Risk factors, clinical features and outcomes of visceral leishmaniasis in solid-organ transplant recipients: a retrospective multicenter case-control study

Leishmaniasis in transplant patients: what do we know so far?

PURPOSE OF REVIEW

The number of cases of visceral leishmaniasis associated with transplant-associated immunosuppression has increased in recent years. Reviewing and updating the latest developments in its diagnostic management, treatment, and follow-up is necessary and relevant.

RECENT FINDINGS

Visceral leishmaniasis cases associated with non-HIV immunosuppression are a growing cause of the parasitic infections, and the transplant patients are included in this context. These have been described especially in kidney transplantation. Liposomal amphotericin B is the first-line treatment. Due to immunosuppression, these patients often suffer from recurrent infections. The use of markers that indicate whether the patient has developed an adequate cellular response against Leishmania after treatment seems to be good biomarkers of cure and useful for monitoring and guiding secondary prophylaxis.

SUMMARY

There is a lack of consensus regarding the need for leishmaniasis screening in donors and recipients and the indications for secondary prophylaxis. The study of new biomarkers of cure may be useful in all three contexts.

Immune response to viscerotropic Leishmania: a comprehensive review

L. donovani and L. infantum infections are associated with a broad clinical spectrum, ranging from asymptomatic cases to visceral leishmaniasis (VL) with high mortality rates. Clinical manifestations such as post-kala-azar dermal leishmaniasis (PKDL) and visceral leishmaniasis-associated hemophagocytic lymphohistiocytosis-mimic (VL-associated HLH-mimic) further contribute to the diversity of clinical manifestations. These clinical variations are intricately influenced by the complex interplay between the host's immune response and the parasite's escape mechanisms. This narrative review aims to elucidate the underlying immunological mechanisms associated with each clinical manifestation, drawing from published literature within the last 5 years. Specific attention is directed toward viscerotropic Leishmania sinfection in patients with inborn errors of immunity and acquired immunodeficiencies. In VL, parasites exploit various immune evasion mechanisms, including immune checkpoints, leading to a predominantly anti-inflammatory environment that favors parasite survival. Conversely, nearly 70% of individuals are capable of mounting an effective pro-inflammatory immune response, forming granulomas that contain the parasites. Despite this, some patients may experience reactivation of the disease upon immunosuppression, challenging current understandings of parasite eradication. Individuals living with HIV and those with inborn errors of immunity present a more severe course of infection, often with higher relapse rates. Therefore, it is crucial to exclude both primary and acquired immune deficiencies in patients presenting disease relapse and VL-associated HLH-mimic. The distinction between VL and HLH can be challenging due to clinical similarities, suggesting that the nosological entity known as VL-associated HLH may represent a severe presentation of symptomatic VL and it should be considered more accurate referring to this condition as VL-associated HLH-mimic. Consequently, excluding VL in patients presenting with HLH is essential, as appropriate antimicrobial therapy can reverse immune dysregulation. A comprehensive understanding of the immune-host interaction underlying Leishmania infection is crucial for formulating effective treatment and preventive strategies to mitigate the disease burden.

Visceral leishmaniasis misdiagnosed as an upper respiratory infection and iron-deficiency anemia in a 20-month-old male patient: a case report

BACKGROUND

Visceral Leishmaniasis should be suspected in every patient with a history of splenomegaly, fever, and pancytopenia. It is one of the most dangerous forms of infection and prompt recognition is the key to positive outcome.

CASE PRESENTATION

A 20-month-old Caucasian male patient was brought to our hospital as an outpatient with the complaint of persistent fever, which did not improve with empiric antibiotic treatment (> 96 hour after the initial dose). The antibiotic treatment had been prescribed by primary care physician at polyclinic, who also referred the patient to hematologist due to anemia, who prescribed iron supplement. Despite multiple subspecialist visits, bicytopenia was, unfortunately, left unidentified. Upon physical examination no specific signs were detected, however, spleen seemed slightly enlarged. Patient was admitted to the hospital for further work-up, management and evaluation. Abdominal ultrasound, complete blood count and c-reactive protein had been ordered. Hematologist and infectionist were involved, both advised to run serology for Epstein-Barr Virus and Visceral Leishmaniasis. The latter was positive; therefore, patient was transferred to the specialized clinic for specific management.

CONCLUSION

Both in endemic and non-endemic areas the awareness about VL should be increased among the medical professionals. We also recommend that our colleagues take the same approach when dealing with bicytopenia and fever, just as with pancytopenia and fever. The medical community should make sure that none of the cases of fever and pancytopenia are overlooked, especially if we have hepatomegaly and/or splenomegaly.

Updated diagnosis and graft involvement for visceral leishmaniasis in kidney transplant recipients: a case report and literature review

Purpose

Visceral leishmaniasis (VL) has become a rising concern to transplantation teams, being associated with graft dysfunction and reduced survival of renal transplant recipients. Here, we describe a case of VL occurring in a kidney transplant (KT) recipient in Italy, a country in which Leishmania infantum is endemic and we reviewed the literature on the clinical course and diagnosis of VL in KT recipients residing or travelling to southern Europe.

