A need for greater awareness: a mixed methods study of patient and healthcare professional perspectives on the diagnosis journey for haemophagocytic lymphohistiocytosis (HLH).

OBJECTIVES: Our aim was to better understand and raise awareness of the diagnosis journey and quantify any barriers for timely diagnosis of haemophagocytic lymphohistiocytosis (HLH), to support patients' struggle with diagnosis and reduce time to diagnosis. METHODS: Patients diagnosed with, or caregivers for those diagnosed with primary or secondary HLH and physicians involved in the treatment of HLH were recruited. Quantitative interviews were undertaken with patients/caregivers to quantify key elements of the diagnosis journey, followed by qualitative interviews with participants. Interviews took place between March-May 2021. RESULTS: Thirty-three patients/caregivers and nine physicians took part in this mixed methods study. Lack of physician awareness of HLH was a common frustration for patients/caregivers, causing delayed diagnosis. All physicians indicated bone-marrow testing is a key step in the diagnosis process, and some patients/caregivers had frustrations around testing. Emergency care doctors, although not usually involved in the diagnosis process, were among the most-seen specialists by patients/caregivers. Patients/caregivers suggested potential improvements in available information, such as providing information on treatment options and condition management. DISCUSSION: Patients/caregivers and physicians agreed on the need to raise overall awareness of HLH signs/symptoms among priority groups of physicians to recognise how signs/symptoms can progress and develop. Improvements in the testing process and communication would directly impact the speed of diagnosis and support patients/caregivers during the diagnostic journey, respectively. CONCLUSION: Raising awareness of key issues, such as signs/symptoms, tests and diagnostic procedures, and improved communication and support for patients/caregivers, are key to speeding up HLH diagnosis and improving outcomes.

Haemophagocytic Lymphohistiocytosis Following the anti-PD-1 Nivolumab in a Patient with Gastric Cancer and Ankylosing Spondylitis.

Background: Autoimmune diseases are not contraindications for immune checkpoint inhibitors (ICI) therapy in patients with cancer. However, immune-related adverse events (irAEs) are frequently observed in patients receiving ICIs including dermatitis, thyroiditis, colitis, and pneumonitis. Thrombocytopenic purpura, aplasia, and haemophagocytic lymphohistiocytosis (HLH) are rarely observed during ICIs. Case description: We report the case of a male patient with pre-existing untreated HLA B27 and ankylosing spondylitis with gastric cancer and liver metastases. The 79-year-old man was treated with anti-HER2 trastuzumab and anti-PD-1 nivolumab. Seventeen days after the seventh cycle of treatment, he presented at the emergency department with acute fever, confusion, and hypotension. Laboratory results showed pancytopenia, and elevation of ferritin and triglyceride. No infections were detected. Although not seen in a bone marrow biopsy, clinical presentation, and absence of infection, together with an H-score of 263, indicated HLH. The patient was treated with dexamethasone for four days and discharged on a tapering dose of steroids. At the two-month follow-up, clinical presentation was normal and blood test almost normalised. At 8 months, no liver metastases were observed. Conclusions: In a patient with a pre-existing autoimmune condition, immunotherapy led to the development of HLH, which was controlled by glucocorticoid. Absence of the feature of haemophagocytosis in the bone marrow biopsy did not exclude the diagnosis, as HLH can occur in the spleen or in the liver. Glucocorticoid therapy did not prevent the anti-cancer effect of ICIs, and liver metastases disappeared 8 months post-HLH. This case warrants further research on the interplay between autoimmunity and ICI response, as well as ICI-induced irAEs. LEARNING POINTS: Haemophagocytic lymphohistiocytosis (HLH) post seventh cycle of trastuzumab (anti-HER2) and nivolumab (anti-PD-1) was controlled with glucocorticoid.Breach of tolerance was due to immunotherapy-induced HLH in a patient with pre-existing autoimmune condition (HLA B27- positive ankylosing spondylitis).There was a complete disappearance of liver metastases 8 months post-HLH.

Haemophagocytic lymphohistiocytosis caused by GATA2 deficiency: a report on three patients.

