Ruxolitinib-based regimen in children with primary hemophagocytic lymphohistiocytosis

Effect of genetic mutations on outcomes of stem cell transplantation in children with hemophagocytic lymphohistiocytosis

Primary hemophagocytic lymphohistiocytosis (p-HLH) can be cured with allogeneic haematopoietic stem cell transplantation (allo-HSCT). It remains unclear whether HSCT outcomes are affected by the presence of different genetic mutations. We used data obtained from children who underwent allo-HSCT for HLH to examine the effects of genetic mutations on HSCT outcomes. Data from 153 paediatric patients in 18 paediatric stem cell centres were retrospectively evaluated. Patients were divided into four groups: 1) with PRF1 mutation (n = 46), 2) with UNC13D mutation (n = 38), 3) with STX11/STXBP2 mutation (n = 25) and 4) with Griscelli syndrome type 2/ Chediak-Higashi syndrome (GS2/CHS) diagnosis (n = 44). Statistical analysis showed no difference between the subgroups in terms of engraftment, VOD, acute GVHD, chronic GVHD, TRM, OS and EFS rates. The most important factor affecting OS and EFS in all genetic subgroups was remission status before HSCT. The 5-year EFS values for children with mutations in PRF1, UNC13D, STX11/STXBP2 and GS2/CHS were 71%, 66.6%, 74% and 66.7, respectively (log-rank >0.05). However, with prospective studies covering more patients, and creating different genetic subgroups by performing more detailed genetic analyses, special approaches for different genetic subgroups can be revealed in the future.

Immune Effector Cell-associated Hemophagocytic Lymphohistiocytosis-like Syndrome (IEC-HS)

Immune effector cell-associated hemophagocytic lymphohistiocytosis-like syndrome (IEC-HS) is a complication of adoptive cell therapy. Presenting with clinical manifestations of hyperinflammation and surrogate indicators of hyperinflammation such as elevations in serum ferritin and hepatic transaminases, decreasing cell counts, and hypofibrinogenemia, IEC-HS resembles primary and other forms of secondary hemophagocytic lymphohistiocytosis. Nonetheless, this is an iatrogenic complication resulting from the induction of hyperinflammatory pathways during T-cell-mediated anticancer targeting. Distinct from cytokine release syndrome, IEC-associated neurotoxicity syndrome, and IEC-associated hematotoxicity, IEC-HS can be life-threatening. Identification of IEC-HS, optimization of treatment strategies, and use of supportive care are critical to improving outcomes.

Clinical Characteristics and Treatment of Familial Hemophagocytic Lymphohistiocytosis

Familial hemophagocytic lymphohistiocytosis (fHLH) comprises a group of autosomal recessive disorders characterized by germline loss-of-function variants that negatively impact lymphocyte cytotoxicity. These disorders exhibit variable clinical presentations, most often in association with severe hyperinflammation. fHLH is diagnosed through clinical and laboratory assessments as well as genetic testing and immunologic assays. In the absence of therapy to control the hyperactive immune system, fHLH is generally fatal. Treatment has historically taken the form of cytotoxic chemotherapy and/or immunosuppressive therapy, although targeted inhibitors of inflammatory cytokines and their downstream signaling are increasingly being utilized. Definitive treatment requires allogeneic hematopoietic cell transplantation.

Advances in diagnosis and treatment of lymphoma-associated hemophagocytic syndrome

Hemophagocytic syndrome (HPS) is a rare clinical disorder characterized by persistent and ineffective activation of the immune system, leading to a severe systemic inflammatory response. Lymphoma-associated hemophagocytic syndrome (LAHS) refers to HPS caused either by lymphoma itself or by immunosuppression during lymphoma chemotherapy at present, there is no standardized consensus on the diagnosis and treatment of LAHS, both domestically and internationally. After remission induced by combination chemotherapy, hematopoietic stem cell transplantation (HSCT) is a commonly used treatment approach. This paper reviews the latest advancements in the diagnosis and treatment of LAHS, providing a reference for its clinical management.

Ruxolitinib-based regimen in children with autoimmune disease or autoinflammatory disease-related haemophagocytic lymphohistiocytosis

For autoimmune disease (AD) and autoinflammatory disease (AID)-related haemophagocytic lymphohistiocytosis (HLH) (AD/AID-HLH), there is still a lack of standardized treatment. Glucocorticoids (GCs) are the main treatment currently; however, 37.9% to 61% of patients fail to achieve effective control of HLH, making it urgent to find novel treatment strategies. We conducted a retrospective, single-centre study examining ruxolitinib (RUX)-based regimen in children with AD/AID-HLH. Patients were first treated with RUX monotherapy, and additional treatments including methylprednisolone and etoposide were added sequentially when the disease could not be controlled. The study included 26 patients with a median follow-up of 23.9 months, of whom 15 had prior treatments. The overall response rate at week 8 with the RUX-based regimen was 96.2%, with 92.3% attaining complete response (CR) and 3.9% attaining partial response. The 2-year overall survival rate was 96.2% (95% CI, 80.4% to 99.9%). During RUX monotherapy, 46.1% of patients achieved CR as the best response, with a median first response time to RUX of 2 days. Additionally, 53.8% of patients required additional GCs and 23.1% required etoposide chemotherapy. All observed adverse events were manageable and acceptable. Overall, our study supports the efficacy and safety of the RUX-based regimen in children with AD/AID-HLH.

