacy and safety of any interventions in patients with cutaneous leishmaniasis. The proportion of patients with complete cure was the primary outcome. The proportion of lesions cured at the end of treatment, the proportion of lesions with minimal/no response to treatment, and proportion of wounds with minimal/no change were the secondary outcomes. Random-effects modeling was used for generating pooled estimates. Rankogram plot was used for identifying the 'best intervention'. For interventions containing a combination of treatments, backslash (/) has been used for depicting the same.

RESULTS

One-hundred and thirty-one studies were included. Intralesional meglumine, topical paromomycin/gentamicin, topical paromomycin, parenteral sodium stibogluconate, topical honey/intralesional meglumine, topical liposomal amphotericin B, oral zinc sulphate, oral miltefosine, parenteral meglumine, heat therapy, topical liposomal azithromycin, intralesional meglumine/silver dressing, intralesional sodium stibogluconate, parenteral meglumine/intralesional meglumine, oral allopurinol/parenteral meglumine, topical trichloroacetic acid/heat therapy, oral zinc sulphate/oral ketoconazole, topical imiquimod/cryotherapy, intralesional meglumine/cryotherapy, topical herbal extract of Z-HE, parenteral pentamidine, topical trichloroacetic acid/intralesional meglumine, carbon-dioxide laser, topical recombinant granulocyte-macrophage colony-stimulating factor/parenteral meglumine, intralesional dapsone, carbon-dioxide laser/intralesional meglumine, moist wet dressing with sodium hypochlorite, parenteral sodium stibogluconate/intralesional recombinant granulocyte-macrophage colony-stimulating factor, oral dapsone, intralesional sodium stibogluconate/oral ketoconazole, intralesional sodium stibogluconate/parenteral sodium stibogluconate and electrocautery/moist wet dressing with sodium hypochlorite were observed with significantly greater proportion of patients with complete cure compared to placebo/untreated controls. Rankogram analysis revealed that parenteral pentamidine has the highest statistical probability of being the best in the pool.

CONCLUSION

We observed several interventions to be effective for treating cutaneous leishmaniasis. However, greater caution is required in interpreting the results as the estimates are likely to change with the advent of results from future studies.

Three decades of clinical trials on immunotherapy for human leishmaniases: a systematic review and meta-analysis

Aim: Current treatments for leishmaniases are not satisfactory, thus alternatives are needed. We searched for clinical trials with immunotherapeutic approaches for patients with leishmaniasis. Materials & methods: Out of 205 articles, 24 clinical trials were selected, and eight submitted to meta-analysis. Results: A reduction in healing time was observed in patients with tegumentary leishmaniasis treated with pentavalent antimony plus granulocyte-macrophage colony-stimulating factor, and therapeutic vaccines. Overall meta-analysis indicated that immunotherapy associated with the standard chemotherapy generated a significantly reduced risk of treatment failure than the pentavalent antimony alone (p = 0.03). Conclusion: Our review confirmed the efficacy of immunotherapies for the treatment of cutaneous and visceral leishmaniasis and highlighted the importance of clinical trials using immunotherapies for leishmaniases.

Safety and immunogenicity of ChAd63-KH vaccine in post-kala-azar dermal leishmaniasis patients in Sudan

Post-kala-azar dermal leishmaniasis (PKDL) is a chronic, stigmatizing skin condition occurring frequently after apparent clinical cure from visceral leishmaniasis. Given an urgent need for new treatments, we conducted a phase IIa safety and immunogenicity trial of ChAd63-KH vaccine in Sudanese patients with persistent PKDL. LEISH2a (ClinicalTrials.gov: NCT02894008) was an open-label three-phase clinical trial involving sixteen adult and eight adolescent patients with persistent PKDL (median duration, 30 months; range, 6-180 months). Patients received a single intramuscular vaccination of 1 × 10¹⁰ viral particles (v.p.; adults only) or 7.5 × 10¹⁰ v.p. (adults and adolescents), with primary (safety) and secondary (clinical response and immunogenicity) endpoints evaluated over 42-120 days follow-up. AmBisome was provided to patients with significant remaining disease at their last visit. ChAd63-KH vaccine showed minimal adverse reactions in PKDL patients and induced potent innate and cell-mediated immune responses measured by whole-blood transcriptomics and ELISpot. 7/23 patients (30.4%) monitored to study completion showed >90% clinical improvement, and 5/23 (21.7%) showed partial improvement. A logistic regression model applied to blood transcriptomic data identified immune modules predictive of patients with >90% clinical improvement. A randomized controlled trial to determine whether these clinical responses were vaccine-related and whether ChAd63-KH vaccine has clinical utility is underway.

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.

Protective Cellular Immune Response Induction for Cutaneous Leishmaniasis by a New Immunochemotherapy Schedule

The palladacycle complex DPPE 1.2 was previously shown to inhibit Leishmania (Leishmania) amazonensis infection in vitro and in vivo. The present study aimed to evaluate the effect of DPPE 1.2 associated with a recombinant cysteine proteinase, rLdccys1, and the adjuvant Propionibacterium acnes on L. (L.) amazonensis infection in two mouse strains, BALB/c, and C57BL/6. Treatment with this association potentiated the leishmanicidal effect of DPPE 1.2 resulting in a reduction of parasite load in both strains of mice which was higher compared to that found in groups treated with either DPPE 1.2 alone or associated with P. acnes or rLdccys1. The reduction of parasite load in both mice strains was followed by immunomodulation mediated by an increase of memory CD4⁺ and CD8⁺ T lymphocytes, IFN-γ levels and reduction of active TGF-β in treated animals. No infection relapse was observed 1 month after the end of treatment in mice which received DPPE 1.2 associated with rLdccys1 or rLdccys1 plus P. acnes in comparison to that exhibited by animals treated with DPPE 1.2 alone. Evaluation of serum levels of AST, ALT, urea, and creatinine showed no alterations among treated groups, indicating that this treatment schedule did not induce hepato or nephrotoxicity. These data indicate the potential use of this association as a therapeutic alternative for cutaneous leishmaniasis caused by L. (L) amazonensis.