BACKGROUND: Haemophagocytic lymphohistiocytosis (HLH) is a syndrome that occurs in patients with severe systemic hyperinflammation. GATA binding protein 2 (GATA2) is a transcription factor and key component in haematopoiesis and stem cell biology. CASE PRESENTATION: Three patients with HLH, one with Mycobacterium avium infection, one with Epstein-Barr virus (EBV) infection, and one with Mycobacterium kansasii infection, were all subsequently found to have a defect in the GATA2 gene through genetic testing. CONCLUSIONS: GATA2 deficiency syndrome should be considered in patients with myelodysplastic syndrome, nontuberculous mycobacterium infection and HLH. In addition, the GATA2 gene variant may be a genetic defect that could be the cause of the primary HLH. However, further studies are needed to confirm the role of GATA2 pathogenic variants in the pathogenesis of HLH.

Prevalence and mortality of haemophagocytic lymphohistiocytosis in dengue fever: a systematic review and meta-analysis.

BACKGROUND: Haemophagocytic lymphohistiocytosis (HLH) is a rare complication of dengue fever with potentially life-threatening consequences and high mortality. Therefore, this study aims to investigate the prevalence, management and outcome of HLH in dengue fever. METHODS: The major electronic databases, including PubMed, ScienceDirect and Ovid SP, were searched from inception until 31 January 2024 to identify relevant studies. Pooled prevalence and mortality were calculated using the random-effects generic inverse variance model with a 95% CI. All the statistical analysis was conducted using R programming. RESULTS: A total of nine studies with 157 patients with HLH, 576 patients with severe dengue and 5081 patients with dengue fever were included in this meta-analysis. The prevalence of HLH in severe dengue (22.1%, 95% CI 8.07 to 48.0%) was significantly higher than the prevalence in dengue fever (3.12%, 95% CI 0.37 to 21.9%). The prevalence of HLH in severe dengue was higher in the paediatric population (22.8%, 95% CI 3.9 to 68.4%) compared with the adult population (19.0%, 95% CI 3.0 to 63.9%). The overall mortality rate was 20.2% (95% CI 9.7 to 37.2%). CONCLUSION: The prevalence of dengue-associated HLH was low in patients with dengue fever but is significantly higher in patients with severe dengue and a high mortality rate.

Does your unwell patient have haemophagocytic lymphohistiocytosis?

Haemophagocytic lymphohistiocytosis is a severe systemic hyperinflammatory syndrome characterised by dysregulation of immune cells and excessive production of cytokines, also known as a cytokine storm. It has distinctive clinical features with fever, hyperferritinaemia and falling blood counts. In adults, this usually occurs secondary to an underlying driver or trigger including infection, malignancy or rheumatic diseases. Prompt treatment with immunomodulatory therapy, including corticosteroids and the recombinant IL-1 receptor antagonist anakinra, is recommended to switch off the cytokine storm. Etoposide-based regimens are sometimes needed, and newer therapies such as emapalumab and JAK inhibitors are increasingly being used. The incidence of haemophagocytic lymphohistiocytosis has increased significantly over the last 20 years which may partly reflect increased awareness of the condition. Although relatively rare, haemophagocytic lymphohistiocytosis can be encountered by a broad range of hospital physicians, so knowing how to diagnose and treat this condition is essential. This article reviews the pathogenesis, clinical features, causes, diagnosis and treatment of haemophagocytic lymphohistiocytosis to improve physician recognition and management of this condition to improve future patient outcomes.

Clinical characterization of hemophagocytic lymphohistiocytosis caused by immune checkpoint inhibitors: a review of published cases.

OBJECTIVE: An association exists between immune checkpoint inhibitors and hemophagocytic lymphohistiocytosis (HLH). Therefore, the main objective of this study was to collect data on this rare but potentially life-threatening immune-related adverse reaction to identify the medications that cause it, the clinical characteristics, and effective treatments. METHODS: Literature in English and Chinese on immune checkpoint inhibitors causing HLH published from August 2014 to March 2024 was analyzed. Immune checkpoint inhibitors, immunotherapy, anti-PD-1, PD-L1 inhibitors, HLH, hemophagocytic lymphohistiocytosis, hemophagocytic syndrome keywords were used to find the literature on China Knowledge Network, Wanfang, PubMed and Emabase Databases. RESULTS AND DISCUSSION: Twenty-four studies were included, with a total of 27 patients (18 males and 9 females) with a mean age of 58 years (range 26-86). The mean time to the onset of symptoms was 10.3 weeks (7 days-14 months). The main clinical characteristics were fever, cytopenia, splenomegaly, methemoglobinemia, hypofibrinogenemia, and bone marrow biopsy showed phagocytosis. Twenty-two patients improved after the treatment with steroids, cytokine blocking therapy and symptomatic treatment, four patients died, and one patient was not described. CONCLUSION: HLH should be not underestimated as a potentially serious adverse effect of immune checkpoint inhibitors since appropriate treatments may save the life of patients.

