Not all hemophagocytes are created equally: appreciating the heterogeneity of the hemophagocytic syndromes. Curr Opin Rheumatol. 2012;24:113-118. [PMID: 22089101 DOI: 10.1097/bor.0b013e32834dd37e]

Dynamic ferritin levels and survival outcomes in secondary hemophagocytic syndrome: a comprehensive analysis

Background

Hemophagocytic syndrome (HPS) is a life-threatening condition characterized by excessive immune activation and cytokine release. Reliable prognostic markers to guide clinical management and predict outcomes are lacking. This study aims to evaluate the prognostic ability of dynamic ferritin levels in patients with HPS and their potential role in guiding treatment modifications.

Materials and methods

We conducted a retrospective cohort study including 99 patients diagnosed with HPS between January 2013 and June 2022. Data on demographic characteristics, clinical presentations, treatment modalities, and laboratory values were collected, including ferritin levels at diagnosis and during treatment. Statistical analyses including Cox proportional hazards models were used to assess the risk factors of mortality, and a receiver operating curve analysis was conducted to assess the association between ferritin level changes and survival outcomes.

Results

Patients exhibiting a decrease in ferritin levels within the first week of treatment had significantly improved survival rates compared to those with increasing levels (p < 0.05). Multivariate analysis identified early ferritin level reduction as an independent predictor of better survival outcomes (HR 0.62, 95% CI: 0.41-0.93, p = 0.02). Notably, decreases below 7.54% in ferritin levels from day 0 to day 3 were associated with 85.19% sensitivity and 57.14% specificity for survival prediction (AUC = 0.684), while increases >36.67% from day 0 to day 5 showed 50.0% sensitivity and 85.0% specificity for mortality prediction (AUC = 0.697). Additionally, the liver injury group demonstrated significantly higher ferritin levels and D-dimer values, with lower fibrinogen and albumin levels compared to the non-liver injury group.

Conclusion

The improved survival associated with early decreases in ferritin levels highlights the potential of ferritin monitoring to guide clinical decision-making and treatment adjustments. Based on the results, the integration of ferritin level dynamics into HPS management protocols could improve patient outcomes.

Infection-associated hemophagocytic lymphohistiocytosis: a case report

Introduction

Hemophagocytic lymphohistiocytosis (HLH) is a rare hyperinflammatory disorder characterized by fever, cytopenia, splenomegaly, and hemophagocytosis. Without prompt treatment, HLH can rapidly progress to life-threatening multiorgan failure. The authors present a case of occult HLH with severe bicytopenia and organ dysfunction requiring intensive care.

Case presentation

A 20-year-old male presented with fever, cough, and constitutional symptoms. He developed hypoxia, elevated transaminases, and bicytopenia. Despite transfusions, platelet counts remained critically low. With high suspicion for HLH, head computed tomography and bone marrow biopsy was although panned but couldn't be performed due to resource less settings. And with suspicion for HLH treatment with high-dose dexamethasone was initiated as counts improved.

Clinical course

The patient required mechanical ventilation for pulmonary infiltrates. He exhibited seizure activity and epistaxis related to coagulopathy. On hospital day 9, he was successfully extubated as counts normalized. He was discharged from the intensive care unit once stable.

Conclusion

This case illustrates a delayed diagnosis of HLH masquerading as a fever of unknown origin. HLH should be urgently considered in patients with unexplained cytopenia, organ dysfunction, and systemic inflammation. Early treatment with immunotherapy can be lifesaving, whereas delays may precipitate irreversible end-organ damage.

Infection-associated hemophagocytic lymphohistiocytosis: a case report

Introduction:

Hemophagocytic lymphohistiocytosis (HLH) is a rare hyperinflammatory disorder characterized by fever, cytopenia, splenomegaly, and hemophagocytosis. Without prompt treatment, HLH can rapidly progress to life-threatening multiorgan failure. The authors present a case of occult HLH with severe bicytopenia and organ dysfunction requiring intensive care.

Case presentation:

A 20-year-old male presented with fever, cough, and constitutional symptoms. He developed hypoxia, elevated transaminases, and bicytopenia. Despite transfusions, platelet counts remained critically low. With high suspicion for HLH, head computed tomography and bone marrow biopsy was although panned but couldn’t be performed due to resource less settings. And with suspicion for HLH treatment with high-dose dexamethasone was initiated as counts improved.

Clinical course:

The patient required mechanical ventilation for pulmonary infiltrates. He exhibited seizure activity and epistaxis related to coagulopathy. On hospital day 9, he was successfully extubated as counts normalized. He was discharged from the intensive care unit once stable.

Conclusion:

This case illustrates a delayed diagnosis of HLH masquerading as a fever of unknown origin. HLH should be urgently considered in patients with unexplained cytopenia, organ dysfunction, and systemic inflammation. Early treatment with immunotherapy can be lifesaving, whereas delays may precipitate irreversible end-organ damage.

Management of Adverse Reactions for BCMA-Directed Therapy in Relapsed Multiple Myeloma: A Focused Review

Anti-B-cell maturation antigen therapies consisting of bispecific antibodies, antibody-drug conjugates, and chimeric antigen receptor T cells have shown promising results in relapsed refractory multiple myeloma (RRMM). However, the severe side effects include cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome, cytopenia(s), infections, hemophagocytic lymphohistiocytosis, and organ toxicity, which could sometimes be life-threatening. This review focuses on these most common complications post-BCMA therapy. We discussed the risk factors, pathogenesis, clinical features associated with these complications, and how to prevent and treat them. We included four original studies for this focused review. All four agents (idecabtagene vicleucel, ciltacabtagene autoleucel, teclistamab, belantamab mafodotin) have received FDA approval for adult RRMM patients. We went through the FDA access data packages of the approved agents to outline stepwise management of the complications for better patient outcomes.

Immune Effector Cell-Associated Hemophagocytic Lymphohistiocytosis-Like Syndrome

T cell-mediated hyperinflammatory responses, such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), are now well-established toxicities of chimeric antigen receptor (CAR) T cell therapy. As the field of CAR T cells advances, however, there is increasing recognition that hemophagocytic lymphohistiocytosis (HLH)-like toxicities following CAR T cell infusion are occurring broadly across patient populations and CAR T cell constructs. Importantly, these HLH-like toxicities are often not as directly associated with CRS and/or its severity as initially described. This emergent toxicity, however ill-defined, is associated with life-threatening complications, creating an urgent need for improved identification and optimal management. With the goal of improving patient outcomes and formulating a framework to characterize and study this HLH-like syndrome, we established an American Society for Transplantation and Cellular Therapy panel composed of experts in primary and secondary HLH, pediatric and adult HLH, infectious disease, rheumatology and hematology, oncology, and cellular therapy. Through this effort, we provide an overview of the underlying biology of classical primary and secondary HLH, explore its relationship with similar manifestations following CAR T cell infusions, and propose the term "immune effector cell-associated HLH-like syndrome (IEC-HS)" to describe this emergent toxicity. We also delineate a framework for identifying IEC-HS and put forward a grading schema that can be used to assess severity and facilitate cross-trial comparisons. Additionally, given the critical need to optimize outcomes for patients experiencing IEC-HS, we provide insight into potential treatment approaches and strategies to optimize supportive care and delineate alternate etiologies that should be considered in a patient presenting with IEC-HS. By collectively defining IEC-HS as a hyperinflammatory toxicity, we can now embark on further study of the pathophysiology underlying this toxicity profile and make strides toward a more comprehensive assessment and treatment approach.

Cutaneous granuloma annulare in an adult patient with macrophage activation syndrome

Macrophage activation syndrome (MAS) is a rare but life-threatening disorder that is associated with multiple organ involvement. Here, we described cutaneous granuloma annulare in MAS. This novel histological finding is a reminder to explore the underlying mechanisms of skin involvement in MAS, which may reveal its pathogenesis.

Secondary haemophagocytic lymphohistiocytosis in COVID-19: correlation of the autopsy findings of bone marrow haemophagocytosis with HScore

BACKGROUND

Secondary haemophagocytic lymphohistiocytosis (sHLH) is characterised by a hyper activation of immune system that leads to multiorgan failure. It is suggested that excessive immune response in patients with COVID-19 could mimic this syndrome. Some COVID-19 autopsy studies have revealed the presence of haemophagocytosis images in bone marrow, raising the possibility, along with HScore parameters, of sHLH.