Results

The VL case was diagnosed 18 months after transplant and 28 days after the onset of symptoms by quantitative PCR (qPCR) on peripheral blood. A graft biopsy showed renal involvement, and PCR performed on graft tissue displayed the presence of Leishmania DNA. The retrospective confirmation of Leishmania-positive serology in a serum sample collected before transplantation, as well as the absence of anti-Leishmania IgG in the graft donor strongly suggest that reactivation of a latent parasitic infection caused VL in the current case.

Conclusion

VL is often underdiagnosed in transplant recipients, despite the presence of latent Leishmania infection being reported in endemic countries. This case report, as well as the literature review on leishmaniasis in KT recipients, underline the importance of rapid VL diagnosis to promptly undergo treatment. Serology is scarcely sensitive in immunocompromised patients, thus molecular tests in peripheral blood should be implemented and standardized for both VL identification and follow-up.

Epidemiology, Clinical Characteristics, Diagnostic Work Up, and Treatment Options of Leishmania Infection in Kidney Transplant Recipients: A Systematic Review

Current knowledge on Leishmania infection after kidney transplantation (KT) is limited. In order to offer a comprehensive guide for the management of post-transplant Leishmaniasis, we performed a systematic review following the latest PRISMA Checklist and using PubMed, Scopus, and Embase as databases. No time restrictions were applied, including all English-edited articles on Leishmaniasis in KT recipients. Selected items were assessed for methodological quality using a modified Newcastle-Ottawa Scale. Given the nature and quality of the studies (case reports and retrospective uncontrolled case series), data could not be meta-analyzed. A descriptive summary was therefore provided. Eventually, we selected 70 studies, describing a total of 159 cases of Leishmaniasis. Most of the patients were adult, male, and Caucasian. Furthermore, they were frequently living or travelling to endemic regions. The onset of the disease was variable, but more often in the late transplant course. The clinical features were basically similar to those reported in the general population. However, a generalized delay in diagnosis and treatment could be detected. Bone marrow aspiration was the preferred diagnostic modality. The main treatment options included pentavalent antimonial and liposomal amphotericin B, both showing mixed results. Overall, the outcomes appeared as concerning, with several patients dying or losing their transplant.

An exploratory analysis of C-X-C motif chemokine ligand 10 as a new biomarker of asymptomatic Leishmania infantum infection in Solid-Organ Transplant Recipients

OBJECTIVE

Sensitive and less laborious assays are needed to detect asymptomatic Leishmania among solid organ transplant (SOT) recipients. Using SLA-stimulated plasma from SOT recipients living where an outbreak of Leishmania infantum occurred, we examined potential biomarkers to identify asymptomatic Leishmania infections.

METHODS

Concentrations of cytokines/chemokines in plasma from whole blood stimulated with specific Leishmania antigen (SLA) were compared against infection status as determined by a currently used cell proliferation assay.

RESULTS

Twenty-six percent (13/50) of the SOT recipients had a cell proliferation assay (CPA) indicating asymptomatic infection, and showed higher processed plasma C-X-C motif chemokine ligand 10 (CXCL10 or IP-10) concentrations than did non-infected subjects (median 2272.0 pg/ml [IQR-1570-2772] vs. 18.2 pg/ml [IQR 1-150.1]; p<0.0001). CXCL10 showed a sensitivity of 93% and a specificity of 95% compared to CPA. In addition, we demonstrated that the number of asymptomatic infections detected using CXCL10, decreased with distance from a park at the centre of the mentioned outbreak.

CONCLUSION

CXCL10 in plasma from SLA-stimulated blood could be a robust biomarker of asymptomatic L. infantum infection in solid organ transplant recipients.

Current status of glucocorticoid usage in solid organ transplantation

Glucocorticoids (GCs) have been the mainstay of immunosuppressive therapy in solid organ transplantation (SOT) for decades, due to their potent effects on innate immunity and tissue protective effects. However, some SOT centers are reluctant to administer GCs long-term because of the various related side effects. This review summarizes the advantages and disadvantages of GCs in SOT. PubMed and Scopus databases were searched from 2011 to April 2021 using search syntaxes covering “transplantation” and “glucocorticoids”. GCs are used in transplant recipients, transplant donors, and organ perfusate solution to improve transplant outcomes. In SOT recipients, GCs are administered as induction and maintenance immunosuppressive therapy. GCs are also the cornerstone to treat acute antibody- and T-cell-mediated rejections. Addition of GCs to organ perfusate solution and pretreatment of transplant donors with GCs are recommended by some guidelines and protocols, to reduce ischemia-reperfusion injury peri-transplant. GCs with low bioavailability and high potency for GC receptors, such as budesonide, nanoparticle-mediated targeted delivery of GCs to specific organs, and combination use of dexamethasone with inducers of immune-regulatory cells, are new methods of GC application in SOT patients to reduce side effects or induce immune-tolerance instead of immunosuppression. Various side effects involving different non-targeted organs/tissues, such as bone, cardiovascular, neuromuscular, skin and gastrointestinal tract, have been noted for GCs. There are also potential drug-drug interactions for GCs in SOT patients.

