The Performance of Diagnostic Criteria for Hemophagocytic Lymphohistiocytosis in Critically Ill Patients

The HScore to Diagnose HLH in Scrub Typhus: Overdiagnosis or under Diagnosis and Does It Really Matter?

How to cite this article: Hegde A. The HScore to Diagnose HLH in Scrub Typhus: Overdiagnosis or under Diagnosis and Does It Really Matter? Indian J Crit Care Med 2024;28(9):811-812.

Value of hemophagocytosis in the diagnosis of hemophagocytic lymphohistiocytosis in critically ill patients

BACKGROUND

Ferritin is an established biomarker in the diagnosis of secondary hemophagocytic lymphohistiocytosis (HLH), which is diagnosed by the HLH-2004 criteria. Among these criteria, detection of hemophagocytosis through invasive procedures may delay early life saving treatment. Our aim was to investigate the value of hemophagocytosis in diagnosing HLH in critically ill patients.

METHODS

In this secondary analysis of a retrospective observational study, we included all patients aged ≥18 years and admitted to any adult ICU at Charité-Universitätsmedizin Berlin between January 2006 and August 2018, who had hyperferritinemia (≥500 μg/L) and underwent bone marrow biopsy during their ICU course.

RESULTS

Two hundred fifty-two patients were included, of whom 31 (12.3%) showed hemophagocytosis. In multivariable logistic regression analysis, maximum ferritin was independently associated with hemophagocytosis. By removing hemophagocytosis from HLH-2004 criteria and HScore, prediction accuracy for HLH diagnosis was only marginally decreased compared to the original scores.

CONCLUSIONS

Our results strengthen the diagnostic value of ferritin and underline the importance of considering HLH diagnosis in patients with high ferritin but only four fulfilled HLH-2004 criteria, when hemophagocytosis was not assessed or not detectable. Proof of hemophagocytosis is not required for a reliable HLH diagnosis.

Cytokine Storm and Sepsis-Induced Multiple Organ Dysfunction Syndrome

There is extensive overlap of clinical features among familial or primary HLH (pHLH), reactive or secondary hemophagocytic lymphohistiocytosis (sHLH) [including macrophage activation syndrome (MAS) related to rheumatic diseases], and hyperferritinemic sepsis-induced multiple organ dysfunction syndrome (MODS); however, the distinctive pathobiology that causes hyperinflammatory process in each condition requires careful considerations for therapeutic decision-making. pHLH is defined by five or more of eight HLH-2004 criteria [1], where genetic impairment of natural killer (NK) cells or CD8+ cytolytic T cells results in interferon gamma (IFN-γ)-induced hyperinflammation regardless of triggering factors. Cytolytic treatments (e.g., etoposide) or anti-IFN-γ monoclonal antibody (emapalumab) has been effectively used to bridge the affected patients to hematopoietic stem cell transplant. Secondary forms of HLH also have normal NK cell number with decreased cytolytic function of varying degrees depending on the underlying and triggering factors. Although etoposide was uniformly used in sHLH/MAS in the past, the treatment strategy in different types of sHLH/MAS is increasingly streamlined to reflect the triggering/predisposing conditions, severity/progression, and comorbidities. Accordingly, in hyperferritinemic sepsis, the combination of hepatobiliary dysfunction (HBD) and disseminated intravascular coagulation (DIC) reflects reticuloendothelial system dysfunction and defines sepsis-associated MAS. It is demonstrated that as the innate immune response to infectious organism prolongs, it results in reduction in T cells and NK cells with subsequent lymphopenia even though normal cytolytic activity continues (Figs. 30.1, 30.2, 30.3, and 30.4). These changes allow free hemoglobin and pathogens to stimulate inflammasome activation in the absence of interferon-γ (IFN-γ) production that often responds to source control, intravenous immunoglobulin (IVIg), plasma exchange, and interleukin 1 receptor antagonist (IL-1Ra), similar to non-EBV, infection-induced HLH.