AIM

Our objective is to ascertain the existence of sHLH in some patients with severe COVID-19.

METHODS

We report the autopsy histological findings of 16 patients with COVID-19, focusing on the presence of haemophagocytosis in bone marrow, obtained from rib squeeze and integrating these findings with HScore parameters. CD68 immunohistochemical stains were used to highlight histiocytes and haemophagocytic cells. Clinical evolution and laboratory parameters of patients were collected from electronic clinical records.

RESULTS

Eleven patients (68.7%) displayed moderate histiocytic hyperplasia with haemophagocytosis (HHH) in bone marrow, three patients (18.7%) displayed severe HHH and the remainder were mild. All HScore parameters were collected in 10 patients (62.5%). Among the patients in which all parameters were evaluable, eight patients (80%) had an HScore >169. sHLH was not clinically suspected in any case.

CONCLUSIONS

Our results support the recommendation of some authors to use the HScore in patients with severe COVID-19 in order to identify those who could benefit from immunosuppressive therapies. The presence of haemophagocytosis in bone marrow tissue, despite not being a specific finding, has proved to be a very useful tool in our study to identify these patients.

Macrophage activation syndrome: A diagnostic challenge (Review)

Macrophage activation syndrome (MAS) represents an acute and severe inflammatory syndrome, idiopathic (primary) or secondary to infections, rheumatic diseases, malignancies, or drugs. MAS is underdiagnosed, being confused with sepsis, adverse effects of anti-arthritic drugs or exacerbated symptoms of evolving rheumatologic or infectious diseases. Because of the late diagnosis, most patients do not benefit from effective therapy, leading to death. Elucidation of valid early diagnostic criteria of MAS would be a particularly important step in reducing the mortality due to this pathology. Thus, the purpose of this review based on 40 studies centered on the diagnostic criteria of MAS. We detailed the main diagnostic criteria and the few diagnostic scores or sets of criteria that have been recently published. The criteria most frequently encountered in the literature include: Fever, hepatosplenomegaly, hyperferritinemia, hepatopathy, coagulopathy, thrombocytopenia, hypertriglyceridemia, decrease in erythrocyte sedimentation rate and bone marrow hemophagocytosis. The most elaborate diagnostic score will result following an ongoing international project and consensus, the Delphi International Survey.

Early Detection and Rescue of an Unusual Case of Pediatric Acute Liver Failure Associated with Secondary Hemophagocytic Lymphophagocytosis: Case Report from a Liver Transplant Center in India

Hemophagocytic lymphohistiocytosis (HLH) is a rare, multisystem, potentially fatal clinicopathologic syndrome. HLH presenting predominantly as pediatric acute liver failure (PALF) has been rarely reported. Early recognition is imperative to initiate life-saving treatment but is often hampered due to the rarity of this syndrome, variable clinical presentations, and nonspecific clinical and laboratory findings. In this article, we reported a case of secondary HLH (H1N1 and RSV positive) presenting as PALF from India. A previously healthy 22-month-old boy presented with fever, vomiting, and altered sensorium for 10 days. He had coagulopathy and deranged liver functions. He was evaluated for underlying etiology and managed on lines of PALF. Due to persistent bicytopenia and excessively high ferritin levels, HLH was strongly suspected though he did not fulfill all clinical criteria for the diagnosis of HLH. Presence of seizures and cerebrospinal fluid analysis was suggestive of central nervous system involvement. There was no evidence of primary HLH on genetic evaluation. Real-time polymerase chain reaction amplifications were positive for RSV and influenza A H1N1, confirming the causative triggers. After the administration of immunosuppressants and oseltamivir, the patient's symptoms improved dramatically and he recovered completely. To the best of our knowledge, this is the fourth case reported worldwide till date of successful rescue of ALF in a child associated with HLH completely without resorting to liver transplantation. Clinical vigilance is crucial for possible presence of HLH with varied initial presentations in PALF despite incomplete diagnostic criteria, with detailed etiological workup for commencing life-saving therapy in time.

Protocol Failure Detection: The Conflation of Acute Respiratory Distress Syndrome, SARS-CoV-2 Pneumonia and Respiratory Dysfunction

In medicine, protocols are applied to assure the provision of the treatment with the greatest probability of success. However, the development of protocols is based on the determination of the best intervention for the group. If the group is heterogeneous, there will always be a subset of patients for which the protocol will fail. Furthermore, over time, heterogeneity of the group may not be stable, so the percentage of patients for which a given protocol may fail may change depending on the dynamic patient mix in the group. This was thrown into stark focus during the severe acute respiratory syndrome-2 coronavirus (SARS-CoV-2) pandemic. When a COVID-19 patient presented meeting SIRS or the Berlin Criteria, these patients met the criteria for entry into the sepsis protocol and/or acute respiratory distress syndrome (ARDS) protocol, respectively and were treated accordingly. This was perceived to be the correct response because these patients met the criteria for the "group" definitions of sepsis and/or ARDS. However, the application of these protocols to patients with SARS-CoV-2 infection had never been studied. Initially, poor outcomes were blamed on protocol noncompliance or some unknown patient factor. This initial perception is not surprising as these protocols are standards and were perceived as comprising the best possible evidence-based care. While the academic response to the pandemic was robust, recognition that existing protocols were failing might have been detected sooner if protocol failure detection had been integrated with the protocols themselves. In this review, we propose that, while protocols are necessary to ensure that minimum standards of care are met, protocols need an additional feature, integrated protocol failure detection, which provides an output responsive to protocol failure in real time so other treatment options can be considered and research efforts rapidly focused.

Pathology of macrophage activation syndrome in humanized NSGS mice

"Humanized" immunodeficient mice generated via the transplantation of CD34+ human hematopoietic stem cells (hHSC) are an important preclinical model system. The triple transgenic NOD.Cg-Prkdc^scidIl2rg^tm1Wjl Tg(CMV-IL3,CSF2,KITLG)1Eav/MloySzJ (NSGS) mouse line is increasingly used as recipient for CD34+ hHSC engraftment. NSGS mice combine the features of the highly immunodeficient NSG mice with transgenic expression of the human myeloid stimulatory cytokines GM-CSF, IL-3, and Kit ligand. While generating humanized NSGS (huNSGS) mice from two independent cohorts, we encountered a fatal macrophage activation syndrome (MAS)-like phenotype resulting from the transplantation of CD34+ hHSC. huNSGS mice exhibiting this phenotype declined clinically starting at approximately 10 weeks following CD34+ hHSC engraftment, with all mice requiring euthanasia by 16 weeks. Gross changes comprised small, irregular liver, splenomegaly, cardiomegaly, and generalized pallor. Hematological abnormalities included severe thrombocytopenia and anemia. Pathologically, huNSGS spontaneously developed a disseminated histiocytosis with infiltrates of activated macrophages and hemophagocytosis predominantly affecting the liver, spleen, bone marrow, and pancreas. The infiltrates were chimeric with a mixture of human and mouse macrophages. Immunohistochemistry suggested activation of the inflammasome in both human and murine macrophages. Active Epstein-Barr virus infection was not a feature. Although the affected mice exhibited robust chimerism of the spleen and bone marrow, the phenotype often developed in the face of low chimerism of the peripheral blood. Given the high penetrance and early lethality associated with the MAS-like phenotype here described, we urge caution when considering the use of huNSGS mice for the development of long-term studies.

