Paromomycin and Miltefosine Combination as an Alternative to Treat Patients With Visceral Leishmaniasis in Eastern Africa: A Randomized, Controlled, Multicountry Trial

BACKGROUND

This study aimed to determine whether paromomycin plus miltefosine (PM/MF) is noninferior to sodium stibogluconate plus paromomycin (SSG/PM) for treatment of primary visceral leishmaniasis in eastern Africa.

METHODS

An open-label, phase 3, randomized, controlled trial was conducted in adult and pediatric patients at 7 sites in eastern Africa. Patients were randomly assigned to either 20 mg/kg paromomycin plus allometric dose of miltefosine (14 days), or 20 mg/kg sodium stibogluconate plus 15 mg/kg paromomycin (17 days). The primary endpoint was definitive cure after 6 months.

RESULTS

Of 439 randomized patients, 424 completed the trial. Definitive cure at 6 months was 91.2% (155 of 170) and 91.8% (156 of 170) in the PM/MF and SSG/PM arms in primary efficacy modified intention-to-treat analysis (difference, 0.6%; 97.5% confidence interval [CI], -6.2 to 7.4), narrowly missing the noninferiority margin of 7%. In the per-protocol analysis, efficacy was 92% (149 of 162) and 91.7% (155 of 169) in the PM/MF and SSG/PM arms (difference, -0.3%; 97.5% CI, -7.0 to 6.5), demonstrating noninferiority. Treatments were well tolerated. Four of 18 serious adverse events were study drug-related, and 1 death was SSG-related. Allometric dosing ensured similar MF exposure in children (<12 years) and adults.

CONCLUSIONS

PM/MF and SSG/PM efficacies were similar, and adverse drug reactions were as expected given the drugs safety profiles. With 1 less injection each day, reduced treatment duration, and no risk of SSG-associated life-threatening cardiotoxicity, PM/MF is a more patient-friendly alternative for children and adults with primary visceral leishmaniasis in eastern Africa.

CLINICAL TRIALS REGISTRATION

NCT03129646.

Revisiting the diagnosis and treatment of Para Kala-azar Dermal Leishmaniasis in the endemic foci of Bangladesh

Para Kala-azar Dermal Leishmaniasis (Para-KDL) manifests the concomitant presence of Post Kala-azar Dermal Leishmaniasis and Visceral Leishmaniasis and works as a reservoir of infection. The study discusses the cases and their management and aims to address the gaps within existing methods of diagnosis and treatment. This retrospective cross-sectional study discusses 16 Para-KDL cases with one-year follow-up data, treated between 2012-2021 at the Surya Kanta Kala-azar Research Center, Bangladesh. We collected data from hospital records and used STATA 16 to analyze and see the frequency distribution and variable means. We found five patients without any history of kala-azar infection. All the patients were treated with 20 mg/kg Liposomal Amphotericin B in 4 divided doses except one with a history of AmBisome hypersensitivity. One year after treatment, all patients were free from skin lesions, with no hepatosplenomegaly, and observed significant improvement in BMI and hemoglobin levels. The Para-KDL patients are challenging to diagnose, and the relapse and treatment failure leishmania patients might have belonged to this rare group, contributing to their poor prognosis. Therefore, developing an appropriate diagnostic workflow and a new drug regimen is essential to sustain the success of our elimination efforts.

Review on the Drug Intolerance and Vaccine Development for the Leishmaniasis

Leishmaniasis is one of the Neglected Tropical Diseases (NTDs), a zoonotic disease of vector-borne nature that is caused by a protozoan parasite Leishmania. This parasite is transmitted by the vector sandfly into the human via a bite. Visceral leishmaniasis (VL), also called kala-azar, is the most fatal among the types of leishmaniasis, with high mortality mostly spread in the East Africa and South Asia regions. WHO report stated that approximately 3.3 million disabilities occur every year due to the disease along with approximately 50,000 annual deaths. The real matter of concern is that there is no particular effective medicine/vaccine available against leishmaniasis to date except a few approved drugs and chemotherapy for the infected patient. The current selection of small compounds was constrained, and their growing drug resistance had been a major worry. Additionally, the serious side effects on humans of the available therapy or drugs have made it essential to discover efficient and low-cost methods to speed up the development of new drugs against leishmaniasis. Ideally, the vaccine could be a low risk and effective alternative for both CL and VL and elicit long-lasting immunity against the disease. There are a number of vaccine candidates at various stages of clinical development and preclinical stage. However, none has successfully passed all clinical trials. But, the successful development and approval of commercially available vaccines for dogs against canine leishmaniasis (CanL) provides evidence that it can be possible for humans in distant future. In the present article, the approaches used for the development of vaccines for leishmaniasis are discussed and the progress being made is briefly reviewed.