CpG ODN D35 improves the response to abbreviated low-dose pentavalent antimonial treatment in non-human primate model of cutaneous leishmaniasis

Cutaneous leishmaniasis (CL) affects the lives of 0.7–1 million people every year causing lesions that take months to heal. These lesions can result in disfiguring scars with psychological, social and economic consequences. Antimonials are the first line of therapy for CL, however the treatment is lengthy and linked to significant toxicities; further, its efficacy is variable and resistant parasites are emerging. Shorter or lower dose antimonial treatment regimens, which would decrease the risk of adverse events and improve patient compliance, have shown reduced efficacy and further increase the risk emergence of antimonial-resistant strains. The progression of lesions in CL is partly determined by the immune response it elicits, and previous studies showed that administration of immunomodulatory type D CpG ODNs, magnifies the immune response to Leishmania and reduces lesion severity in nonhuman primates (NHP) challenged with Leishmania major or Leishmania amazonensis. Here we explored whether the addition of a single dose of immunomodulating CpG ODN D35 augments the efficacy of a short-course, low-dose pentavalent antimonial treatment regimen. Results show that macaques treated with D35 plus 5mg/kg sodium stibogluconate (Sb^V) for 10 days had smaller lesions and reduced time to re-epithelization after infection with Leishmania major. No toxicities were evident during the studies, even at doses of D35 10 times higher than those used in treatment. Critically, pentavalent antimonial treatment did not modify the ability of D35 to induce type I IFNs. The findings support the efficacy of D35 as adjuvant therapy for shorter, low dose pentavalent antimonial treatment.

Cutaneous leishmaniasis is a devastating disease that affects close to a million people every year. Its clinical presentation ranges from small uncomplicated lesions that heal over a few months to debilitating large chronic or recurring lesions that result in disfigurement, stigma, and economic loss. Antimonials are the first line treatment for cutaneous leishmaniasis in most countries, but the lengthy treatment schedules, significant associated toxicities, and the emergence of resistant strains, require the development of alternative strategies. As the immune response is a key determinant of disease course, immunomodulatory therapies could be harnessed to act in concert with antimonials to improve the safety and efficacy of CL treatment. Synthetic oligonucleotide D35 selectively activates plasmacytoid dendritic cells and was previously shown to reduce the severity of L. major and L. amazonensis lesions in rhesus macaques, but its activity in combination with antimonials was unknown. Our studies show that a single subcutaneous dose of innate immune modulator D35 improved the response to a low-dose abbreviated antimonial course, reducing the severity of the lesions and accelerating healing in primates. No toxicities were evident with D35 at doses ten-fold higher than the effective dose. The studies suggest that the combined therapy strategy shows clinical promise.

In vitro and in vivo immunomodulatory properties of octyl-β-D-galactofuranoside during Leishmania donovani infection

BACKGROUND

The chemotherapeutic arsenal available to treat visceral leishmaniasis is currently limited, in view of many drawbacks such as high cost, toxicity or emerging resistance. New therapeutic strategies are particularly needed to improve the management and the outcome in immunosuppressed patients. The combination of an immunomodulatory drug to a conventional anti-Leishmania treatment is an emerging concept to reverse the immune bias from Th2 to Th1 response to boost healing and prevent relapses.

METHODS

Here, immunostimulating and leishmanicidal properties of octyl-β-D-galactofuranose (Galf) were assessed in human monocyte-derived macrophages (HM) and in a murine model, after challenge with Leishmania donovani promastigotes. We recorded parasite loads and expression of various cytokines and immune effectors in HM and mouse organs (liver, spleen, bone marrow), following treatment with free (Galf) and liposomal (L-Galf) formulations.

RESULTS

Both treatments significantly reduced parasite proliferation in HM, as well as liver parasite burden in vivo (Galf, P < 0.05). Consistent with in vitro results, we showed that Galf- and L-Galf-treated mice displayed an enhanced Th1 immune response, particularly in the spleen where pro-inflammatory cytokines TNF-α, IL-1β and IL-12 were significantly overexpressed compared to control group. The hepatic recruitment of myeloid cells was also favored by L-Galf treatment as evidenced by the five-fold increase of myeloperoxidase (MPO) induction, which was associated with a higher number of MPO-positive cells within granulomas. By contrast, the systemic level of various cytokines such as IL-1β, IL-6, IL-17A or IL-27 was drastically reduced at the end of treatment.

CONCLUSIONS

Overall, these results suggest that Galf could be tested as an adjuvant in combination with current anti-parasitic drugs, to restore an efficient immune response against infection in a model of immunosuppressed mice.

