Human immunodeficiency virus and leishmaniasis

Artemisinin: An Anti-Leishmania Drug that Targets the Leishmania Parasite and Activates Apoptosis of Infected Cells

Leishmaniasis is a relevant disease worldwide due to its presence in many countries and an estimated prevalence of 10 million people. The causative agent of this disease is the obligate intracellular parasite Leishmania which can infect different cell types. Part of its success depends on its ability to evade host defense mechanisms such as apoptosis. Apoptosis is a finely programmed process of cell death in which cells silently dismantle and actively participate in several processes such as immune response, differentiation, and cell growth. Leishmania has the ability to delay its initiation to persist in the cell. It has been well documented that different Leishmania species target different pathways that lead to apoptosis of cells such as macrophages, neutrophils, and dendritic cells. In many cases, the observed anti-apoptotic effect has been associated with a significant reduction in caspase-3 activity. Leishmania has also been shown to target several pathways involved in apoptosis such as MAPK, PI3K/Akt, and the antiapoptotic protein Bcl-xL. Understanding the strategies used by Leishmania to subvert the defense mechanisms of host cells, particularly apoptosis, is very relevant for the development of therapies and vaccines. In recent years, the drug artemisinin has been shown to be effective against several parasitic diseases. Its role against Leishmania may be promising. In this review, we provide important aspects of the disease, the strategies used by the parasite to suppress apoptosis, and the role of artemisinin in Leishmania infection.

Synthesis of new 3-acetyl-1,3,4-oxadiazolines combined with pyrimidines as antileishmanial and antiviral agents

A new series of 3-acetyl-1,3,4-oxadiazoline hybrid molecules was designed and synthesized using a condensation between acyclonucleosides and substituted phenylhydrazone. All intermediates and final products were screened against Leishmania donovani, a Protozoan parasite and against three viruses SARS-CoV-2, HCMV and VZV. While no significant activity was observed against the viruses, the intermediate with 6-azatymine as thymine and 5-azathymine-3-acetyl-1,3,4-oxadiazoline hybrid exhibited a significant antileishmanial activity. The later compound was the most promising, exhibiting an IC50 value at 8.98 µM on L. donovani intramacrophage amastigotes and a moderate selectivity index value at 2.4.

Epidemiological, clinical and hematological profiles of visceral leishmaniasis among patients visiting Tefera Hailu Memorial Hospital, Northeast Ethiopia: a 4 year retrospective study

Visceral leishmaniasis is a major, life-threatening parasitic disease that still remains a serious public health problem in Ethiopia. Understanding the epidemiological, clinical, and hematological profiles of visceral leishmaniasis patients is important for implementing evidence-based control strategies. It is also important for early treatment and to decrease the mortality rate from the disease. Therefore, this study was aimed at assessing the epidemiological, clinical, and hematological profiles of visceral leishmaniasis among patients visiting Tefera Hailu Memorial Hospital, Northeast Ethiopia. A retrospective study was conducted at Tefera Hailu Memorial Hospital from September 2017 to August 2021. Data were collected from the medical records of suspected patients who were tested by the rK39 rapid diagnostic by strictly following standard operating procedures. The data was summarized using Microsoft Excel and analyzed using SPSS 26 version software. Descriptive statistics were used to describe the epidemiological, clinical, and hematological profiles of visceral leishmaniasis patients. A p-value < 0.05 was considered statistically significant. The overall positivity rate for visceral leishmaniasis was 23.4% (132/564). The result of this study indicated a fluctuating yet declining trend in VL over the past 4 years. From a total of 132 VL confirmed cases, the numbers of cases were highest among males (78.0%), those 15-29 years of age (37.1%), and urban residents (89.4%). Furthermore, Abergele (11.0%), Sehala (6.0%), and Ziquala (5.0%) districts had the highest number of VL cases. The major clinical presentations of patients were fever (96.2%), splenomegaly (94.7%), and general weakness (80.3%). With regard to hematological profiles, the most common findings were anemia (86.4%), thrombocytopenia (81.8%), leucopenia (78.8%), neutropenia (74.2%), and pancytopenia (71.2%). In the study area, the VL positivity rate was high. Our findings also concluded that VL causes significant alterations in clinical and hematological parameters. Therefore, the zone health office and other concerned stakeholders should strengthen evidence-based control programs for VL.

Potential therapeutic targets shared between leishmaniasis and cancer

The association of leishmaniasis and malignancies in human and animal models has been highlighted in recent years. The misdiagnosis of coexistence of leishmaniasis and cancer and the use of common drugs in the treatment of such diseases prompt us to further survey the molecular biology of Leishmania parasites and cancer cells. The information regarding common expressed proteins, as possible therapeutic targets, in Leishmania parasites and cancer cells is scarce. Therefore, the current study reviews proteins, and investigates the regulation and functions of several key proteins in Leishmania parasites and cancer cells. The up- and down-regulations of such proteins were mostly related to survival, development, pathogenicity, metabolic pathways and vital signalling in Leishmania parasites and cancer cells. The presence of common expressed proteins in Leishmania parasites and cancer cells reveals valuable information regarding the possible shared mechanisms of pathogenicity and opportunities for therapeutic targeting in leishmaniasis and cancers in the future.

Fluralaner (Bravecto®) induces long-term mortality of Lutzomyia longipalpis after a blood meal in treated dogs

BACKGROUND

Leishmania infantum is the etiological agent of visceral leishmaniasis (VL) in the New World, where the sand fly Lutzomyia longipalpis and domestic dogs are considered the main vector and host reservoirs, respectively. Systemic insecticides have been studied as an alternative to control vector-borne diseases, including VL. Fluralaner, an isoxazoline class compound, is a systemic insecticide used in dogs, with proven efficiency against different species of phlebotomine sand flies. However, to date no studies have demonstrated the efficacy of fluralaner on Lu. longipalpis. The aim of this study was to evaluate the insecticidal effect of fluralaner (Bravecto®) on the sand fly Lu. longipalpis after blood meal in treated dogs.

