Autoimmune manifestations in patients with visceral leishmaniasis

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.

Autoimmune Diseases Following Environmental Disasters: A Narrative Review of the Literature

Environmental disasters are extreme environmental processes such as earthquakes, volcanic eruptions, landslides, tsunamis, floods, cyclones, storms, wildfires and droughts that are the consequences of the climate crisis due to human intervention in the environment. Their effects on human health have alarmed the global scientific community. Among them, autoimmune diseases, a heterogeneous group of disorders, have increased dramatically in many parts of the world, likely as a result of changes in our exposure to environmental factors. However, only a limited number of studies have attempted to discover and analyze the complex association between environmental disasters and autoimmune diseases. This narrative review has therefore tried to fill this gap. First of all, the activation pathways of autoimmunity after environmental disasters have been analyzed. It has also been shown that wildfires, earthquakes, desert dust storms and volcanic eruptions may damage human health and induce autoimmune responses to inhaled PM2.5, mainly through oxidative stress pathways, increased pro-inflammatory cytokines and epithelial barrier damage. In addition, it has been shown that heat stress, in addition to increasing pro-inflammatory cytokines, may also disrupt the intestinal barrier, thereby increasing its permeability to toxins and pathogens or inducing epigenetic changes. In addition, toxic volcanic elements may accelerate the progressive destruction of myelin, which may potentially trigger multiple sclerosis. The complex and diverse mechanisms by which vector-borne, water-, food-, and rodent-borne diseases that often follow environmental diseases may also trigger autoimmune responses have also been described. In addition, the association between post-disaster stress and the onset or worsening of autoimmune disease has been demonstrated. Given all of the above, the rapid restoration of post-disaster health services to mitigate the flare-up of autoimmune conditions is critical.

Leishmania donovani Exploits Tunneling Nanotubes for Dissemination and Propagation of B Cell Activation

Polyclonal B cell activation and the resulting hypergammaglobulinemia are a detrimental consequence of visceral leishmaniasis (VL); however, the mechanisms underlying this excessive production of nonprotective antibodies are still poorly understood. Here, we show that a causative agent of VL, Leishmania donovani, induces CD21-dependent formation of tunneling nanotubule (TNT)-like protrusions in B cells. These intercellular connections are used by the parasite to disseminate among cells and propagate B cell activation, and close contact both among the cells and between B cells and parasites is required to achieve this activation. Direct contact between cells and parasites is also observed in vivo, as L. donovani can be detected in the splenic B cell area as early as 14 days postinfection. Interestingly, Leishmania parasites can also glide from macrophages to B cells via TNT-like protrusions. Taken together, our results suggest that, during in vivo infection, B cells may acquire L. donovani from macrophages via TNT-like protrusions, and these connections are subsequently exploited by the parasite to disseminate among B cells, thus propagating B cell activation and ultimately leading to polyclonal B cell activation. IMPORTANCE Leishmania donovani is a causative agent of visceral leishmaniasis, a potentially lethal disease characterized by strong B cell activation and the subsequent excessive production of nonprotective antibodies, which are known to worsen the disease. How Leishmania activates B cells is still unknown, particularly because this parasite mostly resides inside macrophages and would not have access to B cells during infection. In this study, we describe for the first time how the protozoan parasite Leishmania donovani induces and exploits the formation of protrusions that connect B lymphocytes with each other or with macrophages and glides on these structures from one cell to another. In this way, B cells can acquire Leishmania from macrophages and become activated upon contact with the parasites. This activation will then lead to antibody production. These findings provide an explanation for how the parasite may propagate B cell activation during infection.

A Case Report of Two Kala-Azar Cases in China Diagnosed by Metagenomic Next-Generation Sequencing

Background

Leishmaniasis being a local disease, as kala-azar this particular form is a visceral form. It is transmitted by sandflies, and is a parasitic disease involving the reticuloendothelial system of mononuclear macrophages. Due to its poor prognosis and high fatality rate, the fatality rate of patients without effective treatment can exceed 95%. Thereby, early diagnosis and treatment can significantly improve its prognosis. The metagenomic next-generation sequencing (mNGS) has the advantage of being able to find pathogens that cannot be detected by traditional methods. More importantly, it can conduct nucleic acid detection of pathogens covering a wide range in a short time. For infectious diseases like kala-azar, which is clinically complicated and difficult, mNGS detection provides a basis for accurate etiological diagnosis.