Case Report: Autochthonous Disseminated Cutaneous, Mucocutaneous, and Visceral Leishmaniasis Caused by Leishmania martiniquensis in a Patient with HIV/AIDS from Northern Thailand and Literature Review

Autochthonous leishmaniasis cases have been increasing continuously in Thailand over the years. We report multiple presentations of leishmaniasis in a 47-year-old patient with HIV/AIDS from Chiang Rai Province, northern Thailand. Physical examination showed multiple ulcerated papules, nodules, and plaques in a sporotrichoid distribution. Firm mucosal nodules on the hard palate and nasal opening, hepatosplenomegaly, and bilateral inguinal lymphadenopathy were found. Histopathological examination of the biopsies revealed an inflammatory infiltrate containing intramacrophage amastigotes compatible with Leishmania infection. In addition, Leishmania promastigotes were isolated successfully from the palatal biopsy and assigned the code MHOM/TH/2022/CULE6. Using internal transcribed spacer 1 polymerase chain reaction and sequence analysis, the causative parasite was identified as Leishmania martiniquensis. A definitive diagnosis of multiform leishmaniasis with disseminated cutaneous, mucocutaneous, and visceral involvement was established. The patient was administered intravenous amphotericin B 1 mg/kg/d for 2 weeks, followed by oral itraconazole 400 mg daily. At the 2-month follow-up, the cutaneous and mucosal lesions had improved significantly. To our knowledge, this is the first report of mucocutaneous involvement caused by L. martiniquensis in an immunocompromised patient with HIV/AIDS. In addition, we provide a literature review of leishmaniasis cases, reported formally in Thailand, resulting from this autochthonous parasite.

Case Report: Visceral Leishmaniasis-associated Hemophagocytic Lymphohistiocytosis in Adults: A Case Series and Literature Review

Hemophagocytic lymphohistiocytosis (HLH) is a rare and fatal complication of visceral leishmaniasis (VL). To provide a basis for early and correct diagnosis and to improve prognosis in the future, we describe a case series of VL-associated HLH in adults in our center in the past decade after review of all reported cases of adult VL-associated HLH in English through May 2022. In our case series, a total of 111 patients were diagnosed with VL. Among these patients, only six cases were diagnosed with VL-associated HLH. All patients tested positive for serology. Leishmania was detected for the first time by bone marrow aspiration (BMA) in three of the six patients and in the other three patients after three or four BMAs. It took more than 1 month from onset to diagnosis of VL for all the six cases, and the longest time was 6 months. Five of the six patients recovered after receiving sodium stibogluconate. VL-associated HLH is rare but potentially life-threatening in adults and predisposes to early delays in diagnosis. However, diagnostic techniques are not complicated or difficult, so it is more important to consider that it is not recognized by physicians. Although guidelines recommend liposomal amphotericin B as the most effective therapy, our experience suggests that sodium stibogluconate can be an alternative option when liposomal amphotericin B is unavailable or unaffordable.

Antimony resistance mechanism in genetically different clinical isolates of Indian Kala-azar patients

The central theme of this enterprise is to find common features, if any, displayed by genetically different antimony (Sb)-resistant viscerotropic Leishmania parasites to impart Sb resistance. In a limited number of clinical isolates (n = 3), we studied the breadth of variation in the following dimensions: (a) intracellular thiol content, (b) cell surface expression of glycan having N-acetyl-D-galactosaminyl residue as the terminal sugar, and (c) gene expression of thiol-synthesizing enzymes (CBS, MST, gamma-GCS, ODC, and TR), antimony-reducing enzymes (TDR and ACR2), and antimonial transporter genes (AQP1, MRPA, and PRP1). One of the isolates, T5, that was genotypically characterized as Leishmania tropica, caused Indian Kala-azar and was phenotypically Sb resistant (T5-LT-SSG-R), while the other two were Leishmania donovani, out of which one isolate, AG83, is antimony sensitive (AG83-LD-SSG-S) and the other isolate, T8, is Sb resistant (T8-LD-SSG-R). Our study showed that the Sb-resistant parasites, regardless of their genotype, showed significantly higher intracellular thiol compared with Sb-sensitive AG83-LD-SSG-S. Seemingly, T5-LT-SSG-R showed about 1.9-fold higher thiol content compared with T8-LD-SSG-R which essentially mirrored cell surface N-acetyl-D-galactosaminyl expression. Except TR, the expression of the remaining thiol-synthesizing genes was significantly higher in T8-LD-SSG-R and T5-LT-SSG-R than the sensitive one, and between the Sb-resistant parasites, the latter showed a significantly higher expression. Furthermore, the genes for Sb-reducing enzymes increased significantly in resistant parasites regardless of genotype compared with the sensitive one, and between two resistant parasites, there was hardly any difference in expression. Out of three antimony transporters, AQP1 was decreased with the concurrent increase in MRPA and PRP1 in resistant isolates when compared with the sensitive counterpart. Interestingly, no difference in expression of the above-mentioned transporters was noted between two Sb-resistant isolates. The enduring image that resonated from our study is that the genetically diverse Sb-resistant parasites showed enhanced thiol-synthesizing and antimony transporter gene expression than the sensitive counterpart to confer a resistant phenotype.