Reactivation of latent infections in solid organ transplant recipients from sub-Saharan Africa: What should be remembered?

International migration from Sub-Saharan African countries to the European Union and the United States has significantly increased over the past decades. Although the vast majority of these immigrants are young and healthy people, a minority can be affected by chronic conditions eventually leading to solid organ transplantation (SOT). Importantly, these candidates can bear geographically restricted fungal and parasitic latent infections that can reactivate after the procedure. An appropriate evaluation before transplantation followed by treatment, whenever necessary, is essential to minimize such risk, as covered in the present review. In short, infection due to helminths (Schistosoma spp. and Strongyloides stercoralis) and intestinal protozoa (Entamoeba histolytica, Giardia lamblia or Cyclospora cayetanensis) can be diagnosed by multiple direct stool examination, serological assays and stool antigen testing. Leishmaniasis can be assessed by means of serology, followed by nucleic acid amplification testing (NAAT) if the former test is positive. Submicroscopic malaria should be ruled out by NAAT. Screening for Histoplasma spp. or Cryptococcus spp. is not routinely indicated. Consultation with an Infectious Diseases specialist is recommended in order to adjust preemptive treatment among Sub-Saharan African SOT candidates and recipients.

Leishmaniasis in the United States: Emerging Issues in a Region of Low Endemicity

Leishmaniasis, a chronic and persistent intracellular protozoal infection caused by many different species within the genus Leishmania, is an unfamiliar disease to most North American providers. Clinical presentations may include asymptomatic and symptomatic visceral leishmaniasis (so-called Kala-azar), as well as cutaneous or mucosal disease. Although cutaneous leishmaniasis (caused by Leishmania mexicana in the United States) is endemic in some southwest states, other causes for concern include reactivation of imported visceral leishmaniasis remotely in time from the initial infection, and the possible long-term complications of chronic inflammation from asymptomatic infection. Climate change, the identification of competent vectors and reservoirs, a highly mobile populace, significant population groups with proven exposure history, HIV, and widespread use of immunosuppressive medications and organ transplant all create the potential for increased frequency of leishmaniasis in the U.S. Together, these factors could contribute to leishmaniasis emerging as a health threat in the U.S., including the possibility of sustained autochthonous spread of newly introduced visceral disease. We summarize recent data examining the epidemiology and major risk factors for acquisition of cutaneous and visceral leishmaniasis, with a special focus on implications for the United States, as well as discuss key emerging issues affecting the management of visceral leishmaniasis.

Visceral Dissemination of Mucocutaneous Leishmaniasis in a Kidney Transplant Recipient

Intracellular protozoan of the genus Leishmania, endemic in the Mediterranean basin, are the cause of cutaneous (CL), mucocutaneous (MCL), and visceral leishmaniasis (VL). A 75-year-old woman was admitted nine years after a second kidney transplant (KT), due to persistent pancytopenia and fever. She presented edema and erythema of the nose in the last two years and an exophytic nodular lesion located on the left arm, with areas of peripheral necrosis and central ulceration in the last 18 months. A bone marrow biopsy revealed features compatible with Leishmania amastigotes, and polymerase chain reaction test (PCR) for Leishmania infantum was positive. Moreover, biopsy and PCR for L. infantum of the cutaneous lesion on the patient's left arm and nose and PCR from peripheral blood were positive. Thus, a diagnosis of CL, MCL, and VL was made, and liposomal amphotericin B was initiated, but the patient had an unfavorable outcome and died. This is the first report of a KT recipient presenting with the entire spectrum of leishmaniasis. In Portugal, this infection is rare-so a high degree of clinical suspicion is required for its diagnosis, especially in endemic regions, as visceral leishmaniasis is a potentially life-threatening infection.

Asymptomatic Visceral Leishmania infantum Infection in US Soldiers Deployed to Iraq

BACKGROUND

Visceral leishmaniasis (VL), due to Leishmania infantum, is a persistent intracellular parasitic infection transmitted by the bite of infected sand flies. Symptomatic VL has been reported in U.S. soldiers with Iraq deployment. Untreated symptomatic VL can be fatal; asymptomatic VL (AVL) may establish a lifelong risk of reactivation. We report prevalence and AVL risk factors in Operation Iraqi Freedom (OIF) deployers during 2002-11.

METHODS

Healthy soldiers exposed to VL endemic areas in Iraq and 50 controls who never traveled to endemic regions were recruited through military healthcare facilities (2015-17). Responses to a risk factor survey and blood samples were obtained. Leishmania research diagnostics utilized included enzyme-linked immunosorbent assay (ELISA), rk39 test strips, quantitative polymerase chain reaction (PCR), and interferon gamma release (IGRA) assays. Statistical analyses included Fisher exact test, Pearson χ2 test, Mann-Whitney U test, and logistic regression.

