Visceral leishmaniasis. Persistence of parasites in lymph nodes after clinical cure

Systematic Review of Treatment Failure and Clinical Relapses in Leishmaniasis from a Multifactorial Perspective: Clinical Aspects, Factors Associated with the Parasite and Host

Leishmaniasis is a disease caused by protozoa of the genus Leishmania. Treatment options are limited, and there are frequent cases of treatment failure and clinical relapse. To understand these phenomena better, a systematic review was conducted, considering studies published between 1990 and 2021 in Portuguese, English, and Spanish. The review included 64 articles divided into three categories. Case reports (26 articles) focused on treatment failure and clinical relapse in cutaneous leishmaniasis patients (47.6%), primarily affecting males (74%) and children (67%), regardless of the clinical manifestation. Experimental studies on the parasite (19 articles), particularly with L. major (25%), indicated that alterations in DNA and genic expression (44.82%) played a significant role in treatment failure and clinical relapse. Population data on the human host (19 articles) identified immunological characteristics as the most associated factor (36%) with treatment failure and clinical relapse. Each clinical manifestation of the disease presented specificities in these phenomena, suggesting a multifactorial nature. Additionally, the parasites were found to adapt to the drugs used in treatment. In summary, the systematic review revealed that treatment failure and clinical relapse in leishmaniasis are complex processes influenced by various factors, including host immunology and parasite adaptation.

Dosing implications for liposomal amphotericin B in pregnancy

Liposomal amphotericin B (LAmB) is used in the treatment of opportunistic fungal and parasitic infections, including leishmaniasis. Given its lack of known teratogenicity in pregnancy, LAmB is a preferred agent for treatment for these patients. However, significant gaps remain in determining optimal dosing regimens for LAmB in pregnancy. We describe the use of LAmB for a pregnant patient with mucocutaneous leishmaniasis (MCL) using a dosing strategy of 5 mg/kg/day for days 1-7 using ideal body weight followed by 4 mg/kg weekly using adjusted body weight. We reviewed the literature for LAmB dosing strategies, particularly dosing weight, in pregnancy. Of the 143 cases identified in 17 studies, only one reported a dosing weight, in which ideal body weight was used. Five Infectious Diseases Society of America guidelines in total discussed the use of amphotericin B in pregnancy but no guidelines included recommendations for dosing weight. This review describes our experience in using ideal body weight for dosing LAmB in pregnancy for the treatment of MCL. Use of ideal body weight may minimize risk of adverse effects to the fetus compared to the use of total body weight while maintaining efficacy for treatment of MCL in pregnancy.

Review of the Clinical Presentation, Pathology, Diagnosis, and Treatment of Leishmaniasis

Leishmaniasis is a vector-borne infection caused by kinetoplastid protozoans in the genera Leishmania and Endotrypanum. The disease occurs worldwide in the tropics and subtropics and can be particularly burdensome in resource-limited settings. Diseases caused by leishmaniasis range in severity from mild cutaneous lesions to life-threatening visceral and disfiguring mucocutaneous illnesses. Rapid and accurate diagnosis is needed to ensure proper clinical management of patients afflicted with this disease. Complicating matters of diagnosis and treatment are the diversity of species within these 2 genera and the variable specificity of diagnostic assays. This mini-review provides laboratory professionals with an overview of Leishmania epidemiology, biology, pathogenesis, clinical presentations, and treatments with additional emphasis placed on the nuances involved in diagnosis.

The BRCT Domain from the Homologue of the Oncogene PES1 in Leishmania major (LmjPES) Promotes Malignancy and Drug Resistance in Mammalian Cells

Around 15% of cancer cases are attributable to infectious agents. Epidemiological studies suggest that an association between leishmaniasis and cancer does exist. Recently, the homologue of PES1 in Leishmania major (LmjPES) was described to be involved in parasite infectivity. Mammalian PES1 protein has been implicated in cellular processes like cell cycle regulation. Its BRCT domain has been identified as a key factor in DNA damage-responsive checkpoints. This work aimed to elucidate the hypothetical oncogenic implication of BRCT domain from LmjPES in host cells. We generated a lentivirus carrying this BRCT domain sequence (lentiBRCT) and a lentivirus expressing the luciferase protein (lentiLuc), as control. Then, HEK293T and NIH/3T3 mammalian cells were infected with these lentiviruses. We observed that the expression of BRCT domain from LmjPES conferred to mammal cells in vitro a greater replication rate and higher survival. In in vivo experiments, we observed faster tumor growth in mice inoculated with lentiBRCT respect to lentiLuc HEK293T infected cells. Moreover, the lentiBRCT infected cells were less sensitive to the genotoxic drugs. Accordingly, gene expression profiling analysis revealed that BRCT domain from LmjPES protein altered the expression of proliferation- (DTX3L, CPA4, BHLHE41, BMP2, DHRS2, S100A1 and PARP9), survival- (BMP2 and CARD9) and chemoresistance-related genes (DPYD, Dok3, DTX3L, PARP9 and DHRS2). Altogether, our results reinforced the idea that in eukaryotes, horizontal gene transfer might be also achieved by parasitism like Leishmania infection driving therefore to some crucial biological changes such as proliferation and drug resistance.

Visceral leishmaniasis caused by Leishmania (Leishmania) amazonensis associated with Hodgkin's lymphoma

Visceral leishmaniasis (VL) is mainly caused by Leishmania (Leishmania) donovani and Leishmania (L.) infantum; however, other Leishmania species have been associated with VL. We report a case of a patient simultaneously diagnosed with VL caused by Leishmania (L.) amazonensis and Hodgkin’s lymphoma. After treatment with liposomal amphotericin B and chemotherapy, the patient presented a clinical cure. This case report reinforces the hypothesis that other Leishmania species can cause visceral lesions mainly related to immunosuppression.

