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1.
Arch Pathol Lab Med ; 146(4): 507-519, 2022 04 01.
Article in English | MEDLINE | ID: covidwho-1791951

ABSTRACT

CONTEXT.­: Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening disorder of immune regulation that can eventually result in end-organ damage and death. HLH is characterized by uncontrolled activation of cytotoxic T lymphocytes, natural killer cells, and macrophages that can lead to a cytokine storm. The diagnosis of HLH is often challenging due to the diverse clinical manifestations and the presence of several diagnostic mimics. The prognosis is generally poor, warranting rapid diagnosis and aggressive management. OBJECTIVE.­: To provide a comprehensive review of the pathogenesis, clinical features, diagnosis, and management of HLH. DATA SOURCES.­: Peer-reviewed literature. CONCLUSIONS.­: HLH is a condition where a complete understanding of the pathogenesis, early diagnosis, and proper management has an important role in determining patient outcome. Genetic mutations causing impairment in the function of cytotoxic T lymphocytes and natural killer cells have been identified as the root cause of familial HLH; however, the specific pathogenesis of acquired HLH is unclear. The HLH-2004 protocol used in the diagnosis of HLH was originally developed for the pediatric population. The HLH-2004 protocol still forms the basis of the diagnosis of HLH in adults, although its use in adults has not been formally validated yet. Treatment of HLH is primarily based on the HLH-94 protocol, which involves suppressing the inflammatory response, but the treatment needs to be modified in adults depending on the underlying cause and comorbidities.


Subject(s)
Lymphohistiocytosis, Hemophagocytic , Child , Humans , Killer Cells, Natural , Lymphohistiocytosis, Hemophagocytic/diagnosis , Lymphohistiocytosis, Hemophagocytic/genetics , Lymphohistiocytosis, Hemophagocytic/therapy , Macrophages
2.
BMJ Case Rep ; 15(3)2022 Mar 16.
Article in English | MEDLINE | ID: covidwho-1745766

ABSTRACT

The development of vaccinations has been instrumental in the ongoing effort to combat the COVID-19 pandemic. Although the benefits of vaccination are unquestionable, there have been reports of potentially rare life-threatening complications following vaccination including thrombocytopaenia, haemolytic anaemia, vasculitis and myocarditis. Haemophagocytic lymphohistiocytosis (HLH), a rare but life-threatening inflammatory condition, has also been described postadenoviral vector COVID-19 vaccination but it has never been reported post-messenger RNA (mRNA) COVID-19 vaccination. We report two cases of HLH admitted to our hospital after administration of COVID-19 mRNA vaccines. We also searched the vaccine adverse event reporting system and found 50 reports of suspected HLH following COVID-19 vaccination. Presently, we cannot define a causality between COVID-19 mRNA vaccination and HLH development. However, we hope the reporting of our two cases (and additional cases seen in the adverse event reporting database) will help us determine whether there is a potential relationship. Prompt recognition of this condition is of utmost importance to initiate life-saving therapy.


Subject(s)
COVID-19 , Lymphohistiocytosis, Hemophagocytic , COVID-19/prevention & control , COVID-19 Vaccines/adverse effects , Humans , Lymphohistiocytosis, Hemophagocytic/genetics , Pandemics , RNA, Messenger , Vaccination/adverse effects
3.
Blood Adv ; 4(15): 3754-3766, 2020 08 11.
Article in English | MEDLINE | ID: covidwho-1228984