Macrophage Activation Syndrome and Secondary Hemophagocytic Lymphohistiocytosis in Childhood Inflammatory Disorders: Diagnosis and Management

Macrophage activation syndrome (MAS), a form of secondary hemophagocytic lymphohistiocytosis, is a frequently fatal complication of a variety of pediatric inflammatory disorders. MAS has been most commonly associated with systemic juvenile idiopathic arthritis (sJIA), as approximately 10% of children with sJIA develop fulminant MAS, with another 30-40% exhibiting a more subclinical form of the disease. Children with other rheumatologic conditions such as systemic lupus erythematosus and Kawasaki disease are also at risk for MAS. Moreover, MAS also complicates various genetic autoinflammatory disorders such as gain of function mutations in the cytosolic inflammasome NLRC4, pediatric hematologic malignancies (e.g., T-cell lymphoma), and primary immunodeficiencies characterized by immune dysregulation. Disease-specific and broadly inclusive diagnostic criteria have been developed to facilitate the diagnosis of MAS. Recently, simple screening tools such as the serum ferritin to erythrocyte sedimentation rate ratio have been proposed. Early diagnosis and rapid initiation of immunosuppression are essential for the effective management of MAS. With a better understanding of the pathophysiology of MAS and the advent of novel therapeutics, a broad immunosuppressive approach to treatment is giving way to targeted anti-cytokine therapies. These treatments include agents that block interleukin-1 (IL-1), IL-6, IL-18, interferon-γ, as well as inhibitors of downstream targets of cytokine signaling (e.g., Janus kinases). Increased early recognition of MAS among pediatric inflammatory disorders combined with the use of effective and less toxic cytokine-targeted therapies should lower the mortality of this frequently fatal disorder.

Fulminant and rapidly fatal hemophagocytic lymphohistiocytosis in patients with HIV infection: A report of five cases and a review

Hemophagocytic lymphohistiocytosis is a rare entity and diagnosis can be elusive. Commonly recognized inciting causes include autoimmune disorders, malignancies, and a wide variety of infections. With prompt recognition and treatment, survival rates approach 50%. Five cases of reactive hemophagocytic syndrome in patients with underlying HIV infection are reported. All of the patients had CD3/CD4 cell counts of <200 cells/µL. All cases presented with fever and all had marked cytopenias, with platelet counts falling to 10–15,000/µL. Ferritin levels were >5000 ng/mL in all cases. Concomitant inciting conditions included Epstein–Barr virus infection, Pneumocystis jiroveci, multiple myeloma, and Hodgkin’s lymphoma; in one case, no inciting condition was identified. Despite broad-spectrum antimicrobial and immunosuppressive therapy, all five patients died within one month of presentation. The finding of fever and cytopenia in a patient with underlying HIV infection should prompt the clinician to determine a ferritin level. If markedly elevated, an aggressive work-up for hemophagocytic syndrome should be conducted. However, even with prompt recognition, mortality rates may be high in patients with underlying HIV infection.

Evaluation of lymphocyte function by IFN-γ secretion capability assay in the diagnosis of lymphoma-associated hemophagocytic syndrome

Lymphoma-associated hemophagocytic syndrome (LAHS) is a highly life-threatening disease characterized by an uncontrolled immune disorder. Both under-recognition and delayed diagnosis may contribute to aggressive diseases, and a poorer prognosis. Identification of laboratory features specific for LAHS patients may allow for early detection and intervention with improved outcomes. In the present study, 120 lymphoma patients at first diagnosis were recruited and the function of lymphocytes was evaluated by IFN-γ secretion assay at first diagnosis and follow up. During the surveillance period, 20 patients who complicated with hemophagocytic lymphohistiocytosis (HLH) were classified as LAHS group, and 30 patients without infectious diseases during the course of treatment were classified as lymphoma control group. In addition, 20 non-malignant associated HLH patients recruited as HLH control group and 50 healthy control (HC) subjects were also included. The IFN-γ secretion capability of lymphocytes was compared between first diagnosis of lymphoma patients who was complicate with HLH or not in the disease progression. Our results showed that only NK cell activity was decreased in lymphoma control group, but the activities of NK, CD4+ and CD8+ T cells were all significantly decreased at the time of lymphoma diagnosis in those who would progress with HLH. During the course of treatment, lymphocyte function was relatively stable in lymphoma patients but became further decreased when suffering from complication of LAHS. The IFN-γ secretion capability of lymphocytes in LAHS and non-malignant associated HLH patients were all significantly decreased compared with HCs. So the occurrence of HLH was the key factor leading to the impaired activity of lymphocytes. These data suggest that decreased lymphocyte function might be used as a predictor of LAHS, which has critical clinical significance in diagnosis and further understanding the pathogenesis of the disease.

Chronic TLR7 and TLR9 signaling drives anemia via differentiation of specialized hemophagocytes

Cytopenias are an important clinical problem associated with inflammatory disease and infection. We show that specialized phagocytes that internalize red blood cells develop in Toll-like receptor 7 (TLR7)-driven inflammation. TLR7 signaling caused the development of inflammatory hemophagocytes (iHPCs), which resemble splenic red pulp macrophages but are a distinct population derived from Ly6C^hi monocytes. iHPCs were responsible for anemia and thrombocytopenia in TLR7-overexpressing mice, which have a macrophage activation syndrome (MAS)-like disease. Interferon regulatory factor 5 (IRF5), associated with MAS, participated in TLR7-driven iHPC differentiation. We also found iHPCs during experimental malarial anemia, in which they required endosomal TLR and MyD88 signaling for differentiation. Our findings uncover a mechanism by which TLR7 and TLR9 specify monocyte fate and identify a specialized population of phagocytes responsible for anemia and thrombocytopenia associated with inflammation and infection.

Prevalence and Outcome of Secondary Hemophagocytic Lymphohistiocytosis Among SIRS Patients: Results from a Prospective Cohort Study

Secondary hemophagocytic lymphohistiocytosis (sHLH) is a life-threatening condition clinically presenting as SIRS (Systemic Inflammatory Response Syndrome). However, there is no comprehensive data concerning diagnostic algorithms, prevalence, outcome and biomarker performance in SIRS patients. We conducted a prospective observational cohort study on 451 consecutive patients fulfilling ≥2 SIRS criteria. The Hscore and the HLH-2004 criteria were used to determine the presence of sHLH, and the correlation of the screening-biomarkers ferritin, sCD25, and sCD163 with both scores was assessed. Out of 451 standard-care SIRS patients, five patients had high Hscores (≥169), suggesting incipient or HLH-like disease, and these patients were in urgent need for intensified therapy. However, none of these patients fulfilled five HLH-2004 criteria required for formal diagnosis. From the studied biomarkers, ferritin correlated strongest to both the HLH-2004 criteria and the Hscore (rs = 0.72, 0.41, respectively), and was the best predictor of 30-day survival (HR:1.012 per 100 μg/L, 95% CI: 1.004-1.021), when adjusted for patient's age, sex, bacteremia and malignant underlying-disease. Also, the HLH-2004 (HR per point increase: 1.435, 95% CI: 1.1012-2.086) and the Hscore (HR per point increase:1.011, 95% CI: 1.002-1.020) were independent predictors of 30-day-survival. The Hscore detected patients in hyperinflammatory states requiring urgent therapy escalation. Degrees of hyperinflammation, as assessed by ferritin and both HLH scores, are associated with worse outcomes.

Low dose ruxolitinib plus HLH-94 protocol: A potential choice for secondary HLH

Hemophagocytic lymphohistiocytosis (HLH) is an immune-mediated syndrome resulting in cytokine storm. The uncontrolled cytokine storm leads to significant tissue damage and potentially life-threatening multiorgan failure. Conventional first-line treatment for HLH included HLH-94 protocol or HLH-2004 protocol. However, up to 30% of patients do not respond to first-line therapy. We reported 3 cases of secondary HLH/macrophage activation syndrome which were caused by lymphoma (2 cases) and adult-onset still's disease. They received low dose ruxolitinib plus HLH-94 protocol, and had rapid response to treatment without obvious adverse effects. Following the treatment, there was improvement seen in several disease markers, including fever, fibrinogen, serum ferritin, and liver function tests. Our report indicated that treatment with low dose ruxolitinib plus HLH-94 protocol might be a potential choice for secondary HLH, and clinical trials warrants to be further investigated in this treatment regimen.