METHODS

Healthy mongrel dogs (n = 8) were recruited from the Zoonoses Control Center in the city of Natal, Rio Grande do Norte, Brazil, and randomized into two groups: fluralaner treated (n = 4) and non-treated control (n = 4). Colony-reared female specimens of Lu. longipalpis (n = 20) were allowed to feed on all dogs for 40 min before treatment (for fluralaner-treated dogs), at day 1 after treatment and then monthly until 1 year post-treatment.

RESULTS

In the treatment group, there was 100% mortality of Lu. longipalpis for up to 5 months after treatment initiation, decreasing to 72.5% at 6 months post-treatment initiation. The efficacy of fluralaner ranged from 100% at day 1 (P = 0.0002) to 68% ( P = 0.0015) at 6 months, decreasing to 1.4% at 1 year post-treatment. Sand fly mortality carried out blood meal in non-treated control dogs remained constant at ≤ 15%.

CONCLUSIONS

Taken together, our results suggest that fluralaner may be used as a control strategy for VL in dogs in VL endemic areas.

Leucocytes and Th-associated Cytokine Profile of HIV-Leishmaniasis Co-Infected Persons Attending Abuja Teaching Hospital, Nigeria

Objective

T-helper cells (Th)-1& -2 cytokines homeostasis control or predict clinical outcome of infected persons, especially those with HIV /AIDS. This case-control study evaluated the leucocytes differentials, TNF-alpha, interleukin (IL)-2 and -10 levels among HIV infected persons with serological evidence of leishmaniasis attending University of Abuja Teaching Hospital, Nigeria.

Materials and Methods

Blood samples from 28 HIV infected persons who had Leishmania donovani rK39 and Immunoglobulin-G (IgG) positive (group 1), 30 age- & -sex matched HIV infected persons without Leishmania antibodies (group 2) and 30 apparently healthy persons without HIV and Leishmania antibodies (group 3). Full blood counts, TNF alpha, IL-2 and -10 levels were analyzed using automated hematology analyzer and ELISA, respectively. Structured questionnaires were used to collate biodata and clinical presentations of participants.

Results

Ten (35.7%) participants in group 1 were on ART, 15 (50%) in group 2 were on ART, while group 3 were ART naïve. There were significantly higher values in basophil (4.4±2.5%) and eosinophil counts (12.9±3.8%) in HIV/leishmania coinfected persons (p<0.005). However, other white cells subpopulation was significantly lower in HIV/leishmania co-infected participants (p<0.05). There was significantly reduced CD4+ T cell counts ([119±26 versus 348±63 versus 605±116 cells/mm3]), TNF-alpha ([36.82±8.21 versus 64.67±12.54 versus 254.98±65.59 pg/mL]) and IL-2 levels ([142.14±20.91 versus 507.6±84.42 versus 486.62±167.87 pg/mL]) among HIV/Leishmania co-infected participants compared to group 2 and group 3 participants, respectively. However, higher IL-10 level (80.35±14.57 pg/mL) was found in HIV/Leishmania co-infected participants as opposed to the HIV monoinfected (62.2±10.43 pg/mL) and apparently healthy persons (23.97±4.88 pg/mL) (p<0.001).

Conclusion

Eosinophil, basophil counts and serum IL-10 level were high in HIV/Leishmania coinfected persons, demonstrating parasite-induced hypersensitivity and immunosuppression.

Higher levels of TNF and IL-4 cytokines and low miR-182 expression in visceral leishmaniasis-HIV co-infected patients

AIMS

The aim of the present study was to assess serum cytokine and miRNA expression in visceral leishmaniasis-HIV (VL-HIV) co-infection and HIV mono-infection.

METHODS AND RESULTS

We analysed 113 serum samples from HIV patients in areas endemic for leishmaniasis. The diagnosis of VL was confirmed in 65 of these 113 samples. The VL-HIV and HIV groups presented significant differences regarding haemoglobin level (P < .0001), lymphocyte count (P = .0444), white blood cell count (P = .0108), weight loss (P = .0310), HIV load (P < .0001) and CD4+ T-lymphocytes count (P = .0003). Levels of IL-6 and IL-10, IFN-γ and IL-6, IFN-γ and IL-10, TNF and IL-2 were positively correlated in VL-HIV co-infection, indicating higher serum levels of TNF and IL-4 (P < .0001). In addition, miR-182 expression was found to be significantly higher in HIV (P = .009), miR-210 exhibited no statistically significant difference between groups, and nonexpression of miR-122 was found in both groups.

CONCLUSION

Together, TNF, IL-4 and miR-182 may represent circulatory biomarkers of VL-HIV co-infection.

A Case-Control Study on the Association Between Intestinal Helminth Infections and Treatment Failure in Patients With Cutaneous Leishmaniasis

Background

Endemic regions of cutaneous leishmaniasis (CL) and intestinal helminthiasis overlap. CL treatment with systemic pentavalent antimonial drugs (Sb⁵⁺) fails in 10%–30% of patients. The study objective was to assess the etiological role of intestinal helminthiasis in CL treatment failure.

Methods

An unmatched case–control study was done in 4 CL treatment sites in Peru in 2012–2015. Cases were CL patients with Sb⁵⁺ treatment failure; controls were CL patients with Sb⁵⁺ treatment success. Patients with a parasitologically confirmed CL diagnosis who had received supervised Sb⁵⁺ treatment and could be classified as cases or controls were eligible. The main exposure variables were intestinal helminthiasis and strongyloidiasis, diagnosed through direct examination, rapid sedimentation, Baermann, Kato-Katz, or agar culture of stool samples. Additional exposure variables were other infections (HIV, human T-lymphotropic virus 1, tuberculosis, hepatitis B, intestinal protozoa) and noninfectious conditions (diabetes, renal insufficiency, and immunosuppressive medication). Age, gender, CL history, probable exposure place, and Leishmania species were treated as potential confounders in multiple logistic regression.