[Treatment of hemophagocytic lymphohistiocytosis in patients in the intensive care unit]

Hemophagocytic lymphohistiocytosis (HLH) is a hyperinflammatory syndrome characterized by hyperferritinemia. A differentiation is made between hereditary and acquired forms. In contrast to children, almost all cases in adult patients consist of acquired secondary HLH. Infections, malignancies and autoimmune diseases are frequent triggers of secondary HLH. More recently, cases of HLH have also been described in association with immunotherapy, e.g., when using chimeric antigen receptor (CAR) T‑cell treatment. In critically ill patients in the intensive care unit (ICU), sepsis represents the major differential diagnosis of HLH due to the frequently similar clinical presentation. Sometimes both sepsis and HLH are present at the same time. An early diagnosis and timely initiation of immunosuppressive treatment are essential for the further course and prognosis of HLH. Therefore, HLH should be considered as a possible diagnosis in critically ill patients with persistent fever and additional compatible symptoms (e.g., splenomegaly, neurological symptoms) or laboratory parameters (e.g., hyperferritinemia, cytopenia of two or three cell lines, increased transaminases). The diagnosis of HLH is made on the basis of the HLH-2004 criteria. The HScore can be used to estimate the probability of the presence of HLH. Corticosteroids given at high doses are the cornerstone of HLH treatment. Furthermore, immunoglobulins, etoposide, anakinra or ruxolitinib can complement treatment depending on the HLH trigger. The course of HLH depends on the timely initiation of treatment, the underlying trigger and the response to treatment. Despite progress in terms of diagnostics and targeted treatment, the prognosis of critically ill HLH patients is still poor.

Biomarker diversity in increased inflammation: Secondary hemophagocytic syndrome vs. systemic inflammatory response syndrome

INTRODUCTION

Secondary hemophagocytic syndrome (HPS) and systemic inflammatory response syndrome (SIRS) share similar clinical findings as a result of hyperinflammation. Due to high mortality rates in HPS; it is critical to diagnose promptly. Thus, this study aimed to evaluate the diagnostic and prognostic significance of inflammatory markers in these two increased inflammatory states.

METHODS

We conducted a prospective observational study including patients hospitalized in the intensive care unit of the Internal Medicine Department of Ege University Hospital.

RESULTS

Thirty-three patients with HPS and 46 patients with SIRS were evaluated. Serum ferritin and sIL-2r levels were significantly higher in the HPS group than in the SIRS group, as expected. Receiver operating curve (ROC) analysis showed that the optimal cutoff for ferritin to distinguish HPS from SIRS was 1703 μg/L (sensitivity: 75%, specificity: 94.1%, area under the curve (AUC): 0.871, p < 0.001), and that for sIL-2r was 5888 U/ml (sensitivity: 45.5%, specificity: 89.1%, AUC: 0.698, and p = 0.001). Temporal changes (Δ) in ferritin were determined as a mortality predictor. When evaluated in terms of prognostic significance in ROC analysis, a decrease in ferritin of less than 38% was the cutoff value (sensitivity: 92.3%, specificity: 76.9%, AUC: 0.888, and p < 0.001), in mortality. Contrarily, neither baseline nor temporal change in sIL-2r did not achieve prognostic significance as a mortality predictor.

CONCLUSION

In this single-center study, serum ferritin level was found to be a particularly more valuable diagnostic and prognostic marker than sIL-2r in patients with HPS.

Validation of the HScore and the HLH-2004 diagnostic criteria for the diagnosis of hemophagocytic lymphohistiocytosis in a multicenter cohort

Timely diagnosis of hemophagocytic lymphohistiocytosis (HLH) is critical and relies on clinical judgment. The HLH-2004 criteria are commonly used diagnostic criteria, whereas HScore was recently developed for reactive HLH.

OBJECTIVE

In this external validation study, we sought to compare the diagnostic accuracy of the HLH-2004 criteria and HScore and identify optimal cutoffs stratified by underlying etiology.

METHODS

In this retrospective cohort of all hospitalized adults in Alberta, Canada, (1999-2019) who had ferritin >500 ng/ml and underwent either biopsies or soluble CD25 testing, we calculated the diagnostic accuracy of HLH-2004 and HScore for the overall population and different etiologies.

RESULTS

Of 916 patients, 98 (11%) had HLH. HLH-2004 criteria ≥5 predicted HLH with a sensitivity of 91%, specificity of 93%, positive predictive value of 90%, and negative predictive value of 94% (c-statistic 92%). HScore ≥169 predicted HLH with better sensitivity (96%) but reduced specificity (71%), whereas the optimal cutoff ≥200 performed comparably to HLH-2004. HLH-2004 criteria outperformed HScore in most etiologies, whereas HScore improved sensitivity in inflammatory/autoimmune-HLH. The optimal cutoff of HScore was higher in hematopoietic cell transplant due to higher prevalence of fevers and cytopenias.

CONCLUSION

HLH-2004 criteria and HScore demonstrated excellent discriminatory power in identifying HLH. HScore may improve diagnostic accuracy in autoimmune-HLH.