Successful rescue of acute liver failure and hemophagocytic lymphohistiocytosis following varicella infection: A case report and review of literature

Herein we report a case of acute liver failure (ALF) and hemophagocytic lymphohistiocytosis (HLH) induced by varicella infection, successfully rescued by a combination therapy of acyclovir, supportive care, and immunosuppression with dexamethasone and etoposide. A previously healthy 16-year-old boy presented with generalized rash, fever, severe abdominal pain, and abnormal liver function within 4 d. Chickenpox was suspected, and acyclovir and intravenous immunoglobulin were started on admission. However, the patient’s condition deteriorated overnight with soaring transaminases, severe coagulopathy and encephalopathy. On the fourth day of admission, pancytopenia emerged, accompanied by hypofibrinogenemia and hyperferritinemia. The patient was diagnosed with ALF. He also met the diagnostic criteria of HLH according to the HLH-2004 guideline. Polymerase chain reaction (PCR) amplifications of varicella-zoster virus (VZV) were positive, confirming that VZV was a causative trigger for ALF and HLH. In view of the devastating immune activation in HLH, immunosuppression therapy with dexamethasone and etoposide was administered, in addition to high dose acyclovir. The patient’s symptoms improved dramatically and he finally made a full recovery. To our knowledge, this is only the second report of a successful rescue of ALF associated with HLH, without resorting to liver transplantation. The first case was reported in a neonate infected by herpes simplex virus-1. However, survival data in older children and adults are lacking, most of whom died or underwent liver transplantation. Our report emphasizes the clinical vigilance for the possible presence of HLH, and the necessity of extensive investigation for underlying etiologies in patients presenting with indeterminate ALF. Early initiation of specific therapy targeting the underlying etiology, and watchful immunosuppression such as dexamethasone and etoposide, together with supportive therapy, are of crucial importance in this life-threatening disorder.

PLD3 and PLD4 are single-stranded acid exonucleases that regulate endosomal nucleic-acid sensing

The sensing of microbial genetic material by leukocytes often elicits beneficial pro-inflammatory cytokines, but dysregulated responses can cause severe pathogenesis. Genome-wide association studies have linked the gene encoding phospholipase D3 (PLD3) to Alzheimer's disease and have linked PLD4 to rheumatoid arthritis and systemic sclerosis. PLD3 and PLD4 are endolysosomal proteins whose functions are obscure. Here, PLD4-deficient mice were found to have an inflammatory disease, marked by elevated levels of interferon-γ (IFN-γ) and splenomegaly. These phenotypes were traced to altered responsiveness of PLD4-deficient dendritic cells to ligands of the single-stranded DNA sensor TLR9. Macrophages from PLD3-deficient mice also had exaggerated TLR9 responses. Although PLD4 and PLD3 were presumed to be phospholipases, we found that they are 5' exonucleases, probably identical to spleen phosphodiesterase, that break down TLR9 ligands. Mice deficient in both PLD3 and PLD4 developed lethal liver inflammation in early life, which indicates that both enzymes are needed to regulate inflammatory cytokine responses via the degradation of nucleic acids.

A successful treatment of severe systemic lupus erythematosus caused by occult pulmonary infection-associated with hemophagocytic syndrome: A case report

RATIONALE

A 27-year-old woman with a history of systemic lupus erythaematosus (SLE) developed hemophagocytic syndrome (HPS) secondary due to an unrecognized infection that led to severe SLE with a prolonged recovery.

PATIENT CONCERNS

The patient showed a high spiking fever and myalgia. Laboratory data revealed pancytopenia and immunological abnormalities. Pulse methylprednisone plus intravenous immunoglobulin (IVIG) failed to improve the clinical symptoms and laboratory data.

DIAGNOSES

As activated macrophages with hemophagocytosis were confirmed in bone marrow histology, the patient was diagnosed as having reactive HPS.

INTERVENTIONS AND OUTCOMES

Her reactive HPS was successfully treated with intravenous antibiotics and was followed by oral prednisolone and hydroxychloroquine maintenance therapy.

LESSONS

In severe SLE, patients with persistent high fever, cytopenia, and elevated levels of serum ferritin and liver enzymes should be strongly suspected of reactive HPS, and aggressive examination, such as bone marrow biopsy, needs to be considered for early diagnosis and proper treatment.

Lymphocyte-independent pathways underlie the pathogenesis of murine cytomegalovirus-associated secondary haemophagocytic lymphohistiocytosis

Haemophagocytic lymphohistiocytosis (HLH) constitutes a spectrum of immunological disorders characterized by uncontrolled immune activation and key symptoms such as fever, splenomegaly, pancytopenia, haemophagocytosis, hyperferritinaemia and hepatitis. In genetic or primary HLH, hyperactivated CD8+ T cells are the main drivers of pathology. However, in acquired secondary HLH, the role of lymphocytes remains vague. In the present study the involvement of lymphocytes in the pathogenesis of a cytomegalovirus-induced model of secondary HLH was explored. We have previously reported CD8+ T cells to be redundant in this model, and therefore focused on CD4+ helper and regulatory T cells. CD4+ T cells were activated markedly and skewed towards a proinflammatory T helper type 1 transcription profile in mice displaying a severe and complete HLH phenotype. Counter to expectations, regulatory T cells were not reduced in numbers and were, in fact, more activated. Therapeutic strategies targeting CD25high hyperactivated T cells were ineffective to alleviate disease, indicating that T cell hyperactivation is not a pathogenic factor in cytomegalovirus-induced murine HLH. Moreover, even though T cells were essential in controlling viral proliferation, CD4+ T cells, in addition to CD8+ T cells, were dispensable in the development of the HLH-like syndrome. In fact, no T or B cells were required for induction and propagation of HLH disease, as evidenced by the occurrence of cytomegalovirus-associated HLH in severe combined immunodeficient (SCID) mice. These data suggest that lymphocyte-independent mechanisms can underlie virus-associated secondary HLH, accentuating a clear distinction with primary HLH.

The influence of various therapeutic regimens on early clinical and laboratory response and outcome of children with secondary hemophagocytic lymphohistiocytosis

INTRODUCTION

Secondary hemophagocytic lymphohistiocytosis (sHLH) is a life-threatening syndrome of severe hyperinflammation which is often triggered by infection or autoimmune disease (macrophage activation syndrome - MAS). The aim of our study was to assess the frequency of sHLH/MAS in children treated in our institution and to compare the effectiveness of various therapeutic interventions.

MATERIAL AND METHODS

Between 2005 and 2013, 24 children (age: 1-17 years) were consecutively treated for sHLH/MAS. Therapy was based on glucocorticoids (GCs) in high or standard doses (hd-GCs or sd-GCs), intravenous immunoglobulin (IVIG), and cyclosporin A (CyA). A comparison of selected laboratory and clinical parameters during the first 72 h of treatment and after a week from the last intervention applied in the first 72 h after diagnosis was performed retrospectively.

RESULTS

The majority of patients (14/24, 58%) suffered from sHLH/MAS in the course of an autoimmune disease (12 patients diagnosed with a systemic form of juvenile idiopathic arthritis). We found with a confidence level of 95% that the application of hd-GCs in the first 24 h caused rapid alleviation of fever, reduction of hepatosplenomegaly, and an increase in thrombocytes and s-fibrinogen concentrations. The use of combination therapy with hd-GCs, IVIG, and CyA in the first 72 h caused a faster increase in s-fibrinogen. All patients survived and were alive at the follow-up of 1-8 years.

CONCLUSIONS

The results indicate that treatment of sHLH/MAS based on hd-GCs, CyA and IVIG is an effective therapy in children.

[Hemophagocytic lymphohistiocytosis : A diagnostic challenge on the ICU]

BACKGROUND

Hemophagocytic lymphohistiocytosis (HLH) has well been studied as a genetic disorder in children (primary HLH). Mutations in the regulatory complex of the cellular immune synapse lead to a loss of function of cytotoxic T‑cells and natural killer cells with excessive inflammation based on a cytokine storm. During the last decade, an increasing number of adult HLH patients without a family history of HLH (secondary or acquired HLH) have been reported. Various triggers - infections, malignancies or autoimmune diseases - result in an acquired loss of function of these cells and a sepsis-like disease. Missed or late diagnosis is believed to be a major cause of the high mortality.

OBJECTIVES

To describe the current knowledge on HLH and to raise awareness.

MATERIALS AND METHODS

Analysis of case reports, current studies, and expert recommendations.

RESULTS

Increased vigilance in identifying the adult form of HLH resulted in an increasing number of case reports over the past few years. HLH patients typically present with a clinical phenotype resembling severe sepsis or septic shock with fever, cytopenia, and organomegaly, which do not or insufficiently respond to anti-infective treatment. Early recognition of HLH distinction from sepsis, and prompt initiation of treatment - which is fundamentally different from sepsis - are crucial for improved outcome. A promising diagnostic parameter is ferritin, which has gained sufficient specificity, but only in the context of the triad of fever, cytopenia, and organomegaly. Treatment of adult HLH patients requires immunosuppression, with strict therapeutic guidance derived from the triggering disease.