Case Report

We report 2 cases of kala-azar in West China Hospital, Chengdu, China. The first case is a 47-year-old male patient who had recurrent fever for 4 months, accompanied by reduction of red blood cell, white blood cell, and blood platelet. He was detected by mNGS and clinically diagnosed as kala-azar (Leishmania detection), finally died of multiple organ failure. The second patient was a 15-year-old male who had fever for more than 10 days. He was detected by mNGS and clinically diagnosed as kala-azar (Leishmania detection). He recovered and discharged quickly after treatment with sodium stibogluconate.

Conclusion

Efforts should be made to improve early etiological diagnosis in order to improve patient prognosis. mNGS detection is beneficial to the diagnosis and treatment of infectious diseases with unknown causes in the early stage of emergency treatment.

A Case Report of Two Kala-azar Cases in China Diagnosed by Metagenomic Next-Generation Sequencing

Background

Leishmaniasis being a local disease, as kala-azar this particular form is a visceral form. It is transmitted by sandflies, and is a parasitic disease involving the reticuloendothelial system of mononuclear macrophages. Due to its poor prognosis and high fatality rate, the fatality rate of patients without effective treatment can exceed 95%. Thereby, early diagnosis and treatment can significantly improve its prognosis. The metagenomic next-generation sequencing (mNGS) has the advantage of being able to find pathogens that cannot be detected by traditional methods. More importantly, it can conduct nucleic acid detection of pathogens covering a wide range in a short time. For infectious diseases like kala-azar, which is clinically complicated and difficult, mNGS detection provides a basis for accurate etiological diagnosis.

Case Report

We report 2 cases of kala-azar in West China Hospital, Chengdu, China. The first case is a 47-year-old male patient who had recurrent fever for 4 months, accompanied by reduction of red blood cell, white blood cell, and blood platelet. He was detected by mNGS and clinically diagnosed as kala-azar (Leishmania detection), finally died of multiple organ failure. The second patient was a 15-year-old male who had fever for more than 10 days. He was detected by mNGS and clinically diagnosed as kala-azar (Leishmania detection). He recovered and discharged quickly after treatment with sodium stibogluconate.

Conclusion

Efforts should be made to improve early etiological diagnosis in order to improve patient prognosis. mNGS detection is beneficial to the diagnosis and treatment of infectious diseases with unknown causes in the early stage of emergency treatment.

Anti-Leishmania infantum Antibody-Producing Plasma Cells in the Spleen in Canine Visceral Leishmaniasis

The spleen is involved in visceral leishmaniasis immunopathogenesis, and presents alterations in white-pulp microenvironments that are associated with an increased susceptibility to coinfections and patient death. Plasmacytosis in splenic red pulp (RP) is one observed alteration, but the specificity of antibody-secreting cells and the distribution of them has not yet been evaluated. We biotinylated soluble L. infantum membrane antigens (bSLMA) used as probes in modified immunohistochemistry, and detected the presence of anti-L. infantum antibody-secreting cells. Were used spleens from eight dogs from the endemic area for canine visceral leishmaniasis (CanL), and three healthier controls. The spleen sections were cryopreserved, and we performed modified immunohistochemistry. The ratio of plasma cells which were reactive to bSLMA (Anti-Leish-PC) in the spleen RP and periarteriolar lymphatic sheath (PALS) were calculated. Dogs with CanL present hyperglobulinemia and more plasma cells in their RP than the controls. Furthermore, dogs with CanL presented a lower proportion of Anti-Leish-PC in their RP than in PALS. Likewise, dysproteinemia was related to RP and PALS plasmacytosis, and a more severe clinical profile.

Next-generation sequencing technology for diagnosis and efficacy evaluation of a patient with visceral leishmaniasis: A case report

BACKGROUND

Visceral leishmaniasis (VL) is a parasitic disease caused by Leishmania and transmitted by infected sand flies. VL has a low incidence in China, and its clinical presentation is complex and atypical. This disease is easily misdiagnosed and can become life-threatening within a short period of time. Therefore, early, rapid and accurate diagnosis and treatment of the disease are essential.

