Type I interferons induced by endogenous or exogenous viral infections promote metastasis and relapse of leishmaniasis.

The presence of the endogenous Leishmania RNA virus 1 (LRV1) replicating stably within some parasite species has been associated with the development of more severe forms of leishmaniasis and relapses after drug treatment in humans. Here, we show that the disease-exacerbatory role of LRV1 relies on type I IFN (type I IFNs) production by macrophages and signaling in vivo. Moreover, infecting mice with the LRV1-cured Leishmania guyanensis (LgyLRV1- ) strain of parasites followed by type I IFN treatment increased lesion size and parasite burden, quantitatively reproducing the LRV1-bearing (LgyLRV1+ ) infection phenotype. This finding suggested the possibility that exogenous viral infections could likewise increase pathogenicity, which was tested by coinfecting mice with L. guyanensis and lymphocytic choriomeningitis virus (LCMV), or the sand fly-transmitted arbovirus Toscana virus (TOSV). The type I IFN antiviral response increased the pathology of L. guyanensis infection, accompanied by down-regulation of the IFN-γ receptor normally required for antileishmanial control. Further, LCMV coinfection of IFN-γ-deficient mice promoted parasite dissemination to secondary sites, reproducing the LgyLRV1+ metastatic phenotype. Remarkably, LCMV coinfection of mice that had healed from L. guyanensis infection induced reactivation of disease pathology, overriding the protective adaptive immune response. Our findings establish that type I IFN-dependent responses, arising from endogenous viral elements (dsRNA/LRV1), or exogenous coinfection with IFN-inducing viruses, are able to synergize with New World Leishmania parasites in both primary and relapse infections. Thus, viral infections likely represent a significant risk factor along with parasite and host factors, thereby contributing to the pathological spectrum of human leishmaniasis.

Local Delivery of the Toll-Like Receptor 9 Ligand CpG Downregulates Host Immune and Inflammatory Responses, Ameliorating Established Leishmania (Viannia) panamensis Chronic Infection.

Infection by Leishmania (Viannia) panamensis, the predominant etiologic agent for cutaneous leishmaniasis in Colombia, is characterized by a chronic mixed inflammatory response. Current treatment options are plagued by toxicity, lengthy treatment regimens, and growing evidence of drug resistance. Immunotherapy, modulating the immune system to mount a protective response, may provide an alternate therapeutic approach. We investigated the ability of the Toll-like receptor 9 (TLR9) ligand CpG to modulate established disease in the L (V) panamensis mouse model. Treatment of established infection with a high dose (50 µg) of CpG ameliorated disease and lowered parasite burden. Interestingly, immediately after treatment there was a significant increase in transforming growth factor ß (TGF-ß) and concomitantly an increase in T regulatory cell (Treg) function. Although a general reduction in cell-mediated immune cytokine and chemokine (gamma interferon [IFN-γ], interleukin 10 [IL-10], IL-13, IL-6, granulocyte-macrophage colony-stimulating factor [GM-CSF], IL-4, and MIP-1α) responses of the treated mice was observed, certain chemokines (RANTES, monocyte chemoattractant protein 1[MCP-1], and IP-10) were increased. Further, in peripheral blood mononuclear cells (PBMCs) from patients with cutaneous leishmaniasis, CpG treatment similarly exhibited a dose-response effect on the production of IFN-γ, IL-17, IL-10, and IL-13, with reductions observed at higher doses. To further understand the underlying mechanisms and cell populations driving the CpG mediated response, we examined the ex vivo dose effects mediated by the TLR9+ cell populations (dendritic cells, macrophages, and B cells) found to accumulate labeled CpG in vivo Notably, B cells altered the production of IL-17, IL-13, and IFN-γ, supporting a role for B cells functioning as antigen-presenting cells (APCs) and/or regulatory cells during infection. Interestingly, B cells have been previously demonstrated as a primary type of APC in patients infected with L (V) panamensis and thus may be useful targets of immunotherapy. Collectively, our results show that CpG-induced immune regulation leads to a dampening of the host immune response and healing in the mouse model, and it may provide an alternate approach to treatment of cutaneous leishmaniasis caused by L (V) panamensis.

Deforming Mucocutaneous Leishmaniasis of the Nose.

The authors present a clinical report of deforming mucocutaneous leishmaniasis of the nose in a native American woman, left untreated for 25 years. The nose was reconstructed using the local tissue displaced as flaps, and using cartilage grafts taken from the nasal septum and the ear shell. To the best of the authors' knowledge, the literature offers just 1 report on a similar patient.