Results

There were 94 case and 122 control subjects. Overall, infectious and noninfectious comorbidities were frequent both among cases (64%) and controls (71%). The adjusted odds ratio (OR) for the association between any intestinal helminth infection and CL treatment failure was 0.65 (95% confidence interval [CI], 0.30–1.38), and the adjusted OR for the association between strongyloidiasis and CL treatment failure was 0.34 (95% CI, 0.11–0.92).

Conclusions

In the Peruvian setting, high Sb⁵⁺ treatment failure rates are not explained by intestinal helminthiasis. On the contrary, strongyloidiasis had a protective effect against treatment failure.

Antigen Detection in Urine for Noninvasive Diagnosis and Treatment Monitoring of Visceral Leishmaniasis in Human Immunodeficiency Virus Coinfected Patients: An Exploratory Analysis from Ethiopia

Diagnosis of visceral leishmaniasis (VL) and assessment of treatment response in human immunodeficiency virus (HIV)–coinfected patients still relies on invasive tissue aspiration. This hampers scale-up and decentralization of care in resource-limited settings. Noninvasive diagnostics are urgently needed. KATEX is a frequently used latex agglutination test for Leishmania antigen in urine that has never been evaluated in HIV-coinfected individuals from Leishmania donovani–endemic areas. This was an exploratory sub-study embedded within the screening phase of a trial in highly endemic northwestern Ethiopia. All patients were HIV-positive and aspirate-confirmed VL cases. We assessed diagnostic accuracy of KATEX for VL diagnosis and as test of cure at end of treatment, using tissue aspirate parasite load as reference methods. We also described the evolution of weekly antigen levels during treatment. Most of the 87 included patients were male (84, 97%), young (median age 31 years), and had poor immune status (median cluster of differentiation type 4 count 56 cells/μL). KATEX had moderate sensitivity (84%) for VL diagnosis. KATEX had moderate sensitivity (82%) and a moderate negative predictive value (87%) but only low specificity (49%) and a low positive predictive value (40%) for the assessment of treatment outcomes. Weekly antigen levels showed characteristic patterns during treatment of patients with different initial parasite loads and treatment outcomes. Antigen detection in urine using KATEX can contribute to improved VL diagnosis in HIV-coinfected patients but has limited use for monitoring of treatment response. Better noninvasive diagnostics are needed to reduce reliance on invasive methods and thus to expand and improve clinical care for VL in resource-limited settings.

Miltefosine-Lopinavir Combination Therapy Against Leishmania infantum Infection: In vitro and in vivo Approaches

Concurrently, leishmaniasis and AIDS are global public health issues and the overlap between these diseases adds additional treats to the management of co-infected patients. Lopinavir (LPV) has a well characterized anti-HIV and leishmanicidal action, and to analyze its combined action with miltefosine (MFS) could help to envisage strategies to the management of co-infected patients. Here, we evaluate the interaction between LPV and MFS against Leishmania infantum infection by in vitro and in vivo approaches. The effect of the compounds alone or in association was assessed for 72 h in mouse peritoneal macrophages infected with L. infantum by the determination of the IC₅₀s and FICIs. Subsequently, mice were orally treated twice daily during 5 days with the compounds alone or in association and evaluated after 30 days. The in vitro assays revealed an IC₅₀ of 0.24 μM and 9.89 μM of MFS and LPV, respectively, and an additive effect of the compounds (FICI 1.28). The in vivo assays revealed that LPV alone reduced the parasite load in the spleen and liver by 52 and 40%, respectively. The combined treatment of infected BALB/c mice revealed that the compounds alone required at least two times higher doses than when administered in association to virtually eliminate the parasite. Mice plasma biochemical parameters assessed revealed that the combined therapy did not present any relevant hepatotoxicity. In conclusion, the association of MFS with LPV allowed a reduction in each compound concentration to achieve the same outcome in the treatment of visceral leishmaniasis. Although a pronounced synergistic effect was not evidenced, it does not discard that such combination could be useful in humans co-infected with HIV and Leishmania parasites.

Prevalence of HIV and associated factors among visceral leishmaniasis cases in an endemic area of Northeast Brazil

INTRODUCTION

Cases of visceral leishmaniasis (VL) and HIV co-infection have increased worldwide. We investigated the prevalence of HIV and associated factors among VL patients in Sergipe state, Brazil.

METHODS

We conducted a population-based study of all cases of VL and HIV reported in Sergipe from 1999 to 2015.

RESULTS

We studied a total of 917 patients; 41 (4.5%) co-infection cases were detected. VL-HIV co-infected patients were more likely to have weight loss, cough, treatment failure or loss to follow-up and death.

CONCLUSIONS

The prevalence of VL-HIV co-infection was high and co-infected patients were more likely to have adverse outcomes.

Spectrum of clinicohematological profile and its correlation with average parasite density in visceral leishmaniasis

Background:

Leishmaniasis is the prevalent in tropical and subtropical regions of the world. Demonstration of Leishman-Donovan (LD) bodies in the bone marrow aspirates (BMA) is vital to diagnosis of visceral leishmaniasis (VL). In the present study, we studied the clinicohematological parameters encountered in VL and correlated them with parasite load on BMA.

Methods:

Retrospective analysis over 3 years was done; clinical details, biochemical profile, complete hemogram with peripheral smear findings, and BMA smears were reviewed and average parasite density (APD) calculated in each case. Multivariate analysis and tests of significance were applied.

Results:

The study included 28 patients. Splenomegaly showed a positive trend with APD. rK39 antigen detection test was 100% positive in select cases. A strong negative correlation was observed between albumin to globulin ratio and grade of APD. BMA revealed hemophagocytosis (HPS) in 78.57% cases and it had a significant strong correlation with APD (P = 0.014). A significant correlation was also observed between APD and bone marrow plasma cell percentage (P = 0.01). LD bodies were noted in unusual locations such as within myelocytes (14.2%), plasma cells (7.1%), and megakaryocytes (10.7%).