CASE SUMMARY

A 25-year-old male patient presented with the clinical manifestations of irregular fever, hepatosplenomegaly, increased polyclonal globulin, and pancytopenia. The first bone marrow puncture biopsy did not provide a clear diagnosis. In order to relieve the pressure and discomfort of the organs caused by the enlarged spleen and to confirm the diagnosis, splenectomy was performed, and hemophagocytic syndrome was diagnosed by pathological examination of the spleen biopsy. Following bone marrow and spleen pathological re-diagnosis and metagenomic next-generation sequencing (mNGS) technology detection, the patient was finally diagnosed with VL. After treatment with liposomal amphotericin B, the body temperature quickly returned to normal and the hemocytes recovered gradually. Post-treatment re-examination of the bone marrow puncture and mNGS data showed that Leishmania was not detected.

CONCLUSION

As a fast and accurate detection method, mNGS can diagnose and evaluate the efficacy of treatment in suspicious cases of leishmaniasis.

[Visceral leishmaniasis: a challenging diagnosis in internal medicine]

Leishmaniasis is a vector-born parasitic disease characterized by predominant cutaneous or visceral involvement with fever, hepatosplenomegaly and anemia. Leishmaniasis has relatively high prevalence in tropical and subtropical areas. Several sporadic and mostly imported cases are detected in Russian Federation. Nevertheless, some local incidents are noted in southern areas (Crimea, Dagestan). Lack of epidemiological alertness hampers confirmation of diagnosis and may lead to incorrect treatment. The article summarizes current state of knowledge in epidemiology, diagnostic approach and treatment of leishmaniasis. Particular clinical case is discussed.

Prediction of molecular mimicry between antigens from Leishmania sp. and human: Implications for autoimmune response in systemic lupus erythematosus

Pathogens and humans share an intrinsic relation related to molecular mimicry in their antigens. Interactions between immune system and pathogenic antigens result in a production of antibodies that could protect against infection, but develop autoreactive responses mediated by autoantibodies that react to pathogenic and human antigens because they share epitopes. In this study, a pipeline of bioinformatic tools was used to explore the repertory of autoantigens implicated in the develop of Systemic Lupus Erythematosus and their homologous in Leishmania sp. With this, we screened and selected 33 molecular mimicry candidates. In 17 autoantigens from lupus was possible to perform epitope prediction and was found that, at least one potential cross epitope. Some of autoantigens with molecular mimicry were Aquaporin 4, nuclear autoantigens such as: Ubiquitin-related modifier 1 and Small nuclear ribonucleoprotein Sm. Also, mitochondrial, and ribosomal autoantigens were found to share molecular mimicry with antigens from Leishmania sp. In conclusion, this is the first study that provide evidence of molecular mimicry between antigens from Leishmania sp. and human. Implications for the develop of SLE and clinical manifestation deserve more study.

Membranoproliferative Glomerulonephritis and Mixed Cryoglobulinemia as a Form of Presentation of Visceral Leishmaniasis

Patient: Male, 69-year-old

Final Diagnosis: Leishmaniasis

Symptoms: Acute renal failure • purpuric skin lesions

Medication: —

Clinical Procedure: Bone marrow biopsy • renal biopsy • ultrasonography

Specialty: Nephrology

Visceral leishmaniasis mimicking systemic lupus erythematosus

Visceral leishmaniasis (VL), or kala-azar, a serious disease resulting from a systemic infection caused by a protozoan of the genus Leishmania, is potentially fatal to humans. According to data from Sistema de Informação de Agravos de Notificação (Brazil's Information System for Notifiable Diseases) from 2015 to 2016, 6,489 new cases were recorded in Brazil in 22 of the 27 federative units. In addition to typical clinical findings, VL may be associated with autoimmune phenomena, including simulating systemic lupus erythematosus (SLE). We present the first case of autochthonous VL mimicking SLE in Santa Catarina in southern Brazil.

Diagnostic lipid changes in patients with visceral leishmaniasis

BACKGROUND

Visceral leishmaniasis (VL) has been associated with the increase in triglyceride (TG) levels and the decrease in high-density lipoprotein cholesterol (HDL-C) concentration. The aim of the study was to evaluate whether there is a diagnostic cut-off point in these lipid profile changes.

MATERIALS AND METHODS

We included 100 patients with febrile infections. Analytically, 22 patients with VL, 18 patients with leptospirosis, 20 patients with Brucella melitensis, and 40 age- and sex-matched patients with fever and proven bacteremia (endocarditis and pyelonephritis). The lipid parameters were assessed for their diagnostic accuracy using logistic regression and receiver operating characteristic statistics.