Cutaneous and visceral leishmaniasis during anti-TNFα therapy.

The long-term use of novel antipsoriatic systemic biotechnological drugs may increase susceptibility to opportunistic infections. Several cases of visceral leishmaniasis have been reported in immunosuppressed individuals, including those who have been treated with tumour necrosis factor alpha (TNFα) blocking agents. Simultaneous occurrence of cutaneous and visceral involvement has been more rarely recorded in the medical literature. Herein, we describe a case of mucosal leishmaniasis occurring in a farmer living in an endemic region, who was treated with golimumab because of psoriatic arthritis. This highlights the importance of recognizing cutaneous lesions as a first indicator of possible underlying kala-azar disease.

American tegumentary leishmaniasis: T-cell differentiation profile of cutaneous and mucosal forms-co-infection with Trypanosoma cruzi.

American tegumentary leishmaniasis displays two main clinical forms: cutaneous (CL) and mucosal (ML). ML is more resistant to treatment and displays a more severe and longer evolution. Since both forms are caused by the same Leishmania species, the immunological response of the host may be an important factor determining the evolution of the disease. Herein, we analyzed the differentiation and memory profile of peripheral CD4(+) and CD8(+) T lymphocytes of patients with CL and ML and their Leishmania-T. cruzi co-infected counterparts. We measured the expression of CD27, CD28, CD45RO, CD127, PD-1 and CD57, together with interferon-γ and perforin. A highly differentiated phenotype was reflected on both T subsets in ML and preferentially on CD8(+) T cells in CL. A positive trend toward a higher T differentiation profile was found in T. cruzi-infected CL and ML patients as compared with Leishmania single infections. Association between CD8(+) T-cell differentiation and illness duration was found within the first year of infection, with progressive increase of highly differentiated markers over time. Follow-up of patients with good response to therapy showed predominance of early differentiated CD8(+) T cells and decrease of highly differentiated cells, while patients with frequent relapses presented the opposite pattern. CD8(+) T cells showed the most striking changes in their phenotype during leishmaniasis. Patients with long-term infections showed the highest differentiated degree implying a relation between T differentiation and parasite persistence. Distinct patterns of CD8(+) T differentiation during follow-up of different clinical outcomes suggest the usefulness of this analysis in the characterization of Leishmania-infected patients.

Cutaneous and mucocutaneous leishmaniasis: Differential diagnosis, diagnosis, histopathology, and management.

The diagnosis of leishmaniasis can be challenging because it mimics both infectious and malignant conditions. A misdiagnosis may lead to an unfavorable outcome. Using culture, histologic, and/or polymerase chain reaction study results, a diagnosis of leishmaniasis can be established and treatment initiated. Appropriate management requires an accurate diagnosis, which often includes identification of the specific etiologic species. Different endemic areas have varying sensitivities to the same medication, even within individual species. Species identification may be of practical value, because infections with select species have a substantial risk of visceral involvement. In addition, HIV and otherwise immunocompromised patients with leishmaniasis have a propensity for diffuse cutaneous leishmaniasis. For most New World Leishmania species, parenteral antimonial drugs remain the first line of therapy, while Old World species are easily treated with physical modalities. Historically, live organism vaccination has been used and is effective in preventing leishmaniasis, but results in an inoculation scar and an incubation period that may last for years. A more effective method of vaccination would be welcome.

Mucosal leishmaniasis with primary oral involvement: a case series and a review of the literature.

OBJECTIVE: To analyze retrospectively a case series of primary oral leishmaniasis and to review the literature on head-neck primary mucosal leishmaniasis (ML) in immunocompetent patients. SUBJECTS AND METHODS: A PUBMED search was carried out from 1950 to 2013. Clinical records of patients with primary head-neck mucosal manifestations of leishmaniasis were analyzed. In addition, clinical records between 2001 and 2012 of patients with primary oral manifestations were collected in two independent hospitals. RESULTS: Our multicenter case series revealed seven patients with oral leishmaniasis. The most commonly affected site was the tongue (four patients, 57%), and the most common clinical presentation was an exophytic lesion (six patients, 85%). The literature review showed 11 reports published between 2005 and 2013, describing 13 patients (100% male) affected by head-neck primary ML (54% laryngeal, 31% oral, 23% pharyngeal, and 15% endonasal). The most common clinical presentation was an exophytic lesion (69%). CONCLUSIONS: The literature analysis revealed that in immunocompetent patients, the oral mucosa is the second most frequently affected site of the head and neck region. In the oral cavity, the tongue is the most affected site. Diagnosis of oral leishmaniasis represents a challenge but must be considered in any differential diagnosis of exophytic lesions of oral mucosa.