Conclusion:

HPS and bone marrow plasmacytosis were two statistically significant findings, which showed positive correlation with parasite load. The presence of these two findings should prompt hematopathologists for more focused search of hemoparasites in BMA to arrive at a definitive diagnosis. This will avoid unnecessary workups and improve the prognosis. To the best of our knowledge, a statistical correlation between APD and clinicohematological parameters has never been previously studied.

High frequency of subclinical Leishmania infection among HIV-infected patients living in the endemic areas of visceral leishmaniasis in Fars province, southern Iran

Visceral leishmaniasis (VL) is a major health concern in patients with HIV infection in endemic areas of VL. In these areas, a substantial number of infected individuals are asymptomatic and the risk of acute VL infection in HIV/VL co-infected cases is high. The current study aimed to determine the prevalence of asymptomatic VL infection among HIV-infected patients in Fars province, southern Iran. Subjects of the study were 251 HIV-confirmed patients who all were clinically asymptomatic for leishmaniasis. Blood samples were obtained from each participant. Anti-Leishmania antibodies were detected in the sera using ELISA. DNA was extracted from the buffy coat of each subject and PCR amplified, targeting an ITS-2 gene of Leishmania. PCR products were purified from the gel and were sequenced. Overall, 19 out of 251 (7.6%) HIV-infected patients were found to be infected with Leishmania, using serological or molecular methods. Anti-Leishmania antibodies were detected in 13 (5.2%) patients and leishmanial DNA in 8 (3.2%) of the patients. The sequence analysis of DNA-positive cases revealed the species of the parasite as L. infantum. The high prevalence of VL among the patients with HIV is a serious challenge which demands further attention to improve the prophylaxis and treatment measurements of VL/HIV co-infection and thereby promoting the life expectancy and quality of life of these patients.

Epidemiological, clinical and laboratory aspects of human visceral leishmaniasis (HVL) associated with human immunodeficiency virus (HIV) coinfection: a systematic review

Coinfection with human visceral leishmaniasis (HVL) and human immunodeficiency virus (HIV) has become an emerging public health problem in several parts of the world, with high morbidity and mortality rates. A systematic review was carried out in the literature available in PubMed, Scielo and Lilacs related to HVL associated with HIV coinfection, seeking to analyze epidemiological, clinical and laboratory aspects. Of the 265 articles found, 15 articles were included in the qualitative analysis, which referred to the results of HVL treatment in patients coinfected with HIV. In the published articles between 2007 and 2015, 1171 cases of HVL/HIV coinfection were identified, 86% males, average age 34 years, liposomal amphotericin B was the most commonly used drug, cure rates 68 and 20% relapses and 19% deaths, five different countries, bone marrow was used in 10/15 manuscripts. HVL/HIV coinfection is a major challenge for public health, mainly due to the difficulty in establishing an accurate diagnosis, low response to treatment with high relapse rates and evolution to death. In addition, these two pathogens act concomitantly for the depletion of the immune system, contributing to worsening the clinical picture of these diseases, which requires effective surveillance and epidemiological control measures.

Unusual Signs and Symptoms in HIV-Positive Patients Coinfected with Leishmania spp: The Importance of Neglected Tropical Disease in Differential Diagnosis

BACKGROUND:

Leishmaniasis is a parasitic disease affecting both animals and humans, acquired with the bite of sand flies or, in Injection Drug Users (IDUs), with contaminated needles, still hypoendemic in Sicily and the Mediterranean basin. Even though it is responsible for 20,000 to 40,000 deaths per year, this parasitic infection is still considered a neglected tropical disease. People Living with HIV (PLWH) are considered at high-risk of developing Leishmaniasis and, despite the introduction of Highly Active Anti-Retroviral Therapy (HAART), mortality rate and relapses prevalence are still high in coinfected people.

CASE REPORT:

We present a case of HIV-Leishmania coinfection, posing the attention on the atypical signs and symptoms and the importance of thinking about other causes than the HIV infection progression when the patient presents with a worsening of his immune status during HAART.

CONCLUSION:

This parasitic disease has a high mortality rate, so it is mandatory to think about it in all the patients having a low CD4+ T-cell count and an inverted CD4/CD8 ratio under HAART.

Exploring prognosis in chronic relapsing visceral leishmaniasis among HIV-infected patients: Circulating Leishmania DNA

BACKGROUND

Visceral leishmaniasis (VL) affecting HIV-infected patients is considered a challenging condition because of its high mortality and relapse rates. The approach of this condition is still surrounded by many uncertainties, especially regarding the criteria to institute and discontinue secondary prophylaxis for VL. The aim of this study was to evaluate the Leishmania parasitism kinetic assessed by polymerase chain reaction (PCR) as a possible tool in the prognostic assessment in a context in which patients are receiving highly active antiretroviral therapy and secondary prophylaxis.

METHODS

A prospective observation of Leishmania-HIV-co infected patients was performed and two groups with distinct clinical prognosis unpredicted by their CD4 count at the moment of VL diagnosis and not related to their HIV load control were confirmed.

RESULTS

Relapsing (R) and non-relapsing (NR) patients had similar antiviral therapy use rates, CD4 lymphocyte count medians and HIV load levels at VL-diagnosis. At the 12-month follow-up, R-patients presented a significantly lower CD4 lymphocyte count than NR-patients, without difference in HIV load control. The time between HIV and VL diagnoses was longer in the R than NR-group. Comparison between Kaplan-Meier relapse-free survival curves (time to relapse) using a log rank test showed that patients presenting circulating Leishmania DNA had a significantly higher risk of clinical VL relapse within 4 months after a positive test (p=0.001).