Immunomodulatory and antiparasitic effects of garlic-arteether combination via nitric oxide pathway in Plasmodium berghei-infected mice

Many reports indicate medicinal value of garlic (Allium sativum), a popular herbal medicine used worldwide, and its therapeutic effect against several diseases. Earlier studies in our laboratory have shown a potential therapeutic role of garlic-artemisinin combination in mice infected with Plasmodium berghei. A single dose of α, β-arteether with three oral doses of garlic provides almost 95% protection. The present study aims to understand the mode of action of this combination. We have documented the level of nitric oxide (NO), a key molecule of protection and have seen in the reversal of organ morphology caused by malaria infection. The combination effects on the (a) survival rate and degree of parasitemia and (b) NO levels in blood, liver, spleen and thymus of malaria-infected mice were investigated. During the study, liver, spleen and thymus cell suspensions were assessed for immunobiochemical alterations of NO levels. The increase in NO level after infection appears to be unable to protect, whereas striking increase in spleen and thymus leads to protection against infection, and is further confirmed by detection of increased inducible nitric oxide synthase mRNA expression levels in different organs by RT-PCR. In addition, the role of T cell subsets during combination treatment was also studied. All these results indicate a potential mechanism of protection through NO pathway in combination-treated animals after malaria infection and may lead to an immunotherapy trial of malaria disease.

What makes mucosal and anergic diffuse cutaneous leishmaniases so clinically and immunopathogically different? A review in Brazil

American cutaneous leishmaniasis (ACL) is a parasitic protozoan disease caused by different Leishmania species widely distributed throughout Latin America. Fifteen Leishmania species belonging to the subgenera Viannia, Leishmania and Mundinia are known to cause ACL. Seven of these species are found in Brazil, of which Leishmania (Viannia) braziliensis and Leishmania (Leishmania) amazonensis have the highest potential to cause mucosal (ML) and anergic diffuse cutaneous leishmaniasis (DCL), respectively, the most severe forms of ACL. The clinical and immunopathological differences between these two clinical forms are reviewed here, taking into account their different physiopathogenic mechanisms of dissemination from cutaneous lesions to mucosal tissues in the case of ML and to almost all body surfaces in the case of anergic DCL. We also discuss some immunopathogenic mechanisms of species-specific Leishmania antigens (from the subgenera Viannia and Leishmania) that are most likely associated with the clinical and immunopathological differences between ML and anergic DCL. Those discussions emphasize the pivotal importance of some surface antigens of L. (V.) braziliensis and L. (L.) amazonensis, such as lipophosphoglycan, phosphatidylserine and CD200 (an immunoregulatory molecule that inhibits macrophage activation), that have been shown to exert strong influences on the clinical and immunopathological differences between ML and anergic DCL.

Live Leishmania tarentolae secreting HNP1 as an immunotherapeutic tool against Leishmania infection in BALB/c mice

AIM

Several disadvantages about chemotherapy for leishmaniasis has reinforced discovery of novel therapeutic agents especially immunotherapeutics. HNP1, as a member of the mammalian antimicrobial peptides family, is an attractive molecule due to its broad functional spectrum. Here, the in vivo potency of HNP1 in transgenic Leishmania tarentolae as an immunotherapy tool against Leishmania major-infected BALB/c mice was examined.

METHODS & RESULTS

3 weeks after infection with L. major, the treatment effect of L. tarentolae-HNP1-EGFP was pursued. The results were promising in respect to parasite load control and Th1 immune response polarization compared with controls.

CONCLUSION

Immunotherapy by live L. tarentolae secreting HNP1 can elicit cellular immune response in a susceptible mouse model in order to control L. major infection.

Immunomodulatory Therapy of Visceral Leishmaniasis in Human Immunodeficiency Virus-Coinfected Patients

Patients with visceral leishmaniasis (VL)–human immunodeficiency virus (HIV) coinfection experience increased drug toxicity and treatment failure rates compared to VL patients, with more frequent VL relapse and death. In the era of VL elimination strategies, HIV coinfection is progressively becoming a key challenge, because HIV-coinfected patients respond poorly to conventional VL treatment and play an important role in parasite transmission. With limited chemotherapeutic options and a paucity of novel anti-parasitic drugs, new interventions that target host immunity may offer an effective alternative. In this review, we first summarize current views on how VL immunopathology is significantly affected by HIV coinfection. We then review current clinical and promising preclinical immunomodulatory interventions in the field of VL and discuss how these may operate in the context of a concurrent HIV infection. Caveats are formulated as these interventions may unpredictably impact the delicate balance between boosting of beneficial VL-specific responses and deleterious immune activation/hyperinflammation, activation of latent provirus or increased HIV-susceptibility of target cells. Evidence is lacking to prioritize a target molecule and a more detailed account of the immunological status induced by the coinfection as well as surrogate markers of cure and protection are still required. We do, however, argue that virologically suppressed VL patients with a recovered immune system, in whom effective antiretroviral therapy alone is not able to restore protective immunity, can be considered a relevant target group for an immunomodulatory intervention. Finally, we provide perspectives on the translation of novel theories on synergistic immune cell cross-talk into an effective treatment strategy for VL–HIV-coinfected patients.

Leishmaniasis in humans: drug or vaccine therapy?

Leishmania is an obligate intracellular pathogen that invades phagocytic host cells. Approximately 30 different species of Phlebotomine sand flies can transmit this parasite either anthroponotically or zoonotically through their bites. Leishmaniasis affects poor people living around the Mediterranean Basin, East Africa, the Americas, and Southeast Asia. Affected regions are often remote and unstable, with limited resources for treating this disease. Leishmaniasis has been reported as one of the most dangerous neglected tropical diseases, second only to malaria in parasitic causes of death. People can carry some species of Leishmania for long periods without becoming ill, and symptoms depend on the form of the disease. There are many drugs and candidate vaccines available to treat leishmaniasis. For instance, antiparasitic drugs, such as amphotericin B (AmBisome), are a treatment of choice for leishmaniasis depending on the type of the disease. Despite the availability of different treatment approaches to treat leishmaniasis, therapeutic tools are not adequate to eradicate this infection. In the meantime, drug therapy has been limited because of adverse side effects and unsuccessful vaccine preparation. However, it can immediately make infections inactive. According to other studies, vaccination cannot eradicate leishmaniasis. There is no perfect vaccine or suitable drug to eradicate leishmaniasis completely. So far, no vaccine or drug has been provided to induce long-term protection and ensure effective immunity against leishmaniasis. Therefore, it is necessary that intensive research should be performed in drug and vaccine fields to achieve certain results.