Visceral Leishmaniasis in pregnancy and vertical transmission: A systematic literature review on the therapeutic orphans

Background

Reports on the occurrence and outcome of Visceral Leishmaniasis (VL) in pregnant women is rare in published literature. The occurrence of VL in pregnancy is not systematically captured and cases are rarely followed-up to detect consequences of infection and treatment on the pregnant women and foetus.

Methods

A review of all published literature was undertaken to identify cases of VL infections among pregnant women by searching the following database: Ovid MEDLINE; Ovid Embase; Cochrane Database of Systematic Reviews; Cochrane Central Register of Controlled Trials; World Health Organization Global Index Medicus: LILACS (Americas); IMSEAR (South-East Asia); IMEMR (Eastern Mediterranean); WPRIM (Western Pacific); ClinicalTrials.gov; and the WHO International Clinical Trials Registry Platform. Selection criteria included any clinical reports describing the disease in pregnancy or vertical transmission of the disease in humans. Articles meeting pre-specified inclusion criteria and non-primary research articles such as textbook, chapters, letters, retrospective case description, or reports of accidental inclusion in trials were also considered.

Results

The systematic literature search identified 272 unique articles of which 54 records were included in this review; a further 18 records were identified from additional search of the references of the included studies or from personal communication leading to a total of 72 records (71 case reports/case series; 1 retrospective cohort study; 1926–2020) describing 451 cases of VL in pregnant women. The disease was detected during pregnancy in 398 (88.2%), retrospectively confirmed after giving birth in 52 (11.5%), and the time of identification was not clear in 1 (0.2%). Of the 398 pregnant women whose infection was identified during pregnancy, 346 (86.9%) received a treatment, 3 (0.8%) were untreated, and the treatment status was not clear in the remaining 49 (12.3%). Of 346 pregnant women, Liposomal amphotericin B (L-AmB) was administered in 202 (58.4%) and pentavalent antimony (PA) in 93 (26.9%). Outcomes were reported in 176 pregnant women treated with L-AmB with 4 (2.3%) reports of maternal deaths, 5 (2.8%) miscarriages, and 2 (1.1%) foetal death/stillbirth. For PA, outcomes were reported in 88 of whom 4 (4.5%) died, 24 (27.3%) had spontaneous abortion, 2 (2.3%) had miscarriages. A total of 26 cases of confirmed, probable or suspected cases of vertical transmission were identified with a median detection time of 6 months (range: 0–18 months).

Conclusions

Outcomes of VL treatment during pregnancy is rarely reported and under-researched. The reported articles were mainly case reports and case series and the reported information was often incomplete. From the studies identified, it is difficult to derive a generalisable information on outcomes for pregnant women and babies, although reported data favours the usage of liposomal amphotericin B for the treatment of VL in pregnant women.

Visceral Leishmaniasis (VL) is a neglected tropical disease with an estimated incidence of 50,000 to 90,000 cases in 2019. Women who are susceptible to becoming pregnant or those who are pregnant and lactating are regularly excluded from clinical studies of VL. A specific concern of public health relevance is the little knowledge of the consequences of VL and its treatment on the mother and the foetus. We did a systematic review of all published literature with an overarching aim of identifying cases of VL in pregnancy and assessing the risk-benefit balance of antileishmanial treatment to the pregnant women and the child. We identified a total of 72 records (1926–2020) describing 451 VL cases in pregnant women. In 398, infection was identified during pregnancy of whom 202 received Liposomal Amphotericin B (L-AmB) and 93 received pentavalent antimony (PA). In studies that reported maternal outcomes, reports of maternal death abortion/spontaneous abortion, and miscarriages were proportionally lower among those who received L-AmB compared to PA (no formal test of significance carried out). A total of 26 cases of confirmed, probable or suspected cases of vertical transmission were identified and the median time to detection was 6 months (range: 0–18 months). Our review brings together scattered observations of VL in pregnant women in the clinical literature and clearly highlights that the disease in pregnancy is under-reported and under-studied. The collated evidence derived mainly from case reports and case series indicate that L-AmB has a favourable safety profile than the antimony regimen and should be the preferred treatment for VL during pregnancy.

Comparison of Three In-House Real PCR Assays Targeting Kinetoplast DNA, the Small Subunit Ribosomal RNA Gene and the Glucose-6-Phosphate Isomerase Gene for the Detection of Leishmania spp. in Human Serum

To perform PCR from serum for the diagnosis of visceral leishmaniasis is convenient and much less invasive than the examination of deeper compartments such as bone marrow. We compared three Leishmania-specific real-time PCRs with three different molecular targets (kinetoplast DNA, the small subunit-ribosomal RNA-(ssrRNA-)gene, the glucose-6-phosphate isomerase-(gpi-)gene) regarding their sensitivity and specificity in human serum. Residual sera from previous diagnostic assessments at the German National Reference Center for Tropical Pathogens Bernhard Nocht Institute for Tropical Medicine Hamburg and the Swiss Tropical and Public Health Institute were used. The sensitivities of kinetoplast DNA-PCR, ssrRNA-gene PCR, and gpi-PCR were 93.3%, 73.3%, and 33.3%, respectively, with 15 initial serum samples from visceral leishmaniasis patients, as well as 9.1%, 9.1%, and 0.0%, respectively, with 11 follow-up serum samples taken at various time points following anti-leishmanial therapy. Specificity was 100.0% in all assays as recorded with 1.137 serum samples from deployed soldiers and migrants without clinical suspicion of visceral leishmaniasis. Kinetoplast-DNA PCR from serum was confirmed as a sensitive and specific approach for the diagnosis of visceral leishmaniasis. The results also indicate the suitability of serum PCR for diagnostic follow-up after therapy, in particular regarding therapeutic failure in case of persisting positive PCR results.