Salivary gland homogenates from wild-caught sand flies Lutzomyia flaviscutellata and Lutzomyia (Psychodopygus) complexus showed inhibitory effects on Leishmania (Leishmania) amazonensis and Leishmania (Viannia) braziliensis infection in BALB/c mice.

During the natural transmission of Leishmania parasites, the infected sand fly female regurgitates promastigotes into the host's skin together with its saliva. It has been reported that vector saliva contains immunomodulatory molecules that facilitate the establishment of infection. Thus, the main objective of this study was to evaluate the specificity of Lutzomyia (Lu.) flaviscutellata and Lu. (Psychodopygus) complexus salivas on the infectivity of Leishmania (L.) (Leishmania) amazonensis and L. (Viannia) braziliensis, respectively. BALB/c mice were inoculated into the skin of hind footpad with L. (L.) amazonensis and L. (V.) braziliensis promastigotes in the absence or presence of Lu. flaviscutellata and Lu. (P.) complexus salivary gland homogenates (SGHs). The evolution of the infection was evaluated by lesion size, histopathological analysis and determination of the parasite load in the skin biopsies collected from the site of infection at 4 and 8 weeks PI. The lesion size and the parasite load of both groups of mice infected in the presence of SGHs were smaller than the control groups. The histopathological features showed that the inflammatory reaction was less prominent in the groups of mice infected in the presence of both SGHs when compared to the control group. The results showed that the presence of SGHs of Lu. flaviscutellata and Lu. (P.) complexus led to induction of processes that were disadvantageous to parasite establishment during infection by L. (L.) amazonensis and L. (V.) braziliensis. An inhibitory effect on Leishmania infection could be observed in both groups inoculated with SGHs, especially when the SGH from Lu. (P.) complexus was used.

Oral Leishmaniasis in HIV-Positive and HIV-Negative Patients: A Comparative Analysis with Two New Case Reports.

PURPOSE: This case report examines the clinical presentation, diagnosis, treatment, and outcomes of mucocutaneous leishmaniasis with primary oral involvement in HIV-positive and HIV-negative patients diagnosed in Brazil. METHODS: We discuss the clinical manifestations, diagnostic methods, and therapeutic strategies, highlighting the clinical and histopathologic diagnostic features and distinct progression patterns based on HIV status. Our findings are compared with patterns observed in other countries, emphasizing the differences between the Americas and Europe, Asia, and Africa. RESULTS: In the Americas, particularly in Brazil, mucocutaneous leishmaniasis often presents with localized oral lesions, even in the presence of systemic immunosuppression, whereas in the Europe, Asia, and Africa, oral involvement is typically associated with visceral leishmaniasis in immunocompromised patients. These differences were due to variations in the parasite species involved. CONCLUSION: This comparison underscores the importance of regional and immunological factors in diagnosing and managing this neglected infectious disease.

Golden hamster (Mesocricetus auratus) as an experimental model for Leishmania (Viannia) braziliensis infection.

The lack of an adequate model for Leishmania (Viannia) braziliensis infection is a limiting factor for studying American tegumentary leishmaniasis (ATL). The golden hamster (Mesocricetus auratus) is a promising model because besides being highly susceptible to dermotropic Leishmania infection, the lesions are very similar to cutaneous leishmaniasis (CL) in humans. However, different Leishmania isolates or species and/or protocols have resulted in different outcomes, whereas no study has evaluated the reproducibility of L. braziliensis infection in this model. The natural history of L. braziliensis infection in 34 hamsters was evaluated by using a single parasite isolate in 8 independent experiments under similar experimental conditions. Clinical, histological and immunological analyses were performed. The hamsters presented skin ulcers similar to those observed in ATL. The intra-experiment lesion increment tended to show an intermediary variance. Histological analysis of infected skins showed granulomatous reaction, scarce amastigotes, and Schaumann's bodies. Blood lymphocytes proliferated in response to leishmanial antigens. The severity of the infection was positively correlated to spleen weight, and the titres of anti-Leishmania IgG antibodies. Our findings indicate that the hamster is an appropriate model for immunopathogenesis studies of CL caused by L. braziliensis, supporting its use in clinical, vaccine and chemotherapy experimental protocols.