In Vitro and In Vivo Control of Secondary Bacterial Infection Caused by Leishmania major

Bacterial infections of cutaneous leishmaniasis cause skin ulcers on mice, resulting in increased tissue deterioration, and these infections can be controlled with liquid allicin. To isolate and identify the incidences of real secondary bacterial infections in mice, we performed the current study by injecting mice (n = 50) with Leishmania major. L. major infections were initiated by an intramuscular injection of 0.1 mL Roswell Park Memorial Institute (RPMI 1640 media/mouse (107 promastigote/mL)). Scarring appeared 2-6 weeks after injection, and the bacteria were isolated from the skin ulcer tissues. Allicin (50 µL/mL) and ciprofloxacin (5 μg; Cip 5) were used for controlling L. major and bacteria. One hundred samples from skin ulcers of mice were examined, and 200 bacterial colonies were isolated. Forty-eight different genera and species were obtained and identified by Gram staining and physiological and biochemical characterization using identification kits. All samples were positive for secondary bacterial infections. Of the isolates, 79.16% were identified as Gram-negative bacteria, and 28.84% were identified as Gram-positive bacteria; only one yeast species was found. Interestingly, pure allicin liquid at a concentration 50 µL/mL exhibited antibacterial activity against a wide range of Gram-negative and some Gram-positive bacteria, in addition to yeast, and was 71.43% effective. Antimicrobial resistance patterns of all genera and species were determined using 15 different antibiotics. Allicin (50 µL/mL) and Cip 5 were the most effective against L. major and 92.30% of isolated bacteria. Stenotrophomonas maltophilia was the most resistant bacterium to the tested antibiotics with a survival rate of 73.33%, and it exhibited resistance to allicin.

A third generation vaccine for human visceral leishmaniasis and post kala azar dermal leishmaniasis: First-in-human trial of ChAd63-KH

BACKGROUND

Visceral leishmaniasis (VL or kala azar) is the most serious form of human leishmaniasis, responsible for over 20,000 deaths annually, and post kala azar dermal leishmaniasis (PKDL) is a stigmatizing skin condition that often occurs in patients after successful treatment for VL. Lack of effective or appropriately targeted cell mediated immunity, including CD8+ T cell responses, underlies the progression of VL and progression to PKDL, and can limit the therapeutic efficacy of anti-leishmanial drugs. Hence, in addition to the need for prophylactic vaccines against leishmaniasis, the development of therapeutic vaccines for use alone or in combined immuno-chemotherapy has been identified as an unmet clinical need. Here, we report the first clinical trial of a third-generation leishmaniasis vaccine, developed intentionally to induce Leishmania-specific CD8+ T cells.

METHODS

We conducted a first-in-human dose escalation Phase I trial in 20 healthy volunteers to assess the safety, tolerability and immunogenicity of a prime-only adenoviral vaccine for human VL and PKDL. ChAd63-KH is a replication defective simian adenovirus expressing a novel synthetic gene (KH) encoding two Leishmania proteins KMP-11 and HASPB. Uniquely, the latter was engineered to reflect repeat domain polymorphisms and arrangements identified from clinical isolates. We monitored innate immune responses by whole blood RNA-Seq and antigen specific CD8+ T cell responses by IFNγ ELISPOT and intracellular flow cytometry.

FINDINGS

ChAd63-KH was safe at intramuscular doses of 1x1010 and 7.5x1010 vp. Whole blood transcriptomic profiling indicated that ChAd63-KH induced innate immune responses characterized by an interferon signature and the presence of activated dendritic cells. Broad and quantitatively robust CD8+ T cell responses were induced by vaccination in 100% (20/20) of vaccinated subjects.

CONCLUSION

The results of this study support the further development of ChAd63-KH as a novel third generation vaccine for VL and PKDL.

TRIAL REGISTRATION

This clinical trial (LEISH1) was registered at EudraCT (2012-005596-14) and ISRCTN (07766359).

A Vaccine Therapy for Canine Visceral Leishmaniasis Promoted Significant Improvement of Clinical and Immune Status with Reduction in Parasite Burden

