Hyperferritinemic Sepsis: An Opportunity for Earlier Diagnosis and Intervention?

Hemophagocytic Lymphohistiocytosis Triggered by Herpes Simplex Virus 1 and 2: A Narrative Review

Introduction: Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening syndrome characterized by an uncontrolled hyperinflammatory reaction. HLH is classified into primary (familial) and secondary (acquired). Secondary HLH is commonly triggered by infections, with viral infections being a leading cause. Its epidemiology and clinical features in cases associated with herpes simplex virus 1 and 2 remain underexplored. This study aimed to review all previously described cases of HSV-1 or -2-triggered HLH and provide information about this syndrome's epidemiology, microbiology, clinical characteristics, treatment, and outcomes. Methods: A narrative review was performed based on a search in PubMed, the Cochrane Library, and Scopus. Studies published until 27 April 2024 providing relevant data for HLH due to HSV 1 and 2 in humans were included. Results: We identified 29 eligible studies reporting HLH due to HSV 1 and 2, involving 34 patients. Half of them were adults, and half were neonates. Fever and splenomegaly were the most common clinical findings. Most patients were diagnosed with HSV-1 (64.7%), with PCR being the primary diagnostic method. The median duration of in-hospital treatment was 21 days, with acyclovir and steroids being the mainstays of therapy. The overall mortality rate was 41.2%, and AST levels emerged as an independent predictor of mortality. Conclusions: Our findings underscore the need for heightened awareness surrounding HLH triggered by HSV 1 and 2 and the importance of prompt diagnosis and tailored treatment approaches.

Macrophage Activation Syndrome in Viral Sepsis

Macrophage activation syndrome (MAS) is a life-threatening systemic hyperinflammatory syndrome triggered by various infections, particularly viral infections, autoimmune disorders, and malignancy. The condition is characterized by an increased production of proinflammatory cytokines resulting in a cytokine storm and has been associated with poor clinical outcomes. During the COVID-19 pandemic, patients with severe manifestations developed features similar to those of MAS, although these characteristics remained well defined within the lung. Additionally, other viral infections including EBV, the herpes family of viruses, hepatitis viruses, influenza, HIV, and hemorrhagic fevers can be complicated by MAS. The diagnosis and management of the condition remain challenging due to the lack of consensus on specific guidelines, especially among the adult population. Currently, therapeutic options primarily rely on medications that are typically used to treat primary hemophagocytic lymphohistiocytosis, such as corticosteroids and etoposide. In addition, cytokine-targeted therapies present promising treatment options. The objective of this review is to discuss the emergence of MAS in the context of viral infections including, but not limited to, its occurrence in COVID-19.

Neonatal hemophagocytic lymphohistiocytosis: A meta-analysis of 205 cases

BACKGROUND

Neonatal hemophagocytic lymphohistiocytosis (nHLH), defined as HLH that presents in the first month of life, is clinically devastating. There have been few large descriptive studies of nHLH.

OBJECTIVES

The objective of this study was to perform a meta-analysis of published cases of nHLH.

METHODS

A comprehensive literature database search was performed. Cases of HLH were eligible for inclusion if clinical analysis was performed at age ≤30 days. Up to 70 variables were extracted from each case.

RESULTS

A total of 544 studies were assessed for eligibility, and 205 cases of nHLH from 142 articles were included. The median age of symptom onset was day of life 3 (interquartile range [IQR]: 0-11, n = 141). Median age at diagnosis was day of life 15 (IQR: 6-27, n = 87). Causes of HLH included familial HLH (48%, n = 99/205), infection (26%, n = 53/205), unknown (17%, n = 35/205), macrophage activation syndrome/rheumatologic (2.9%, n = 4/205), primary immune deficiency (2.0%, n = 5/205), inborn errors of metabolism (2.4%, n = 5/205), and malignancy (2.0%, n = 4/205). Fever was absent in 19% (n = 28/147) of all neonates and 39% (n = 15/38) of preterm neonates. Bicytopenia was absent in 26% (n = 47/183) of patients. Central nervous system (CNS) manifestations were reported in 63% of cases (n = 64/102). Liver injury (68%, n = 91/134) and/or liver failure (24%, n = 32/134) were common. Flow cytometry was performed in 22% (n = 45/205) of cases. Many patients (63%, n = 121/193) died within the period of reporting. Discernable values for HLH diagnostic criteria were reported between 30% and 83% of the time.

CONCLUSIONS

Evaluation of nHLH requires rapid testing for a wide range of differential diagnoses. HLH diagnostic criteria such as fever and bicytopenia may not occur as frequently in the neonatal population as in older pediatric populations. Neurologic and hepatic manifestations frequently occur in the neonatal population. Current reports of nHLH suggest a high mortality rate. Future publications containing data on nHLH should improve reporting quality by reporting all clinically relevant data.