ABSTRACT

We report the largest prospective study thus far on hematopoietic stem cell transplantation (HSCT) in hemophagocytic lymphohistiocytosis (HLH), a life-threatening hyperinflammatory syndrome comprising familial/genetic HLH (FHL) and secondary HLH. Although all patients with HLH typically need intensive anti-inflammatory therapy, patients with FHL also need HSCT to be cured. In the international HLH-2004 study, 187 children aged <18 years fulfilling the study inclusion criteria (5 of 8 diagnostic criteria, affected sibling, or molecular diagnosis in FHL-causative genes) underwent 209 transplants (2004-2012), defined as indicated in patients with familial/genetic, relapsing, or severe/persistent disease. Five-year overall survival (OS) post-HSCT was 66% (95% confidence interval [CI], 59-72); event-free survival (EFS) was 60% (95% CI, 52-67). Five-year OS was 81% (95% CI, 65-90) for children with a complete response and 59% (95% CI, 48-69) for those with a partial response (hazard ratio [HR], 2.12; 95% CI, 1.06-4.27; P = .035). For children with verified FHL (family history/genetically verified, n = 134), 5-year OS was 71% (95% CI, 62-78) and EFS was 62% (95% CI, 54-70); 5-year OS for children without verified FHL (n = 53) was significantly lower (52%; 95% CI, 38-65) (P = .040; HR, 1.69; 95% CI, 1.03-2.77); they were also significantly older. Notably, 20 (38%) of 53 patients without verified FHL had natural killer cell activity reported as normal at diagnosis, after 2 months, or at HSCT, suggestive of secondary HLH; and in addition 14 (26%) of these 53 children had no evidence of biallelic mutations despite having 3 or 4 FHL genes analyzed (natural killer cell activity not analyzed after 2 months or at HSCT). We conclude that post-HSCT survival in FHL remains suboptimal, and that the FHL diagnosis should be carefully investigated before HSCT. Pretransplant complete remission is beneficial but not mandatory to achieve post-HSCT survival. This trial was registered at www.clinicaltrials.gov as #NCT00426101.


Subject(s)
COVID-19 , Hematopoietic Stem Cell Transplantation , Lymphohistiocytosis, Hemophagocytic , Adolescent , Child , Humans , Lymphohistiocytosis, Hemophagocytic/diagnosis , Lymphohistiocytosis, Hemophagocytic/genetics , Lymphohistiocytosis, Hemophagocytic/therapy , Prospective Studies , SARS-CoV-2 , Systemic Inflammatory Response Syndrome
4.
J Exp Med ; 218(6)2021 06 07.
Article in English | MEDLINE | ID: covidwho-1203555

ABSTRACT

Multisystem inflammatory syndrome in children (MIS-C) emerged in April 2020 in communities with high COVID-19 rates. This new condition is heterogenous but resembles Kawasaki disease (KD), a well-known but poorly understood and clinically heterogenous pediatric inflammatory condition for which weak associations have been found with a myriad of viral illnesses. Epidemiological data clearly indicate that SARS-CoV-2 is the trigger for MIS-C, which typically occurs about 1 mo after infection. These findings support the hypothesis of viral triggers for the various forms of classic KD. We further suggest that rare inborn errors of immunity (IEIs) altering the immune response to SARS-CoV-2 may underlie the pathogenesis of MIS-C in some children. The discovery of monogenic IEIs underlying MIS-C would shed light on its pathogenesis, paving the way for a new genetic approach to classic KD, revisited as a heterogeneous collection of IEIs to viruses.


Subject(s)
COVID-19/etiology , Mucocutaneous Lymph Node Syndrome/genetics , Mucocutaneous Lymph Node Syndrome/virology , SARS-CoV-2/pathogenicity , Systemic Inflammatory Response Syndrome/etiology , Biomarkers/blood , COVID-19/epidemiology , COVID-19/immunology , Child , Cytokines/blood , Genetic Predisposition to Disease , Genome-Wide Association Study , Humans , Inflammation/etiology , Inflammation/genetics , Inflammation/immunology , Inflammation Mediators/blood , Lymphohistiocytosis, Hemophagocytic/genetics , Lymphohistiocytosis, Hemophagocytic/virology , Models, Biological , Mucocutaneous Lymph Node Syndrome/epidemiology , Pandemics , SARS-CoV-2/immunology , Systemic Inflammatory Response Syndrome/epidemiology , Systemic Inflammatory Response Syndrome/immunology
5.
Eur J Hum Genet ; 29(8): 1312-1315, 2021 08.
Article in English | MEDLINE | ID: covidwho-1191639