CONCLUSIONS

Because of the similar clinical presentation to that of sepsis, HLH is often not recognized, resulting in a fatal outcome. In "sepsis" patients on the ICU with deterioration despite a standard of care, HLH needs to be considered by testing for ferritin when considering differential diagnoses. The complexity of the illness requires interdisciplinary patient care with specific integration of the hematologist in the diagnostic workup and therapeutic management, because of the frequent use of chemotherapy-based immunosuppression.

Impairment of Immune Function in Children with Familial Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a severe systemic syndrome associated with hyperactivation of macrophages and impaired regulation of the immune system. Two forms of HLH are currently recognized: genetically determined or familial (FHLH), and secondarily developed in the course of primary diseases, like autoimmune disorders, rheumatoid disorders, cancers, or infections. In the Polish population, FHLH is rather rare. The aim of the present study was to assess the immune function in a group of children with clinical symptoms suggesting FHLH. Forty five children with suspected HLH of the median age of 4 years and 15 healthy children, taken as a control group, were enrolled into the study. All presented results were obtained with the use of flow cytometry. In the HLH group, there were only three cases identified with the UNC13D gene mutation responsible for the FHLH3 phenotype. Another four children, without known mutation, were classified as FHLH because of frequent recurrence of the disease. In all cases of FHLH, cell cytotoxicity was impaired compared with healthy children (p = 0.003). Perforin expression in FHLH was normal or higher than that observed in controls (p = 0.09). In case of patients with mutation in the Munc13 protein, degranulation was lower than that in healthy children (<5 %). The findings of this study demonstrate that children with known mutations responsible for the FHLH development are immunocompromised. However, it requires further elucidation whether the presence of currently unknown mutations could lead to a similar phenotype.

A xenograft model of macrophage activation syndrome amenable to anti-CD33 and anti-IL-6R treatment

Transgenic expression of key myelosupportive human cytokines in immune-deficient mice corrects for the lack of cross-species activities of stem cell factor (SCF), IL-3, and GM-CSF. When engrafted with human umbilical cord blood (UCB), these triple-transgenic mice produce BM and spleen grafts with much higher myeloid composition, relative to nontransgenic controls. Shortly after engraftment with UCB, these mice develop a severe, fatal macrophage activation syndrome (MAS) characterized by a progressive drop in rbc numbers, increased reticulocyte counts, decreased rbc half-life, progressive cytopenias, and evidence of chronic inflammation, including elevated human IL-6. The BM becomes strikingly hypocellular, and spleens are significantly enlarged with evidence of extramedullary hematopoiesis and activated macrophages engaged in hemophagocytosis. This manifestation of MAS does not respond to lymphocyte-suppressive therapies such as steroids, i.v. immunoglobulin, or antibody-mediated ablation of human B and T cells, demonstrating a lymphocyte-independent mechanism of action. In contrast, elimination of human myeloid cells using gemtuzumab ozogamicin (anti-CD33) completely reversed the disease. Additionally, the IL-6R antibody tocilizumab delayed progression and prolonged lifespan. This new model of MAS provides an opportunity for investigation of the mechanisms driving this disease and for the testing of directed therapies in a humanized mouse.

Prognostic factors of macrophage activation syndrome, at the time of diagnosis, in adult patients affected by autoimmune disease: Analysis of 41 cases collected in 2 rheumatologic centers

Macrophage activation syndrome (MAS) is a rare, life-threatening disease in which early diagnosis and aggressive therapeutic strategy may improve the outcome. Due to its rarity, epidemiologic data are still lacking. Hyperferritinemia is frequently associated with MAS and might modulate the cytokine storm, which is involved in the development of multiple organ failure. In this paper, we investigated clinical data, treatments, and outcome of a homogeneous cohort of 41 adult MAS patients, complicating autoimmune rheumatic diseases. MAS-related death occurred in 17 patients (42.5%) during the follow-up, and older age and increased serum ferritin levels, at the time of diagnosis, were significantly associated with mortality. In conclusion, adult MAS is associated with high mortality rate. Some clinical features at diagnosis may be predictive of MAS-associated death.

Intravascular large B-cell lymphoma associated with silicone breast implant, HLA-DRB1*11:01, and HLA-DQB1*03:01 manifesting as macrophage activation syndrome and with severe neurological symptoms: a case report

BACKGROUND

Silicone implants have been successfully used for breast augmentation and reconstruction in millions of women worldwide. The reaction to the silicone implant is highly variable; it can lead to local inflammatory symptoms, and sometimes to systemic symptoms and disease. Over 80 cases of anaplastic lymphoma kinase-negative anaplastic large cell lymphoma have been reported in patients with silicone breast implants and have been accepted as a new clinical entity. To the best of our knowledge, an intravascular large B-cell lymphoma associated with a silicone breast implant has not been reported previously.

CASE PRESENTATION

A 48-year-old Caucasian woman who presented with high fever was found to have splenomegaly on physical examination. A laboratory diagnosis revealed pancytopenia, hypertriglyceridemia, and hyperferritinemia. She developed signs of altered sensorium, hemiparesis, aphasia, and cauda equina syndrome. On further evaluation, she fulfilled the necessary five out of eight criteria for diagnosis of macrophage activation syndrome/hemophagocytic lymphohistiocytosis. Dexamethasone administration was followed by prompt improvement; however, 3 days later she again manifested high fever, which persisted despite administration of immunoglobulin and cyclosporine A. Her silicone breast implant was considered a possible contributor to her macrophage activation syndrome and was therefore removed. A histological examination of the capsule tissue showed an extensive lymphohistiocytic/giant cell foreign body reaction suggestive of autoimmune/inflammatory syndrome induced by adjuvants. However, the histological examination unexpectedly also revealed an intravascular large B-cell lymphoma.

CONCLUSIONS

The genetic background of our patient with silicone breast implants might have predisposed her to three rare and difficult to diagnose syndromes/diseases: macrophage activation syndrome/hemophagocytic lymphohistiocytosis, autoimmune/inflammatory syndrome induced by adjuvants, and intravascular large B-cell lymphoma. The simultaneous manifestation of all three syndromes suggests causal interrelationships. Human leukocyte antigen testing in all women who undergo silicon breast implantation could in the future enable us to better evaluate the risk of potential side effects.

Understanding the spectrum of haemophagocytic lymphohistiocytosis: update on diagnostic challenges and therapeutic options

The cytokine storm syndrome 'haemophagocytic lymphohistiocytosis' (HLH) is an under-recognized hyperinflammatory disorder, causing high morbidity and mortality risk in children and adults. It can be subdivided into a primary, genetic form and a secondary, acquired form that complicates diverse infections, malignancies and autoimmune or autoinflammatory disorders. Both subtypes present with the same spectrum of non-specific symptoms, making accurate diagnosis and rapid treatment initiation challenging. In the last decade, increased awareness and international collaborative efforts fuelled a marked progress in diagnostic protocols and novel treatment strategies for HLH and new diagnostic guidelines are being tailored to specific secondary HLH subtypes. Therapy is gradually shifting its focus from overall immunosuppression towards targeting specific cytokines, cell types or signalling pathways underlying pathophysiology. Nevertheless, continued research efforts remain indispensable to customize therapy to individual patient needs.