Is splenectomy an option for multiple relapses in a child with visceral leishmaniasis? A case report

Visceral leishmaniasis (VL) is an infectious disease caused by Leishmania spp. The recurrence of the disease occurs, in general, in patients with decreased or loss of T-cell function, whether due to the use of corticosteroids, immunosuppressive disease, or another cause. In some cases, splenectomy may be a therapeutic option. However, the effectiveness of splenectomy is not well defined. This report describes the evolution of a pediatric patient with seven recurrences of VL, who relapsed post-surgery after drug therapy and splenectomy.

[Cutaneous leishmaniasis]

Cutaneous leishmaniasis is a parasitic infection caused by a flagellated parasite belonging to the genus Leishmania. In most cases, it is a zoonotic disease transmitted via a bite by bloodsucking sand-flies of the genus Phlebotomus. The disease reservoirs consist of wild or semi-domesticated animals, generally rodents or dogs. The disease itself is distributed extensively worldwide in the Americas, Asia, Europe and Africa. Epidemiology is affected by environmental, migratory and climatic factors. Identification of the different types of leishmaniasis is based chiefly on the biochemical characteristics (isoenzymes) on which their classification is based. The offending parasites are dimorphic intracellular organisms within the phagosome of the host's immune cells, and a single-cell flagellated protozoan with a kinetoplast contained in the gut of the vector and in culture. Three major clinical forms are seen: cutaneous leishmaniasis, mucosal leishmaniasis and visceral leishmaniasis. The clinical presentation depends on factors associated with the virulence of the parasite, with individual immune response and with the site of lesions. Although each type of leishmaniasis may have its own specific cutaneous signs and endemic regions, the most common presentations are crusted, ulcerated nodules and plaques. The natural history of leishmaniasis must also be considered when formulating therapeutic strategies. Cutaneous leishmaniasis resolves spontaneously within between one month and six years. While numerous therapeutic options have been considered in recent decades, very few have shown proven efficacy and safety. Antimony compounds administered either directly to the lesion or parenterally remain the standard treatment and their toxicity calls for vigilance and monitoring of therapy.

Long term outcomes and prognostics of visceral leishmaniasis in HIV infected patients with use of pentamidine as secondary prophylaxis based on CD4 level: a prospective cohort study in Ethiopia

Background

The long-term treatment outcome of visceral leishmaniasis (VL) patients with HIV co-infection is complicated by a high rate of relapse, especially when the CD4 count is low. Although use of secondary prophylaxis is recommended, it is not routinely practiced and data on its effectiveness and safety are limited.

Methods

A prospective cohort study was conducted in Northwest Ethiopia from August 2014 to August 2017 (NCT02011958). HIV-VL patients were followed for up to 12 months. Patients with CD4 cell counts below 200/μL at the end of VL treatment received pentamidine prophylaxis starting one month after parasitological cure, while those with CD4 count ≥200 cells/μL were followed without secondary prophylaxis. Compliance, safety and relapse-free survival, using Kaplan-Meier analysis methods to account for variable time at risk, were summarised. Risk factors for relapse or death were analysed.

Results

Fifty-four HIV patients were followed. The probability of relapse-free survival at one year was 50% (95% confidence interval [CI]: 35–63%): 53% (30–71%) in 22 patients with CD4 ≥200 cells/μL without pentamidine prophylaxis and 46% (26–63%) in 29 with CD4 <200 cells/μL who started pentamidine. Three patients with CD4 <200 cells/μL did not start pentamidine. Amongst those with CD4 ≥200 cells/μL, VL relapse was an independent risk factor for subsequent relapse or death (adjusted rate ratio: 5.42, 95% CI: 1.1–25.8). Except for one case of renal failure which was considered possibly related to pentamidine, there were no drug-related safety concerns.

Conclusion

The relapse-free survival rate for VL patients with HIV was low. Relapse-free survival of patients with CD4 count <200cells/μL given pentamidine secondary prophylaxis appeared to be comparable to patients with a CD4 count ≥200 cells/μL not given prophylaxis. Patients with relapsed VL are at higher risk for subsequent relapse and should be considered a priority for secondary prophylaxis, irrespective of their CD4 count.

Achieving parasitological cure at the end of visceral leishmaniasis (VL) treatment in HIV co-infected patients does not assure definitive cure, as the disease will recur within a year in many patients. In this cohort study, the probability of relapse-free survival at one-year was 50% in all patients. The use of monthly pentamidine infusion for those with lower CD4 counts (<200 cells/μL) at the time of VL cure appeared to result in a comparable relapse-free survival rate to those patients with higher CD4 count (≥200 cells/μL) who did not receive secondary prophylaxis. On the other hand, patients with a history of previous VL treatment (VL relapse) remained at high risk of relapse despite achieving CD4 count ≥200 cells/μL at the end of the VL treatment. While all VL patients with HIV co-infection may benefit from secondary prophylaxis, those with CD4 <200 cells/μL and previous history of treatment should be prioritized for secondary prophylaxis. New modalities for prevention of VL relapse in HIV patients should also be explored.