Herein, we evaluated the treatment strategy employing a therapeutic heterologous vaccine composed of antigens of Leishmania braziliensis associated with MPL adjuvant (LBMPL vaccine) for visceral leishmaniasis (VL) in symptomatic dogs naturally infected by Leishmania infantum. Sixteen dogs received immunotherapy with MPL adjuvant (n = 6) or with a vaccine composed of antigens of L. braziliensis associated with MPL (LBMPL vaccine therapy, n = 10). Dogs were submitted to an immunotherapeutic scheme consisting of 3 series composed of 10 subcutaneous doses with 10-day interval between each series. The animals were evaluated before (T0) and 90 days after treatment (T90) for their biochemical/hematological, immunological, clinical, and parasitological variables. Our major results showed that the vaccine therapy with LBMPL was able to restore and normalize main biochemical (urea, AST, ALP, and bilirubin) and hematological (erythrocytes, hemoglobin, hematocrit, and platelets) parameters. In addition, in an ex vivo analysis using flow cytometry, dogs treated with LBMPL vaccine showed increased CD3⁺ T lymphocytes and their subpopulations (TCD4⁺ and TCD8⁺), reduction of CD21⁺ B lymphocytes, increased NK cells (CD5^-CD16⁺) and CD14⁺ monocytes. Under in vitro conditions, the animals developed a strong antigen-specific lymphoproliferation mainly by TCD4⁺ and TCD8⁺ cells; increasing in both TCD4⁺IFN-γ⁺ and TCD8⁺IFN-γ⁺ as well as reduction of TCD4⁺IL-4⁺ and TCD8⁺IL-4⁺ lymphocytes with an increased production of TNF-α and reduced levels of IL-10. Concerning the clinical signs of canine visceral leishmaniasis, the animals showed an important reduction in the number and intensity of the disease signs; increase body weight as well as reduction of splenomegaly. In addition, the LBMPL immunotherapy also promoted a reduction in parasite burden assessed by real-time PCR. In the bone marrow, we observed seven times less parasites in LBMPL animals compared with MPL group. The skin tissue showed a reduction in parasite burden in LBMPL dogs 127.5 times higher than MPL. As expected, with skin parasite reduction promoted by immunotherapy, we observed a blocking transmission to sand flies in LBMPL dogs with only three positive dogs after xenodiagnosis. The results obtained in this study highlighted the strong potential for the use of this heterologous vaccine therapy as an important strategy for VL treatment.

Leishmaniasis and various immunotherapeutic approaches

Leishmaniasis is a vector-borne infectious disease caused by multiple Leishmania (L.) species with diverse clinical manifestations. There is currently no vaccine against any form of the disease approved in humans, and chemotherapy is the sole approach for treatment. Unfortunately, treatment options are limited to a small number of drugs, partly due to high cost and significant adverse effects. The other obstacle in leishmaniasis treatment is the potential for drug resistance, which has been observed in multiple endemic countries. Immunotherapy maybe another important avenue for controlling leishmaniasis and could help patients control the disease. There are different approaches for immunotherapy in different infectious diseases, generally with low-cost, limited side-effects and no possibility to developing resistance. In this paper, different immunotherapy approaches as alternatives to routine drug treatment will be reviewed against leishmaniasis.

Zinc(II)-Dipicolylamine Coordination Complexes as Targeting and Chemotherapeutic Agents for Leishmania major

Cutaneous leishmaniasis is a neglected tropical disease that causes painful lesions and severe disfigurement. Modern treatment relies on a few chemotherapeutics with serious limitations, and there is a need for more effective alternatives. This study describes the selective targeting of zinc(II)-dipicolylamine (ZnDPA) coordination complexes toward Leishmania major, one of the species responsible for cutaneous leishmaniasis. Fluorescence microscopy of L. major promastigotes treated with a fluorescently labeled ZnDPA probe indicated rapid accumulation of the probe within the axenic promastigote cytosol. The antileishmanial activities of eight ZnDPA complexes were measured using an in vitro assay. All tested complexes exhibited selective toxicity against L. major axenic promastigotes, with 50% effective concentration values in the range of 12.7 to 0.3 μM. Similar toxicity was observed against intracellular amastigotes, but there was almost no effect on the viability of mammalian cells, including mouse peritoneal macrophages. In vivo treatment efficacy studies used fluorescence imaging to noninvasively monitor changes in the red fluorescence produced by an infection of mCherry-L. major in a mouse model. A ZnDPA treatment regimen reduced the parasite burden nearly as well as the reference care agent, potassium antimony(III) tartrate, and with less necrosis in the local host tissue. The results demonstrate that ZnDPA coordination complexes are a promising new class of antileishmanial agents with potential for clinical translation.

Differentiation of Leishmania species by FT-IR spectroscopy

Leishmaniasis is a parasitic infectious disease caused by protozoa that belong to the genus Leishmania. It is transmitted by the bite of an infected female Sand fly. The disease is endemic in 88 countries Desjeux (2001) [1] (16 developed countries and 72 developing countries) on four continents. In Brazil, epidemiological data show the disease is present in all Brazilian regions, with the highest incidences in the North and Northeast. There are several methods used to diagnose leishmaniasis, but these procedures have many limitations, are time consuming, have low sensitivity, and are expensive. In this context, Fourier Transform Infrared Spectroscopy (FT-IR) analysis has the potential to provide rapid results and may be adapted for a clinical test with high sensitivity and specificity. In this work, FT-IR was used as a tool to investigate the promastigotes of Leishmaniaamazonensis, Leishmaniachagasi, and Leishmaniamajor species. The spectra were analyzed by cluster analysis and deconvolution procedure base on spectra second derivatives.

RESULTS

cluster analysis found four specific regions that are able to identify the Leishmania species. The dendrogram representation clearly indicates the heterogeneity among Leishmania species. The band deconvolution done by the curve fitting in these regions quantitatively differentiated the polysaccharides, amide III, phospholipids, proteins, and nucleic acids. L. chagasi and L. major showed a greater biochemistry similarity and have three bands that were not registered in L. amazonensis. The L. amazonensis presented three specific bands that were not recorded in the other two species. It is evident that the FT-IR method is an indispensable tool to discriminate these parasites. The high sensitivity and specificity of this technique opens up the possibilities for further studies about characterization of other microorganisms.