RESULTS

It was observed that coexistence of HDL-C < 15 mg/dL and ΤG > 180 mg/dL had 100% sensitivity and 67.5% specificity for the confirmation of VL. The corresponding positive and negative predictive values were 59.4% and 100%, respectively.

CONCLUSION

Coexistence of high TGs and low HDL-C values may suggest VL infection in a febrile patient.

The role of infections in neuropsychiatric lupus

Opportunistic infections can cause manifestations that resemble neuropsychiatric systemic lupus erythematosus and they can also trigger lupus flares. Therefore, central nervous system infections as differential diagnosis in neuropsychiatric systemic lupus erythematosus may be difficult, leading to delayed diagnosis and specific treatment. Central nervous system infection in systemic lupus erythematosus is not common but, if left misdiagnosed and not treated promptly, can be fatal. Complementary diagnosis tests are generally non-specific and disappointing. Caution with immunosuppressive drug treatment should be emphasized while an opportunistic infection cannot be ruled out. In this review, we discuss the various types of central nervous system infections reported in systemic lupus erythematosus patients, highlighting the importance of their early recognition in order to improve morbidity and mortality. Prevention with vaccination is a recommended approach.

Autoantibodies in a Three-Year-Old Girl with Visceral Leishmaniasis: A Potential Diagnostic Pitfall

Visceral leishmaniasis (VL), a life-threatening parasitic infection, is endemic in the Mediterranean region. Diagnosis of VL is based on epidemiologic, clinical, and laboratory findings. However, sometimes, clinical features and laboratory findings overlap with those of autoimmune diseases. In some cases, autoantibodies are detected in patients with VL and this could be a potential diagnostic pitfall. In this study, we have reported on a three-year-old girl from a VL-endemic area in Iran, who presented with prolonged fever and splenomegaly. Bone marrow examination, serologic tests, and the molecular PCR assay were performed; however, results were inconclusive. The levels of anti-double stranded DNA, cytoplasmic antineutrophil cytoplasmic autoantibody, and perinuclear antineutrophil cytoplasmic autoantibody were elevated and, at the end, splenic biopsy was performed. The splenic tissue PCR test detected the DNA of Leishmania infantum. The patient's condition improved with anti-Leishmania therapy, and the autoantibodies disappeared within the following four months. Clinical presentations and laboratory findings of VL and autoimmune diseases may overlap in some patients.

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.

Leishmaniasis revisited: Current aspects on epidemiology, diagnosis and treatment

Leishmaniasis is a vector-borne disease caused by protozoan parasites of the genus Leishmania. It is transmitted by phlebotomine female sand flies of the genera Phlebotomus and Lutzomyia in the old and new world, respectively. More than 20 well-recognized Leishmania species are known to infect humans and cause visceral (VL), cutaneous (CL) and mucocutaneous (ML) forms of the disease. Approximately 350 million people are at risk of contracting the disease and an estimated 1.6 million new cases occur annually. The disease mainly affects poor people in Africa, Asia and Latin America, and is associated with malnutrition, population migration, poor residency conditions, frail immune system and lack of resources. Previously, diagnosis of leishmaniasis relied mainly on invasive techniques of detecting parasites in splenic and bone marrow aspirates. Nevertheless, serological tests using the recombinant kinesin antigen (rK39) and molecular methods (polymerase chain reaction) are considered the best options for diagnosis today, despite problems related to varying sensitivities and specificities and field adaptability. Therapy of leishmaniasis ranges from local treatment of cutaneous lesions to systemic often toxic, therapy for disseminated CL, ML and VL. Agents with efficacy against leishmaniasis include amphotericin B, pentavalent antimonial drugs, paromomycin and miltefosine. No single therapy of VL currently offers satisfactory efficacy along with safety. This article provides a brief and updated systematic review on the epidemiology, diagnosis and treatment of this neglected disease.

Current clinical, laboratory, and treatment outcome characteristics of visceral leishmaniasis: results from a seven-year retrospective study in Greece

OBJECTIVES

Visceral leishmaniasis (VL) is re-emerging in endemic areas. The epidemiological, clinical, laboratory, and treatment outcome characteristics in a large cohort of VL patients is described herein.

METHODS

The cases of 67 VL patients (57% male, mean age 56 years) treated in two Greek hospitals over the last 7 years were identified and evaluated retrospectively.