Features and outcomes of patients admitted to the ICU for chimeric antigen receptor T cell-related toxicity: a French multicentre cohort.

BACKGROUND: Chimeric antigen receptor T-cell (CAR-T) therapy is increasingly used in patients with refractory haematological malignancies but can induce severe adverse events. We aimed to describe the clinical features and outcomes of patients admitted to the intensive care unit (ICU) after CAR-T therapy. METHODS: This retrospective observational cohort study included consecutive adults admitted to either of two French ICUs in 2018-2022 within 3 months after CAR-T therapy. RESULTS: Among 238 patients given CAR-T therapy, 84 (35.3%) required ICU admission and were included in the study, a median of 5 [0-7] days after CAR-T infusion. Median SOFA and SAPSII scores were 3 [2-6] and 39 [30-48], respectively. Criteria for cytokine release syndrome were met in 80/84 (95.2%) patients, including 18/80 (22.5%) with grade 3-4 toxicity. Immune effector cell-associated neurotoxicity syndrome (ICANS) occurred in 46/84 (54.8%) patients, including 29/46 (63%) with grade 3-4 toxicity. Haemophagocytic lymphohistiocytosis was diagnosed in 15/84 (17.9%) patients. Tocilizumab was used in 73/84 (86.9%) patients, with a median of 2 [1-4] doses. Steroids were given to 55/84 (65.5%) patients, including 21/55 (38.2%) given high-dose pulse therapy. Overall, 23/84 (27.4%) patients had bacterial infections, 3/84 (3.6%) had fungal infections (1 invasive pulmonary aspergillosis and 2 Mucorales), and 2 (2.4%) had cytomegalovirus infection. Vasopressors were required in 23/84 (27.4%), invasive mechanical ventilation in 12/84 (14.3%), and dialysis in 4/84 (4.8%) patients. Four patients died in the ICU (including 2 after ICU readmission, i.e., overall mortality was 4.8% of patients). One year after CAR-T therapy, 41/84 (48.9%) patients were alive and in complete remission, 14/84 (16.7%) were alive and in relapse, and 29/84 (34.5%) had died. These outcomes were similar to those of patients never admitted to the ICU. CONCLUSION: ICU admission is common after CAR-T therapy and is usually performed to manage specific toxicities. Our experience is encouraging, with low ICU mortality despite a high rate of grade 3-4 toxicities, and half of patients being alive and in complete remission at one year.

Drug-induced secondary haemophagocytic lymphohistiocytosis in hairy cell leukaemia.

Haemophagocytic lymphohistiocytosis (HLH) is a rare, aggressive, excess immune activation syndrome. Diagnosis can be challenging due to its several clinical mimics including sepsis. There are multiple aetiologies of HLH; in adults, it is most commonly triggered by infection, malignancy, drugs and autoimmune processes. Failure to rapidly diagnose and treat this condition can be fatal. The management of HLH includes identifying and removing the trigger, supportive management and immunosuppression. Identifying the trigger is essential to inform the most appropriate type of immunosuppression. Here, we report a case of likely drug-induced HLH in a patient recently treated for hairy cell leukaemia. The culprit drug was thought to be co-trimoxazole and this case report highlights a very rare complication of this commonly used drug. We discuss our management approach with steroid monotherapy and withdrawal of co-trimoxazole.

Immune checkpoint inhibitor-associated hemophagocytic lymphohistiocytosis in a patient with chronic lymphocytic leukemia.