Historical review of clinical vaccine studies at Oswaldo Cruz Institute and Oswaldo Cruz Foundation--technological development issues

This paper presents, from the perspective of technological development and production, the results of an investigation examining 61 clinical studies with vaccines conducted in Brazil between 1938-2013, with the participation of the Oswaldo Cruz Institute (IOC) and the Oswaldo Cruz Foundation (Fiocruz). These studies have been identified and reviewed according to criteria, such as the kind of vaccine (viral, bacterial, parasitic), their rationale, design and methodological strategies. The results indicate that IOC and Fiocruz have accumulated along this time significant knowledge and experience for the performance of studies in all clinical phases and are prepared for the development of new vaccines products and processes. We recommend national policy strategies to overcome existing regulatory and financing constraints.

Identifying vaccine targets for anti-leishmanial vaccine development

Leishmaniasis is a neglected tropical disease spread by an arthropod vector. It remains a significant health problem with an incidence of 0.2–0.4 million visceral leishmaniasis and 0.7–1.2 million cutaneous leishmaniasis cases each year. There are limitations associated with the current therapeutic regimens for leishmaniasis and the fact that after recovery from infection the host becomes immune to subsequent infection therefore, these factors force the feasibility of a vaccine for leishmaniasis. Publication of the genome sequence of Leishmania has paved a new way to understand the pathogenesis and host immunological status therefore providing a deep insight in the field of vaccine research. This review is an effort to study the antigenic targets in Leishmania to develop an anti-leishmanial vaccine.

An update on pharmacotherapy for leishmaniasis

INTRODUCTION

Leishmaniasis broadly manifests as visceral leishmaniasis (VL), cutaneous leishmaniasis (CL) and mucocutaneous leishmaniasis. The treatment of leishmaniasis is challenging and the armamentarium of drugs is small, duration of treatment is long, and most drugs are toxic.

AREAS COVERED

A literature search on treatment of leishmaniasis was done on PubMed. Single dose of liposomal amphotericin B (L-AmB) and multidrug therapy (L-AmB + miltefosine, L-AmB + paromomycin (PM), or miltefosine + PM) are the treatment of choice for VL in the Indian subcontinent. A 17-day combination therapy of pentavalent antimonials (Sb(v)) and PM remains the treatment of choice for East African VL. L-AmB at a total dose of 18 - 21 mg/kg is the recommended regimen for VL in the Mediterranean region and South America. Treatment of CL should be decided by the severity of clinical lesions, etiological species and its potential to develop into mucosal leishmaniasis.

EXPERT OPINION

There is an urgent need to implement a single-dose L-AmB or combination therapy in the Indian subcontinent. Shorter and more acceptable regimens are needed for the treatment of post - kala-azar dermal leishmaniasis. Combination therapy with newer drugs needs to be tested in Africa. Due to the toxicity of systemic therapy, a trend toward local treatment for New World CL is preferred in patients without risk of mucosal disease.

Parasites and immunotherapy: with or against?

Immunotherapy is a sort of therapy in which antibody or antigen administrates to the patient in order to treat or reduce the severity of complications of disease. This kind of treatment practiced in a wide variety of diseases including infectious diseases, autoimmune disorders, cancers and allergy. Successful and unsuccessful immunotherapeutic strategies have been practiced in variety of parasitic infections. On the other hand parasites or parasite antigens have also been considered for immunotherapy against other diseases such as cancer, asthma and multiple sclerosis. In this paper immunotherapy against common parasitic infections, and also immunotherapy of cancer, asthma and multiple sclerosis with parasites or parasite antigens have been reviewed.

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.

Immunotherapy and targeted therapies in treatment of visceral leishmaniasis: current status and future prospects

Visceral leishmaniasis (VL) is a vector-borne chronic infectious disease caused by the protozoan parasite Leishmania donovani or Leishmania infantum. VL is a serious public health problem, causing high morbidity and mortality in the developing world with an estimated 0.2-0.4 million new cases each year. In the absence of a vaccine, chemotherapy remains the favored option for disease control, but is limited by a narrow therapeutic index, significant toxicities, and frequently acquired resistance. Improved understanding of VL pathogenesis offers the development and deployment of immune based treatment options either alone or in combination with chemotherapy. Modulations of host immune response include the inhibition of molecular pathways that are crucial for parasite growth and maintenance; and stimulation of host effectors immune responses that restore the impaired effector functions. In this review, we highlight the challenges in treatment of VL with a particular emphasis on immunotherapy and targeted therapies to improve clinical outcomes.

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.

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.

Development of Leishmania vaccines: predicting the future from past and present experience

Leishmaniasis is a disease that ranges in severity from skin lesions to serious disfigurement and fatal systemic infection. Resistance to infection is associated with a T-helper-1 immune response that activates macrophages to kill the intracellular parasite in a nitric oxide-dependent manner. Conversely, disease progression is generally associated with a T-helper-2 response that activates humoral immunity. Current control is based on chemotherapeutic treatments which are expensive, toxic and associated with high relapse and resistance rates. Vaccination remains the best hope for control of all forms of the disease, and the development of a safe, effective and affordable antileishmanial vaccine is a critical global public-health priority. Extensive evidence from studies in animal models indicates that solid protection can be achieved by immunization with defined subunit vaccines or live-attenuated strains of Leishmania. However, to date, no vaccine is available despite substantial efforts by many laboratories. Major impediments in Leishmania vaccine development include: lack of adequate funding from national and international agencies, problems related to the translation of data from animal models to human disease, and the transition from the laboratory to the field. Furthermore, a thorough understanding of protective immune responses and generation and maintenance of the immunological memory, an important but least-studied aspect of antiparasitic vaccine development, during Leishmania infection is needed. This review focuses on the progress of the search for an effective vaccine against human and canine leishmaniasis.