CONCLUSIONS

These results reinforce that a negative PCR could be a useful tool to support prophylaxis interruption among patients with CD4 counts above 200cells/mm³ and that a positive PCR suggests imminent VL relapse.

Indian visceral leishmaniasis with extensive lymphadenopathy - An unusual presentation: A case report with literature review

Visceral leishmaniasis (VL), also known as kala-azar, is a life-threatening systemic disease caused by the obligate intracellular protozoan, Leishmania, and transmitted to humans by the female phlebotomine sand fly (Phlebotomus argentipes). The disease is fatal, if left untreated. We report a case of a patient clinically suspected of disseminated tuberculosis, but fine needle aspiration cytology of cervical and axillary lymph nodes yielded a diagnosis of leishmaniasis. Diagnosis of VL was challenging as the disease closely mimicked tuberculosis in the setting of extensive lymphadenopathy including conglomerate of mesenteric lymph nodes, on and off fever, and granulomatous lymphadenitis on aspiration. Bone marrow examination was further performed. A detailed workup revealed patient to be severely immunocompromised and newly diagnosed human immunodeficiency virus (HIV) positive. Worldwide, India has the largest number of VL cases, accounting for 40%-50% of world's disease burden and the second largest HIV-infected population, accounting for approximately 10% of the global disease burden. HIV increases the risk of developing VL by 100-2320 times in endemic areas and concurrently VL promotes the clinical progression of HIV disease. Co-infection with HIV alters the body's immune response to leishmaniasis thus leading to unusual presentations. This case highlights the diagnostic problem in the aforesaid setting. Moreover, co-infection with HIV in VL can be a potential source of drug resistance. An early diagnosis and intensified treatment is the key to patient management.

Visceral Leishmaniasis in a patient with rheumatoid arthritis undergoing treatment with methotrexate: Case report and review of the literature

There is growing concern regarding the emergence of visceral leishmaniasis (VL), a disseminated parasitic disease caused by protozoa of the genus Leishmania, as an opportunistic infection in immunocompromised patients. This association has been principally studied in the context of human immunodeficiency virus infection, but VL has also been reported in patients undergoing treatment with immunosuppressive medication for various indications. Here a case of VL in a patient with rheumatoid arthritis undergoing treatment with methotrexate and corticosteroid is presented. Despite the rarity of such incidents, physicians should include VL in the differential diagnosis because this infection, if left untreated, is characterized by significant mortality.

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.

Hepatic stellate cells regulate liver immunity to visceral leishmaniasis through P110δ-dependent induction and expansion of regulatory T cells in mice

Visceral leishmaniasis (VL) is associated with severe immune dysfunction and if untreated leads to death. Because the liver is one of the primary target organs in VL, unraveling the mechanisms governing the local hepatic immune response is important for understanding the immunopathogenesis of VL. We previously reported that mice with inactivating knockin mutation in the p110δ gene (p110δ(D910A) ) are resistant to VL, due in part to impaired regulatory T-cell (Treg) expansion. In this study, we investigated the mechanism of this resistance by focusing on hepatic stellate cells (HSCs), which are known to regulate Treg induction and expansion. We show that HSCs are infected with Leishmania donovani in vivo and in vitro and that this infection leads to the production of interleukin-2, interleukin-6, and transforming growth factor-β, cytokines known to induce Tregs. We further demonstrate that L. donovani infection leads to expansion of HSCs in a p110δ-dependent manner and that this correlated with proliferation of hepatic Tregs in vivo. In vitro studies clearly show that L. donovani-infected HSCs induce CD4(+) T cells to become Tregs and expand Tregs in a p110δ-dependent manner. Targeted depletion of HSCs during infection caused a dramatic reduction in liver Treg numbers and proliferation, which was associated with a decrease in interleukin-10 production by hepatic T cells and a more efficient parasite control.

CONCLUSION

These results demonstrate the critical role of HSCs in the pathogenesis of VL and suggest that the enhanced resistance of p110δ(D910A) mice to L. donovani infection is due in part to impaired expansion and inability of their HSCs to induce and expand Tregs in the liver.

A Potential Role for Mononuclear Phagocytes in Cutaneous Ulcer Development in Human Immunodeficiency Virus-Leishmania braziliensis Coinfection

Skin ulcer development in cutaneous leishmaniasis due to Leishmania braziliensis infection is associated with a mononuclear cell infiltrate and high levels of tumor necrosis factor (TNF). Herein, we show that despite the absence of Leishmania-driven TNF, a cutaneous leishmaniasis patient with acquired immunodeficiency syndrome developed a skin ulcer. The presence of mononuclear phagocytes and high levels of TNF, chemokine (C-C motif) ligand 2 (CCL2), and metalloproteinase-9 in tissue are identified as potential contributors to immunopathology observed in L. braziliensis-infected patients.

Green Synthesis of Silver and Titanium Dioxide Nanoparticles Using Euphorbia prostrata Extract Shows Shift from Apoptosis to G0/G1 Arrest followed by Necrotic Cell Death in Leishmania donovani