Haemophagocytic lymphohistiocytosis (HLH) is a rare complication of immune checkpoint inhibitor therapy. A 55-year-old male with stable chronic lymphocytic leukemia presented with fevers and symptomatic anaemia after nine cycles of nivolumab for metastatic melanoma. Investigations were consistent with autoimmune haemolytic anemia and corticosteroids were initiated. Thrombocytopenia and elevated liver enzymes without evidence of chronic lymphocytic leukaemia transformation was present. Ferritin was elevated, and thus HLH was considered and subsequently confirmed on a bone marrow biopsy. Corticosteroid monotherapy was continued, with resolution of fevers and improvement in cytopenias and liver enzymes. A six month corticosteroid tapering regimen was initiated, and he remains in HLH remission. This case highlights the importance of prompt recognition of immune checkpoint inhibitor-related HLH in patients with concurrent haematological malignancy.

A 55-year-old man had skin cancer and treatment was started. He also had a blood cancer around the same time that was not causing any problems. The skin cancer treatment started to cause problems many weeks later. His immune system started to react and become more active and so his liver started to suffer. The treatment for his skin cancer was stopped and steroids were started, which eventually improved his condition. These treatments for skin cancer can activate the immune system, but to this extent is not very common. It is important to know that it is possible and needs to be actioned early.

Disseminated tuberculosis, CMV viraemia & haemophagocytic-lymphohistiocystosis syndrome in an adult patient with anti- IFNγ autoantibodies - case report and brief review.

We report a case of an adult female with disseminated tuberculosis, cytomegalovirus viraemia and haemophagocytic-lymphohistiocystosis syndrome associated with neutralizing anti- interferon gamma (IFNγ) autoantibodies demonstrated by absent IFNγ stimulated STAT1 phosphorylation in the presence of patient sera. A brief review of immunodeficiency caused by anti-IFNγ autoantibodies is also described.

Haemophagocytic lymphohistiocytosis due to Burkholderia pseudomallei in a primigravida.

Introduction: Melioidosis is caused by Burkholderia pseudomallei, a Gram-negative, saprophytic bacillus, commonly found in soil or contaminated water. As infection with this bacterium produces a wide variety of clinical manifestations the organism is aptly called the 'great mimicker'. Even though it is non-fastidious and an easily cultivable organism, it can be misidentified in automated identification systems. Case report: A 24-year-old primigravida presented with complaints of fever and myalgia of 45 days' duration. She was diagnosed to have haemophagocytic lymphohistiocytosis (HLH) based on clinical and laboratory parameters. Blood and bone marrow culture sent to the microbiology laboratory grew non-fermenting Gram-negative bacilli which were misidentified as Burkholderia cepacia by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) technology. It was subsequently identified as B. pseudomallei by 16S rRNA gene sequencing. The patient was commenced on intensive phase therapy with intravenous ceftazidime for 2 weeks, followed by maintenance therapy with oral trimethoprim and sulfamethoxazole for 3 months. In view of HLH, she was treated with intravenous dexamethasone for 2 weeks which was later switched to oral dexamethasone for a period of 6 weeks. She responded well to the treatment, but had to undergo medical termination of her pregnancy as there was severe intrauterine growth restriction of the fetus. Conclusion: Prognosis of melioidosis is excellent if early diagnosis and appropriate antibiotic treatment is provided. In this era of automation, it is important to determine if the suspected pathogen is listed in the database of the automated identification system.

Epidemiology, characteristics, and outcomes of adult haemophagocytic lymphohistiocytosis in the USA, 2006-19: a national, retrospective cohort study.