Knowledge, Attitude, and Practices among HIV/Leishmaniasis Co-Infected Patients in Bihar, India

Visceral leishmaniasis (VL) is a serious public health concern in the Indian state of Bihar, which has been exacerbated by an increasing HIV/AIDS incidence that has resulted in poor clinical outcomes. So far, there has been no investigation into the knowledge, attitude, and practices (KAP) of people who have been subjected to hospital-based supervision for VL or HIV/VL co-infection. This study assessed the KAP toward VL infection among 210 VL-infected patients (126 participants with VL and 84 participants with HIV/VL) using a pretested standard questionnaire. The findings are summarized descriptively and KAP scores are classified dichotomously (good/poor). Multivariable logistic regression and bivariate correlation were used in the analysis. The study showed that both VL-infected and co-infected patients exhibited similar deficits in KAP scores toward VL. The HIV/VL participants who had a personal or family history of VL were more likely to have appropriate awareness of and preventive practices toward VL. The independent predictors of attitude index in HIV/VL participants were education, VL family history, and marital status. There was a weak but significant positive correlation between knowledge and practice (rs = 0.321, p<0.001), and attitude and practice (rs = 0.294, p<0.001), while knowledge was strongly correlated with attitude (rs = 0.634, p<0.001). Based on the study findings, it is recommended that treatment programs in Bihar should concentrate on strengthening KAP among VL and HIV/VL co-infected patients to prevent reinfection-related complications. Behavior change communication intervention is ideal for tackling this problem. This proposal entails building a comprehensive public health program in endemic regions.

Case Report: Cutaneous Leishmaniasis in a Rheumatoid Arthritis Patient Receiving Methotrexate

The immunosuppressive effect of methotrexate has rarely been associated with reactivation of cutaneous leishmaniasis. Here we present a case of a cutaneous leishmaniasis patient with atypical clinical symptoms without splenomegaly but with cutaneous manifestations after treatment of rheumatoid arthritis with methotrexate and blood recovery of the parasite. Next-generation sequencing was used to identify Leishmania infantum chagasi in the patient's blood sample.

Splenectomy in Patients with Visceral Leishmaniasis Resistant to Conventional Therapy and Secondary Prophylaxis: A Retrospective Cohort

Some patients with visceral leishmaniasis (VL), or kala-azar, suffer relapses and low quality of life despite adequate drug therapy, especially those co-infected with HIV. Occasionally, physicians indicate splenectomy, but the benefit of the procedure needs to be analyzed systematically. Therefore, a retrospective open cohort study was conducted in Teresina, Brazil. Inpatients from a reference hospital with relapsing VL who had a rescue splenectomy between 2012 and 2019 after the nationally recommended drug therapy failed were studied. The procedure's risks and benefits were assessed in a limited-resource setting. The primary outcomes were surgical complications, complete blood count, CD4+ cell count, hospitalizations, survival time, and medical complications preceding death. Thirteen adult patients received medical and surgical indications of splenectomy (12 men and one woman). Eleven had HIV infection. Two had early and two had late complications. Four died, all of whom were infected with HIV. An additional HIV-coinfected patient, apart from the cohort, died just before surgery. The death rate after surgery was 13.3 overall and 22.1 per 100 person-years among HIV-infected patients (31% overall and 36%, respectively). The impressive rise of complete blood counts and reduction of blood transfusions and hospitalizations were observed among all patients. Also, a meaningful increase in CD4+ cells in HIV-infected patients was noted. Splenectomy may benefit patients with relapsing VL. However, before performing splenectomy, available combined drug therapy for VL should be tried.