Low utility of the H-Score and HLH-2004 criteria to identify patients with secondary hemophagocytic lymphohistiocytosis after CAR-T cell therapy for relapsed/refractory diffuse large B-Cell lymphoma

Secondary hemophagocytic lymphohistiocytosis (HLH) is a life-threatening immune dysregulation disorder. Use of chimeric antigen receptor T-cell therapy (CAR-T) is associated with cytokine release syndrome (CRS), Immune Effector Cell Associated Neurotoxicity Syndrome (ICANS) and secondary HLH. However, application of HLH scoring systems (H-score, HLH-2004 criteria) are not validated in this setting. We analyzed the utility of applying the H-score and the HLH-2004 criteria to identify patients with possible HLH post-CAR-T for Relapsed/Refractory Diffuse Large B-cell Lymphoma. Only two of four patients with post CAR-T HLH met five or more of the diagnostic criteria for HLH by HLH 2004 criteria. In contrast all four post CAR-T HLH patients had a high H-score (>169); however, an additional ten patients that did not have HLH also had a high H-score. Thus, in this patient population, both scoring systems were demonstrated to have low prognostic significance in differentiating between high grade CRS and HLH.

Die hämophagozytische Lymphohistiozytose bei kritisch kranken Patienten

Bei der hämophagozytischen Lymphohistiozytose (HLH) handelt es sich um ein Hyperinflammationssyndrom bedingt durch aberrant aktivierte Makrophagen und T‑Zellen. Beim Erwachsenen ist in erster Linie die erworbene Form anzutreffen. Häufige Auslöser sind Infektionen, Malignome und Autoimmunerkrankungen. Zuletzt wurden zudem zunehmend Fälle berichtet, in denen das Auftreten im Zusammenhang mit stattgehabten Immuntherapien zu sehen war. Auf der Intensivstation ist die HLH aufgrund des ähnlichen klinischen Erscheinungsbilds oft schwer von der Sepsis abzugrenzen. Zum Teil liegen beide zeitgleich vor. Die frühzeitige Diagnosestellung und Einleitung einer adäquaten immunsuppressiven Therapie ist für den weiteren Verlauf und die Prognose der HLH essenziell. Deshalb muss bei kritisch kranken Patienten mit persistierendem Fieber und entsprechenden Symptomen (z. B. Splenomegalie, neurologische Auffälligkeiten) oder Laborveränderungen (z. B. erhöhter Ferritinwert, Zytopenie von 2 oder 3 Zellreihen, erhöhte Transaminasen) das Vorliegen einer HLH in Betracht gezogen werden. Die Diagnose wird mithilfe der HLH-2004-Kriterien gestellt. Mit dem HScore kann die Wahrscheinlichkeit des Vorliegens einer HLH berechnet werden. Hochdosierte Kortikosteroide stellen den Grundpfeiler der HLH-Therapie dar. Je nach Auslöser werden Etoposid, Immunglobuline, Anakinra oder weitere Medikamente ergänzt. Der Verlauf hängt neben einem frühzeitigen Behandlungsbeginn vom Auslöser sowie dem Ansprechen auf die Therapie ab. Insgesamt ist die Prognose der HLH trotz maximaler intensivmedizinischer Behandlung ungünstig und sie ist mit einer hohen Letalität assoziiert.

Hemophagocytic lymph histiocytosis (HLH): etiologies, pathogenesis, treatment, and outcomes in critically ill patients: a review article and literature to review

Hemophagocytic lymph histiocytosis (HLH) is not an independent disease but is instead a clinical syndrome that occurs in many underlying conditions involving all age groups. HLH is the consequence of a severe, uncontrolled hyperinflammatory reaction that in most cases is triggered by an infectious agent. Acquired HLH is much more common than primary HLH syndrome but primary is more fatal, and it does have the worst prognosis with no definitive treatment available to date. This review article mentioned all the latest advancements regarding etiologies, pathogenesis, treatment, and outcomes in critically ill patients who got diagnosed with HLH syndrome in last 15 years.

[Hemophagocytic lymphohistiocytosis in critically ill patients]