Case Report: Successful avoidance of etoposide for primary hemophagocytic lymphohistiocytosis-induced multiple organ dysfunction syndrome using emapalumab

We describe the case of an infant who presented with simple rhinovirus/enterovirus bronchiolitis whose condition worsened with rapid progression to multiple organ dysfunction syndrome (MODS). The patient was presumed to have either primary or secondary hemophagocytic lymphohistiocytosis (HLH), and treatment was initiated using dexamethasone, anakinra, and intravenous immunoglobulin to modulate the immune system. Due to the organ dysfunction, the use of etoposide was avoided and instead, emapalumab, an interferon gamma antagonist, was administered at a dose of 6 mg/kg. The patient's organ failure improved, and the levels of inflammatory markers decreased. The flow cytometry analysis revealed that cytotoxic cells lacked perforin expression, and subsequent genetic analysis confirmed homozygous pathogenic mutations in the perforin gene. This case highlights the potential avoidance of etoposide in cases of primary HLH, the possible benefit of an elevated initial dose of emapalumab, and the contribution offered by a multi-specialty team approach to complex 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.

Coagulation profile and correlation between D-dimer, inflammatory markers, and COVID-19 severity in an Indonesian national referral hospital

Background

Coagulopathy and inflammation are associated with coronavirus disease 2019 (COVID-19) severity. This study assessed D-dimer concentration and its correlation with inflammatory markers and COVID-19 severity.

Methods

This was a retrospective cross-sectional study involving 194 COVID-19 cases, with the severity of infection graded in accordance with the World Health Organization (WHO) guidelines. We measured D-dimer, C-reactive protein (CRP), and ferritin on admission and determined the cutoff values for D-dimer and CRP and evaluated the correlation between D-dimer and CRP and ferritin.

Results

Median D-dimer, CRP, and ferritin concentrations were 2240 µg/L, 73.2 mg/L, and 1173.8 µg/mL, respectively. The highest median D-dimer value was seen in mild and moderate acute respiratory distress syndrome (ARDS). The highest ferritin concentration was seen in severe ARDS. There was a significant correlation between D-dimer value and CRP (r = 0.327), but no significant correlation between D-dimer and ferritin (r = 0.101). The area under the receiver operating characteristic curve (AUC) for the combination of CRP ≥72.65 mg/L and D-dimer ≥1250 µg/L as a marker of COVID-19 severity was 0.722 (95% confidence interval (CI): 0.615–0.781).

Conclusion

The combination of CRP ≥72.65 mg/L and D-dimer ≥1250 µg/L can be used as marker of COVID-19 severity, with moderate accuracy.

Hyperferritinemia: A Diagnostic Marker for Disseminated Neonatal Herpes Simplex Virus Infection?

Although the prognosis of neonatal herpes simplex virus (HSV) infection has improved with intravenous acyclovir, the morbidity and mortality of disseminated disease remains high. Transaminitis and thrombocytopenia have been reported to be sensitive markers of neonatal HSV disease; however, early diagnosis remains a challenge due to a lack of specific clinical and laboratory indicators for this disease process. Ferritin, an acute phase reactant known for its use in diagnosing hemophagocytic lymphohistiocytosis, has recently been reported as extremely elevated in neonates with disseminated HSV due to its high inflammatory nature. We report three cases of neonates at a single institution with hyperferritinemia in the setting of disseminated HSV. Based on this case series, we discuss whether ferritin can be used as an early diagnostic marker in the setting of suspected neonatal HSV disease. [Pediatric Annals. 2021;50(6):e264-e267.].

Prolonged fever and hyperferritinaemia: a puzzling diagnosis of neonatal herpes simplex virus infection during COVID-19 pandemic

Neonatal herpes simplex virus (HSV) infection is rare, with an estimated incidence of 3.58 per 100 000 live births in the UK and should be suspected in any newborn with fever and bacterial culture-negative sepsis. We describe a case of a previously well full-term male neonate who presented with persistent fever and elevated ferritin level that was carried out during the era of the COVID-19 pandemic as part of SARS-CoV-2 panel investigations. Despite the initial negative HSV serology, HSV-1 PCR from a scalp lesion returned positive. He made a full recovery after acyclovir therapy. This case highlights the importance of maintaining a high clinical index of suspicion of HSV infection in any febrile neonate even with absence of maternal history and negative serology, particularly if associated with hyperferritinaemia. We also address the challenge of interpreting inflammatory biomarkers' results for SARS-CoV-2 infection in neonates.