Case Report: The First Case Report of Visceral Leishmaniasis in Cambodia

Leishmaniasis is considered a neglected tropical disease that is commonly found in Asia, Africa, South America, and Mediterranean countries. Visceral leishmaniasis (VL) is the most severe form of the disease and is almost universally fatal if left untreated. The symptoms of VL overlap with many infectious diseases, malignancies, and other blood disorders. The most common findings include fever, cytopenias, and splenomegaly. Given the nonspecific symptoms, the diagnosis requires detailed laboratory investigations, including bone marrow examination, that can be challenging in low- and middle-income countries. Diagnostic limitations likely lead to the underdiagnosis or delay in diagnosis of VL. We describe, to our knowledge, the first case report of VL in Cambodia in a child presenting with fever, anemia, and thrombocytopenia. The diagnosis required a liver biopsy and multiple bone marrow biopsies to visualize intracellular Leishmania spp. Our case illustrates the diagnostic challenges and the importance of timely diagnosis. This case also highlights the need for heightened awareness of the diagnostic findings of VL and improved reporting of tropical diseases.

Case Report: Leishmaniasis in a 33-Year-Old Man with Multiple Sclerosis

Leishmaniasis is a protozoan disease caused by species of genus Leishmania. Immunosuppression increases the risk of severe clinical forms and impairs response to treatment. The expansion of the use of immunomodulatory drugs for different conditions has raised the number of these cases. In this report, we present a case of visceral leishmaniasis in a patient with multiple sclerosis (MS) under fingolimod treatment. He presented with the triad of fever, visceromegaly, and pancytopenia and was diagnosed by the presence of amastigotes in a bone marrow sample. Furthermore, we discuss the previous published cases of MS patients under different immunosuppressant therapies to highlight its risk in endemic areas and suggest a therapeutic approach.

Leishmania donovani Dipeptidylcarboxypeptidase Inhibitor as a Potential Oral Treatment for Visceral Leishmaniasis

Chemotherapy is the key intervention to control visceral leishmaniasis (VL), a neglected tropical disease. Current regimens include not only a few drugs but also present several drawbacks, including moderate to severe toxicity, cost, long-term administration, patient compliance, and growing drug resistance. Thus, the need for better treatment options against VL is a priority. In an endeavor to find an orally active and affordable antileishmanial agent, we evaluated the therapeutic potential of compounds belonging to the (2Z,2'Z)-3,3'-(ethane-1,2-diylbis(azanediyl))bis(1-(4-halophenyl)-6-hydroxyhex-2-en-1-ones) series, identified as inhibitor(s) of Leishmania donovani dipeptidylcarboxypeptidase, a novel drug target. Among them, compound 3c exhibited best in vivo antileishmanial efficacy via both intraperitoneal and oral routes. Therefore, the present study led to the identification of compound 3c as the lead candidate for treating VL.

Stakeholders’ views and perspectives on treatments of visceral leishmaniasis and their outcomes in HIV-coinfected patients in East Africa and South-East Asia: A mixed methods study

Background

In visceral leishmaniasis (VL) patients coinfected with human immunodeficiency virus (HIV), combination therapy (liposomal amphotericin B infusion and oral miltefosine) is being considered as an alternative to liposomal amphotericin B monotherapy. We aimed to assess the views of stakeholders in relation to these treatment options.

Methodology

In a mixed methods study, we surveyed and interviewed patients, government functionaries, programme managers, health service providers, nongovernmental organizations, researchers, and World Health Organization (WHO) personnel. We used the Evidence to Decision (EtD) framework for data collection planning and analysis. Constructs of interest included valuation of outcomes, impact on equity, feasibility and acceptability of the treatment options, implementation considerations, monitoring and evaluation, and research priorities.

Principal findings/Conclusion

Mortality and non-serious adverse events were rated as “critical” by respectively the highest (61%) and lowest percentages (47%) of survey participants. Participants viewed clinical cure as essential for patients to regain productivity. Non-patient stakeholders emphasized the importance of “sustained” clinical cure. For most survey participants, combination therapy, compared with monotherapy, would increase health equity (40%), and be more acceptable (79%) and feasible (57%). Interviews revealed that combination therapy was more feasible and acceptable than monotherapy when associated with a shorter duration of hospitalization. The findings of the interviews provided insight into those of the survey. When choosing between alternative options, providers should consider the outcomes that matter to patients as well as the impact on equity, feasibility, and acceptability of the options.