ABSTRACT

Critically ill coronavirus disease 2019 (COVID-19) is characterized by severe cytokine storms, a hyperinflammatory condition intimately related to the development of fatal outcomes. Why some individuals seem particularly vulnerable to severe cytokine storms is still unknown. Primary immunodeficiency (PID)-related genes are inherited factors that dysregulate host inflammatory responses to infection, especially hemophagocytic lymphohistiocytosis (HLH)-related genes, established as contributors to the development of excessive cytokine storms. We analyzed the association between PID gene variants with severe cytokine storms in COVID-19. We conducted whole-exome sequencing in 233 hospitalized COVID-19 patients and identified four PID gene (UNC13D, AP3B1, RNF168, DHX58) variants were significantly enriched in COVID-19 patients experiencing severe cytokine storms. The total percentage of COVID-19 patients with variants in UNC13D or AP3B1, two typical HLH genes, was dramatically higher in high-level cytokine group than in low-level group (33.3 vs. 5.7%, P < 0.001). Germline variants in UNC13D and AP3B1 were associated with the development of severe cytokine storms, fatal outcomes in COVID-19. These findings advance the understanding of individual susceptibility to severe cytokine storms and help optimize the current management of COVID-19.


Subject(s)
Adaptor Protein Complex 3/genetics , Adaptor Protein Complex beta Subunits/genetics , COVID-19/genetics , COVID-19/pathology , Membrane Proteins/genetics , Adaptor Protein Complex 3/metabolism , Adaptor Protein Complex beta Subunits/metabolism , Aged , COVID-19/immunology , COVID-19/metabolism , Cytokine Release Syndrome/genetics , Humans , Lymphohistiocytosis, Hemophagocytic/genetics , Membrane Proteins/metabolism , Middle Aged
6.
PLoS Comput Biol ; 17(3): e1008810, 2021 03.
Article in English | MEDLINE | ID: covidwho-1121603

ABSTRACT

Abnormal coagulation and an increased risk of thrombosis are features of severe COVID-19, with parallels proposed with hemophagocytic lymphohistiocytosis (HLH), a life-threating condition associated with hyperinflammation. The presence of HLH was described in severely ill patients during the H1N1 influenza epidemic, presenting with pulmonary vascular thrombosis. We tested the hypothesis that genes causing primary HLH regulate pathways linking pulmonary thromboembolism to the presence of SARS-CoV-2 using novel network-informed computational algorithms. This approach led to the identification of Neutrophils Extracellular Traps (NETs) as plausible mediators of vascular thrombosis in severe COVID-19 in children and adults. Taken together, the network-informed analysis led us to propose the following model: the release of NETs in response to inflammatory signals acting in concert with SARS-CoV-2 damage the endothelium and direct platelet-activation promoting abnormal coagulation leading to serious complications of COVID-19. The underlying hypothesis is that genetic and/or environmental conditions that favor the release of NETs may predispose individuals to thrombotic complications of COVID-19 due to an increase risk of abnormal coagulation. This would be a common pathogenic mechanism in conditions including autoimmune/infectious diseases, hematologic and metabolic disorders.


Subject(s)
COVID-19/complications , COVID-19/genetics , Extracellular Traps/genetics , Lymphohistiocytosis, Hemophagocytic/complications , Lymphohistiocytosis, Hemophagocytic/genetics , Models, Biological , SARS-CoV-2/genetics , Thrombosis/etiology , Thrombosis/genetics , Algorithms , Cell Degranulation/genetics , Computational Biology , Gene Expression Regulation , Gene Regulatory Networks , Genetic Predisposition to Disease , Humans , Pandemics , Protein Interaction Maps , Pulmonary Embolism/etiology , Pulmonary Embolism/genetics , Viral Proteins/genetics
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