Mouse Cytomegalovirus Infection in BALB/c Mice Resembles Virus-Associated Secondary Hemophagocytic Lymphohistiocytosis and Shows a Pathogenesis Distinct from Primary Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening immunological disorder that is characterized by systemic inflammation, widespread organ damage, and hypercytokinemia. Primary HLH is caused by mutations in granule-mediated cytotoxicity, whereas secondary HLH occurs, without a known genetic background, in a context of infections, malignancies, or autoimmune and autoinflammatory disorders. Clinical manifestations of both HLH subtypes are often precipitated by a viral infection, predominantly with Herpesviridae. Exploiting this knowledge, we established an animal model of virus-associated secondary HLH by infecting immunocompetent wild-type mice with the β-herpesvirus murine CMV. C57BL/6 mice developed a mild inflammatory phenotype, whereas BALB/c mice displayed the clinicopathologic features of HLH, as set forth in the Histiocyte Society diagnostic guidelines: fever, cytopenia, hemophagocytosis, hyperferritinemia, and elevated serum levels of soluble CD25. BALB/c mice also developed lymphadenopathy, liver dysfunction, and decreased NK cell numbers. Lymphoid and myeloid cells were in a hyperactivated state. Nonetheless, depletion of CD8(+) T cells could not inhibit or cure the HLH-like syndrome, highlighting a first dissimilarity from mouse models of primary HLH. Immune cell hyperactivation in BALB/c mice was accompanied by a cytokine storm. Notably, plasma levels of IFN-γ, a key pathogenic cytokine in models of primary HLH, were the highest. Nevertheless, murine CMV-infected IFN-γ-deficient mice still developed the aforementioned HLH-like symptoms. In fact, IFN-γ-deficient mice displayed a more complete spectrum of HLH, including splenomegaly, coagulopathy, and decreased NK cell cytotoxicity, indicating a regulatory role for IFN-γ in the pathogenesis of virus-associated secondary HLH as opposed to its central pathogenic role in primary HLH.

An update on renal involvement in hemophagocytic syndrome (macrophage activation syndrome)

CONTEXT

Hemophagocytic syndrome (HPS) is mainly characterized by massive infiltration of bone marrow by activated macrophages and often presents with pancytopenia. Thrombotic microangiopathy (TMA) is also present with thrombocytopenia and renal involvement. Both conditions could coexist with each other and complicate the condition.

EVIDENCE ACQUISITION

Directory of Open Access Journals (DOAJ), EMBASE, Google Scholar, PubMed, EBSCO, and Web of Science with keywords relevant to; Hemophagocytic syndrome, macrophage activation syndrome, interferon-gamma and thrombotic microangiopathy, have been searched.

RESULTS

Viral infection, rheumatologic disease and malignancies are the main underlying causes for secondary HPS. calcineurin inhibitors and viral infections are also the main underlying causes of TMA in transplant recipients. In this review, we discussed a 39-year-old male who presented with pancytopenia and renal allograft dysfunction. With the diagnosis of HPS induced TMA his renal condition and pancytopenia improved after receiving intravenous immunoglobulin (IVIG) and plasmapheresis therapy.

CONCLUSIONS

HPS is an increasingly recognized disorder in the realm of different medical specialties. Renal involvement complicates the clinical picture of the disease, and this condition even is more complex in renal transplant recipients. We should consider the possibility of HPS in any renal transplant recipient with pancytopenia and allograft dysfunction. The combination of HPS with TMA future increases the complexity of the situation.

Therapeutic Potential of Interferon-γ and Its Antagonists in Autoinflammation: Lessons from Murine Models of Systemic Juvenile Idiopathic Arthritis and Macrophage Activation Syndrome

Interferon-γ (IFN-γ) affects immune responses in a complex fashion. Its immunostimulatory actions, such as macrophage activation and induction of T helper 1-type responsiveness, are widely acknowledged, however, as documented by a large body of literature, IFN-γ has also the potential to temper inflammatory processes via other pathways. In autoimmune and autoinflammatory disorders, IFN-γ can either play a disease-enforcing role or act as protective agent, depending on the nature of the disease. In animal models of any particular autoimmune disease, certain changes in the induction procedure can reverse the net outcome of introduction or ablation of IFN-γ. Here, we review the role of endogenous IFN-γ in inflammatory disorders and related murine models, with a focus on systemic juvenile idiopathic arthritis (sJIA) and macrophage activation syndrome (MAS). In particular, we discuss our recent findings in a mouse model of sJIA, in which endogenous IFN-γ acts as a regulatory agent, and compare with results from mouse models of MAS. Also, we elaborate on the complexity in the activity of IFN-γ and the resulting difficulty of predicting its value or that of its antagonists as treatment option.

Bacterial Stimulation of Toll-Like Receptor 4 Drives Macrophages To Hemophagocytose

During acute infection with bacteria, viruses or parasites, a fraction of macrophages engulf large numbers of red and white blood cells, a process called hemophagocytosis. Hemophagocytes persist into the chronic stage of infection and have an anti-inflammatory phenotype. Salmonella enterica serovar Typhimurium infection of immunocompetent mice results in acute followed by chronic infection, with the accumulation of hemophagocytes. The mechanism(s) that triggers a macrophage to become hemophagocytic is unknown, but it has been reported that the proinflammatory cytokine gamma interferon (IFN-γ) is responsible. We show that primary macrophages become hemophagocytic in the absence or presence of IFN-γ upon infection with Gram-negative bacterial pathogens or prolonged exposure to heat-killed Salmonella enterica, the Gram-positive bacterium Bacillus subtilis, or Mycobacterium marinum. Moreover, conserved microbe-associated molecular patterns are sufficient to stimulate macrophages to hemophagocytose. Purified bacterial lipopolysaccharide (LPS) induced hemophagocytosis in resting and IFN-γ-pretreated macrophages, whereas lipoteichoic acid and synthetic unmethylated deoxycytidine-deoxyguanosine dinucleotides, which mimic bacterial DNA, induced hemophagocytosis only in IFN-γ-pretreated macrophages. Chemical inhibition or genetic deletion of Toll-like receptor 4, a pattern recognition receptor responsive to LPS, prevented both Salmonella- and LPS-stimulated hemophagocytosis. Inhibition of NF-κB also prevented hemophagocytosis. These results indicate that recognition of microbial products by Toll-like receptors stimulates hemophagocytosis, a novel outcome of prolonged Toll-like receptor signaling, suggesting hemophagocytosis is a highly conserved innate immune response.

Clinical significance of bone marrow hemophagocytosis in adult patients with malignancy and non-malignancy-induced hemophagocytic lymphohistiocytosis

Bone marrow hemophagocytosis is a frequently observed but not mandatory finding for the diagnosis of hemophagocytic lymphohistiocytosis (HLH). However, the impact of bone marrow hemophagocytosis on the diagnosis of HLH is still not clear in adult patients. Thus, we retrospectively analyzed adult patients with bone marrow hemophagocytosis between 2000 and 2014 to determine its clinical significance. Among 264 patients with bone marrow hemophagocytosis, malignant disorders were the predominant underlying cause (n = 170, 64 %), especially T/NK-cell (n = 88) and B-cell (n = 45) lymphomas compared to infectious disease (48/264, 18 %). The data for HLH-2004 diagnostic criteria was available in 182 patients, and only 29 % (77/264) of patients with ≥ five positive criteria could be diagnosed with HLH. Among the criteria for the diagnosis of HLH, increased serum ferritin (89 %) was more common than hypofibrinogenemia, hypertriglyceridemia, and bicytopenia (<40 %). The median overall survival was worse in patients with malignancy (9.0 months, 95 % confidence interval [CI] 5.6-12.5) than in those with non-malignant disorders (71.8 months, 95 % CI 56.5-87.1, P < 0.001). In patients with malignancy, the overall survival of patients fulfilling the HLH-2004 criteria was significantly worse than patients who did not (P < 0.001). In conclusion, our results suggest that bone marrow hemophagocytosis might be an important finding in the diagnosis of HLH in adult patients. Considering the high incidence of malignancy as a predisposing disorder for HLH, immediate evaluation should be performed in adult patients with bone marrow hemophagocytosis.

Hemophagocytic lymphohistiocytosis secondary to infections: a tropical experience!

Hemophagocytic lymphohistiocytosis (HLH) is a potentially fatal hyper inflammatory condition, if not recognized and treated in time. A high index of suspicion can help identify the condition early. This condition can occur in the primary or secondary form. Secondary HLH or hemophagocytic syndrome (HPS) secondary to infections is an important clinical entity especially in tropical world. In this article, we share our experience with this entity and make an attempt to explore literature about ravenous macrophages which occurs secondary to infections. It is a series of six cases of HLH secondary to infectious disease in our center in a coastal city in South India over last one year with follow up.

Clinical characteristics and prognostic factors of adult hemophagocytic syndrome patients: a retrospective study of increasing awareness of a disease from a single-center in China

Background

Hemophagocytic lymphohistiocytosis (HLH) is a relatively rare but life-threatening disease with confusing clinical manifestations, rapidly deteriorating health, high morbidity and mortality.