The aim of the present study was to synthesize silver (Ag) and titanium dioxide (TiO2) nanoparticles (NPs) using green synthesis from aqueous leaf extract of Euphorbia prostrata as antileishmanial agents and to explore the underlying molecular mechanism of induced cell death. In vitro antileishmanial activity of synthesized NPs was tested against promastigotes of Leishmania donovani by alamarBlue and propidium iodide uptake assays. Antileishmanial activity of synthesized NPs on intracellular amastigotes was assessed by Giemsa staining. The leishmanicidal effect of synthesized Ag NPs was further confirmed by DNA fragmentation assay and by cell cycle progression and transmission electron microscopy (TEM) of the treated parasites. TEM analysis of the synthesized Ag NPs showed a spherical shape with an average size of 12.82 ± 2.50 nm, and in comparison to synthesized TiO2 NPs, synthesized Ag NPs were found to be most active against Leishmania parasites after 24 h exposure, with 50% inhibitory concentrations (IC50) of 14.94 μg/ml and 3.89 μg/ml in promastigotes and intracellular amastigotes, respectively. A significant increase in G0/G1 phase of the cell cycle with a subsequent decrease in S (synthesis) and G2/M phases compared to controls was observed. The growth-inhibitory effect of synthesized Ag NPs was attributed to increased length of S phase. A decreased reactive oxygen species level was also observed, which could be responsible for the caspase-independent shift from apoptosis (G0/G1 arrest) to massive necrosis. High-molecular-weight DNA fragmentation as a positive consequence of necrotic cell death was also visualized. We also report that the unique trypanothione/trypanothione reductase (TR) system of Leishmania cells was significantly inhibited by synthesized Ag NPs. The green-synthesized Ag NPs may provide promising leads for the development of cost-effective and safer alternative treatment against visceral leishmaniasis.

Immunity to visceral leishmaniasis: implications for immunotherapy

Visceral leishmaniasis, caused by Leishmania donovani, L. infantum (syn. Leishmania chagasi), is a globally widespread disease with a burden of about 400,000 new infections reported annually. It is the most dangerous form of human leishmaniasis in terms of mortality and morbidity and is spreading to several nonendemic areas because of migration, global traveling and military conflicts. The emergence of Leishmania-HIV co-infection and increased prevalence of drug-resistant strains have worsened the impact of the disease. The traditional low-cost drugs are often toxic with several adverse effects, highlighting the need for development of new therapeutic and prophylactic strategies. Therefore, a detailed understanding of mechanisms of protective immunity is extremely important in order to develop new therapeutics in the form of vaccines or immunotherapies. This review gives an overview of visceral leishmaniasis, with particular emphasis on the innate and adaptive immune responses, vaccine and vaccination strategies and their potentials for immunotherapy against the disease.

Anti-HIV drugs, lopinavir/ritonavir and atazanavir, modulate innate immune response triggered by Leishmania in macrophages: the role of NF-κB and PPAR-γ

This study evaluated the influence of HIV protease inhibitors lopinavir/ritonavir (LPV/RTV) and atazanavir (ATV) on macrophage functions during their first interaction with Leishmania. Macrophages from BALB/c mice treated for 10days with LPV/RTV and ATV, infected or not in vitro with L. (L.) amazonensis, were used to investigate the effects of these drugs on infection index, leishmanicidal capacity, cytokine production and PPAR-γ and RelB expression. LPV/RTV and ATV treatments significantly increased the infection index and the percentage of Leishmania-infected macrophages compared to untreated infected macrophages. There was no correlated increase in the production of NO and H2O2 leishmanicidal molecules. Promastigotes derived from Leishmania-infected macrophages from LPV/RTV and ATV-treated BALB/c mice had an in vitro growth 45.1% and 56.4% higher in groups treated with LPV/RTV and ATV than with PBS in culture. ATV treatment reduced IL-12p70 and IL-10 secretion in Leishmania-infected macrophages, but had no effect on IL-23 and TNF production. LPV reduced IL-10 and had no effect on IL-12p70, TNF and IL-23 secretion. ATV treatment decreased PPAR-γ expression in Leishmania-infected macrophages compared to untreated infected macrophages. In addition, LPV/RTV, but not ATV, reduced RelB cytoplasm-to-nucleus translocation in Leishmania-infected macrophages. Results showed that LPV/RTV and ATV HIV protease inhibitors were able to modulate innate defense mechanisms against Leishmania via different intracellular pathways. Although HIV protease inhibitors are highly efficient to control the Human Immunodeficiency Virus, these drugs might also influence the course of leishmaniasis in HIV-Leishmania-co-infected individuals.

Visceral leishmaniasis: a differential diagnosis to remember after bone marrow transplantation

Leishmania infection in immunocompromised hosts is reported in the literature, mostly concerning human immunodeficiency virus infected patients. It is not well characterized in the context of stem cell transplantation. We report a rare case clinical case of visceral leishmaniasis after allogeneic bone marrow transplantation. A 50-year-old Caucasian male was referred to allogeneic bone marrow transplantation with a high-risk acute lymphoblastic B leukemia in first complete remission. Allogeneic SCT was performed with peripheral blood stem cells from an unrelated Portuguese matched donor. In the following months, patient developed mild fluctuating cytopenias, mostly thrombocytopenia (between 60 and 80∗10⁹/L). The only significant complaint was intermittent tiredness. The common causes for thrombocytopenia in this setting were excluded—no evidence of graft versus host disease, no signs of viral or bacterial infection, and no signs of relapsed disease/dysplastic changes. The bone marrow smear performed 12 months after transplantation revealed an unsuspected diagnosis: a massive bone marrow infiltration with amastigotes.

Epidemiology of human immunodeficiency virus-visceral leishmaniasis-co-infection

In Brazil, the rates of mother-to-child-transmission (MTCT) of human immunodeficiency virus (HIV) decreased from 20% to 1-2% in some regions. However, the country contains 90% of individuals infected with visceral leishmaniasis (VL) in Latin America, and the west region of São Paulo state faces an alarming expansion of the disease. We describe the epidemiological aspects of the expanding infection of VL and a case report of an HIV-VL-co-infected child from the west region of São Paulo state. The patient was an AIDS-C3 with low levels of CD4, high viral load, severe diarrhea, oral and perineal candidiasis, severe thrombocytopenia, and protein-caloric malnourishment. She evolved with sepsis, renal and cardiac failure. An rK rapid diagnosis test, indirect fluorescent antibody test (IFAT), and bone marrow aspirate were performed for VL. Her symptoms improved significantly after liposomal amphotericin B administration. From the 45 municipalities that compose the Regional Health Department of Presidente Prudente, Lutzomyia longipalpis vectors were found in 58% of them. VL infected dogs were found in 33% of those municipalities, infected dogs and humans were found in 29%, 20% are starting and 33% of the municipalities are preparing VL investigation. It is likely, in this patient, that VL advanced the clinical progression of the HIV disease and the development of AIDS severity. Supported by favorable conditions, the region becomes a new frontier of VL in Brazil.