T-cell tolerance as a potential effect of congenital leishmaniasis on offspring immunity

Congenital transmission of leishmaniasis is recognized in cases detected by passive surveillance. Most cases are from low-resource countries, limiting the study of several important aspects of this route of infection, including the offspring's immune response. Studies on natural and experimentally infected animals suggest that parasites might be transmitted to the embryo or foetus at any time during pregnancy. As immune system undergoes sequential stages of development, an infection before the time of self-recognition could lead to central tolerance, making an individual specifically tolerant and susceptible to infection. In the alternative scenario, infection after self-recognition would allow the proper development of T-lymphocyte clones in response to Leishmania antigens, providing resistance to the disease. Newborns undergo a transient period of low expression of several immune surface molecules and a naïve adaptive immune response with no memory, which together might contribute to slow elimination of the parasite over several months. This insight is a proposed independent mechanism of the previously proven T-cell exhaustion and must be investigated. Analyses of infected placenta, cord blood and infant immunity are required for a better understanding of immunity in congenital leishmaniasis infection.

Evaluation of a Pan-Leishmania Spliced-Leader RNA Detection Method in Human Blood and Experimentally Infected Syrian Golden Hamsters

Several methods have been developed for the detection of Leishmania, mostly targeting the minicircle kinetoplast DNA (kDNA). A new RNA real-time quantitative PCR (qPCR) assay was developed targeting the conserved and highly expressed spliced-leader (SL) mini-exon sequence. This study compared the limits of detection of various real-time PCR assays in hamsters infected with Leishmania infantum, in spiked human blood, and in clinical blood samples from visceral leishmaniasis patients. The SL-RNA assay showed an excellent analytical sensitivity in tissues (0.005 and 0.002 parasites per mg liver and spleen, respectively) and was not prone to false-positive reactions. Evaluation of the SL-RNA assay on clinical samples demonstrated lower threshold cycle values than the kDNA qPCR, an excellent interrun stability of 97%, a 93% agreement with the kDNA assay, and an estimated sensitivity, specificity, and accuracy of 93.2%, 94.3%, and 93.8%, respectively. The SL-RNA qPCR assay was equally efficient for detecting Leishmania major, Leishmania tropica, Leishmania mexicana, Leishmania guayensis, Leishmania panamensis, Leishmania braziliensis, L. infantum, and Leishmania donovani and revealed similar SL-RNA levels in the different species and the occurrence of polycistronic SL-containing transcripts in Viannia species. Collectively, this single SL-RNA qPCR assay enables universal Leishmania detection and represents a particularly useful addition to the widely used kDNA assay in clinical studies in which the detection of viable parasites is pivotal to assess parasitological cure.

Withania somnifera chemotype NMITLI 101R significantly increases the efficacy of antileishmanial drugs by generating strong IFN-γ and IL-12 mediated immune responses in Leishmania donovani infected hamsters

BACKGROUND

Withania somnifera (L.) Dunal (Solanaceae), commonly known as Ashwagandha, is one of the most important medicinal plant in the traditional Indian medical systems. Pharmacological studies have established that root extracts of W. somnifera contain several bioactive constituents called withanolides. The plant has long been used for its several beneficial properties and recently as an immunomodulator.

HYPOTHESIS/PURPOSE

A combination therapy including a potential and safe immunostimulant with lower doses of effective drug, which can reduce the parasitic burden and simultaneously can produce an enhancement of adaptive immunity, has proven to be significantly a more effective approach than immunotherapy or drug therapy alone.

STUDY DESIGN

Evaluation of the immunostimulatory effect of W. somnifera chemotype NMITLI 101R when used in combination with ED₅₀ doses of antileishmanial drugs in Leishmania donovani infected hamsters.

METHODS

Infected animals were administered with chemotype 101R(30mg/kg × 15 days) either alone or in combination with ED₅₀ doses of miltefosine (10mg/kg × 5 days), paromomycin (30mg/kg × 5 days) or amphotericin B (0.5mg/kg × 5 days). The treated animals were euthanized on days 30 and 60 post-treatment (p.t.) and checked for parasite clearance, delayed type hypersensitivity (DTH) response, cytokine and inducible nitric oxide synthase levels by real-time PCR, nitric oxide (NO) production, reactive oxygen species (ROS) generation, lymphoproliferative and antibody responses.

RESULTS

The group of animals that received 101R and ED₅₀ dose of miltefosine showed optimum inhibition of parasite multiplication (∼98%) by day 60 p.t. followed by the group that received 101R plus paromomycin (∼94%) and 101R plus amphotericin B (∼93%). The efficacy was well supported by the increased inducible NO synthase mRNA transcript, strong IFN-γand IL-12 mediated Th1 immune responses and significantly suppressed levels of Th2 cytokines (IL-4, IL-10 and TGF-β). Additionally, same therapy also induced significant increase in the level of NO production, ROS generation, Leishmania specific IgG2 antibody along with profound DTH and strong T-cell responses as compared with all the other treated groups.

CONCLUSION

Our results suggest that combination of chemotype 101R with ED₅₀ doses of antileishmanial drugs may provide a promising alternative for the cure of visceral leishmaniasis with significant restoration of the host immune response.

Leishmaniasis-HIV coinfection: current challenges

Leishmaniasis – human immunodeficiency virus (HIV) coinfection can manifest itself as tegumentary or visceral leishmaniasis. Almost 35 countries have reported autochthonous coinfections. Visceral leishmaniasis is more frequently described. However, usual and unusual manifestations of tegumentary leishmaniasis have been reported mainly in the Americas, but the real prevalence of Leishmania infection in HIV-infected patients is not clear. Regarding the clinical manifestations, there are some reports showing unusual manifestations in visceral leishmaniasis and tegumentary leishmaniasis in HIV-infected patients; yet, the usual manifestations are more frequent. Leishmaniasis diagnosis relies on clinical methods, but serological tests are used to diagnose visceral leishmaniasis despite them having a low sensitivity to tegumentary leishmaniasis. The search for the parasite is used to diagnose both visceral leishmaniasis and tegumentary leishmaniasis. Nevertheless, in HIV-infected patients, the sensitivity of serology is very low. Drugs available to treat leishmaniasis are more restricted and cause severe side effects. Furthermore, in HIV-infected patients, these side effects are more prominent and relapses and lethality are more recurrent. In this article, we discuss the current challenges of tegumentary leishmaniasis and visceral leishmaniasis–HIV infection, focusing mainly on the clinical manifestations, diagnosis, and treatment of leishmaniasis.

