Case Report: Secondary Hemophagocytic Lymphohistiocytosis With Disseminated Infection in Chronic Granulomatous Disease-A Serious Cause of Mortality

Prognostic factors in patients with secondary hemophagocytic lymphohistioc ytosis in a Chinese cohort

Hemophagocytic lymphohistiocytosis (HLH) is a rare hyperinflammatory syndrome with high mortality mediated by an unbridled and persistent activation of cytotoxic T lymphocytes and natural killer cells. However, the influence factors of early death in adult sHLH patients are still not fully elucidated, which need further investigating. We have conducted an observational study of adult HLH patients between January 2016 and December 2022. All patients are enrolled according to HLH-2004 criteria. Clinical manifestations, laboratory data, treatments, and outcomes have been recorded. Influence factors associated with prognosis are calculated by using logistic regression models. Overall, 220 patients enrolled in this study. The etiologies of HLH were divided into five groups including autoimmune-associated hemophagocytic syndrome (AAHS) (n = 90, 40.9%), malignancies (n = 73, 33.2%), EBV-HLH (n = 18, 8.2%), infection excluded EBV (n = 24, 10.9%), and other triggers (n = 15, 6.8%). Among them, EBV-HLH had the highest mortality (77.8%), and AAHS had the lowest mortality (14.4%). Multivariate analysis indicated that age (≥ 38 years old), cytopenia ≥ 2 lines, platelets (≤ 50 × 109/L), aspartate aminotransferase (≥ 135U/L), prothrombin time (≥ 14.9 s) and activated partial thromboplastin time (≥ 38.5s), EBV, and fungal infection are independent risk factors for poor prognosis of HLH. Adult HLH patients with elder age, cytopenia ≥ 2 lines, levels of decreased platelets, increased AST, prolonged PT and APTT, EBV, and fungal infection tend to have a poor prognosis.

HLH as an additional warning sign of inborn errors of immunity beyond familial-HLH in children: a systematic review

Background

Hemophagocytic Lymphohistiocytosis (HLH) is a rare and life-threatening condition characterized by a severe impairment of the immune homeostasis. While Familial-HLH (FHL) is a known cause, the involvement of other Inborn Errors of Immunity (IEI) in pediatric-HLH remains understudied.

Objective

This systematic review aimed to assess the clinical features, triggers, laboratory data, treatment, and outcomes of pediatric HLH patients with IEI other than FHL (IEInotFHL), emphasizing the importance of accurate identification and management.

Methods

A systematic search for studies meeting inclusion criteria was conducted in PubMed, EMBASE, MEDLINE, and Cochrane Central. Quality assessment was performed through JBI criteria.

Results

A comprehensive search yielded 108 records meeting inclusion criteria, involving 178 patients. We identified 46 different IEI according to IUIS 2022 Classification. Combined immunodeficiencies, immune dysregulation disorders, and phagocyte defects were the IEI most frequently associated with HLH. In 75% of cases, HLH preceded the IEI diagnosis, often with an unrecognized history of severe infections. Triggers reflected the specific infection susceptibilities within IEI groups. Liver and central nervous system involvement were less common than in FHL cases. Treatment approaches and outcomes varied, with limited long-term follow-up data, limiting the assessment of therapeutic efficacy across IEI groups.

Conclusion

A comprehensive evaluation encompassing immunological, infectious, and genetic aspects is essential in pediatric-HLH. Relying solely on FHL or EBV susceptibility disorders tests is insufficient, as diverse other IEI can contribute to HLH. Early recognition of HLH as a potential warning sign can guide timely diagnostic investigations and facilitate tailored therapeutic interventions for improved outcomes.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=371425, PROSPERO, CRD42022371425.

Genetics of Acquired Cytokine Storm Syndromes : Secondary HLH Genetics

Secondary hemophagocytic lymphohistiocytosis (sHLH) has historically been defined as a cytokine storm syndrome (CSS) occurring in the setting of triggers leading to strong and dysregulated immunological activation, without known genetic predilection. However, recent studies have suggested that existing underlying genetic factors may synergize with particular diseases and/or environmental triggers (including infection, autoimmune/autoinflammatory disorder, certain biologic therapies, or malignant transformation), leading to sHLH. With the recent advances in genetic testing technology, more patients are examined for genetic variations in primary HLH (pHLH)-associated genes, including through whole exome and whole genome sequencing. This expanding genetic and genomic evidence has revealed HLH as a more complex phenomenon, resulting from specific immune challenges in patients with a susceptible genetic background. Rather than a simple, binary definition of pHLH and sHLH, HLH represents a spectrum of diseases, from a severe complication of common infections (EBV, influenza) to early onset familial diseases that can only be cured by transplantation.