RESULTS

200 deployed subjects were enrolled, mostly males (84.0%), of white ethnicity (79.0%), and median age 41 (range 24-61) years. 64% were seropositive for Phlebotomus alexandri saliva antibodies. Prevalence of AVL (any positive test result) was 39/200 (19.5%, 95% confidence interval 14.4%-25.8%). Two (1.0%) PCR, 10 (5%) ELISA, and 28 (14%) IGRA samples were positive. Travel to Ninewa governorate increased risk for AVL (P = .01).

CONCLUSION

AVL was identified in 19.5% of OIF deployers; travel to northwest Iraq correlated with infection. Further studies are needed to inform risk for reactivation VL in US veterans and to target additional blood safety and surveillance measures.

Visceral Leishmaniasis in a Liver Transplant Patient: A Case Report

Leishmaniasis is an infection caused by protozoa of the genus Leishmania, transmitted by sandflies and endemic to more than 88 countries. Visceral leishmaniasis in immunosuppressed patients is a growing concern. We report the case of a 61-year-old male patient with a previous history of alcoholic cirrhosis and portal vein thrombosis who underwent liver transplantation for the treatment of hepatocellular carcinoma. Thirty-six days after the procedure, the patient showed an increase in liver enzymes and was diagnosed with moderate acute rejection of the graft. He was treated with high-dose intravenous corticosteroids, and while showing improvement in biochemical markers, he became febrile 12 days after corticosteroid treatment. He presented daily episodes of fever, even after the use of several antimicrobial, antiviral, and antifungal agents, and a number of negative cultures from different sites were obtained. A bone marrow biopsy was then performed, showing a large number of amastigote forms of Leishmania spp. Treatment with liposomal amphotericin B was initiated; however, the patient progressed to refractory septic shock and death. This case highlights several aspects of visceral leishmaniasis in liver transplant recipients, such as the association of malnutrition to Leishmania infection and the challenges of diagnosing leishmaniasis in cirrhotic patients in which splenomegaly and pancytopenia, the hallmarks of leishmaniasis, may also be attributed to portal hypertension and end-stage liver disease. A high index of suspicion is necessary for the correct diagnosis and treatment of leishmaniasis in this group of patients. This study is compliant with the Helsinki Congress and the Istanbul Declaration.

Emerging and neglected zoonoses in transplant population

Zoonoses represent a problem of rising importance in the transplant population. A close relationship and changes between human, animal and environmental health (“One Health” concept) significantly influence the transmission and distribution of zoonotic diseases. The aim of this manuscript is to perform a narrative review of the published literature on emerging and neglected zoonoses in the transplant population. Many reports on donor-derived or naturally acquired (re-)emerging arboviral infections such as dengue, chikungunya, West Nile, tick-borne encephalitis and Zika virus infection have demonstrated atypical or more complicated clinical course in immunocompromised hosts. Hepatitis E virus has emerged as a serious problem after solid organ transplantation (SOT), leading to diverse extrahepatic manifestations and chronic hepatitis with unfavorable outcomes. Some neglected pathogens such as lymphocytic choriomeningitis virus can cause severe infection with multi-organ failure and high mortality. In addition, ehrlichiosis may be more severe with higher case-fatality rates in SOT recipients. Some unusual or severe presentations of borreliosis, anaplasmosis and rickettsioses were also reported among transplant patients. Moreover, toxoplasmosis as infectious complication is a well-recognized zoonosis in this population. Although rabies transmission through SOT transplantation has rarely been reported, it has become a notable problem in some countries. Since the spreading trends of zoonoses are likely to continue, the awareness, recognition and treatment of zoonotic infections among transplant professionals should be imperative.

Screening strategies for the diagnosis of asymptomatic Leishmania infection in dialysis patients as a model for kidney transplant candidates

Despite being considered a tropical disease, visceral leishmaniasis (VL) caused by L. infantum is also endemic in the Mediterranean Europe and represents an increasing cause of morbidity and mortality in solid organ transplant (SOT) recipients. VL occurring in kidney transplant recipients is a severe event, often worsening the renal damage and leading to poor outcome. It is believed that most of VL cases in transplant recipients are caused by reactivation of a pre-existent, dormant leishmanial infection induced by the immunosuppressive drugs. Nevertheless, the prevalence of asymptomatic Leishmania infection in candidates to kidney transplant residing in or visiting endemic areas is unknown. As L. infantum is highly circulating in northeastern Italy, we aimed to examine the occurrence of this parasitic infection in 119 dialysis patients living in the mentioned area, 71 of whom were potential candidates to kidney transplant. By employing a combination of sensitive serological and molecular methods, we observed a prevalence of 15.9% asymptomatic Leishmania infection in the study cohort. This finding emphasizes the need of further evaluating potential screening strategies for Leishmania infection in solid organ transplant candidates residing in or visiting endemic areas.