Molecular detection of infection homogeneity and impact of miltefosine treatment in a Syrian golden hamster model of Leishmania donovani and L. infantum visceral leishmaniasis

Control of visceral leishmaniasis caused by Leishmania infantum and Leishmania donovani primarily relies on chemotherapy using an increasingly compromised repertoire of antileishmanial compounds. For evaluation of novel drugs, the Syrian golden hamster is considered as a clinically relevant laboratory model. In this study, two molecular parasite detection assays were developed targeting cathepsin-like cysteine protease B (CPB) DNA and 18S rRNA to achieve absolute amastigote quantification in the major target organs liver and spleen. Both quantitative PCR (qPCR) techniques showed excellent agreement with a strong correlation with the conventional microscopic reading of Giemsa-stained tissue smears. Using multiple single tissue pieces and all three detection methods, we confirmed homogeneity of infection in liver and spleen and the robustness of extrapolating whole organ burdens from a small single tissue piece. Comparison of pre- and post-treatment burdens in infected hamsters using the three detection methods consistently revealed a stronger parasite reduction in the spleen compared to the liver, indicating an organ-dependent clearance efficacy for miltefosine. In conclusion, this study in the hamster demonstrated high homogeneity of infection in liver and spleen and advocates the use of molecular detection methods for assessment of low (post-treatment) tissue burdens.

[Visceral leishmaniasis concurrent with splenic marginal zone B-cell lymphoma]

Splenic marginal zone B-cell lymphoma (SMZBCL) is a rare non-Hodgkin B-cell lymphoma that presents with morphologically mature lymphoid cells corresponding in their immunological characteristics to secondary follicular marginal zone lymphocytes. It is clinically characterized by splenomegaly, moderate lymphocytosis, usually focal bone marrow lesion, sometimes moderate of monoclonal immunoglobulin in the serum (generally IgM or IgG) and/or urea, and a relatively benign course. Leishmaniasis is a transmissible natural focal infectious endemic disease that has a great diversity of clinical manifestations. The authors describe Russia's first case of SMZBCL concurrent with visceral leishmaniasis in a 52-year-old female patient admitted to a hematology hospital with weakness, splenomegaly, and lymphadenopathy. The simultaneous detection of lymphoma and leishmaniasis in the same biopsy specimen is extremely rare. Visceral leishmaniasis should be borne in mind as an opportunistic infection in patients with malignancies, particularly in immunocompromised persons who live or have stayed in the endemic areas.

Comparative immune study on cutaneous leishmaniasis patients with single and multiple sores

Ninety-five Iraqi patients with cutaneous leishmaniasis (CL) caused by Leishmania tropica at AL-Karama Hospital in Baghdad were included in this study. Sixty patients were with single sore and the remaining with multiple sores. The study also included 10 atopic patients and 30 healthy individuals as a control group. Cellular and humoral immune response at different stages of the disease activity (early and late) were evaluated by estimation of serum IFN-γ, IL-4 and total IgE antibodies using ELISA kits while, the detection of specific anti leishmanial IgE antibodies was done manually. Specific IgE antibodies were only detected in early CL (<2 months) patients 68 (71.57 %) while, were not detected in late CL, atopic and healthy controls 30 (100 %). The results also showed a positive relationship between this antibody and the number of sores. Th-2 predominates during the early stage of the disease then shifts to Th-1 that proceed in the late stage, but both cytokines increased in CL patients in comparison to control group. The immune response of CL infection is possibly regulated by both Th-1 and Th-2. Multiple sores patients showed an increase of anti leishmanial IgE (0.120 ± 0.014), total IgE (120.7 ± 39.58 IU/ml), IFN-γ (87.4 ± 30.52 pg/ml) and IL-4 (63.70 ± 20.32 pg/ml) levels than single sore patients with mean value of 0.108 ± 0.14, 92.3 ± 35.23 IU/ml, 47.2 ± 27.80 pg/ml and 51.04 ± 15.0 pg/ml respectively. It can be presented also as ratio of INF-γ/IL-4 = 1.37 which is greater than those for single sore 0.9. These results indicated that the immune response of multiple sores patient's is higher than that with single sores.

Atypical manifestations of visceral leishmaniasis in patients with HIV in north Ethiopia: a gap in guidelines for the management of opportunistic infections in resource poor settings

In regions where it is endemic, visceral leishmaniasis is an important opportunistic infectious disease in people living with HIV. Typically, clinical presentation of visceral leishmaniasis includes chronic fever, hepatosplenomegaly, and weight loss. In Leishmania infantum endemic regions in Europe, atypical visceral leishmaniasis presentations have been well documented, with almost every possible organ involved. However, such reports are rare in Leishmania donovani endemic regions such as east Africa. In this Personal View, we describe the various atypical disease presentations in patients screened as part of an HIV and visceral leishmaniasis clinical trial in north Ethiopia, where up to 40% of patients with visceral leishmaniasis are co-infected with HIV. Atypical presentations such as these are not covered in clinical guidelines used in these settings. Apart from the lack of diagnostic facilities, this gap contributes to the underdiagnosis of atypical visceral leishmaniasis, with associated morbidity and mortality. Involvement of clinicians experienced with the management of HIV and visceral leishmaniasis co-infection in the development of HIV clinical guidelines in affected regions is warranted.