Bei der hämophagozytischen Lymphohistiozytose (HLH) handelt es sich um ein Hyperinflammationssyndrom bedingt durch aberrant aktivierte Makrophagen und T‑Zellen. Beim Erwachsenen ist in erster Linie die erworbene Form anzutreffen. Häufige Auslöser sind Infektionen, Malignome und Autoimmunerkrankungen. Zuletzt wurden zudem zunehmend Fälle berichtet, in denen das Auftreten im Zusammenhang mit stattgehabten Immuntherapien zu sehen war. Auf der Intensivstation ist die HLH aufgrund des ähnlichen klinischen Erscheinungsbilds oft schwer von der Sepsis abzugrenzen. Zum Teil liegen beide zeitgleich vor. Die frühzeitige Diagnosestellung und Einleitung einer adäquaten immunsuppressiven Therapie ist für den weiteren Verlauf und die Prognose der HLH essenziell. Deshalb muss bei kritisch kranken Patienten mit persistierendem Fieber und entsprechenden Symptomen (z. B. Splenomegalie, neurologische Auffälligkeiten) oder Laborveränderungen (z. B. erhöhter Ferritinwert, Zytopenie von 2 oder 3 Zellreihen, erhöhte Transaminasen) das Vorliegen einer HLH in Betracht gezogen werden. Die Diagnose wird mithilfe der HLH-2004-Kriterien gestellt. Mit dem HScore kann die Wahrscheinlichkeit des Vorliegens einer HLH berechnet werden. Hochdosierte Kortikosteroide stellen den Grundpfeiler der HLH-Therapie dar. Je nach Auslöser werden Etoposid, Immunglobuline, Anakinra oder weitere Medikamente ergänzt. Der Verlauf hängt neben einem frühzeitigen Behandlungsbeginn vom Auslöser sowie dem Ansprechen auf die Therapie ab. Insgesamt ist die Prognose der HLH trotz maximaler intensivmedizinischer Behandlung ungünstig und sie ist mit einer hohen Letalität assoziiert.

Can we truly diagnose adult secondary hemophagocytic lymphohistiocytosis (HLH)? A critical review of current paradigms

The HLH-2004 criteria were initially conceived as inclusion criteria for a clinical trial investigating therapy for (largely primary) pediatric hemophagocytic lymphohistiocytosis (HLH). These criteria have since been extrapolated to diagnose adult secondary HLH despite their questionable generalizability. It remains unclear whether these diagnostic criteria are truly applicable among adult secondary cases, and rigorous evidence for their use among such patients is lacking. This review critically examines the utility of the HLH-2004 criteria for the diagnosis of adult secondary HLH. It is framed as a reappraisal of each of the criteria's individual components, with an assessment of the relevance of, and/or evidence regarding, each. There are clear limitations to these criteria as they apply to adult secondary HLH, however they may help guide our understanding of the disease to some extent. Some new paradigms are emerging for the diagnosis of adult secondary HLH, however these too are limited by the difficulties inherent in formulating specific criteria for a very non-specific syndrome, which lacks any single gold-standard diagnostic test.

Hemophagocytic lymphohistiocytosis in critically ill patients: diagnostic reliability of HLH-2004 criteria and HScore

BACKGROUND

Hemophagocytic lymphohistiocytosis (HLH) is a rare though often fatal hyperinflammatory syndrome mimicking sepsis in the critically ill. Diagnosis relies on the HLH-2004 criteria and HScore, both of which have been developed in pediatric or adult non-critically ill patients, respectively. Therefore, we aimed to determine the sensitivity and specificity of HLH-2004 criteria and HScore in a cohort of adult critically ill patients.

METHODS

In this further analysis of a retrospective observational study, patients ≥ 18 years admitted to at least one adult ICU at Charité - Universitätsmedizin Berlin between January 2006 and August 2018 with hyperferritinemia of ≥ 500 μg/L were included. Patients' charts were reviewed for clinically diagnosed or suspected HLH. Receiver operating characteristics (ROC) analysis was performed to determine prediction accuracy.

RESULTS

In total, 2623 patients with hyperferritinemia were included, of whom 40 patients had HLH. We found the best prediction accuracy of HLH diagnosis for a cutoff of 4 fulfilled HLH-2004 criteria (95.0% sensitivity and 93.6% specificity) and HScore cutoff of 168 (100% sensitivity and 94.1% specificity). By adjusting HLH-2004 criteria cutoffs of both hyperferritinemia to 3000 μg/L and fever to 38.2 °C, sensitivity and specificity increased to 97.5% and 96.1%, respectively. Both a higher number of fulfilled HLH-2004 criteria [OR 1.513 (95% CI 1.372-1.667); p <  0.001] and a higher HScore [OR 1.011 (95% CI 1.009-1.013); p <  0.001] were significantly associated with in-hospital mortality.

CONCLUSIONS

An HScore cutoff of 168 revealed a sensitivity of 100% and a specificity of 94.1%, thereby providing slightly superior diagnostic accuracy compared to HLH-2004 criteria. Both HLH-2004 criteria and HScore proved to be of good diagnostic accuracy and consequently might be used for HLH diagnosis in critically ill patients.

CLINICAL TRIAL REGISTRATION

The study was registered with www.ClinicalTrials.gov (NCT02854943) on August 1, 2016.