[Visceral leishmaniasis]

Visceral leishmaniasis is a worldwide distributed infectious zoonotic disease caused by protozoan pathogens of the genus Leishmania which are transmitted by sandflies. The main hosts are dogs. The prevalence in Germany is low. Predominantly affected are migrants and travelers returning from Mediterranean countries. The main clinical symptoms are fever, hepatosplenomegaly and pancytopenia. The diagnosis is made by polymerase chain reaction of peripheral blood or direct detection of Leishmania in bone marrow aspirates. Lesions of the liver and spleen can easily be misinterpreted as numerous benign or malignant differential diagnoses. Treatment is always systemic with antiparasitic drugs. Immunosuppressed patients with HIV co-infection or after solid organ transplantation are prone to infection as well as atypical and severe courses.

Imported visceral leishmaniasis and immunosuppression in seven Norwegian patients

Background

Visceral leishmaniasis (VL) is a protozoal disease that may be aggravated by immunosuppression. In recent years, a growing number of patients with chronic diseases use biological treatment. When such immunosuppressed patients travel to endemic areas, they are facing the risk of VL. Increased incidence of leishmaniasis is reported in endemic areas like the Mediterranean basin, an area frequently visited by Norwegian tourists. This may lead to an increased number of patients, many presenting to health personnel unfamiliar with the disease, in their home countries.

Methods

We reviewed the files of seven immunosuppressed patients with VL, admitted to Oslo and Haukeland University Hospitals in Norway in the period 2009-2018.

Results

The patients were 41-83 (median 66) years of age; four had rheumatic disease all of whom used methotrexate; one had advanced HIV infection, one had inflammatory bowel disease and one had myelofibrosis. Leishmania infantum was confirmed in five patients by polymerase chain reaction (PCR) and sequencing. In the remaining two patients, a definite Leishmania species could not be identified. All patients had a history of recent recreational travel to Spain. Most patients underwent extensive diagnostic work-up before diagnosed with VL. All received treatment with liposomal amphotericin B and all were cured; albeit two after re-treatment due to relapse.

Conclusions

Visceral leishmaniasis is a potentially life-threatening but usually treatable condition. It is endemic in Southern Europe, including popular tourist destinations such as the Mediterranean basin. It is relatively unknown to most medical practitioners in non-endemic areas and clinical vigilance is required to identify those who are infected.

Tissue and blood protozoa including toxoplasmosis, Chagas disease, leishmaniasis, Babesia, Acanthamoeba, Balamuthia, and Naegleria in solid organ transplant recipients- Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of tissue and blood protozoal infections in the pre- and post-transplant period. Significant new developments in the field have made it necessary to divide the previous single guideline published in 2013 into two sections, with the intestinal parasites separated from this guideline devoted to tissue and blood protozoa. The current update reflects the increased focus on donor screening and risk-based recipient monitoring for parasitic infections. Increased donor testing has led to new recommendations for recipient management of Toxoplasma gondii and Trypanosoma cruzi. Molecular diagnostics have impacted the field, with access to rapid diagnostic testing for malaria and polymerase chain reaction testing for Leishmania. Changes in Babesia treatment regimens in the immunocompromised host are outlined. The risk of donor transmission of free-living amebae infection is reviewed. Changing immigration patterns and the expansion of transplant medicine in developing countries has contributed to the recognition of parasitic infections as an important threat to transplant outcomes. Medications such as benznidazole and miltefosine are now available to US prescribers as access to treatment of tissue and blood protozoa is increasingly prioritized.

Visceral leishmaniasis in hematopoietic cell transplantation: Case report and review of the literature

Visceral leishmaniasis has been recognized as an opportunistic infection affecting people with cellular-immunity impairment, including hematopoietic cell transplantation (HCT) recipients. We describe the case of a young Italian man with Hodgkin lymphoma, who developed visceral leishmaniasis after multiple lines of chemotherapy and allogenic HCT. Literature review of visceral leishmaniasis in HCT recipients was also performed. Eleven patients (median age 50 years, 9 male) developed visceral leishmaniasis after allogenic (n = 9) and autologous (n = 2) HCT. Most of them presented with fever and pancytopenia. Bone marrow examination was the main diagnostic technique; liposomal amphotericin B was the treatment of choice. Four out of eight patients (for whom data are available) experienced visceral leishmaniasis relapse. Visceral leishmaniasis in HCT recipients is a rare event that should be suspected in patients with persistent fever, pancytopenia and possible exposure to Leishmania spp., remembering that - as well as South-East Asia, East Africa and South America - it is endemic in several European regions.