Combination of liposomal CpG oligodeoxynucleotide 2006 and miltefosine induces strong cell-mediated immunity during experimental visceral leishmaniasis

Immuno-modulators in combination with antileishmanial drug miltefosine is a better therapeutic approach for treatment of Visceral Leishmaniasis (VL) as it not only reduces the dose of miltefosine but also shortens the treatment regimen. However, immunological mechanisms behind the perceived benefits of this combination therapy have not been investigated in detail. In the present study, we hypothesized that potential use of drugs that target the host in addition to the parasite might represent an alternative strategy for combination therapy. We investigated immune responses generated in Leishmania donovani infected animals (hamsters and mice) treated with combination of CpG-ODN-2006 and miltefosine at short dose regimen. Infected animals were administered CpG-ODN-2006 (0.4 mg/kg, single dose), as free and liposomal form, either alone or in combination with miltefosine for 5 consecutive days and parasite clearance was evaluated at day 4 and 7 post treatment. Animals that received liposomal CpG-ODN-2006 (lipo-CpG-ODN-2006) and sub-curative miltefosine (5 mg/kg) showed the best inhibition of parasite multiplication (∼97%) which was associated with a biased Th1 immune response in. Moreover, compared to all the other treated groups, we observed increased mRNA expression levels of pro-inflammatory cytokines (IFN-γ, TNF-α and IL-12) and significantly suppressed levels of Th2 cytokines (IL-10 and TGF-β) on day 4 post treatment in animals that underwent combination therapy with lipo-CpG-ODN-2006 and sub-curative miltefosine. Additionally, same therapy also induced heightened iNOS mRNA levels and NO generation, increased IgG2 antibody level and strong T-cell response in these hamsters compared with all the other treated groups. Collectively, our results suggest that combination of lipo-CpG-ODN-2006 and sub-curative miltefosine generates protective T-cell response in an animal model of visceral leishmaniasis which is characterized by strong Th1 biased immune response thereby underlining our hypothesis that combination therapy, at short dose regimen can be used as a novel way of treating visceral leishmaniasis.

Human hepatic stellate cells in primary culture are safe targets forLeishmania donovani

Leishmaniaparasites can escape the immune response by invading cell types lacking leishmanicidal mechanisms. Silent persistence ofLeishmaniaparasites in the host organism is responsible for asymptomatic carriage and relapses after cured leishmaniasis. Here, we studied the interaction between Hepatic Stellate Cells (HSC) andLeishmania.An original model of human HSC in primary culture infected withL. donovaniwas developed. The presence of intracellular parasites was studied and quantified using optical and confocal microscopy. HSC characteristics were studied using microscopy, methylene blue assay, long-term cultures and qPCR. We showed for the first time that human HSC are permissive toL. donovaniinfection, with no modification of HSC survival, growth rate and proinflammatory and fibrogenic characteristics. Intracellular parasites did not replicate but HSC had no effect on their survival. Indeed, after a 40-day culture, infected HSC cultures transferred on NNN medium yielded new promastigotes that were able to proliferate and efficiently infect new cells. HSC are permissive toL. donovani, with neither parasite killing nor apparent cell damage. Thus, HSC could act as potent sanctuary cells forLeishmaniain the liver, which could partially explain parasite reactivation after an asymptomatic carriage or a cured visceral leishmaniasis.

Splenectomy in a patient with treatment-resistant visceral leishmaniasis: a case report

Visceral leishmaniasis (VL), also known as Kala-azar, is a systemic infection caused by a protozoan (Leishmania) and, in its classic form, is a serious illness associated with malnutrition, anemia, hepatosplenomegaly, infectious processes and coagulopathies. The effect of splenectomy in patients with visceral leishmaniasis is not well defined; however, it is known that the spleen is the largest reservoir of infected cells belonging to the reticulo endothelial system. Therefore, the surgical procedure is an option for the debulking of parasites, providing a cure for refractory VL and minimizing the complications of hypersplenism.

Rare association of Visceral leishmaniasis with Hodgkin's disease: A case report

We present here a case of young male with complaints of fever and swelling in the neck for eight months. History of progressive weakness associated with weight loss was present. Physical examination revealed pallor, multiple enlarged cervical lymph nodes and hepatosplenomegaly. Investigations showed pancytopenia, hyperglobinemia and Leishman-Donovan bodies on bone marrow aspiration. Serological test confirmed diagnosis of visceral leishmaniasis. However, cervical lymph node aspiration and biopsy were suggestive of Mixed cellularity Hodgkin's disease. This made it a very rare case of Leishmaniasis as an opportunistic infection in a patient of pre-chemotherapy Hodgkin's disease. There was marked improvement in haematological profile and regression of hepatosplenomegaly with Amphotericin B treatment followed by favourable response to chemotherapy. The case emphasizes the suspicion for leishmaniasis as a masquerader and as an opportunistic infection in haematological malignancies.

Role of fine-needle aspiration cytology in the prompt diagnosis of recurrence of visceral leishmaniasis presented as isolated cervical leishmanial lymphadenopathy

We report a case of isolated cervical leishmanial lymphadenopathy diagnosed by fine-needle aspiration cytology (FNAC) in apparently cured case of visceral leishmaniasis. A 28-year-old female presented with cervical lymphnode enlargement to surgery outpatient department and was subjected for FNAC. Smear showed numerous Leishmania donovani bodies in the cytoplasm of macrophages and giant cells, and extracellular spaces. She was treated by Amphotericin B for alternate 14 days and the size of the lymphnode regressed. She was found asymptomatic for 1 year of follow-up.