Case Report: Rapid Recognition and Immune Modulation of Secondary HLH Due to Disseminated HSV Infection

We describe the case of a newborn who presented with multiple organ dysfunction syndrome (MODS) and hyperferritinemia, who eventually met criteria for hemophagocytic lymphohistiocytosis (HLH) due to disseminated herpes simplex virus 1 (HSV-1). While the cytokine storm abated after administration of multiple immune modulatory therapies including dexamethasone, etoposide, intravenous immune globulin, anakinra, as well as the interferon gamma antagonist emapalumab, multiple organ dysfunction syndrome progressed. Care was withdrawn after 5 days. Subsequent genetic testing did not reveal any mutations associated with familial HLH. This case highlights that even with appropriate antiviral treatment and immune suppression, disseminated HSV is often fatal. Further study is warranted to determine whether early immune modulatory therapy including interferon gamma blockade can interrupt the HLH inflammatory cascade and prevent progression of MODS.

Low iron mitigates viral survival: insights from evolution, genetics, and pandemics-a review of current hypothesis

Background

Upon re-examination of our human history, evolutionary perspectives, and genetics, a prevailing iron deficiency phenotype appears to have evolved to protect the human race from extinction.

Body

In this review, we summarize the evolutionary and genetic perspectives pointing towards the hypothesis that low iron mitigates infection. The presence of infection promotes the generation of resistance alleles, and there are some evolutionary and genetic clues that suggest the presence of an iron deficiency phenotype that may have developed to protect against infection. Examples include the relative paucity of iron overload genes given the essential role of iron, as well as the persistence of iron deficiency among populations in spite of public health efforts to treat it. Additional examination of geographic areas with severe iron deficiency in the setting of pandemics including H1N1, SARS, and COVID-19 reveals that areas with higher prevalence of iron deficiency are less affected. RNA viruses have several evolutionary adaptations which suggest their absolute need for iron, and this dependency may be exploited during treatment.

Conclusion

RNA viruses pose a unique challenge to modern healthcare, with an average of 2-3 new pathogens being discovered yearly. Their overarching requirements for iron, along with human evolutionary and genetic adaptations which favored an iron deficiency phenotype, ultimately suggest the potential need for iron control in these infections.

Suspecting Hyperferritinemic Sepsis in Iron-Deficient Population: Do We Need a Lower Plasma Ferritin Threshold?

OBJECTIVES

Hyperferritinemia is being suggested to identify patients with sepsis-induced macrophage activation syndrome for early intervention. However, data among iron-deficient children are scarce. This study was planned to explore the biological behavior of plasma ferritin in children from communities with a high frequency of iron deficiency with septic shock and its association with the outcome.

DESIGN

Prospective observational study.

SETTING

Tertiary care teaching hospital in a low-middle income economy of South Asia.

PATIENTS OR SUBJECTS

Patients (6 mo to 12 yr) (n = 42) with septic shock and their healthy siblings as controls (n = 36). Patients/controls with blood transfusion/iron supplement during last 6 months or with any chronic disease were excluded.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Ferritin was measured in patients at enrollment and then at 1 month of hospital discharge while they were not on iron supplementation and in controls as indicative of baseline level. Patients' median age was 30 months (13.5-87 mo), 31% were malnourished, majority (86%) had anemia, and two thirds had microcytic hypochromic red cells. Ferritin at admission was 763 ng/mL (480-1,820 ng/mL) in nonsurvivors, whereas 415 ng/mL (262-852 ng/mL) in survivors (p = 0.11). Pediatric Logistic Organ Dysfunction score and C-reactive protein correlated positively with plasma ferritin (p = 0.03 and p = 0.01, respectively) at enrollment. Elevated ferritin of greater than 500 ng/mL (relative risk, 2.48; 95% CI, 0.95-6.43) and greater than 1,000 ng/mL (relative risk, 1.94; 95% CI, 0.94-4.02) were associated with higher mortality but not independently. Among survivors, the 1-month follow-up ferritin fell significantly to 97 ng/mL (16-118 ng/mL) (p = 0.001). However, it was still significantly higher than that in sibling controls (19 ng/mL [10-54 ng/mL]) (p = 0.003).

CONCLUSIONS

Ferritin rises significantly in septic shock patients despite iron deficiency and seems to correlate with the severity of inflammation and organ dysfunction. Even a lower threshold (of 500 or 1,000 ng/mL) could predict higher mortality. It may suggest the need for redefining the plasma ferritin threshold for suspecting hyperferritinemic sepsis and sepsis-induced macrophage activation syndrome in these patients. Larger studies with frequent ferritin measurements are desirable to validate these initial observations.