Methods

To improve the recognition as well as understanding of this disorder, we analyzed clinical characteristics and prognostic factors from 85 adult patients diagnosed with HLH in our hospital from April 2005 to June 2014.

Results

Patients with HLH displayed variable clinical markers across a wide spectrum. These included fever and hyperferritinemia (100%), elevated lactate dehydrogenase (LDH) (98.8%), two or three cytopenia (92.2%), splenomegaly (72.9%), hypofibrinogenemia (69.4%), hypertriglyceridemia (64.7%), hemophagocytosis (51.7%), and hepatomegaly (24.7%). Patients with active Epstien-Barr Virus (EBV) infection had a median overall survival (OS) of 65 days. Those displaying malignancy had very poor survival (median OS: 40 days). However, patients in rheumatic and non-EBV infection groups had relatively superior prognosis (not reached). Univariate analysis showed that Fibrinogen (Fbg) <1.5 g/L, platelet number (PLT) <40 × 10⁹/L and LDH ≥1000 U/L were factors that negatively affected survival (P = 0.004, 0.000, 0.002). Multivariate analysis showed that PLT <40 × 10⁹/L was the independent adverse factor (HR = 0.350, 95% CI: 0.145-0.844, P = 0.019).

Conclusions

HLH had very complex clinical manifestations and high death rate. Patients with active EBV infection, malignancy, Fbg <1.5 g/L, PLT <40 × 10⁹/L and LDH ≥1000 U/L had high risk of death as well as inferior survival, and these patients require systemic targeted treatments as early as possible.

Pathophysiology and epidemiology of hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a syndrome characterized by extreme immune activation, resulting in pathologic inflammation. The diagnosis includes a spectrum of inherited or acquired defects in cytotoxic lymphocyte function, often with uncontrolled infections. HLH may also arise as the result of persistent antigen stimulation due to autoimmune disease or malignancy. HLH is often described in binary terms as "primary," indicating Mendelian inheritance of gene mutations resulting in cytotoxic lymphocyte dysfunction, or "secondary" indicating an acquired reactive disorder. Increasing evidence describes HLH as more complex phenomenon, resulting from specific immune challenges in patients with a susceptible genetic background. Early recognition of HLH and evaluation of potential causes is critically important, as survival generally requires urgent treatment with immune suppression and resolution of the activating antigen. However, the diagnosis of HLH is challenged by the myriad of pathways that lead to pathologic inflammation and the clinical overlap with other conditions. Further improvements in therapy will require prospective trials to define optimal strategies for each patient based on the individual paths that lead to pathologic inflammation.

Secondary haemophagocytic lymphohistiocytosis: Experience from the Uppsala University Hospital

BACKGROUND

Haemophagocytic lymphohistiocytosis (HLH) is a rare clinical syndrome characterized by fever, hepatosplenomegaly, cytopenia, and progressive multiple-organ failure. HLH in adults is often secondary to autoimmune diseases, cancer, or infections in contrast to familial HLH. Treatment of secondary HLH is directed against the triggering disease in addition to immunosuppressive therapy, the latter commonly according to the HLH-2004 protocol.

METHODS

We conducted a retrospective study to identify triggering diseases, disease-specific and immunosuppressive therapy administered, and prognosis in adult patients with secondary HLH. Patient data were collected from October 2010 to January 2015.

RESULTS

Ten adult patients with secondary HLH were identified. Seven were men, and the median age at diagnosis was 62 years. Five cases were triggered by malignant disease and five by infection. The median patient fulfilled five of the eight HLH-2004 diagnostic criteria. All patients fulfilled the criteria fever, cytopenia, and ferritin >500 µg/L. Median time from hospital admission to HLH diagnosis was 20 days. Four patients received immunosuppressive therapy according to the HLH-2004 protocol. The prognosis was dismal, especially for the patients with malignancy-associated HLH, of whom all died.

CONCLUSION

HLH should be suspected in patients who present with fever, cytopenia, and ferritin >500 µg/L. Secondary HLH has a dismal prognosis. None of the patients with HLH triggered by malignancy survived. Achieving remission of the triggering disease seems to be important for a favourable outcome as, in all surviving patients, the haemophagocytic syndrome resolved after remission of the underlying infection.

Reactive hemophagocytic syndrome in adult-onset Still disease: clinical features, predictive factors, and prognosis in 21 patients

Hemophagocytic syndrome (HPS) is a potentially life-threatening complication of systemic inflammatory disorders. Adult-onset Still disease (AOSD) is one of the systemic autoimmune diseases associated with reactive hemophagocytic syndrome (RHS). This study aimed to evaluate the characteristic findings, predictive factors, and prognosis of RHS in patients with AOSD. We retrospectively evaluated 109 patients diagnosed with AOSD and reviewed their clinical data and laboratory findings, including the biopsy results of 21 AOSD patients with RHS. Moreover, data from 17 hemophagocytic lymphohistiocytosis (HLH) patients evaluated during the same period were compared with those from the RHS patients. Twenty-one patients (19.3%) developed RHS during the course of AOSD, and only 7 patients (6.4%) were confirmed by bone marrow, liver, or lymph node biopsy. AOSD patients with RHS showed significantly higher frequencies of splenomegaly, hepatomegaly, and lymphadenopathy than did those without RHS. Moreover, patients with RHS showed significantly higher relapse rates than those without RHS (61.9% vs 18.2%, P < 0.001). Possible triggering factors inducing hemophagocytosis were detected in 16 of 21 RHS patients (76.2%): disease flare in 12 patients (75%), infection in 3 patients (18.8%), and drug use in 1 patient (6.3%). AOSD patients with RHS showed higher frequencies of leukopenia, anemia, thrombocytopenia, hypoalbuminemia, hypofibrinogenemia, hypertriglyceridemia, hyperferritinemia, and elevated lactate dehydrogenase levels than did those without RHS. Multivariate logistic regression with forward selection procedure showed that low platelet count (<121,000/mm³), anemia, and hepatomegaly were independent predictors of RHS. Patients with definite RHS and those with probable RHS showed comparable results. Although RHS is a life-threatening complication of AOSD, long-term prognosis was observed to be similar in patients with and those without RHS. Compared to RHS patients, HLH patients had poor prognosis, such as higher death rates (52.9% vs 9.5%, P = 0.005). RHS can be considered when an AOSD patient shows at least 2 of the following 3 findings: low platelet count, anemia, and hepatomegaly. Diagnostic confirmation by biopsy may not be essential if typical clinical findings of RHS are present. Moreover, prognosis of RHS was better than that of HLH diagnosed by the presence of trilineage cytopenia at admission.

Hemophagocytic syndrome in children and adults

Hemophagocytic syndrome, also known as hemophagocytic lymphohistiocytosis (HLH), is a heterogenic syndrome, which leads to an acute, life-threatening inflammatory reaction. HLH occurs both in children and adults, and can be triggered by various inherited as well as acquired factors. Depending on the etiology, HLH can be divided into genetic (i.e., primary) and acquired (i.e., secondary) forms. Among genetic HLH forms, one can distinguish between familial HLH and other genetically conditioned forms of HLH. Acquired HLH can be typically triggered by infections, autoimmune diseases, and malignancies. The most common symptoms of HLH are unremitting fever, splenomegaly, and peripheral blood cytopenia. Some severely ill patients present with central nervous system involvement. Laboratory tests reveal hyperferritinemia (often >10,000 μg/L), increased serum concentration of soluble receptor α for interleukin-2 (>2,400 U/L), hypertriglyceridemia, hypofibrinogenemia, coagulopathy, hyponatremia, hypoproteinemia, and elevated liver transaminases and bilirubin. Prognosis in HLH is very serious. Genetic HLH is always lethal if adequate therapy is not administered. Similarly, severe acquired cases often lead to death without appropriate treatment. Since HLH can be encountered by various specialists in the medical field, basic knowledge of this entity such as diagnostic criteria and treatment should be familiar to all physicians.