Solid Organ Transplant and Parasitic Diseases: A Review of the Clinical Cases in the Last Two Decades

The aim of this study was to evaluate the occurrence of parasitic infections in solid organ transplant (SOT) recipients. We conducted a systematic review of literature records on post-transplant parasitic infections, published from 1996 to 2016 and available on PubMed database, focusing only on parasitic infections acquired after SOT. The methods and findings of the present review have been presented based on the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) checklist. From data published in the literature, the real burden of parasitic infections among SOT recipients cannot really be estimated. Nevertheless, publications on the matter are on the increase, probably due to more than one reason: (i) the increasing number of patients transplanted and then treated with immunosuppressive agents; (ii) the “population shift” resulting from immigration and travels to endemic areas, and (iii) the increased attention directed to diagnosis/notification/publication of cases. Considering parasitic infections as emerging and potentially serious in their evolution, additional strategies for the prevention, careful screening and follow-up, with a high level of awareness, identification, and pre-emptive therapy are needed in transplant recipients.

New insights into leishmaniasis in the immunosuppressed

Immunosuppression contributes significantly to the caseload of visceral leishmaniasis (VL). HIV coinfection, solid organ transplantation, malnutrition, and helminth infections are the most important immunosuppression-related factors. This review briefly describes the challenges of these associations. East Africa and the Indian subcontinent are the places where HIV imposes the highest burden in VL. In the highlands of Northern Ethiopia, migrant rural workers are at a greater risk of coinfection and malnutrition, while in India, HIV reduces the sustainability of a successful elimination programme. As shown from a longitudinal cohort in Madrid, VL is an additional threat to solid organ transplantation. The association with malnutrition is more complex since it can be both a cause and a consequence of VL. Different regimes for therapy and secondary prevention are discussed as well as the role of nutrients on the prophylaxis of VL in poverty-stricken endemic areas.

Current approaches to visceral leishmaniasis treatment in solid organ transplant recipients

INTRODUCTION

The increasing number of transplants performed worldwide and the growing global mobility with migration and travel to and from developing countries and tropical areas are bringing new challenges for the management of transplant infectious diseases, previously less commonly seen, such as Leishmaniasis. However, in this scenario there is a lack of information and the current knowledge is based on a few studies. The selection of the most appropriate treatment depends on various factors, such as patient profile, Leishmania species, disease extent, drug availability, concomitant infections and previous treatments. Therapeutic options may include different formulations of amphotericin B, pentavalent antimonials, miltefosine and paromomycin, among others. These drugs can be used alone or in combination. Areas covered: This review is a practical guide for Visceral Leishmaniasis (VL) specific treatment in solid organ transplant recipients (SOT), including therapeutic options and assessment of therapy response. Expert commentary: The main challenges for treatment of leishmaniasis in SOT recipients are related to the duration of therapy, curative criteria and secondary prophylaxis. Immunosuppression dose reduction is often recommended, but such decisions must be made on an individual basis. At present, Liposomal Amphotericin B is the best choice for treatment and prophylaxis.

Environmental Factors as Key Determinants for Visceral Leishmaniasis in Solid Organ Transplant Recipients, Madrid, Spain

During a visceral leishmaniasis outbreak in an area of Madrid, Spain, the incidence of disease among solid organ transplant recipients was 10.3% (7/68). Being a black person from sub-Saharan Africa, undergoing transplantation during the outbreak, and residing <1,000 m from the epidemic focus were risk factors for posttransplant visceral leishmaniasis.

Is Visceral Leishmaniasis Different in Immunocompromised Patients Without Human Immunodeficiency Virus? A Comparative, Multicenter Retrospective Cohort Analysis

Although visceral leishmaniasis (VL) can affect immunocompromised patients, data from the human immunodeficiency virus (HIV) infection context are limited, and the characteristics of VL in other immunosuppression scenarios are not well defined. A retrospective review of all cases of VL in immunocompromised patients from January 1997 to December 2014 in two Spanish hospitals on the Mediterranean coast was performed. We included 18 transplant recipients (kidney: 7, liver: 4, lung: 3, heart: 2, and blood marrow: 2), 12 patients with other causes of immunosuppression (myasthenia gravis: 3 and rheumatoid arthritis: 2), and 73 VL HIV-positive patients. Fever was more common in transplant patients (94.4%) and patients with other types of immunosuppression (100%) than in HIV-positive individuals (73.3%). Hepatomegaly was less common in transplant recipients (27.8%) and patients with other types of immunosuppression (41.7%) compared with HIV-positive patients (69.9%) (P = 0.01; P = 0.001, respectively). Patients with other types of immunosuppression had a median leukocyte count of 1.5 × 10⁹/L, significantly lower than HIV-positive patients (2.5 × 10⁹/L) (P = 0.04). Serology was more commonly positive in nontransplant immunosuppressed individuals (75%) and transplant recipients (78.6%) than in HIV-patients (13.8%) (P < 0.001). Antimonial therapy was rarely used in transplant recipients (1.9%) and never in patients with other immunosuppressive conditions, whereas 34.2% of HIV-positive patients received it (P = 0.05 and P = 0.01, respectively). Mortality was 16.7% in both transplant recipients and patients with other immunosuppressive conditions and 15.1% in HIV-positive patients. The features of VL may be different in immunosuppressed patients, with more fever and less hepatomegaly and leukopenia than in HIV-infected patients.