In East Africa and South Asia, the number of patients with visceral leishmaniasis (VL) co-infected with human immunodeficiency virus (HIV) has been increasing over the years. In addition to independently posing major health challenges, the two conditions have detrimental effects on each other. In light of new evidence on treatment regimens for this patient population, the World Health Organization (WHO) recently updated its evidence-based region-specific treatment recommendations. To inform this process, we assessed the views of stakeholders on the outcomes of interest and on medication treatment options. The mixed methods study consisted of an online survey and semi-structured interviews. Outcomes such as mortality, complications, clinical cure, relapse and serious adverse events were viewed as important because of the burden associated with their experience, their consequences, and the co-infection status of the patients. Outcomes such as non-serious adverse events were viewed as less important for reasons relating to patient tolerability and ease of treatment. As compared to monotherapy, combination therapy was found to be more equitable, acceptable, and feasible. While our findings are important to consider by clinicians treating patients with VL patients coinfected with HIV, they also inform decisions made by other stakeholders such as guideline developers and program managers.

Following successful anti-leishmanial treatment, neutrophil counts, CD10 expression and phagocytic capacity remain reduced in visceral leishmaniasis patients co-infected with HIV

Visceral leishmaniasis (VL) patients co-infected with HIV (VL/HIV patients) experience frequent treatment failures, VL relapses, opportunistic infections, and higher mortality. Their immune system remains profoundly suppressed after clinical cure and they maintain higher parasite load. This is in contrast with patients with VL alone (VL patients). Since neutrophils play a critical role in the control of Leishmania replication and the regulation of immune responses, we tested the hypothesis that neutrophil activation status and effector functions are fully restored in VL, but not in VL/HIV patients. Our results show the neutrophil counts and all activation markers and effector functions tested in our study were reduced at the time of diagnosis in VL and VL/HIV patients as compared to controls. CD62L, CD63, arginase 1 expression levels and reactive oxygen species production were restored at the end of treatment in both groups. However, neutrophil counts, CD10 expression and phagocytosis remained significantly lower throughout follow-up in VL/HIV patients; suggesting that dysregulated neutrophils contribute to the impaired host defence against pathogens in VL/HIV patients.

Clinical and parasitological impact of short-term treatment using miltefosine and allopurinol monotherapy or combination therapy in canine visceral leishmaniasis

Canine visceral leishmaniasis is an endemic zoonosis in Brazil. Dogs are the main hosts in urban environments. The treatment has gained popularity since the Brazilian government authorized miltefosine for canine treatment. The aim of this study was to investigate the clinical and parasitological impact of short-term treatment with miltefosine and allopurinol, alone and in combination. We evaluated the ability of pharmacotherapy to reduce clinical signs of disease, antibody levels using the indirect fluorescence antibody test (IFAT) and skin parasite load via qPCR after 28 days of treatment. The therapeutic protocols promoted a significant decline in clinical signs and in the skin parasite load in dogs (p < 0.01). We observed a moderate correlation between the skin parasite load and the clinical score in all three treatment groups (r > 0.5) Antibody levels did not decrease in this short period. It was concluded that the treatment with allopurinol reduced the number of parasites in the skin of dogs with visceral leishmaniasis in the short term. However, its efficiency is potentiated when associated with miltefosine.

Ascaridole exerts the leishmanicidal activity by inhibiting parasite glycolysis

BACKGROUND

The global burden of leishmaniasis is exacerbated by the limited repertoire of drugs, resulting in an urgent need to develop new therapeutic alternatives. Endoperoxides like ascaridole have emerged as promising anti-parasitic candidates, and its effectiveness was established in an animal model of cutaneous leishmaniasis (CL). However, its impact on Leishmania donovani parasites, causative of visceral leishmaniasis (VL) remains to be established.

PURPOSE

This study aimed to delineate the underlying mechanisms contributing towards the leishmanicidal effect of ascaridole in terms of its impact on the cellular redox status and metabolic bioenergetics of L. donovani parasites.

METHODOLOGY

The anti-promastigote activity of ascaridole was established by a cell viability assay in L. donovani [MHOM/IN/1983/AG83] and anti-amastigote activity by microscopy and ddPCR (droplet digital polymerase chain reaction). The cellular redox status, mitochondrial membrane potential (MMP), annexin V positivity and cell cycle arrest was evaluated by flow cytometry, while cellular and mitochondrial bioenergetics was assessed using Agilent XFp Analyzer, and the levels of ATP was measured by chemiluminescence.