Hemophagocytic lymphohistiocytosis caused by multiple infections during primary chemotherapy for pediatric acute lymphoblastic leukemia: a case report

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory disorder that occurs as a consequence of immune dysregulation. HLH can be primary (familial or non-familial) or secondary to infection, autoimmune disease or malignancy. Malignancy-associated HLH is often accompanied by hematologic and lymphoid neoplasms. This report describes the case of a 3-year-old girl with an initial diagnosis of acute lymphoblastic leukemia who subsequently developed HLH during primary chemotherapy. She was admitted with a pulmonary infection, and initial blood tests showed thrombocytopenia and anemia. Whole-exome sequencing of gene and whole transcriptome RNA sequencing data indicated mutations of UNC13D. The hospital course was complicated by multiple infections, altered mental status and acute respiratory distress syndrome. HLH secondary to multiple infections that achieved remission following targeted therapy with ruxolitinib, in conjunction with corticosteroids and other complementary treatments. This report provides a synopsis of the diagnostic and treatment procedures implemented in this case.

Pre-diagnostic trajectory of pediatric hemophagocytic lymphohistiocytosis: observations from hematological and hepatic parameters

Understanding the early features and characteristics of hemophagocytic lymphohistiocytosis (HLH) is essential for identifying high-risk individuals and also providing valuable pathological insights. This study aims to investigate the characteristics and trends of blood and hepatic parameters before an HLH diagnosis was established. Longitudinal hematological and hepatic test results from pediatric patients with HLH and an age- and sex-matched control group were analyzed. According to the length of time between hospital admission and the establishment of the HLH diagnosis, the HLH cases were divided into early-onset (≤ 7 days) and late-onset (> 7days) groups. Among the 229 pediatric HLH patients, the length of time between hospital admission and the establishment of an HLH diagnosis ranged from 0 to 41 days (median = 4 days). Over 80% of pediatric HLH patients presented abnormal laboratory results for aspartate aminotransferase (AST), triglycerides, lactate dehydrogenase (LDH), and hemoglobin at admission. The abnormal rates in the initial platelet count, neutrophil count, and fibrinogen tests were 67.3%, 48.3%, and 52.2%, respectively. The initial test results for AST, alanine aminotransferase (ALT), LDH, serum sodium, and albumin showed AUCs > 80% for discriminating early-onset HLH. For the discrimination of late-onset HLH, the performance of initial test results was poor. To conclude, abnormalities in AST, triglycerides, LDH, and hemoglobin are early presentations of pediatric HLH; platelet, neutrophil, and fibrinogen levels may become abnormal at a relatively late stage of the HLH disease trajectory; and the initial test results for AST, ALT, LDH, serum sodium, and albumin can be used to identify suspected early-onset HLH.

Clinicopathological characteristics, prognostic factors, and outcomes of elderly patients with lymphoma-associated hemophagocytic lymphohistiocytosis: A multicenter analysis

BACKGROUND

Lymphoma is the most common secondary cause of hemophagocytic lymphohistiocytosis (HLH) in adults. Lymphoma-associated HLH (LA-HLH) in the elderly population is not rare, however, little has been reported regarding clinicopathological characteristics, prognostic factors, and outcomes of LA-HLH in the elderly population.

METHODS

We retrospectively analyzed a multicenter cohort of elderly patients with LA-HLH. Clinicopathological features and treatment information were collected. The impacts of baseline characteristics and treatments on survival outcomes were analyzed.

RESULTS

A total of 173 elderly patients with LA-HLH were included. Compared with young patients, elderly patients showed different clinical and laboratory features. Regarding lymphoma subtypes, B-cell lymphoma was more common in elderly patients (elderly 61.3% vs. young 32.3%, p < 0.001) while T/NK-cell lymphoma was more common in young patients (65.3% vs. 35.3%, p < 0.001). The median survival of elderly patients with LA-HLH was only 92 days. The prior use of HLH therapy or etoposide-containing HLH therapy was not associated with improved overall survival. T/NK-cell subtype, a lower platelet count (≤53 × 109/L), a lower albumin level (≤32.1 g/L), a higher LDH level (>1407 U/L), and a higher creatinine level (>96.8 μmol/L) were independent predictors of decreased overall survival and 60-day survival. A prognostic index was established and demonstrated to be robust in predicting the overall survival and 60-day survival of elderly patients with LA-HLH.

