Comparison of the clinical features and outcome of children with hemophagocytic lymphohistiocytosis (HLH) secondary to visceral leishmaniasis and primary HLH: a single-center study

Hemophagocytic lymphohistiocytosis secondary to visceral leishmaniasis in children: case report and systematic review

Background

Visceral leishmaniasis (VL) can lead to complications such as hemophagocytic lymphohistiocytosis (HLH) in children. The clinical features of VL overlap with that of HLH, and thus the diagnosis of VL-induced HLH can be challenging for clinicians.

Methods

We describe two pediatric cases and systematically review all reported cases of pediatric VL-related HLH in literatures until May 2024.

Results

The demographic characteristics, clinical manifestations, treatment and prognosis of our reported cases are presented. The systematic review included 29 articles with a total of 135 cases. More than half of the children (89/125, 71.2%) were under 3 years old, and 8.9% (n = 12/135) had specific epidemiological histories. The main clinical presentations were hypertriglyceridemia (34/45, 75.6%), hypofibrinogenemia (24/36, 66.7%), and hyperferritinemia (95/132, 72.0%). Bone marrow aspiration (BMA) analysis indicated positive evidence of leishmania infection in 84.7% (83/98) of cases, while 37.8% (14/37) of patients tested negative for leishmania on the first BMA smear. All patients were treated against leishmania with amphotericin B (76/135, 56.3%) or antimony (77/135, 57.0%), and 13.3% (n = 18/135) of patients received both medications, in which amphotericin B was used as rescue treatment. The prognosis was favorable, with the exception of two deaths.

Conclusions

Vigilance towards screening for leishmania infection induced HLH is imperative, particularly when there is a suspicious epidemiological history, ineffective chemotherapy, or prior to bone marrow transplantation. Early recognition, accurate diagnosis, and prompt treatment initiation can significantly alter the course of the disease and favor the prognosis in childhood with HLH secondary to VL.

Visceral leishmaniasis related secondary haemophagocytic syndrome: A case report

Visceral leishmaniasis (VL) is a parasitic disease that can trigger haemophagocytic syndrome (HPS), making its prompt diagnosis crucial. The application of metagenome next-generation sequencing (mNGS) provides a rapid diagnostic approach, particularly for patients with negative bone marrow aspiration results. We present here, a case of a male patient in his early 50s who presented with fever and abdominal pain. Routine examinations failed to identify its specific cause. However, diagnosis through mNGS helped prevent a potentially fatal outcome.

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.

Hemophagocytic lymphohistiocytosis secondary to visceral leishmaniasis: A case report of a rare complication of visceral leishmaniasis

Hemophagocytic lymphohistiocytosis (HLH) is a rare, potentially life-threatening clinical syndrome characterized by hyperactivation of inflammatory mediators and harmful end-organ damage. Visceral leishmaniasis (VL)-induced HLH is a rare disease with significant diagnostic and management implications. Herein, we present a case of secondary HLH as a complication of visceral leishmaniasis in a two-year-old toddler. A 2-year-old male toddler was admitted for evaluation of a prolonged 4-week fever. Accompanying the fever, he developed progressive abdominal swelling, intermittent bilateral nasal bleeding, and repeated chest-focus infections of similar duration. The patient was acutely sick, with chronic signs of malnutrition (mid-upper arm circumference of 10.5 cm), fever (39 °C), tachypnea (70 breaths/min), tachycardia (132 beats/min), pallor, and hepatosplenomegaly. Initial investigation revealed leukopenia (2240/μl), anemia (7.3 g/dl), and severe thrombocytopenia (26,000/μl). With consideration of febrile neutropenia, the patient was started on cefepime with further revision to vancomycin and meropenem based on the culture result. After 10 days of persistent fever and poor clinical condition, an immunochromatographic rapid test with the rK39 antigen was conducted, and the patient was found to be positive for Leishmania spp. Intravenous liposomal amphotericin B (AmBisome) was initiated. On the 6th day of treatment, the patient's clinical and laboratory profiles severely deteriorated, and further laboratory investigation showed elevated triglyceride (524 mg/dl) and ferritin levels (1500 ng/mL). VL-induced secondary HLH was confirmed, and intravenous dexamethasone was initiated. Subsequently, his clinical and laboratory findings significantly improved, and he was discharged with PO dexamethasone. Our case highlights the intricate nature of VL-induced HLH and the need for high index of suspicion and timely management.