RESULTS

Ascaridole demonstrated strong anti-promastigote and anti-amastigote activities in l. donovani, IC₅₀ (half maximal Inhibitory concentration) being 2.47 ± 0.18 µM and 2.00±0.34 µM respectively, while in J774.A1 and murine peritoneal macrophages, the CC₅₀ (half maximal cytotoxic concentration) was 41.47 ± 4.89 µM and 37.58 ± 5.75 µM respectively. Ascaridole disrupted the redox homeostasis via an enhanced generation of reactive oxygen species (ROS), lipid peroxidation and concomitant depletion of thiols. However, it failed to increase the generation of mitochondrial superoxide, which minimally impacted on mitochondrial respiration and was corroborated by energy metabolism studies. Instead, ascaridole inhibited glycolysis of promastigotes, caused a loss in MMP, which translated into ATP depletion. In promastigotes, ascaridole enhanced annexin-V positivity and caused a cell cycle arrest at sub- G₀/G₁ phase.

CONCLUSION

In summary, ascaridole displays its leishmanicidal activity possibly due to its ability to auto-generate free radicals following cleavage of its endoperoxide bridge that led to disruption of the redox homeostasis, inhibition of glycolysis and culminated in an apoptotic like cell death.

The increasing incidence of visceral leishmaniasis relapse in South Sudan: A retrospective analysis of field patient data from 2001-2018

BACKGROUND

Visceral Leishmaniasis (VL) is endemic in South Sudan, manifesting periodically in major outbreaks. Provision of treatment during endemic periods and as an emergency response is impeded by instability and conflict. Médecins Sans Frontières (MSF) has provided health care in South Sudan since the late 1980's, including treatment for 67,000 VL patients. In recent years, MSF monitoring data have indicated increasing numbers of VL relapse cases. A retrospective analysis of these data was performed in order to provide insight into the possible causes of this increase.

METHODOLOGY/PRINCIPAL FINDINGS

Programme monitoring data from the MSF hospital in Lankien, Jonglei State, South Sudan, for the period 2001-2018 were analysed to detect trends in VL relapse as a proportion of all VL cases presenting to MSF treatment centres. Routinely collected patient-level data from relapse and primary VL cases treated at all MSF sites in South Sudan over the same period were analysed to describe patient characteristics and treatments received. VL relapse as a proportion of all VL cases increased by 6.5% per annum (95% CI 0.3% to 13.0%, p = 0.04), from 5.2% during 2001-2003 to 14.4% during 2016-2018. Primary VL and VL relapse patients had similar age, sex and anthropometric characteristics, the latter indicating high indices of undernutrition which were relatively constant over time. Clinical factors (Hb, spleen size, and VL severity score) also did not vary substantially over time. SSG/PM was the main treatment regimen from 2001-2018, used in 68.7% of primary and 70.9% of relapse VL cases; AmBisome was introduced in 2013, received by 22.5% of primary VL and 32.6% of VL relapse cases from 2013-2018.

CONCLUSION

Increasing incidence of VL relapse in South Sudan does not appear to be explained by changes in patient characteristics or other factors. Our data are concerning and may indicate an emergence of treatment-resistant parasite strains, decreasing the effectiveness of treatment regimens. This warrants further investigation as a causal factor. New chemical entities that will enable safe and highly effective short-course oral treatments for VL are urgently needed.

Comparison of serum cytokine levels in symptomatic and asymptomatic HIV-Leishmania coinfected individuals from a Brazilian visceral leishmaniasis endemic area

Background

Visceral leishmaniasis (VL) remains an important infectious disease worldwide. VL-HIV coinfected individuals can present with atypical clinical forms of VL and have a high risk of VL relapse. Some cytokines have been described as potential markers to diagnose active VL and to predict the severity of the cases. However, few studies have included VL-HIV coinfected patients. We aimed to characterize the levels of several cytokines among VL-HIV coinfected individuals living in a VL-endemic area in Northeast Brazil.

Methods

This was a retrospective, cross-sectional study, aiming to estimate the levels of various cytokines in symptomatic and asymptomatic VL-HIV coinfected individuals. There were 134 study participants (35 symptomatic VL-HIV, 75 asymptomatic VL-HIV, and 24 healthy controls), all ≥ 18 years-old. Serum cytokine levels (interferon-γ, tumor necrosis factor, and interleukins 2, 4, 6, 10, and 17A) were quantified using the Becton Dickinson-BD’s Cytometric Bead Array (CBA) system.

Results

The population mainly consisted of men (64.9%), with a median age of 35 (27–41) years. Asymptomatic individuals were younger (p = 0.013), with more years of education (p < 0.001), and were more often on antiretroviral therapy (p < 0.001) than those in the symptomatic group. Hemoglobin levels (p < 0.001), lymphocytes (p < 0.001) and CD4 count (p < 0.001) were lower in symptomatic individuals, while HIV viral loads were higher (p < 0.001). In the symptomatic VL-HIV coinfected group, we observed increased serum levels of IL-17A, IL-6, and IL-10 compared to asymptomatic patients and the healthy controls. There were no differences in the levels of all cytokines between asymptomatic VL-HIV coinfected individuals and the healthy controls.