CONCLUSIONS

LA-HLH in elderly patients displayed heterogeneous clinicopathological features and survival outcomes. Treatments need to be optimized to improve the outcomes of elderly patients with LA-HLH.

Dengue-Associated Hemophagocytic Lymphohistiocytosis: A Narrative Review of Its Identification and Treatment

Dengue's lack of specific treatments beyond supportive care prompts a focus on uncovering additional pathophysiological factors. Dengue-associated hemophagocytic lymphohistiocytosis (HLH), characterized by dysregulated macrophage activation and cytokine storm, remains underexplored despite its potential to worsen disease severity and mortality. While rare, dengue-associated HLH disproportionately affects severe cases, significantly impacting mortality rates. To mitigate high mortality, early identification and familiarity with dengue-associated HLH are imperative for prompt treatment by clinicians. This narrative review therefore aims to examine the current clinical and therapeutic knowledge on dengue-associated HLH, and act as a resource for clinicians to improve their management of HLH associated with severe dengue. Dengue-associated HLH should be considered for all cases of severe dengue and may be suspected based on the presence of prolonged or recurrent fever for >7 days, or anemia without intravascular hemolysis or massive bleeding. Diagnosis relies on fulfilling at least five of the eight HLH-2004 criteria. Treatment predominantly involves short courses (3-4 days) of high-dose steroids (e.g., dexamethasone 10 mg/m2), with additional therapies considered in more severe presentations. Notably, outcomes can be favorable with steroid therapy alone.

Survival in primary hemophagocytic lymphohistiocytosis, 2016 to 2021: etoposide is better than its reputation

ABSTRACT

Primary hemophagocytic lymphohistiocytosis (pHLH) is a life-threatening hyperinflammatory syndrome that develops mainly in patients with genetic disorders of lymphocyte cytotoxicity and X-linked lymphoproliferative syndromes. Previous studies with etoposide-based treatment followed by hematopoetic stem cell transplantation (HSCT) resulted in 5-year survival of 50% to 59%. Contemporary data are lacking. We evaluated 88 patients with pHLH documented in the international HLH registry from 2016-2021. In 12 of 88 patients, diagnosis was made without HLH activity, based on siblings or albinism. Major HLH-directed drugs (etoposide, antithymocyte globulin, alemtuzumab, emapalumab, ruxolitinib) were administered to 66 of 76 patients who were symptomatic (86% first-line etoposide); 16 of 57 patients treated with etoposide and 3 of 9 with other first-line treatment received salvage therapy. HSCT was performed in 75 patients; 7 patients died before HSCT. Three-year probability of survival (pSU) was 82% (confidence interval [CI], 72%-88%) for the entire cohort and 77% (CI, 64%-86%) for patients receiving first-line etoposide. Compared with the HLH-2004 study, both pre-HSCT and post-HSCT survival of patients receiving first-line etoposide improved, 83% to 91% and 70% to 88%. Differences to HLH-2004 included preferential use of reduced-toxicity conditioning and reduced time from diagnosis to HSCT (from 148 to 88 days). Three-year pSU was lower with haploidentical (4 of 9 patients [44%]) than with other donors (62 of 66 [94%]; P < .001). Importantly, early HSCT for patients who were asymptomatic resulted in 100% survival, emphasizing the potential benefit of newborn screening. This contemporary standard-of-care study of patients with pHLH reveals that first-line etoposide-based therapy is better than previously reported, providing a benchmark for novel treatment regimes.

Immune Effector Cell-Associated HLH-like Syndrome: A Review of the Literature of an Increasingly Recognized Entity

Since CAR-T cell therapy was initially approved in 2017, its use has become more prevalent and so have its side effects. CAR-T-related HLH, also named immune effector cell-associated HLH-like syndrome (IEC-HS), is a rare but fatal toxicity if not recognized promptly. We conducted a review of the literature in order to understand the prevalence of IEC-HS as well as clarify the evolution of the diagnostic criteria and treatment recommendations. IEC-HS occurrence varies between CAR-T cell products and the type of malignancy treated. Diagnosis can be challenging as there are no standardized diagnostic criteria, and its clinical features can overlap with cytokine release syndrome and active hematological disease. Suggested treatment strategies have been extrapolated from prior experience in HLH and include anakinra, corticosteroids and ruxolitinib. IEC-HS is a potentially fatal toxicity associated with CAR-T cell therapy. Early recognition with reliable diagnostic criteria and prompt implementation of treatment specific to IEC-HS is imperative for improving patient outcomes.