RESULTS

Forty-six percent of patients reported contact with animals. Seventeen patients (25%) were immunocompromised, and 22% were co-infected with another pathogen. Sixty-four percent of patients had fever, 57% had weakness, 37% had sweats, 21% had weight loss, and 13% had a dry cough, while 6% developed haemophagocytic syndrome. The median duration of symptoms was 28 days. Fifty-eight percent of patients had splenomegaly, 49% had hepatomegaly, and 36% had lymphadenopathy. The diagnosis was established by positive PCR in peripheral blood (73%) and/or bone marrow specimens (34%). Sixty-one patients (91%) received liposomal amphotericin (L-AMB). Six patients (10%) did not respond or relapsed but were eventually cured after a second cycle of L-AMB. During a 6-month follow-up, the overall mortality was 9%, although none of these deaths was attributed to VL.

CONCLUSIONS

VL is still a common disease in endemic areas, affecting immunocompetent and immunocompromised patients. Its diagnosis is challenging, and molecular techniques are valuable and helpful tools to achieve this. Treatment with L-AMB is safe and very effective.

Visceral Leishmaniasis as a Possible Reason for Pancytopenia

Leishmaniasis is caused by different species of the protozoa, Leishmania, and frequently found in South-Western Asia, Eastern Africa, Brazil, and Mediterranean countries. Leishmania are transmitted to humans by the bite of sandflies. After weeks to months, unspecific symptoms may occur, accompanied by more specific findings like pancytopenia and organomegaly. We report two children with pancytopenia and hepato-/splenomegaly: a 1-year-old boy was first diagnosed with an Adenovirus-infection, accompanied by fever, pancytopenia, and hepatosplenomegaly who had spent his summer vacation in Spain and a 3-year-old boy of Macedonian origin who was first diagnosed with a Parvovirus B19-infection again accompanied by splenomegaly and pancytopenia. In both children, leukemia was excluded by an initial bone marrow puncture. As fever was still persistent weeks after the children's first hospital stay, both children received antibiotics empirically without sustainable effect. While different autoantibodies were present in both children, an immunosuppressive therapy was initiated in the younger boy without therapeutic success. A second bone marrow puncture was performed and Leishmania were finally detected morphologically and proven serologically. After weight-adjusted treatment with liposomal Amphotericin B for 10 days, both children recovered completely without relapse. Aim of this report is to broaden the spectrum of differential diagnoses in children with pancytopenia, splenomegaly, and fever to visceral leishmaniasis particularly when travel history is positive for the Mediterranean area. The infection may mimic more common diseases, such as leukemia, viral infections, or autoimmune diseases, because polyclonal B cell activation and other mechanisms may lead to multiple positive serologic tests. Both cases illustrate typical pitfalls and shall encourage taking Leishmaniasis into diagnostic consideration.

Visceral leishmaniasis mimicking systemic lupus erythematosus: Case series and a systematic literature review

OBJECTIVE

Systemic lupus erythematosus (SLE) is an autoimmune disease that may present manifestations that resemble other diseases. Visceral leishmaniasis (VL) is a parasitic infection whose hallmarks may mimic SLE symptoms. Here, we report a case series and evaluate the published, scientific evidence of the relationship between SLE and VL infection.

METHODS

To assess original studies reporting cases of VL-infected patients presenting manifestations that are capable of leading to inappropriate suspicions of SLE or mimicking an SLE flare, we performed an extensive search in several scientific databases (MEDLINE, LILACS, SciELO, and Scopus). Two authors independently screened all citations and abstracts identified by the search strategy to identify eligible studies. Secondary references were additionally obtained from the selected articles.

RESULTS

The literature search identified 53 eligible studies, but only 17 articles met our criteria. Among these, 10 lupus patients with VL mimicking an SLE flare and 18 cases of VL leading to unappropriated suspicions of SLE were described. The most common manifestations in patients infected with VL were intermittent fever, pancytopenia, visceromegaly, and increased serum level of acute phase reactants. The most frequent autoantibodies were antinuclear antibodies, rheumatoid factor, and direct Coombs' test.

CONCLUSION

In endemic areas for VL, the diagnosis of SLE or its exacerbation may be a clinical dilemma. Hepatosplenomegaly or isolated splenomegaly was identified in the majority of the reported cases where VL occurred, leading to unappropriated suspicions of SLE or mimicking an SLE flare. Furthermore, the lack of response to steroids, the normal levels of complement proteins C3 and C4, and the increased level of transaminases suggest a possible infectious origin.