Avanços no tratamento da leishmaniose tegumentar do novo mundo nos últimos dez anos: uma revisão sistemática da literatura

INTRODUÇÃO: O arsenal terapêutico contra a leishmaniose tegumentar é muito restrito. Os antimoniais pentavalentes permanecem como as drogas de escolha para seu tratamento há mais de 50 anos. Apesar da sua eficácia, necessita de injeções diárias, apresenta muitos efeitos colaterais e tempo de cura prolongado. OBJETIVO: Realizar uma revisão sistemática da literatura sobre os avanços no tratamento da leishmaniose tegumentar do novo mundo nos últimos dez anos. METODOLOGIA: Realizou-se em junho de 2009 uma busca eletrônica nas bases de dados Pubmed, LILACS e na biblioteca eletrônica Scielo. As palavras de busca em inglês foram: "cutaneous", "leishmaniasis" e "treatment". Foram incluÃdos apenas ensaios clÃnicos randomizados, duplo-cegos, placebo controlados. Utilizou-se a escala de Jadad para avaliar a qualidade dos estudos selecionados. RESULTADOS: Segundo os critérios de inclusão e exclusão, apenas 8 artigos foram selecionados. As drogas avaliadas nos estudos selecionados foram Glucantime®, miltefosine, imunoterapia, imiquimod, rhGM-CSF, pentoxifilina e paramomicina. CONCLUSÃO: Apesar de a leishmaniose tegumentar ser um importante problema de saúde pública, os dados publicados sobre o uso de novas drogas para o tratamento da leishmaniose tegumentar em nosso meio ainda são bastante limitados

Drug combinations for visceral leishmaniasis

PURPOSE OF REVIEW

Several attempts have been made to combine drugs for treating visceral leishmaniasis, but only recently have effective drugs become available and combinations been tested systematically.

RECENT FINDINGS

Sequential treatments with liposomal amphotericin B followed by miltefosine or paromomycin (as short as 7 days), as well as the concomitant administration of miltefosine and paromomycin (for 10 days) are very effective in India (>95%). Sodium stibogluconate plus paromomycin for 17 days is more than 90% effective in East Africa. The shortened combination regimens are cost-effective in India. No combination has been tested so far in Brazil, Nepal and Bangladesh, although studies may be expected in the near future. No cost-effectiveness analysis has been done as yet outside India.

SUMMARY

There is evidence of high efficacy and benefits with sequential and co-administration treatments in India. More studies are needed in other endemic areas. Introducing combinations and scaling up their use will be challenging. Experience acquired with malaria may be useful. Proper monitoring of use and effects (efficacy and safety) will be required. Currently there are no options for fixed-dose combination treatments for leishmaniasis.

A chronic mutilating rhinopathy with a delayed diagnosis of mucocutaneous leishmaniasis

BACKGROUND

Mucocutaneous leishmaniasis is a granulomatous disease clinically characterized by ulcerated skin and mucosal lesions. Mucocutaneous leishmaniasis is very rare in India and to our knowledge, only two cases have been reported, and this is the first case of mucocutaneous leishmaniasis presenting with mutilating rhinopathy reported from the Indian subcontinent.

CASE REPORT

A 64-year-old man presented with a destructive ulceration of the central face of 23 years' duration, who was diagnosed to have mucocutaneous leishmaniasis, and showed dramatic response to intramuscular injections of sodium stibogluconate.

RESULTS

Histopathologic examination of skin biopsy revealed a granulomatous infiltrate with the presence of leishmania donovani (LD) bodies. The clinical picture, plus the pathologic findings, and the response to sodium stibogluconate confirmed mucocutaneous leishmaniasis.

CONCLUSION

Mucocutaneous leishmaniasis is a rare disease in the Indian subcontinent, and clinicians from this region should have a high index of suspicion on encountering mucocutaneous ulcerative lesions.

A clinical trial to evaluate the safety and immunogenicity of the LEISH-F1+MPL-SE vaccine when used in combination with meglumine antimoniate for the treatment of cutaneous leishmaniasis

Forty-four adult patients with cutaneous leishmaniasis (CL) were enrolled in a randomized, double-blind, controlled, dose-escalating clinical trial and were randomly assigned to receive three injections of either the LEISH-F1+MPL-SE vaccine (consisting of 5, 10, or 20 μg recombinant Leishmania polyprotein LEISH-F1 antigen+25 μg MPL-SE adjuvant) (n=27), adjuvant alone (n=8), or saline placebo (n=9). The study injections were given subcutaneously on Days 0, 28, and 56, and the patients were followed through Day 336 for safety, immunological, and clinical evolution endpoints. All patients received chemotherapy with meglumine antimoniate starting on Day 0. The vaccine was safe and well tolerated. Nearly all vaccine recipients and no adjuvant-alone or placebo recipients demonstrated an IgG antibody response to LEISH-F1 at Day 84. Also at Day 84, 80% of vaccine recipients were clinically cured, compared to 50% and 38% of adjuvant-alone and placebo recipients. The LEISH-F1+MPL-SE vaccine was safe and immunogenic in CL patients and appeared to shorten their time to cure when used in combination with meglumine antimoniate chemotherapy.

Immunological stimulation for the treatment of leishmaniasis: a modality worthy of serious consideration

Instead of relying on drugs to reduce the parasite burden of leishmaniasis, and waiting for the effector immune response to develop in time to control the parasites, immunotherapy in conjunction with chemotherapy can rapidly induce the effector immune response. With a safe and potent drug plus an affordable therapeutic vaccine (immunostimulant), which remains to be developed, a single visit by patients with visceral or cutaneous leishmaniasis might be sufficient to induce a quick and lasting recovery. Drug toxicity and the emergence of resistance could also be dramatically reduced compared with present long-term monotherapy. Immunotherapy could be an effective addition to chemotherapy for leishmaniasis.