Outcome and Prognostic Factors of Hemophagocytic Lymphohistiocytosis in Children: Experience From a Low- and Middle-Income Country

Objective Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening condition especially in low- and middle-income countries (LMICs). This study was done to evaluate the outcome and prognostic factors of HLH in patients presenting to our center. Methods The study was carried out at the Paediatric Oncology Department of Combined Military Hospital (CMH) in Rawalpindi, Pakistan. All cases of HLH, from one month to 15 years of age enrolled between January 1, 2013 to June 30, 2023, were included. IBM SPSS Statistics for Windows, version 25.0 (released 2017, IBM Corp., Armonk, NY) was used for statistical analysis, and t-test and chi-square tests were used for comparison between continuous and categorical variables. Frequencies and percentages were calculated for categorical variables. Results Out of 115 patients, seven (6%) abandoned the treatment. The data of 108 cases, including 58 males (53.7%), were analyzed. The mean age at diagnosis was 31.5 ± 39.03 months. The mean time to reach a pediatric oncologist was 30.20 ± 22.15 days. Fever and pallor were common symptoms occurring in 107 (99.1%) and 98 (90.7%) cases, respectively. Jaundice was present in 44 (40.7%), visceromegaly in 64 (59.3%), and bruising/bleeding in 16 cases (14.8%). Twenty-six (24.1%) patients underwent hematopoietic stem cell transplant (HSCT), out of which 17 (65.4%) children were cured. Overall survival at two years, five years, and 10 years was 38%, 37%, and 36.1%, respectively. Disease-free survival at two years, five years, and 10 years was 33.3%, 32.4%, and 31.5%, respectively. Conclusion HLH leads to high mortality due to delayed or misdiagnosis in LMICs. Early diagnosis and early referral to a pediatric oncologist is the detrimental factor in survival for HLH. HSCT is the treatment of choice for primary, refractory, or relapse cases.

Secondary hemophagocytic lymphohistiocytosis in pediatric patients with visceral leishmaniasis and Epstein-Barr virus infection

Visceral leishmaniasis-associated hemophagocytic lymphohistiocytosis (VL-HLH) is indistinguishable from those of HLH of other etiologies due to the overlap symptoms, posing a serious threat to life. In this study, we aimed to provide insights for early diagnosis and improve outcomes in pediatric patients with VL-HLH. We retrospectively analyzed the clinical and laboratory data of 10 pediatric patients with VL-HLH and 58 pediatric patients with Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis (EBV-HLH). The median time from symptom onset to cytopenia in patients with VL-HLH and EBV-HLH was 11 days (interquartile range, 7-15 days) and five days (interquartile range, 3.75-9.25 days) (P = 0.005). Both groups showed liver injury and increased lactate dehydrogenase levels; however the levels of aspartate aminotransferase, alanine aminotransferase, direct bilirubin, and lactate dehydrogenase in patients with VL-HLH were significantly lower than those in patients with EBV-HLH (P < 0.05). The fibrinogen and triglyceride levels were almost normal in VL-HLH patients but were significantly altered in EBV-HLH cases ( P < 0.05). The positive rate of first bone marrow microscopy examination, anti-rK39 IgG detection, and blood metagenomic next-generation sequencing was 50%, 100%, and 100%, respectively. After VL diagnosis, eight patients were treated with sodium stibogluconate and two were treated with liposomal amphotericin B. All the patients with VL-HLH recovered. Our study demonstrates that regular triglyceride and fibrinogen levels in pediatric patients with VL-HLH may help in differential diagnosis from EBV-HLH. VL-HLH is milder than EBV-HLH, with less severe liver injury and inflammatory responses, and timely treatment with antileishmanial agents is essential to improve the outcomes of pediatric patients with VL-HLH.