Conclusions

Higher serum levels of IL-17A, IL-6, and IL-10 cytokines were observed in symptomatic coinfected individuals but not in asymptomatically infected individuals. More studies among HIV-positive persons are needed to better understand the role of serum cytokines for prognosis, to define cure and predict VL relapses in VL-HIV coinfected individuals.

Visceral leishmaniasis (VL) is a parasitic disease, classified as a neglected disease by the World Health Organization. It is present in more than 60 countries in four continents, with most tropical and subtropical countries affected. Without treatment, the disease is fatal. HIV-positive persons are especially affected by VL, with a worst prognosis. One of the main complications is the frequent reactivation of the disease even after successful treatment (VL relapse). Up to now, it is not clear why and when these reactivations occur, and many researches are trying to find some biological markers to answer this. Cytokines are one of these markers that may explain the progression of the disease. In this study, we compared the level of several key cytokines in symptomatic VL-HIV coinfected patients, asymptomatic VL-HIV coinfected individuals, and healthy controls living in a VL-endemic region in Northeastern Brazil. The serum cytokine levels were higher in symptomatic patients when compared with asymptomatic and healthy controls. More studies following VL-HIV patients are necessary to understand how these cytokines and the other biomarkers vary over time and whether they can predict VL relapse, and also the progression and the prognosis of the disease.

Pamidronate, a promising repositioning drug to treat leishmaniasis, displays antileishmanial and immunomodulatory potential

Visceral leishmaniasis (VL) is an infectious disease caused by Leishmania infantum (L. infantum). Currently, there are no vaccines and/or prophylactic therapies against VL, and the recentpharmacological approaches come from the drug repositioning strategy. Here, we evaluated the anticancer drug pamidronate (PAM) to identify a new therapeutic option for the treatment of human VL. We assessed its in vitro antileishmanial activity against the promastigote and amastigote forms of L. infantum by evaluating cell cytotoxicity. The antileishmanial and immunomodulatory activities were assessed using human peripheral blood leukocytes ex vivo. PAM induced the formation of vacuoles in the cytoplasm of the promastigotes and alterations in the morphology of the kinetoplast and mitochondria in vitro, which indicates anti-promastigote activity. PAM also reduced the number of infected macrophages and intracellular amastigotes in a concentration-dependent manner, with cell viability above 70%. In ex vivo, PAM reduced the internalized forms of L. infantum in the classical monocyte subpopulation. Furthermore, it enhanced IL-12 and decreased IL-10 and TGF-β by monocytes and neutrophils. Increased IFN-γ and TNF levels for CD8^- and CD8⁺ T lymphocytes and B lymphocytes, respectively, were observed after the treatment with PAM, as well as a reduction in IL-10 by the lymphocyte subpopulations evaluated. Taken together, our results suggest that PAM may be eligible as a potential therapeutic alternative for drug repurposing to treat human visceral leishmaniasis.

Metalloprotease Gp63-Targeting Novel Glycoside Exhibits Potential Antileishmanial Activity

Visceral leishmaniasis (VL) and post kala-azar dermal leishmaniasis (PKDL) affect most of the poor populations worldwide. The current treatment modalities include liposomal formulation or deoxycholate salt of amphotericin B, which has been associated with various complications and severe side effects. Encouraged from the recent marked antimalarial effects from plant-derived glycosides, in this study, we have exploited a green chemistry-based approach to chemically synthesize a library of diverse glycoside derivatives (Gly1–12) and evaluated their inhibitory efficacy against the AG83 strain of Leishmania donovani. Among the synthesized glycosides, the in vitro inhibitory activity of Glycoside-2 (Gly2) (1.13 µM IC50 value) on L. donovani promastigote demonstrated maximum cytotoxicity with ~94% promastigote death as compared to amphotericin B that was taken as a positive control. The antiproliferative effect of Gly2 on promastigote encouraged us to analyze the structure–activity relationship of Gly2 with Gp63, a zinc metalloprotease that majorly localizes at the surface of the promastigote and has a role in its development and multiplication. The result demonstrated the exceptional binding affinity of Gly2 toward the catalytic domain of Gp63. These data were thereafter validated through cellular thermal shift assay in a physiologically relevant cellular environment. Mechanistically, reduced multiplication of promastigotes on treatment with Gly2 induces the destabilization of redox homeostasis in promastigotes by enhancing reactive oxygen species (ROS), coupled with depolarization of the mitochondrial membrane. Additionally, Gly2 displayed strong lethal effects on infectivity and multiplication of amastigote inside the macrophage in the amastigote–macrophage infection model in vitro as compared to amphotericin B treatment. Gp63 is also known to bestow protection against complement-mediated lysis of parasites. Interestingly, Gly2 treatment enhances the complement-mediated lysis of L. donovani promastigotes in serum physiological conditions. In addition, Gly2 was found to be equally effective against the clinical promastigote forms of PKDL strain (IC50 value of 1.97 µM); hence, it could target both VL and PKDL simultaneously. Taken together, this study reports the serendipitous discovery of Gly2 with potent antileishmanial activity and proves to be a novel chemotherapeutic prototype against VL and PKDL.