Pentavalent antimonials: new perspectives for old drugs

Pentavalent antimonials, including meglumine antimoniate and sodium stibogluconate, have been used for more than half a century in the therapy of the parasitic disease leishmaniasis. Even though antimonials are still the first-line drugs, they exhibit several limitations, including severe side effects, the need for daily parenteral administration and drug resistance. The molecular structure of antimonials, their metabolism and mechanism of action are still being investigated. Some recent studies suggest that pentavalent antimony acts as a prodrug that is converted to active and more toxic trivalent antimony. Other works support the direct involvement of pentavalent antimony. Recent data suggest that the biomolecules, thiols and ribonucleosides, may mediate the actions of these drugs. This review will summarize the progress to date on the chemistry and biochemistry of pentavalent antimony. It will also present the most recent works being done to improve antimonial chemotherapy. These works include the development of simple synthetic methods for pentavalent antimonials, liposome-based formulations for targeting the Leishmania parasites responsible for visceral leishmaniasis and cyclodextrin-based formulations to promote the oral delivery of antimony.

Tropical dermatology: Tropical diseases caused by protozoa

Protozoan infections are very common among tropical countries and have an important impact on public health. Leishmaniasis is the most widely disseminated protozoan infection in the world, while the trypanosomiases are widespread in both Africa and South America. Amebiasis, a less common protozoal infection, is a cause of significant morbidity in some regions. Toxoplasmosis and pneumocystosis (formerly thought to be caused by a protozoan) are worldwide parasitic infections with a very high incidence in immunocompromised patients but are not restricted to them. In the past, most protozoan infections were restricted to specific geographic areas and natural reservoirs. There are cases in which people from other regions may have come in contact with these pathogens. A common situation involves an accidental contamination of a traveler, tourist, soldier, or worker that has contact with a reservoir that contains the infection. Protozoan infections can be transmitted by arthropods, such as sandflies in the case of leishmaniasis or bugs in the case of trypanosomiases. Vertebrates also serve as vectors as in the case of toxoplasmosis and its transmission by domestic cats. The recognition of the clinical symptoms and the dermatologic findings of these diseases, and a knowledge of the geographic distribution of the pathogen, can be critical in making the diagnosis of a protozoan infection.

LEARNING OBJECTIVES

After completing this learning activity, participants should be able to recognize the significance of protozoan infections worldwide, identify the dermatologic manifestations of protozoan infections, and select the best treatment for the patient with a protozoan infection.

Interventions for American cutaneous and mucocutaneous leishmaniasis

BACKGROUND

Pentavalent antimonial drugs are the most prescribed treatment for American cutaneous and mucocutaneous leishmaniasis. Other drugs have been used with varying success.

OBJECTIVES

To assess the effects of therapeutic interventions for American cutaneous and mucocutaneous leishmaniasis.

SEARCH STRATEGY

We searched the Cochrane Skin Group Specialised Register (January 2009), the Register of Controlled Clinical Trials in The Cochrane Library (Issue 1,2009), MEDLINE (2003 to January 2009), EMBASE (2005 to January 2009), LILACS (from inception to January 2009), CINAHL (1982-May 2007) and other databases.

SELECTION CRITERIA

Randomised controlled trials (RCTs) assessing treatments for American cutaneous and mucocutaneous leishmaniasis.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data.

MAIN RESULTS

We included 38 trials involving 2728 participants. Results are based on individual studies or limited pooled analyses. There was good evidence in:Leishmania braziliensis and L. panamensis infections:Intramuscular (IM) meglumine antimoniate (MA) was better than oral allopurinol for 28 days (1RCT n=127, RR 0.39; 95% CI 0.26, 0.58). Intravenous (IV)MA for 20-days was better than 3-day and 7-day IVMA plus 15% paromomycin plus 12% methylbenzethonium chloride (PR-MBCL) or 7-day IVMA (1RCT n= 150, RR 0.24; 95% CI 0.11, 0.50; RR 0.69; 95% CI 0.53, 0.90; RR 0.64; 95% CI 0.44, 0.92 respectively). Oral allopurinol plus antimonials was better than IV antimonials (2RCT n= 168, RR 1.90; 95% CI 1.40, 2.59; I(2)=0%).L. braziliensis infections:Oral pentoxifylline plus IV sodium stibogluconate (SSG) was better than IVSSG (1RCT n= 23, RR 1.66; 95% CI 1.03, 2.69); IVMA was better than IM aminosidine sulphate (1RCT n= 38, RR 0.05; 95% CI 0.00, 0.78) and better than IV pentamidine isethionate (1RCT n= 80, RR 0.45; 95% CI 0.29, 0.71). Intramuscular MA was better than Bacillus Calmette-Guérin (1RCT n= 93, RR 0.46; 95% CI 0.32, 0.65).L .panamensis infections:Oral allopurinol was better than IVMA (1RCT n= 58, RR 2.20; 95% CI 1.34, 3.60). Aminosidine sulphate at doses of 12 mg/kg/day and 18 mg/kg/day for 14 days were better than aminosidine sulphate 12 mg/kg/day for 7 days (1RCT n= 60, RR 0.23; 95% CI 0.07, 0.73; RR 0.23; 95% CI 0.07, 0.73 respectively). Oral ketoconazole for 28 days, oral miltefosine and topical PR-MBCL were better than placebo.

AUTHORS' CONCLUSIONS

Most trials have been designed and reported so poorly that they are inconclusive. There is a need for large well conducted studies that evaluate long-term effects of current therapies to improve quality and standardization of methods.