Importance of nonenteric protozoan infections in immunocompromised people

There are many neglected nonenteric protozoa able to cause serious morbidity and mortality in humans, particularly in the developing world. Diseases caused by certain protozoa are often more severe in the presence of HIV. While information regarding neglected tropical diseases caused by trypanosomatids and Plasmodium is abundant, these protozoa are often not a first consideration in Western countries where they are not endemic. As such, diagnostics may not be available in these regions. Due to global travel and immigration, this has become an increasing problem. Inversely, in certain parts of the world (particularly sub-Saharan Africa), the HIV problem is so severe that diseases like microsporidiosis and toxoplasmosis are common. In Western countries, due to the availability of highly active antiretroviral therapy (HAART), these diseases are infrequently encountered. While free-living amoebae are rarely encountered in a clinical setting, when infections do occur, they are often fatal. Rapid diagnosis and treatment are essential to the survival of patients infected with these organisms. This paper reviews information on the diagnosis and treatment of nonenteric protozoal diseases in immunocompromised people, with a focus on patients infected with HIV. The nonenteric microsporidia, some trypanosomatids, Toxoplasma spp., Neospora spp., some free-living amoebae, Plasmodium spp., and Babesia spp. are discussed.

ExperimentalLeishmania (L.) amazonensisLeishmaniasis: Characterization and Immunogenicity of Subcellular Fractions

A technique developed in Trypanosoma cruzi biochemical studies was successfully used to fractionate Leishmania (Leishmania) amazonensis promastigotes. Ultrastructural analyses revealed a membrane fraction (MF) associated to subpellicular microtubules, a ribosomal-rich microsomal fraction (MicF), and a flagellar fraction (FF) free of associated membrane. All fractions proved to be immunogenic through delayed type hypersensitivity reaction assays. Therefore, a protocol was designed to test whether these fractions could elicit a protective response in mice infected by L. (L), amazonensis. The protocol consisted of a BCG injection (as cellular immunity inducer), followed by cyclophosphamide (once its cytotoxic effect is over, this immunosuppressor can increase the number of circulating leukocytes), then an injection with one of the fractions followed by a challenge. When compared to infected control animals, mice injected with any of the fractions presented a smaller footpad swelling, especially those injected with MicF or FF. Macroscopically, immunized mice under modulation by BCG presented no swelling. Histopathological studies performed on day 120 revealed fewer amastigotes and more intense inflammation in lesions of MicF and FF injected mice. Animals injected with MF presented an intermediate pattern. Parasite quantification corroborated these results. The results show that all fractions are potent immunostimulators, but MicF and FF have the strongest protective ability.

Directions for the diagnosis, clinical staging, treatment and prevention of canine leishmaniosis

Canine leishmaniosis (CanL) due to Leishmania infantum is a life threatening zoonotic disease with a wide distribution in four continents and importance also in non-endemic regions. The purpose of this report is to present a consensus of opinions on the diagnosis, treatment, prognosis and prevention of CanL in order to standardize the management of this infection. CanL is a disease in which infection does not equal clinical illness due to the high prevalence of subclinical infection among endemic canine populations. The most useful diagnostic approaches include serology by quantitative techniques and PCR. High antibody levels are associated with severe parasitism and disease and are diagnostic of clinical leishmaniosis. However, the presence of lower antibody levels is not necessarily indicative of disease and further work-up is necessary to confirm CanL by other diagnostic methods such as cytology, histopathology and PCR. We propose a system of four clinical stages, based on clinical signs, clinicopathological abnormalities and serological status. Suitable therapy and expected prognosis are presented for each of the stages. The combination of meglumine antimoniate and allopurinol constitutes the first line pharmaceutical protocol. However, although most dogs recover clinically after therapy, complete elimination of the parasite is usually not achieved and infected dogs may eventually relapse. Follow-up of treated dogs with blood counts, serum biochemistry, urinalysis, serology and PCR is essential for prevention of relapses. Protection against sand fly bites by topical insecticides is effective in reducing infection, and recent development of vaccines has indicated that prevention by vaccination is feasible.

Multiple relapses of visceral leishmaniasis in an adolescent with idiopathic CD4+ lymphocytopenia associated with novel immunophenotypic and molecular features

An adolescent with idiopathic CD4 lymphocytopenia suffered from 4 visceral leishmaniasis relapses despite appropriate treatment. CD8 lymphocytopenia and abnormal expansion of TCRalphabeta, CD4, CD8 cells were consistently detected together with reduced export of mature T cells from thymus. This novel form of idiopathic CD4 lymphocytopenia may predispose to multiple visceral leishmaniasis relapses.

Aspects of the association between leishmaniasis and malignant disorders

Given the prevalence of leishmaniasis and cancer, the co-existence of these two diseases may be merely coincidental. However, a number of epidemiological, experimental and laboratory studies suggest that an association between these two entities does exist. The aim of this review is to summarise the occurrence of leishmaniasis as an opportunistic infection associated with malignant disorders and to present the available literature potentially linking this infection with the development of cancerous lesions. We searched electronic databases and evaluated 37 studies involving 44 patients. Four different types of association between leishmaniasis and cancer were established: leishmaniasis mimicking a malignant disorder, such as lymphoma; leishmaniasis arising as a difficult to diagnose and treat infection among patients receiving chemotherapy for various malignant disorders; simultaneous diagnosis of leishmaniasis and a neoplastic disorder in the same tissue samples of immunocompromised patients; and direct involvement of Leishmania spp. in the pathogenesis/occurrence of malignant lesions, especially of the skin and mucous membranes. The main conclusion of this review is that leishmaniasis can directly or indirectly affect the presentation, diagnosis and course of various malignant disorders and it should be considered in the differential diagnosis of malignancies in geographic areas where it is endemic and/or in patients with travel history to these areas.