Post-Kala-Azar Dermal Leishmaniasis: A Paradigm of Paradoxical Immune Reconstitution Syndrome in Non-HIV/AIDS Patients

Visceral leishmaniasis (VL) is a parasitic disease characterized by immune suppression. Successful treatment is usually followed by immune reconstitution and a dermatosis called post-Kala-azar dermal leishmaniasis (PKDL). Recently, PKDL was described as one of the immune reconstitution syndromes (IRISs) in HIV/VL patients on HAART. This study aimed to present PKDL as a typical example of paradoxical IRIS in non-HIV/AIDS individuals. Published and new data on the pathogenesis and healing of PKDL was reviewed and presented. The data suggested that PKDL is a typical example of paradoxical IRIS, being a new disease entity that follows VL successful treatment and immune recovery. PKDL lesions are immune inflammatory in nature with granuloma, adequate response to immunochemotherapy, and an ensuing hypersensitivity reaction, the leishmanin skin test (LST). The data also suggested that the cytokine patterns of PKDL pathogenesis and healing are probably as follows: an active disease state dominated by IL-10 followed by spontaneous/treatment-induced IL-12 priming, IL-2 stimulation, and INF-γ production. INF-γ-activated macrophages eliminate the Leishmania parasites/antigen to be followed by LST conversion and healing. In conclusion, PKDL is a typical example of paradoxical IRIS in non-HIV/AIDS individuals with anti-inflammatory cytokine patterns that are superseded by treatment-induced proinflammatory cytokines and lesions healing.

Visceral leishmaniasis: host-parasite interactions and clinical presentation in the immunocompetent and in the immunocompromised host

Visceral leishmaniases are vector-borne parasitic diseases caused by protozoa belonging to the genus Leishmania. The heterogeneity of clinical manifestations and epidemiological characteristics of the disease reflect the complex interplay between the infecting Leishmania species and the genetic and immunologic characteristics of the infected host. The clinical presentation of visceral leishmaniasis depends strictly on the immunocompetency of the host and ranges from asymptomatic to severe forms. Conditions of depression of the immune system, such as HIV infection or immunosuppressive treatments, impair the capability of the immune response to resolve the infection and allow reactivation and relapses of the disease.

The diagnostic accuracy of serologic and molecular methods for detecting visceral leishmaniasis in HIV infected patients: meta-analysis

Background

Human visceral leishmaniasis (VL), a potentially fatal disease, has emerged as an important opportunistic condition in HIV infected patients. In immunocompromised patients, serological investigation is considered not an accurate diagnostic method for VL diagnosis and molecular techniques seem especially promising.

Objective

This work is a comprehensive systematic review and meta-analysis to evaluate the accuracy of serologic and molecular tests for VL diagnosis specifically in HIV-infected patients.

Methods

Two independent reviewers searched PubMed and LILACS databases. The quality of studies was assessed by QUADAS score. Sensitivity and specificity were pooled separately and compared with overall accuracy measures: diagnostic odds ratio (DOR) and symmetric summary receiver operating characteristic (sROC).

Results

Thirty three studies recruiting 1,489 patients were included. The following tests were evaluated: Immunofluorescence Antibody Test (IFAT), Enzyme linked immunosorbent assay (ELISA), immunoblotting (Blot), direct agglutination test (DAT) and polimerase chain reaction (PCR) in whole blood and bone marrow. Most studies were carried out in Europe. Serological tests varied widely in performance, but with overall limited sensitivity. IFAT had poor sensitivity ranging from 11% to 82%. DOR (95% confidence interval) was higher for DAT 36.01 (9.95–130.29) and Blot 27.51 (9.27–81.66) than for IFAT 7.43 (3.08–1791) and ELISA 3.06 (0.71–13.10). PCR in whole blood had the highest DOR: 400.35 (58.47–2741.42). The accuracy of PCR based on Q-point was 0.95; 95%CI 0.92–0.97, which means good overall performance.

Conclusion

Based mainly on evidence gained by infection with Leishmania infantum chagasi, serological tests should not be used to rule out a diagnosis of VL among the HIV-infected, but a positive test at even low titers has diagnostic value when combined with the clinical case definition. Considering the available evidence, tests based on DNA detection are highly sensitive and may contribute to a diagnostic workup.

Human visceral leishmaniasis (VL), a potentially fatal disease, has emerged as an important opportunistic condition in HIV infected patients. In immunocompromised patients, serological investigation is considered not an accurate diagnostic method for VL diagnosis and molecular techniques seem especially promising. Demonstration of Leishmania parasites in bone marrow aspirate or in other biologic specimen, either by visualization or culture, remains the most reliable diagnostic technique in the setting of HIV co-infection. However, these tests are difficult to perform in rural areas and some of them are invasive and carry a risk of complication. This work is a systematic review to evaluate the accuracy of serologic and molecular tests for VL diagnosis in HIV-infected patients. Two reviewers searched the literature, evaluating quality of studies and comparing performance of diagnostic tests. Thirty three studies were included. Most studies were carried out in Europe. Serological tests varied in performance, but with overall limited sensitivity. Based on the evidence, serological tests should not be used to rule out a diagnosis of VL among HIV-patients, but a positive test at even low titers has diagnostic value when combined with the clinical case definition. Tests based on DNA detection are highly sensitive and may contribute to a diagnostic workup.