The paradox of autoimmunity and autoinflammation in inherited neutrophil disorders - in search of common patterns

Congenital defects of neutrophil number or function are associated with a severe infectious phenotype that may require intensive medical attention and interventions to be controlled. While the infectious complications in inherited neutrophil disorders are easily understood much less clear and explained are autoimmune and autoinflammatory phenomena. We survey the clinical burden of autoimmunity/autoinflammation in this setting, search for common patterns, discuss potential mechanisms and emerging treatments.

Inherited and acquired errors of type I interferon immunity govern susceptibility to COVID-19 and multisystem inflammatory syndrome in children

Since the beginning of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)/coronavirus disease 2019 (COVID-19) pandemic, global sequencing efforts have led in the field of inborn errors of immunity, and inspired particularly by previous research on life-threatening influenza, they have revealed that known and novel inborn errors affecting type I interferon immunity underlie critical COVID-19 in up to 5% of cases. In addition, neutralizing autoantibodies against type I interferons have been identified in up to 20% of patients with critical COVID-19 who are older than 80 years and 20% of fatal cases, with a higher prevalence in men and individuals older than 70 years. Also, inborn errors impairing regulation of type I interferon responses and RNA degradation have been found as causes of multisystem inflammatory syndrome in children, a life-threatening hyperinflammatory condition complicating otherwise mild initial SARS-CoV-2 infection in children and young adults. Better understanding of these immunologic mechanisms can aid in designing treatments for severe COVID-19, multisystem inflammatory syndrome in children, long COVID, and neuro-COVID.

Carnitine Palmitoyltransferase System: A New Target for Anti-Inflammatory and Anticancer Therapy?

Lipid metabolism involves multiple biological processes. As one of the most important lipid metabolic pathways, fatty acid oxidation (FAO) and its key rate-limiting enzyme, the carnitine palmitoyltransferase (CPT) system, regulate host immune responses and thus are of great clinical significance. The effect of the CPT system on different tissues or organs is complex: the deficiency or over-activation of CPT disrupts the immune homeostasis by causing energy metabolism disorder and inflammatory oxidative damage and therefore contributes to the development of various acute and chronic inflammatory disorders and cancer. Accordingly, agonists or antagonists targeting the CPT system may become novel approaches for the treatment of diseases. In this review, we first briefly describe the structure, distribution, and physiological action of the CPT system. We then summarize the pathophysiological role of the CPT system in chronic obstructive pulmonary disease, bronchial asthma, acute lung injury, chronic granulomatous disease, nonalcoholic fatty liver disease, hepatic ischemia–reperfusion injury, kidney fibrosis, acute kidney injury, cardiovascular disorders, and cancer. We are also concerned with the current knowledge in either preclinical or clinical studies of various CPT activators/inhibitors for the management of diseases. These compounds range from traditional Chinese medicines to novel nanodevices. Although great efforts have been made in studying the different kinds of CPT agonists/antagonists, only a few pharmaceuticals have been applied for clinical uses. Nevertheless, research on CPT activation or inhibition highlights the pharmacological modulation of CPT-dependent FAO, especially on different CPT isoforms, as a promising anti-inflammatory/antitumor therapeutic strategy for numerous disorders.

Secondary Hemophagocytic Lymphohistiocytosis and Autoimmune Cytopenias: Case Description and Review of the Literature

Hemophagocytic lymphohistocytosis (HLH) is a rare hyperinflammatory condition which may be primary or secondary to many diseases, including hematologic malignancies. Due to its life-threatening evolution, a timely diagnosis is paramount but challenging, since it relies on non-specific clinical and laboratory criteria. The latter are often altered in other diseases, including autoimmune cytopenias (AIC), which in turn can be secondary to infections, systemic autoimmune or lymphoproliferative disorders. In the present article, we describe two patients presenting at the emergency department with acute AICs subsequently diagnosed as HLH with underlying diffuse large B cell lymphoma. We discuss the diagnostic challenges in the differential diagnosis of acute cytopenias in the internal medicine setting, providing a literature review of secondary HLH and AIC.