Background: Haemophagocytic lymphohistiocytosis (HLH) is a rare and life-threatening syndrome characterized by an excessive inflammatory response. Limited data exist on adult HLH. Methods: In this national, retrospective cohort study, we analysed data from the US National Inpatient Sample database collected between October 1, 2006 and December 31, 2019. Using the International Classification of Diseases (ICD) codes, we identified all adult patients who were admitted non-electively with the diagnosis of HLH. We described demographic characteristics, triggers, and associated conditions. Trends of diagnosis, treatment, and in-hospital mortality were analysed using joinpoint models. In-hospital mortality rates were compared using multivariable logistic regression models that adjusted for demographic characteristics and associated conditions. Finally, we described resource utilization outcomes including cost of hospitalization and length of stay. Findings: We identified 16,136 non-elective adult HLH admissions. The population pyramid showed a bimodal distribution, with peaks in young adults (16-30 years) and older adults (56-70 years). Joinpoint regression analysis revealed a significant increase in HLH incidence per 100,000 admissions over the study period (Average Annual Percent Change [APC] = 25.3%, p < 0.0001), and no significant change in rates of in-hospital mortality (slope = -0.01; p = 0.95) or administration of in-hospital HLH treatment (slope = 0.46, p = 0.20). The most common associated conditions were malignancy (4953 admissions [30.7%]), infections (3913 admissions [24.3%]), autoimmune conditions (3362 admissions [20.8%]), organ transplant status (639 admissions [4%]), and congenital immunodeficiency syndromes (399 admissions [2.5%]). In-hospital mortality was higher in older adults and males. Furthermore, Congenital immunodeficiency syndromes had the worst in-hospital mortality rate (mortality rate 31.1%, adjusted OR 2.36 [1.56-3.59]), followed by malignancies (mortality rate 28.4%, adjusted OR 1.80 [1.46-2.22]), infections (mortality rate 21.4%, adjusted OR 1.33 [1.10-1.62]), other/no trigger (mortality rate 13.6%, adjusted OR 0.73 [0.58-0.92]), autoimmune (mortality rate 13%, adjusted OR 0.72 [0.57-0.92]), and post-organ transplant status (mortality rate 14.1%, adjusted OR 0.64 [0.43-0.97]). The overall mean length of stay was 14.3 ± 13.9 days, and the mean cost of hospitalization was $54,900 ± 59,800. Interpretation: We provide insight into the burden of adult HLH in the USA. The incidence has been increasing and the outcomes remain dismal. This signifies the growing need for the development of updated diagnosis and treatment protocols that are specific to adult HLH. Funding: None.

A case of T-cell-Epstein-Barr virus-haemophagocytic lymphohistiocytosis and sustained remission following ruxolitinib therapy.

Objectives: Epstein-Barr virus (EBV) is a common cause of secondary haemophagocytic lymphohistiocytosis (HLH). While B cells are reservoirs for EBV, infection within T cells and NK cells in this disease can be difficult to treat. Methods: A 19-year-old female presented with a 6-week history of coryzal symptoms on a background of Crohn's disease. On examination, she was febrile and tachycardic with mild tonsillar enlargement and splenomegaly. New trilineage cytopenias and elevation in liver enzymes were detected, with acute EBV subsequently confirmed on whole blood PCR. A diagnosis of EBV-associated HLH was supported further with elevated serum ferritin, triglycerides and soluble CD25, low fibrinogen and the presence of haemophagocytosis in the bone marrow. Results: Corticosteroids, IVIG and rituximab were given, and anakinra was subsequently added due to ongoing fevers. EBV infection was then demonstrated within CD8+ T cells on EBER Flow-FISH assay. Ruxolitinib was commenced and her fevers abated on day 5, with improvement in other HLH parameters. She was discharged after a 39-day hospital admission. To date, she has remained in remission of HLH, despite developing COVID-19 infection during the convalescence phase of HLH. Conclusion: EBV viraemia requires adequate treatment to control EBV-associated HLH as rituximab may be insufficient, and corticosteroid resistance can result in continued EBV infection in CD8+ T cells. This entity is known as T-cell-EBV-HLH. Ruxolitinib is a novel treatment strategy in this specific context and has several advantages, including inhibition of corticosteroid resistance to promote apoptosis of EBV-infected T cells.

Intravenous anakinra for the treatment of haemophagocytic lymphohistiocytosis/macrophage activation syndrome: A systematic review.