Experience with miltefosine for persistent or relapsing visceral leishmaniasis in solid organ transplant recipients: A case series from Spain

The incidence of visceral leishmaniasis (VL) after solid organ transplantation (SOT) is increasing. The optimal therapy for post-transplant VL remains unclear, as relapses after liposomal amphotericin B (L-AmB) are common. Miltefosine has been shown to be effective for treating VL in immunocompetent patients, although data in the specific population of SOT recipients are lacking. In the setting of an outbreak of leishmaniasis occurring in Southwest Madrid, we reviewed our experience in 6 SOT recipients with persistent or relapsing VL who received a 28-day course of miltefosine (2.5 mg/kg/day) as salvage therapy. All patients had been treated previously with L-AmB as first-line therapy. The incident episode of VL occurred at a median of 14 months after transplantation. Two patients experienced persistent infection and the remaining 4 had a relapse after a median interval of 168 days since the completion of the course of L-AmB. All the patients had an apparent initial clinical improvement with miltefosine. However, VL relapsed in 3 of them (after a median interval of 46 days), which required retreatment with L-AmB-based regimens. Miltefosine therapy was followed by a prolonged secondary prophylaxis with L-AmB in the only 2 cases with sustained clinical response and ongoing immunosuppression. No adverse effects associated with miltefosine were observed. Albeit limited, our experience suggests that miltefosine monotherapy likely has a limited utility to obtain a long-lasting clinical response in complicated (persistent or relapsing) forms of post-transplant VL, although its role in association with L-AmB-based secondary prophylaxis may merit further investigation.

Leishmaniasis in solid organ and hematopoietic stem cell transplant recipients

Leishmaniasis occurs in <1% of solid organ and hematopoietic stem cell transplant recipients in endemic countries in which transplants are performed. Visceral leishmaniasis (VL) makes up the bulk of reported cases. The onset generally occurs months after transplantation and the mode of acquisition is often impossible to determine, but de novo vector-borne infection and reactivation of inapparent infection are thought to be the principal means. The potential role of clinically inapparent donor infection is uncertain and screening is not currently recommended, nor is it recommended for recipients from endemic areas, some of whom may have detectable circulating protozoan nucleic acid. While transplant recipients with VL often present with the non-specific findings of fever and cytopenia, the additional presence of hepatosplenomegaly in patients from endemic areas should lead to a directed diagnostic evaluation with bone marrow examination and PCR testing of marrow and peripheral blood having a high yield. Management may often be complicated by the presence of concomitant infections. A lipid formulation of amphotericin B is the preferred treatment, especially for VL, but the relapse rate in transplant recipients is approximately 25%. PCR monitoring of blood for either secondary prophylaxis or preemptive therapy requires further study.

Diagnosis and Treatment of Leishmaniasis: Clinical Practice Guidelines by the Infectious Diseases Society of America (IDSA) and the American Society of Tropical Medicine and Hygiene (ASTMH)

It is important to realize that leishmaniasis guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. The IDSA and ASTMH consider adherence to these guidelines to be voluntary, with the ultimate determinations regarding their application to be made by the physician in the light of each patient's individual circumstances.

Visceral leishmaniasis in a lung transplant recipient: usefulness of highly sensitive real-time polymerase chain reaction for preemptive diagnosis

We report the case of a lung transplant recipient in whom the diagnosis of visceral leishmaniasis (VL) was made by detection of parasites in a peripheral blood smear when the parasite load already reached 8.9 × 10³ parasites/mL. We demonstrated that the VL diagnosis could have been done months before the development of symptoms by the use of Leishmania-specific real-time polymerase chain reaction (PCR), suggesting the role of preemptive PCR-based diagnosis in transplant recipients at risk for VL.

Visceral leishmaniasis: a forgotten epidemic

Visceral leishmaniasis (VL or kala-azar) is most endemic in Asia and Africa and commonly affects young children. It is usually caused by Leishmania donovani or Leishmania infantum that are transmitted by Phlebotomine sand flies. Transmission may be anthroponotic or zoonotic or both, depending on the endemic area. Clinical features include fever, hepatosplenomegaly, weight loss and pancytopenia. Younger age, malnutrition and immunosuppression (HIV infection, use of immunosuppressive drugs) are risk factors. Many infections remain asymptomatic. Diagnosis is made by demonstration of the Leishmania parasite in aspirates of lymph node, bone marrow or spleen. Serological tests such as rK39 strip test are widely used but the sensitivity varies. qPCR is useful to detect low numbers of parasites and to monitor treatment. Treatment is with AmBisome monotherapy in most areas but with drug combinations elsewhere. HIV co-infected patients are most difficult to treat and often relapse. Control efforts focus on case finding, availability of diagnostic tools, reservoir control and protection from sand flies (insecticides, bed nets). There is no human vaccine.