TREM-1 Expression on the Surface of Neutrophils in Patients With Visceral Leishmaniasis Is Associated With Immunopathogenesis

Visceral leishmaniasis (VL) is a systemic chronic and potentially fatal disease for humans. Mechanisms related to the dysregulation of the inflammatory response may be involved in both the pathogenesis and prognosis of VL. Triggering Receptor Expressed on Myeloid Cells-1 (TREM-1) is a receptor constitutively expressed on neutrophils and monocyte subsets. The protein serves to regulate and amplify inflammatory responses. This study aimed to evaluate the expression profile of TREM-1 on the surface of neutrophils from patients with VL at varying time points during leishmanicidal treatment. For this purpose, neutrophils were isolated from the peripheral blood of patients with VL at different stages of treatment, which include 0, 7, and 30 days after treatment. Surface TREM-1 expression was assessed by immunophenotyping neutrophil populations. In addition, the association of TREM-1 expression on the surface of neutrophils with clinical and laboratory parameters and serum levels of inflammatory mediators was also evaluated. Results demonstrate a lower surface expression of TREM-1 in VL patients in the absence of treatment. However, increased levels of TREM-1 expression were observed 7 and 30 days after the start of treatment, with levels similar to those of healthy controls. TREM-1 expression was directly correlated with lymphocyte and erythrocyte count and indirectly correlated with spleen and liver size. Furthermore, elevated levels of TREM-1 expression were also correlated with lower serum levels of interleukin (IL)-22. Taken together, these results suggest that infection by Leishmania infantum leads to depressed TREM-1 expression on the neutrophil surface and may contribute to the inflammatory imbalance that characterizes active VL disease.

Immunochemotherapy for visceral leishmaniasis: combinatorial action of Miltefosine plus LBSapMPL vaccine improves adaptative Th1 immune response with control of splenic parasitism in experimental hamster model

The control of human visceral leishmaniasis (VL) is hard since there are no vaccines available as well as the treatment is hampered by toxicity and resistant parasites. Furthermore, as human, and canine VL causes immunosuppression, the combination of drugs with immunostimulatory agents is interesting to upregulate the immunity, reducing side-effects, improving treatment approaches against disease. Herein, we assessed the immunochemotherapy using miltefosine along with a vaccine formulated by Leishmania braziliensis antigens + saponin + monophosphoryl lipid-A (LBSapMPL) in L. infantum-infected hamsters. Two months after infection, the animals received treatments, and after 15 days they were evaluated for the treatment effect. The potential anti-Leishmania effect of miltefosine + LBSapMPL-vaccine was revealed by a specific immune response activation reflecting in control of spleen parasitism using half the miltefosine treatment time. The treated animals also showed an increase of total and T-CD4 splenocytes producing IFN-γ and TNF-α and a decrease of interleukin-10 and anti-Leishmania circulating IgG. In addition, it was demonstrated that the control of spleen parasitism is related to the generation of a protective Th1 immune response. Hence, due to the combinatorial action of miltefosine with LBSapMPL-vaccine in immunostimulating and controlling parasitism, this immunochemotherapy protocol can be an important alternative option against canine and human VL.

Splenectomy for Visceral Leishmaniasis Out of an Endemic Region: A Case Report and Literature Review

Visceral leishmaniasis (also known as kala-azar) is characterized by fever, weight loss, swelling of the spleen and liver, and pancytopenia. If it is not treated, the fatality rate in developing countries can be as high as 100% within 2 years. In a high risk situation for perioperative bleeding due to severe thrombocytopenia/coagulopathy, we present a rare challenge for urgent splenectomy in a patient with previously undiagnosed visceral leishmaniasis. A histologic examination of the spleen revealed a visceral leishmaniasis, and the patient was successfully treated with amphotericin B.