BACKGROUND: Haemophagocytic lymphohistiocytosis (HLH) or macrophage activation syndrome (MAS) has a potentially high mortality rate. Anakinra, an interleukin-1 receptor antagonist, is now recommended early in HLH/MAS, with intravenous (IV) use proposed in critically unwell patients. This systematic review establishes the literature relating to IV anakinra in secondary HLH/MAS (sHLH/MAS). METHODS: We screened Embase, PubMed, and Medline, including all reports of IV anakinra for HLH or MAS. We extracted age, HLH/MAS trigger, continuous infusion or bolus dosing, and survival. RESULTS: Twenty-nine case reports/series identified 87 patients (median age 22 years, range 22 months to 84 years), all with sHLH. Amongst identifiable triggers, 43% were systemic infection, 33% rheumatological, 9% oncological. Children had predominantly a rheumatological trigger (48%), whilst adults were more commonly infection-driven (50%). Overall, rheumatologically triggered disease showed greater survival (83.3%), particularly compared with oncological triggers (42.9%). Children had a greater survival, particularly under 10 years (83%, vs. adults, 63%). CONCLUSIONS: Despite IV anakinra recipients likely to be critically unwell, this cohort had similar disease triggers and survival compared to large historical cohorts, and enhances awareness of age and trigger-specific survival patterns. IV anakinra had a wide therapeutic dosing range and tolerability, regardless of trigger, demonstrating substantial utility in severe sHLH/MAS.

Hemophagocytic Syndrome and COVID-19: A Comprehensive Review.

Hemophagocytic lymphohistiocytosis (HLH), a hyperinflammatory hyperferritinemic syndrome, is triggered by various etiologies and diseases and can lead to multiorgan dysfunction and death. There are two types of HLH: primary and secondary. Primary HLH (pHLH) is caused by a genetic mutation resulting in dysfunction in cytotoxic T lymphocytes (CTLs), natural killer (NK) cells, hyperactivated immune cells, and hypercytokinemia. In secondary HLH (sHLH), an underlying etiology is the cause of the disease. Infections, malignancy, and autoimmune diseases are well-known triggers for sHLH. Infectious triggers for sHLH are most frequently viruses, where different mechanisms, including dysregulated CTLs and NK cell activity and persistent immune system stimulation, have been reported. Similarly, in severe coronavirus disease 2019 (COVID-19) patients, a hyperinflammatory mechanism leading to hypercytokinemia and hyperferritinemia has been demonstrated. A similar dysfunction in CTLs and NK cells, persistent immune system stimulation with increased cytokines production, and severe end-organ damage have been reported. Therefore, a significant overlap is present between the clinical and laboratory features seen in COVID-19 and sHLH. However, SARS-CoV-2, similar to other viruses, can trigger sHLH. Hence, a diagnostic approach is needed in severe COVID-19 patients presenting with multiorgan failure, in whom sHLH should be considered.

Case report: Virus-induced hemophagocytic lymphohistiocytosis in a patient with APECED.

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED), also known as autoimmune polyglandular syndrome type 1 (APS-1) is a rare autosomal recessive inborn error of immunity (IEI), which is accompanied by immune dysregulation. Hypoparathyroidism, adrenocortical failure and candidiasis are its typical manifestations. Here we report about recurrent COVID-19 in a 3-year-old boy with APECED, who developed retinopathy with macular atrophy and autoimmune hepatitis after the first episode of SARS-CoV-2 infection. Primary Epstein-Barr virus infection and a new episode of SARS-CoV-2 infection with COVID pneumonia triggered the development of severe hyperinflammation with signs of hemophagocytic lymphohistiocytosis (HLH): progressive cytopenia (thrombocytopenia, anemia, lymphopenia), hypoproteinemia, hypoalbuminemia, high levels of liver enzymes, hyperferritinemia, increased triglycerides levels; and coagulopathy with a low level of fibrinogen. Treatment with corticosteroids and intravenous immunoglobulins did not lead to a significant improvement. The progression of HLH and COVID-pneumonia resulted in a fatal outcome. The rarity and varied presentation of the HLH symptoms led to diagnostic difficulties and diagnosis delay. HLH should be suspected in a patient with immune dysregulation and impaired viral response. Treatment of infection-HLH is a major challenge due to the difficulties in balancing immunosuppression and management of underlying/triggering infection.

Immune checkpoint inhibitor-related haemophagocytic lymphohistiocytosis in a patient with non-small cell lung carcinoma.

Hemophagocytic lymphohistiocytosis (HLH) has been reported as a rare complication of immune checkpoint inhibitors (ICI); however, ICI-related HLH is a life-threatening and comparatively late adverse event. Early diagnosis is critical, and it should be included in the differential diagnosis especially in patients with cytopenia with fever and hyperferritinaemia.