Fever with perinasal and tongue lesions: A diagnostic challenge.

The diagnosis may be challenging, and high suspicion index should be maintained in immunosuppressed patients with unusual mucocutaneous lesions, even in non-endemic areas for mucocutaneous leishmaniasis.

Mixed mucosal leishmaniasis infection caused by Leishmania tropica and Leishmania major.

Mixed infections with different Leishmania species could explain differences in the clinical courses of these infections. On identification of Leishmania parasites from Iranian patients with mucosal leishmaniasis (ML), a patient with both oral and nasal lesions was found to be concomitantly infected with Leishmania tropica and L. major. Mixed infection was identified by PCR amplification of Leishmania kinetoplast DNA on scraping of cytological smears and histopathological sections. L. major and L. tropica were isolated from the nasal and oral lesions, respectively. These species were also confirmed by immunohistochemistry. This seems to be the first reported case of concurrent ML infection with two Leishmania species. It indicates that, at least in this patient, previous infection with one of these Leishmania species did not protect against infection with the other. This result has important implications for the development of vaccines against leishmaniases and implies careful attention in the treatment of this infectious disease.

Acute New World cutaneous leishmaniasis presenting as tuberculoid granulomatous dermatitis.

Acute primary cutaneous leishmaniasis typically presents microscopically with a lymphohistiocytic infiltrate containing admixed plasma cells, parasitized macrophages and abundant organisms. Tuberculoid granulomatous changes may occur in the later phases of primary infection. A 23-year-old male presented 1 month after visiting Peru with classic clinical findings of acute primary cutaneous leishmaniasis, while histopathology showed a tuberculoid granulomatous process that lacked any organisms in hematoxylin-eosin and fungal stains. Polymerase chain reaction (PCR) analysis and tissue cultures confirmed the diagnosis of cutaneous leishmaniasis with Leishmania (Viannia) panamensis infection. A pauci-organism tuberculoid granulomatous process may uncommonly be the presenting histopathology in the acute infectious phase of cutaneous leishmaniasis. Clinicians and dermatopathologists should be aware of this atypical presentation, which may cause diagnostic confusion and delay proper treatment. PCR testing should be employed in cases with high clinical suspicion when histopathology is not definitive.

Molecular diagnosis and species identification of mucosal leishmaniasis in Iran and correlation with cytological findings.

OBJECTIVE: Mucosal leishmaniasis (ML) is a rare destructive disease that mainly affects the mucous membranes of the mouth and nose. The etiologic agent(s) of ML are not well known in the Middle East. STUDY DESIGN: Cytologic smears of ML from the mucosal lesions of 7 patients were prepared by scraping. In 2 patients with nasal lesions, exfoliative cytology was made by washing the nasal cavity. The smears were both air dried and fixed in alcohol and stained. Scrapings from the same smears were then tested for leishmanial DNA by nested PCR. RESULTS: This study characterized 9 isolates of ML, with 7 cases identified as Leishmania major and 2 as Leishmania tropica. While 6 patients were found to be positive by the cytology technique, the nested PCR was positive for all of these samples. CONCLUSIONS: Presence of granuloma and multinucleated giant cells in the negative smears of the patients who showed clinical manifestation of ML was an important clue for diagnosis of this disease. The PCR-based method not only appears to be a precise diagnostic approach in the identification of suspected cases of ML but is also efficient in determining the species of the parasite. L. major and L. tropica can lead to ML, but they result in different cytologic features.

Atypical mucocutaneous involvement with Leishmania donovani.

Mucocutaneous leishmaniasis has rarely been reported from India. The usual causative organisms of this infection are Leishmania braziliensis and L. tropica. Another species, L. donovani, which usually causes visceral leishmaniasis, has recently been reported to cause mucocutaneous disease in a few patients from Sri Lanka. We report two patients who had undiagnosed chronic skin lesions for several years. Skin biopsies revealed Leishmania and the species was characterized as L. donovani in both patients. There was considerable improvement in the skin lesions following treatment with liposomal amphotericin B.

[Cutaneous leishmaniasis as travelers' disease. Clinical presentation, diagnostics and therapy]. / Kutane Leishmaniasis als Reisedermatose. Klinik, Diagnostik und Therapie.