Leishmaniasis

Epidemiology, disease patterns, immunology, diagnosis, treatment and control measures of leishmaniasis are described. Various issues relating to leishmaniasis are highlighted: the relative lack of importance given to this disease compared with other infections, climate change and its possible impact on extension of endemicity of this infection, and new diagnostic tests which are improving diagnosis, especially in resource poor areas. Other important aspects discussed include the potential for newer oral therapy to change the way this disease is managed; Leishmania-HIV coinfection and groups at risk; and development of an effective vaccine.

Leishmaniasis

Epidemiology, disease patterns, immunology, diagnosis, treatment and control measures of leishmaniasis are described. Various issues relating to leishmaniasis are highlighted: the relative lack of importance given to this disease is compared with other infections, climate change and its possible effect on extension of endemicity of this infection, and new diagnostic tests that are helping better diagnosis, especially in resource-poor areas. Other important aspects discussed include the potential for newer oral treatment to change the way this disease is managed; leishmania-HIV coinfection and groups at risk; and the development of an effective vaccine.

Chemotherapy in the treatment and control of leishmaniasis

Drugs remain the most important tool for the treatment and control of both visceral and cutaneous leishmaniasis. Although there have been several advances in the past decade, with the introduction of new therapies by liposomal amphotericin, oral miltefosine and paromomycin (PM), these are not ideal drugs, and improved shorter duration, less toxic and cheaper therapies are required. Treatments for complex forms of leishmaniasis and HIV co-infections are inadequate. In addition, full deployment of drugs in treatment and control requires defined strategies, which can also prevent or delay the development of drug resistance.

Advances in leishmaniasis

Governed by parasite and host factors and immunoinflammatory responses, the clinical spectrum of leishmaniasis encompasses subclinical (inapparent), localised (skin lesions), and disseminated infection (cutaneous, mucosal, or visceral). Symptomatic disease is subacute or chronic and diverse in presentation and outcome. Clinical characteristics vary further by endemic region. Despite T-cell-dependent immune responses, which produce asymptomatic and self-healing infection, or appropriate treatment, intracellular infection is probably life-long since targeted cells (tissue macrophages) allow residual parasites to persist. There is an epidemic of cutaneous leishmaniasis in Afghanistan and Pakistan and of visceral infection in India and Sudan. Diagnosis relies on visualising parasites in tissue or serology; culture and detection of parasite DNA are useful in the laboratory. Pentavalent antimony is the conventional treatment; however, resistance of visceral infection in India has spawned new treatment approaches--amphotericin B and its lipid formulations, injectable paromomycin, and oral miltefosine. Despite tangible advances in diagnosis, treatment, and basic scientific research, leishmaniasis is embedded in poverty and neglected. Current obstacles to realistic prevention and proper management include inadequate vector (sandfly) control, no vaccine, and insufficient access to or impetus for developing affordable new drugs.

Prevention of Relapse after Chemotherapy in a Chronic Intracellular Infection: Mechanisms in Experimental Visceral Leishmaniasis

In visceral leishmaniasis, chemotherapy probably seldom eradicates all parasites in tissue macrophages; nevertheless, most T cell-intact patients show long-lasting clinical cure after treatment despite residual intracellular infection. To characterize prevention of posttreatment relapse, amphotericin B was used to kill approximately 90-95% of Leishmania donovani in livers of mice deficient in mechanisms of acquired antileishmanial resistance. Recrudescence subsequently developed 1) in animals deficient in both CD4 and CD8 T cells as well as CD40L-mediated T cell costimulation, but not in a) CD4 or CD8 cells alone, b) NK cell lytic activity, or c) ICAM-1-recruited monocytes; and 2) in mice deficient in IFN-gamma, but not in the IFN-gamma-inducing cytokines, a) IL-12, b) IL-12 and IL-23, or c) IL-18. Posttreatment recrudescence also did not develop in animals deficient in macrophage phagocyte NADPH oxidase (phox) or inducible NO synthase (iNOS) alone or, surprisingly, in those deficient in both phox and iNOS. Therefore, regulation of the intracellular replication of residual Leishmania donovani that escape chemotherapy evolves to a host mechanism distinguishable from initial acquired resistance at the T cell, cytokine, and macrophage levels. Posttreatment, either CD8 or CD4 cells can direct the response, IL-12 is not required, and iNOS and phox, the activated macrophage's primary IFN-gamma-inducible leishmanicidal pathways, both become dispensable.

Visceral leishmaniasis in pregnancy: a case series and a systematic review of the literature

OBJECTIVES

Visceral leishmaniasis (VL) is endemic in tropical and sub-tropical areas. Only anecdotal cases of VL in pregnancy are reported in the literature, although the disease is life-threatening for both mothers and infants. Here we report a small series of pregnant women with VL observed in the Neapolitan area over a 7 year period and carry out a systematic review of the literature on this topic.

METHODS

Consecutive cases of VL in HIV-negative female patients between 1996 and 2002 were evaluated. Pregnant women who fulfilled criteria for VL diagnosis were included and diagnostic, clinical and therapeutic features were considered. The outcome for both the pregnant woman and the fetus was evaluated over a 24 month period of post-therapy follow-up. A systematic search of English language literature through the MEDLINE database and Cochrane Library with the search strings 'leishmaniasis AND pregnancy' and 'leishmaniasis AND visceral AND congenital' integrated with a manual search completed our study.

RESULTS

Five consecutive pregnant women were diagnosed as having VL. Fever and hepatosplenomegaly were the main presenting symptoms. All received liposomal amphotericin B without any toxicity to either the mothers or newborns. No treatment failure or congenital VL case was observed. The systemic review of the literature revealed 17 cases of VL during pregnancy. Untreated VL resulted in consequences on the fetus or congenital VL.

CONCLUSIONS

The efficacy and safety of amphotericin B formulations for mother and fetus are supported by the cumulative analysis of our data and literature data.