Association of a decreased platelet count with poor survival in patients with adult secondary hemophagocytic lymphohistiocytosis

We aimed to examine the association between baseline platelet count (PLT) and the prognosis of adult secondary hemophagocytic lymphohistiocytosis (sHLH). Data from 292 patients with pretreatment platelet counts were retrospectively analysed from January 2016 to December 2020. We categorized platelet count into quartiles. Multivariable Cox proportional hazards models and restricted cubic splines (RCS) were used to evaluate the relationship between platelet count and mortality. During a median follow-up of 53 (interquartile ranges, 17-223) days, a total of 208 deaths occurred. After adjusting for multiple variables, a non-linear and inverse relationship was observed between platelet count and mortality in sHLH patient (P for nonlinearity=0.002). For non- lymphoma-associated haemophagocytic lymphohistiocytosis (non-LHLH), a similar curve was also observed (P for nonlinearity =0.028). Decreased PLT (PLT Q4) was associated with an increased risk of mortality (adjusted hazard ratio: 1.97; 95% confidence interval: 1.28-3.04; Ptrend =0.005). Similar results were observed in the LHLH subgroup (adjusted hazard ratio: 1.84; 95% confidence interval: 1.05-3.24; Ptrend =0.024) but not in the non-LHLH subgroup (Ptrend =0.266). Baseline platelet count demonstrated a nonlinear and inverse association with an increased risk of mortality among adult sHLH patients. This method is used to identify sHLH patients with inferior overall survival due to its low cost and universal availability.

Infectious Diseases Evaluation of the Child With Suspected Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of excessive and maladaptive inflammation. In this review, we discuss how the clinical and laboratory features of HLH overlap with infection and propose a diagnostic and treatment strategy to identify patients with infections mimicking HLH.

Parasitic and Fungal Triggers of Cytokine Storm Syndrome

Infections caused by parasites and fungi can trigger the cytokine storm syndrome (CSS). These infections causing CSS can occur together with acquired immunodeficiencies, lymphomas, the use of immunosuppressive medications, transplant recipients, cancer, autoinflammatory, and autoimmune diseases or less frequently in healthy individuals. Histoplasma, Leishmania, Plasmodium, and Toxoplasma are the most frequent organisms associated with a CSS. It is very important to determine a previous travel history when evaluating a patient with a CSS triggered by these organisms as this may be the clue to the causal agent. Even though CSS is treated with specific therapies, an effort to find the causal organism should be carried out since the treatment of the infectious organism may stop the CSS. Diagnosing a CSS in the presence of parasitic or fungal sepsis should also lead to the study of an altered cytotoxic or hemophagocytic response in the susceptible host.

Secondary hemophagocytic lymphohistiocytosis in children (Review)

Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening condition characterized by hyperinflammation in an uncontrolled and ineffective immune response. Despite great improvement in diagnosis and treatment, it still represents a challenge in clinical management, with poor prognosis in the absence of an aggressive therapeutic approach. The present literature review focuses on secondary HLH at pediatric age, which represents a heterogeneous group in terms of etiology and therapeutic approach. It summarizes the most recent evidence on epidemiology, pathophysiology, diagnosis, treatment and prognosis, and provides a detailed description and comparison of the major subtypes of secondary HLH. Finally, it addresses the open questions with a focus on diagnosis and new treatment insights.

Case Report: Diagnosis and Treatment of Two Clinical Cases of Visceral Leishmaniasis-Related Hemophagocytic Lymphohistiocytosis

Visceral leishmaniasis-related hemophagocytic lymphohistiocytosis (VL-HLH) is a potentially life-threatening secondary hemophagocytic lymphocytic syndrome caused by protozoan parasites of the Leishmania species and transmitted by infected sandflies. Therefore, it is important to be highly vigilant of the infection, particularly the visceral subtype, to share information with the public health system, and to improve the early diagnosis rate so that appropriate treatment can be initiated promptly. We report two isolated cases of VL-HLH. The main clinical manifestations were fever, pancytopenia, splenomegaly, hypofibrinogenemia, and hyperferremia, which meet the HLH-2004 diagnostic criteria. In our experience, anti-HLH treatment was not very effective for either case. No Leishmania organism was found in the first bone marrow smear of either patient. The first patient was diagnosed after identification of Leishmania amastigotes via sternal bone marrow biopsy, rK39 immunochromatography test, and metagenomic next-generation sequencing. The other patient was diagnosed by rK39-rapid diagnostic test and polymerase chain reaction. However, because of the delayed diagnosis in both cases, their conditions continued to deteriorate and both patients eventually died of the disease. Leishmaniasis is a parasitic disease with regional specificity and a low incidence. The occurrence of secondary HLH has a great impact on prognosis. When encountering secondary HLH in clinical practice, leishmaniasis should remain on the list of differential causes. Because of a high mortality rate if diagnosed late, it is crucial to be vigilant of VL-HLH in practice so that early detection, diagnosis, and treatment of the disease can be achieved to reduce adverse patient outcomes.