Visceral leishmaniasis after orthotopic liver transplantation: a rare cause of infection

Visceral leishmaniasis (VL) was known as an opportunistic infection associated with immunosuppression, particularly related to human immunodeficiency virus infection and rarely to solid organ transplant recipients. We report a case of VL, 6 months after liver transplantation, in a patient who presented with febrile pancytopenia. The diagnosis was made by demonstration of amastigotes in smears from bone marrow. VL is a very rare infection in patients who undergo liver transplantation and, to our knowledge, this is the first case diagnosed in Portugal.

Antimony to Cure Visceral Leishmaniasis Unresponsive to Liposomal Amphotericin B

We report on 4 patients (1 immunocompetent, 3 immunosuppressed) in whom visceral leishmaniasis had become unresponsive to (or had relapsed after) treatment with appropriate doses of liposomal amphotericin B. Under close follow-up, full courses of pentavalent antimony were administered without life-threatening adverse events and resulted in rapid and sustained clinical and parasitological cure.

Visceral leishmaniasis causes fever, enlargement of internal organs like the liver and the spleen, and leads to death if no treatment is given. It is caused by a microbe called Leishmania and affects children and adults in warm and temperate regions of the world. Antimony in different forms has been used to treat Visceral Leishmaniasis for almost one century and is still in use in several countries despite the fact that it sometimes displays toxic effects, especially in patients with underlying health problems. Because it is better tolerated and at least as effective as antimony, liposomal amphotericin B is now used as the first treatment for Visceral Leishmaniasis in Southern Europe. We observed that a small proportion of patients—especially those with an impaired immune system—do not cure even after several courses of liposomal amphotericin B. In 4 such patients with “unresponsiveness” to liposomal amphotericin B, antimony provided a sustained cure without major side effects. We conclude that when multiple failures or relapses occur after treatment with liposomal amphotericin B, antimony is a reasonable, potentially life-saving treatment option. These observations also suggest that “unresponsiveness” to amphotericin B results from unusual resistance mechanisms.

Cytokine Release Assays as Tests for Exposure to Leishmania, and for Confirming Cure from Leishmaniasis, in Solid Organ Transplant Recipients

Spain has one of the world’s largest pools of organ donors and is a global leader in terms of the number of transplants it performs. The current outbreak of leishmaniasis in Fuenlabrada (in the southwest of the region of Madrid, Spain) has involved 600 clinical cases since late 2009 (prevalence 0.2%). It may therefore be wise to monitor the town’s transplanted population for Leishmania infantum; its members are immunosuppressed and at greater risk of infection and relapse following treatment. The present work examines the use of cytokine release assays to determine the prevalence of Leishmania infection in this population, and to confirm recovery following treatment for visceral leishmaniasis (VL). The humoral and cellular immune responses to L. infantum were characterized in 63 solid organ transplant (SOT) recipients from Fuenlabrada, 57 of whom reported no previous episode of VL (NVL subjects), and six of whom had been cured of VL (CVL subjects). Seventeen subjects (12 NVL and 5 CVL) showed a patent lymphoproliferative response to soluble Leishmania antigen (SLA). Stimulation of peripheral blood mononuclear cell cultures and of whole blood with SLA led to the production of different combinations of cytokines that might serve to confirm Leishmania infection or recovery from VL and help prevent cured patients from relapsing into this serious condition.

We have used cytokine release assays to determine the prevalence of Leishmania infantum infection in solid organ transplant (SOT) recipients living in an area where the organism is endemic following an outbreak. Some 21.05% of SOT recipients with no previous history of leishmaniasis had been in contact with the parasite; the risk of these individuals becoming infected by Leishmania is high, a consequence of their need to be maintained in an immunosuppressed state. The results indicate the usefulness of whole blood stimulation assays, and of IFN-γ/TNF-α analysis, for determining exposure to Leishmania and confirming cure from visceral leishmaniasis in SOT recipients.

Transplantation in the tropics: lessons on prevention and management of tropical infectious diseases

Tropical infectious diseases (IDs) remain a rare complication in transplant recipients even in tropical settings, but this topic has become increasingly important during the last decade due to multiple factors. Interestingly, non-tropical countries report most of the experiences with tropical diseases. The reported experience from non-endemic regions, however, does not always reflect the experience of endemic areas. Most of the guidelines and recommendations in the literature may not be applicable in tropical settings due to logistical difficulties, cost, and lack of proven benefit. In addition, certain post-transplant prevention measures, as prophylaxis and reducing exposure risk, are not feasible. Nonetheless, risk assessment and post-transplant management of tropical IDs in tropical areas should not be neglected, and clinicians need to have a higher clinical awareness for tropical ID occurring in this population. Herein, we review the more significant tropical ID in transplant patients, focusing on relevant experience reported by tropical settings.