Leishmaniasis is a disease with worldwide increasing incidence, which in Germany is almost exclusively observed in patients who have travelled to classical endemic regions such as the Mediterranean basin. Cause of the disease is an infection with protozoan parasites of the genus Leishmania, which are transmitted by sand flies and replicate intracellularly within mammalian hosts. Depending on the inoculated parasite (sub-) species and the immune status of the host, a local cutaneous, diffuse cutaneous, mucocutaneous or visceral form of leishmaniasis will develop. Cutaneous leishmaniasis, which frequently appears only weeks after the bite of a sand fly, starts with the formation of a papule, which subsequently can turn into a skin ulcer. The latter may heal spontaneously after months leaving behind a scar or persist as chronic, non-healing cutaneous leishmaniasis. If cutaneous leishmaniasis is suspected, a sterile skin biopsy followed by appropriate diagnostic measures in a specialized laboratory to identify the pathogen should be performed. For the decision on the type of therapy, several clinical parameters (e.g. number and localization of lesions, immune status) and, most importantly, the underlying parasite (sub-) species need to be considered. Therapy can consist of a variety of topical measures or systemic drug treatment. A modern and safe vaccine does not yet exist.

Leishmania RNA virus-1 is similarly detected among metastatic and non-metastatic phenotypes in a prospective cohort of American Tegumentary Leishmaniasis.

American Tegumentary Leishmaniasis (ATL) is an endemic and neglected disease of South America. Here, mucosal leishmaniasis (ML) disproportionately affects up to 20% of subjects with current or previous localised cutaneous leishmaniasis (LCL). Preclinical and clinical reports have implicated the Leishmania RNA virus-1 (LRV1) as a possible determinant of progression to ML and other severe manifestations such as extensive cutaneous and mucosal disease and treatment failure and relapse. However, these associations were not consistently found in other observational studies and are exclusively based on cross-sectional designs. In the present study, 56 subjects with confirmed ATL were assessed and followed out for 24-months post-treatment. Lesion biopsy specimens were processed for molecular detection and quantification of Leishmania parasites, species identification, and LRV1 detection. Among individuals presenting LRV1 positive lesions, 40% harboured metastatic phenotypes; comparatively 58.1% of patients with LRV1 negative lesions harboured metastatic phenotypes (p = 0.299). We found treatment failure (p = 0.575) and frequency of severe metastatic phenotypes (p = 0.667) to be similarly independent of the LRV1. Parasite loads did not differ according to the LRV1 status (p = 0.330), nor did Leishmanin skin induration size (p = 0.907) or histopathologic patterns (p = 0.780). This study did not find clinical, parasitological, or immunological evidence supporting the hypothesis that LRV1 is a significant determinant of the pathobiology of ATL.

Recurrent leishmaniasis in kidney transplant recipients: report of 2 cases and systematic review of the literature.

The characteristics of 8 episodes of leishmaniasis with atypical manifestations in 2 Italian kidney transplant recipients are analyzed and contextualized among those of 52 other episodes of leishmaniasis observed in 19 transplant recipients found through a systematic review of the international literature. In all the patients, the initial episode was visceral leishmaniasis, which was associated with mucocutaneous involvement in 2 cases. With the exception of 1 case of post kala-azar dermal leishmaniasis, 2 episodes of Leishmania endophthalmitis, and 3 episodes of mucocutaneous leishmaniasis, all the recurrences were characterized by visceral involvement. The potential role of polymerase chain reaction in monitoring the infection, the importance of a long follow-up, the potential benefit of chemoprophylaxis, and the therapeutic challenges are discussed.

Tongue Nodule as Primary Manifestation of American Cutaneous Leishmaniasis in an Immunocompetent Patient.

Leishmaniasis is a parasitic disease considered an endemic public health problem in developing countries, where it is a reportable disease. Isolated oral manifestation is rare, and its clinical manifestations are variable. In this paper we describe an unusual case of an immunocompetent patient, 57-year-old man with a painless reddish submucosal nodule located on the tongue dorsum. Microscopical analysis showed chronic inflammatory infiltrate with macrophages containing leishmania in cytoplasmic vacuoles. PCR assays confirmed the diagnosis and patient was treated with meglumine antimoniate for 30 days. Absence of the parasite was confirmed by PCR. Thirteen years after treatment, a scar fibrosis persisted on the tongue dorsum. The case reported reveals that leishmaniasis should be considered in the diagnosis of tongue nodules in immunocompetent patients.