From Infection to Death: An Overview of the Pathogenesis of Visceral Leishmaniasis

Kala-azar, also known as visceral leishmaniasis (VL), is a disease caused by Leishmania infantum and L. donovani. Patients experience symptoms such as fever, weight loss, paleness, and enlarged liver and spleen. The disease also affects immunosuppressed individuals and has an overall mortality rate of up to 10%. This overview explores the literature on the pathogenesis of preclinical and clinical stages, including studies in vitro and in animal models, as well as complications and death. Asymptomatic infection can result in long-lasting immunity. VL develops in a minority of infected individuals when parasites overcome host defenses and multiply in tissues such as the spleen, liver, and bone marrow. Hepatosplenomegaly occurs due to hyperplasia, resulting from parasite proliferation. A systemic inflammation mediated by cytokines develops, triggering acute phase reactants from the liver. These cytokines can reach the brain, causing fever, cachexia and vomiting. Similar to sepsis, disseminated intravascular coagulation (DIC) occurs due to tissue factor overexpression. Anemia, hypergammaglobulinemia, and edema result from the acute phase response. A regulatory response and lymphocyte depletion increase the risk of bacterial superinfections, which, combined with DIC, are thought to cause death. Our understanding of VL's pathogenesis is limited, and further research is needed to elucidate the preclinical events and clinical manifestations in humans.

Ferritin in pediatric critical illness: a scoping review

This scoping review aimed to elucidate and summarize the predictive role of serum ferritin in critical pediatric illness. The Preferred Reporting Items for Systematic reviews and Meta-Analyses methodology was employed to conduct a scoping review of 5 databases (MEDLINE, CENTRAL, ProQuest, ScienceDirect, and Epistemonikos) from the date of inception through January 24, 2022. Primary research studies involving subjects aged <18 years and serum ferritin levels were screened and reviewed independently following an a priori defined protocol. Of the 1,580 retrieved studies, 66 were analyzed. Summary statistics of serum ferritin levels for overall and condition-specific studies were reported in 30 (45.4%) and 47 studies (71.2%), respectively. The normal range was defined in 16 studies (24.2%), whereas the threshold was determined in 43 studies (65.1%). A value of <500 ng/mL was most often the upper limit of the normal range. Serum ferritin as a numerical variable (78.9%) was usually significantly higher (80.8%) in the predicted condition than in controls, while as a categorical variable with preset thresholds, ferritin was a significant predictor in 84.6% of studies. A total of 22 predictive thresholds predicted mortality (12 of 46 [26.1%]), morbidity (18 of 46 [39.1%]), and specific (16 of 46 [34.8%]) outcomes in 15 unique conditions. Increased precision in serum ferritin measures followed by close attention to the threshold modeling strategy and reporting can accelerate the translation from evidence to clinical practice.

Reactive Hemophagocytic Lymphohistiocytosis Secondary to Ovarian Adenocarcinoma: A Rare Case Report

Background

Hemophagocytic lymphohistiocytosis (HLH), a syndrome of immune hyperactivation and abnormal regulation that causes life-threatening inflammation, is mainly characterized by fever, hepatosplenomegaly, cytopenia, and other symptoms. Reactive HLH (rHLH) is typically secondary to immune deregulation caused by underlying rheumatologic, infectious, or malignant conditions. Malignancy-associated HLH (M-HLH) continues to be a critical health problem worldwide. Most malignancies associated with HLH are hematologic tumors, and M-HLH in non-hematologic tumors very rarely occurs.

Case Report

A 34-year-old Chinese woman had a history of persistent fever, acute dizziness, and bicytopenia. She was found to have developed bilateral ovarian cancer. Additional tests showed splenomegaly, hemophagocytes in the bone marrow, low natural killer activity, and hyperferritinemia, which met the diagnostic criteria put forth in the Histiocyte Society HLH-2004. The patient was treated with correcting anemia, increased platelets, and glucocorticoid therapy but showed no response. She progressively deteriorated and died 55 days later.

Conclusion

Hemophagocytic lymphohistiocytosis related to a solid tumor is extremely rare. To the best of the authors’ knowledge, the present case was the first to report rHLH secondary to ovarian adenocarcinoma. It is very significant for a better understanding of the disease mechanisms of HLH and should attract the attention of hematologists and other clinicians as the condition progresses and the cost of treating it increases.