Clinical pleiomorphism in human leishmaniases, with special mention of asymptomatic infection

This review gives an update of current knowledge on the clinical pleiomorphism of Leishmania, with a special emphasis on the case of asymptomatic carriage. The first part describes the numerous unusual expressions of the disease that occur besides the classic (visceral, cutaneous, and mucocutaneous) forms of leishmaniases. The second part deals with progress in the understanding of disease outcome in humans, and the possible future approaches to improve our knowledge in the field. The third part highlights the role of the too often neglected asymptomatic carrier compartment. This group could be key to understanding infraspecific differences in virulence and pathogenicity of the parasite, as well as identifying the genetic determinants involved in the expression of the disease.

Comparative assessment of a DNA and protein Leishmania donovani gamma glutamyl cysteine synthetase vaccine to cross-protect against murine cutaneous leishmaniasis caused by L. major or L. mexicana infection

Leishmaniasis is a major health problem and it is estimated that 12 million people are currently infected. A vaccine which could cross-protect people against different Leishmania spp. would facilitate control of this disease as more than one species of Leishmania may be present. In this study the ability of a DNA vaccine, using the full gene sequence for L. donovani gamma glutamyl cysteine synthetase (γGCS) incorporated in the pVAX vector (pVAXγGCS), and a protein vaccine, using the corresponding recombinant L. donovani γGCS protein (LdγGCS), to protect against L. major or L. mexicana infection was evaluated. DNA vaccination gave transient protection against L. major and no protection against L. mexicana despite significantly enhancing specific antibody titres in vaccinated infected mice compared to infected controls. Vaccination with the LdγGCS protected against both species but only if the protein was incorporated into non-ionic surfactant vesicles for L. mexicana. The results of this study indicate that a L. donovani γGCS vaccine could be used to vaccinate against more than one Leishmania species but only if the recombinant protein is used.

Disseminated Rhodococcus equi infection in HIV infection despite highly active antiretroviral therapy

BACKGROUND

Rhodococcus equi (R.equi) is an acid fast, GRAM + coccobacillus, which is widespread in the soil and causes pulmonary and extrapulmonary infections in immunocompromised people. In the context of HIV infection, R.equi infection (rhodococcosis) is regarded as an opportunistic disease, and its outcome is influenced by highly active antiretroviral therapy (HAART).

CASE PRESENTATION

We report two cases of HIV-related rhodococcosis that disseminated despite suppressive HAART and anti-rhodococcal treatment; in both cases there was no immunological recovery, with CD4+ cells count below 200/μL. In the first case, pulmonary rhodococcosis presented 6 months after initiation of HAART, and was followed by an extracerebral intracranial and a cerebral rhodococcal abscess 1 and 8 months, respectively, after onset of pulmonary infection. The second case was characterized by a protracted course with spread of infection to various organs, including subcutaneous tissue, skin, colon and other intra-abdominal tissues, and central nervous system; the spread started 4 years after clinical resolution of a first pulmonary manifestation and progressed over a period of 2 years.

CONCLUSIONS

Our report highlights the importance of an effective immune recovery, despite fully suppressive HAART, along with anti-rhodococcal therapy, in order to clear rhodococcal infection.

Protease expression by microorganisms and its relevance to crucial physiological/pathological events

The treatment of infections caused by fungi and trypanosomatids is difficult due to the eukaryotic nature of these microbial cells, which are similar in several biochemical and genetic aspects to host cells. Aggravating this scenario, very few antifungal and anti-trypanosomatidal agents are in clinical use and, therefore, therapy is limited by drug safety considerations and their narrow spectrum of activity, efficacy and resistance. The search for new bioactive agents against fungi and trypanosomatids has been expanded because progress in biochemistry and molecular biology has led to a better understanding of important and essential pathways in these microorganisms including nutrition, growth, proliferation, signaling, differentiation and death. In this context, proteolytic enzymes produced by these eukaryotic microorganisms are appointed and, in some cases, proven to be excellent targets for searching novel natural and/or synthetic pharmacological compounds, in order to cure or prevent invasive fungal/trypanosomatid diseases. With this task in mind, our research group and others have focused on aspartic-type proteases, since the activity of this class of hydrolytic enzymes is directly implicated in several facets of basic biological processes of both fungal and trypanosomatid cells as well as due to the participation in numerous events of interaction between these microorganisms and host structures. In the present paper, a concise revision of the beneficial effects of aspartic protease inhibitors, with emphasis on the aspartic protease inhibitors used in the anti-human immunodeficiency virus therapy, will be presented and discussed using our experience with the following microbial models: the yeast Candida albicans, the filamentous fungus Fonsecaea pedrosoi and the protozoan trypanosomatid Leishmania amazonensis.

Activity and turnover of eosinophil and neutrophil granulocytes are altered in visceral leishmaniasis

Visceral leishmaniasis (VL) is a health issue in Sudan. Our aim was to investigate the involvement of eosinophils and neutrophils in VL by serum and plasma measurements of eosinophil cationic protein (ECP) and myeloperoxidase (MPO) and some key cytokines and chemokines. Blood was collected from 125 VL patients and 181 healthy Sudanese controls from the same rural area. Results showed reduced eosinophil and neutrophil counts in the VL group (P=0.0001 and P=0.002, respectively). Serum-ECP levels were higher in the controls (P<0.0001), while plasma MPO levels were higher in the VL group (P<0.0001). Levels of IL-5, granulocyte macrophage-colony stimulating factor (GM-CSF) and IL-17 were increased among the VL group (P<0.0001, P=0.017 and P=0.03, respectively), whereas eotaxin and IL-8 levels were reduced (P<0.0001 and P=0.002, respectively). Positive correlations were found between IL-8 and ECP/MPO (P<0.0001). We conclude that eosinophil and neutrophil turnover and activity are increased in subjects in rural areas of Sudan. In VL the turnover was further increased, but the relatively low secretory activity of eosinophils and neutrophils in VL may relate to the reduced production and availability of the chemokines eotaxin and IL-8. The combined assay of ECP and MPO in serum and plasma provides further insight into the mechanisms of eosinophil and neutrophil involvement in disease and constitutes a novel approach to the study of disease processes.