An activating NLRC4 inflammasome mutation causes autoinflammation with recurrent macrophage activation syndrome

Inflammasomes are innate immune sensors that respond to pathogen and damage-associated signals with caspase-1 activation, IL-1β and IL-18 secretion, and macrophage pyroptosis. The discovery that dominant gain-of-function mutations in NLRP3 cause the Cryopyrin Associated Periodic Syndromes (CAPS) and trigger spontaneous inflammasome activation and IL-1β oversecretion, led to successful treatment with IL-1 blocking agents¹. Herein, we report a de novo missense mutation, c.1009A>T, p.Thr337Ser, in the nucleotide-binding domain of inflammasome component NLRC4 (IPAF/CARD12) that causes early-onset recurrent fever flares and Macrophage Activation Syndrome (MAS). Functional analyses demonstrated spontaneous inflammasome formation and production of the inflammasome-dependent cytokines IL-1β and IL-18, the latter exceeding levels in CAPS. The NLRC4 mutation caused constitutive caspase-1 cleavage in transduced cells and increased production of IL-18 by both patient and NLRC4 mutant macrophages. Thus, we describe a novel monoallelic inflammasome defect that expands the monogenic autoinflammatory disease spectrum to include MAS and suggests novel targets for therapy.

Brief report: alternative activation of laser-captured murine hemophagocytes

OBJECTIVE

Hemophagocytes (HPCs) are activated macrophages that have engulfed other hematopoietic cells. Although HPCs are rarely identified in normal spleen tissue and bone marrow, an excess of these macrophages characterizes many cytokine storm syndromes, particularly macrophage activation syndrome and hemophagocytic lymphohistiocytosis. This study was undertaken to assess the functions of HPCs and their significance in acute inflammatory conditions.

METHODS

HPCs were generated in wild-type mice using repeated stimulation with Toll-like receptor 9 (TLR-9) and interleukin-10 receptor blockade. RNA was extracted from HPCs that had been isolated by lasercaptured microdissection. Transcriptional profiles of the HPCs were then compared to those of resting splenic macrophages. In addition, bone marrow samples were obtained from a diverse cohort of patients in whom excess hemophagocytosis was identified by clinical bone marrow biopsy or aspiration. The bone marrow samples were analyzed by immunohistochemistry for markers of classic (CD64) or alternative (CD163 and CD206) macrophage activation.

RESULTS

Differential gene expression and gene set enrichment analyses of murine HPCs identified upregulation of genes and gene sets associated with alternative activation of HPCs. Immunohistochemical analyses of HPCs in human bone marrow samples showed universal staining of HPCs for CD163, but rarely for CD206 or CD64.

CONCLUSION

Laser-captured murine TLR-9– induced HPCs had a transcriptional profile similar to that of alternatively activated macrophages. In addition, HPC expression of CD163 was confirmed in a uniquely diverse cohort of patients with hemophagocytic syndromes. Collectively, these data support the hypothesis that HPCs have both immunoregulatory and clean-up functions.

Adult haemophagocytic syndrome

Haemophagocytic syndromes (haemophagocytic lymphohistiocytosis) have a wide range of causes, symptoms, and outcomes, but all lead to a hyperinflammatory response and organ damage--mainly reported in paediatric patients, but reports of adult presentation are increasing. Analysis of the genetic and molecular pathophysiology of these syndromes have improved the understanding of the crosstalk between lymphocytes and histiocytes and their regulatoty mechanisms. Clinical presentations with a broad differential diagnosis, and often life-threatening outcome, complicate the management, which might include supportive intensive care, immunosuppressive and biological treatments, or haemopoietic stem cell transplantation. Insufficient knowledge of these syndromes could contribute to poor prognosis. Early diagnosis is essential to initiate appropriate treatment and improve the quality of life and survival of patients with this challenging disorder.

Treatment of juvenile idiopathic arthritis: a revolution in care

A generation ago, children with arthritis faced a lifetime of pain and disability. Today, there are a multitude of treatment options, including a variety of biologics targeting key cytokines and other inflammatory mediators. While non-steroidal anti-inflammatory drugs and corticosteroids were once the mainstay of therapy, they are now largely used as bridge or adjunctive therapies. Among the conventional disease-modifying anti-rheumatic drugs, methotrexate remains first-line therapy for most children with juvenile idiopathic arthritis (JIA) due to its long track record of safety and effectiveness in the management of peripheral arthritis. Sulfasalazine and leflunomide may also have a secondary role. The tumor necrosis factor inhibitors (TNFi) have shown tremendous benefit in children with polyarticular JIA and likely in enthesitis-related arthritis and psoriatic JIA as well. There may be additional benefit in combining TNFi with methotrexate. Abatacept and tocilizumab also appear to benefit polyarticular JIA; the role of rituximab remains unclear. For the treatment of systemic JIA, while the TNFi are of less benefit, blockade of interleukin-1 or interleukin-6 is highly effective. Additionally, interleukin-1 blockade appears to be effective treatment of macrophage activation syndrome, one of the most dangerous complications of JIA; specifically, anakinra in combination with cyclosporine and corticosteroids may obviate the need for cytotoxic approaches. In contrast, methotrexate along with the TNFi and abatacept are effective agents for the management of uveitis, another complication of JIA. Overall, the biologics have demonstrated an impressive safety record in children with JIA, although children do need to be monitored for rare but potentially dangerous adverse events, such as tuberculosis and other infections; paradoxical development of additional autoimmune diseases; and possibly an increased risk of malignancy. Finally, there may be a window of opportunity during which children with JIA will demonstrate most optimal responses to aggressive therapy, underscoring the need for rapid diagnosis and initiation of treatment.

Children and adolescents with SLE: not just little adults

Juvenile-onset systemic lupus erythematosus (JSLE) represents 15–20% of all SLE cases. Whilst features of this chronic complex multisystem autoimmune disorder are highly variable, children and adolescents generally present with a more severe illness than adults and accrue greater disease damage over time. JSLE has a less striking female preponderance and differs from the adult form in pattern of major organ manifestations. Corticosteroids are used in almost all children with JSLE along with the majority requiring additional immunosuppressive medications. Making the diagnosis early and optimizing disease control are essential to ensure that normal childhood and adolescent development is not impeded. In this young population, special consideration must be given to the long-term sequelae of the disease and treatment-related toxicity. There is a current lack of paediatric-specific controlled trials and treatment strategies are generally guided by adult data. The enormous psychological and social impact of the disease and its treatments upon the child or young person and their family necessitates a comprehensive, holistic, specialized multidisciplinary approach to managing JSLE.

Interferon-γ mediates anemia but is dispensable for fulminant toll-like receptor 9-induced macrophage activation syndrome and hemophagocytosis in mice

OBJECTIVE

Macrophage activation syndrome (MAS) is a devastating cytokine storm syndrome complicating many inflammatory diseases and characterized by fever, pancytopenia, and systemic inflammation. It is clinically similar to hemophagocytic lymphohistiocytosis (HLH), which is caused by viral infection of a host with impaired cellular cytotoxicity. Murine models of MAS and HLH illustrate that interferon-γ (IFNγ) is the driving stimulus for hemophagocytosis and immunopathology. This study was undertaken to investigate the inflammatory contributors to a murine model of Toll-like receptor 9 (TLR-9)-induced fulminant MAS.

METHODS

Wild-type, transgenic, and cytokine-inhibited mice were treated with an IL-10 receptor blocking antibody and a TLR-9 agonist, and parameters of MAS were evaluated.

RESULTS

Fulminant MAS was characterized by dramatic elevations in IFNγ, IL-12, and IL-6 levels. Increased serum IFNγ levels were associated with enhanced IFNγ production within some hepatic cell populations but also with decreased numbers of IFNγ-positive cells. Surprisingly, IFNγ-knockout mice developed immunopathology and hemophagocytosis comparable to that seen in wild-type mice. However, IFNγ-knockout mice did not become anemic and had greater numbers of splenic erythroid precursors. IL-12 neutralization phenocopied disease in IFNγ-knockout mice. Interestingly, type I IFNs contributed to the severity of hypercytokinemia and weight loss, but their absence did not otherwise affect MAS manifestations.

CONCLUSION

These data demonstrate that both fulminant MAS and hemophagocytosis can arise independently of IFNγ, IL-12, or type I IFNs. They also suggest that IFNγ-mediated dyserythropoiesis, not hemophagocytosis, is the dominant cause of anemia in fulminant TLR-9-induced MAS. Thus, our data establish a novel mechanism for the acute anemia of inflammation, but suggest that a variety of triggers can result in hemophagocytic disease.