Haemophagocytic syndrome and COVID-19.

Primary and secondary haemophagocytic lymphohistiocytosis (HLH) are hyperferritinaemic hyperinflammatory syndromes with a common terminal pathway triggered by different etiopathogenetic factors. HLH is characterised by a decreased capacity of interferon gamma production with an activated NK phenotype profile similar to other hyperinflammatory syndromes. Viruses are closely linked to the development of HLH as infectious triggers, and the break of tolerance to self-antigens is considered a critical mechanism involved in the development of immune-mediated conditions triggered by viral infections. Emerging studies in patients with COVID-19 are suggesting a key role of monocytes/macrophages in the pathogenesis of this viral infection, and there is a significant overlap between several features reported in severe COVID-19 and the features included in the HLH-2004 diagnostic criteria. Therefore, SARS-Cov-2, as other respiratory viruses, may also be considered a potential etiological trigger of HLH. The frequency of HLH in adult patients with severe COVID-19 is lower than 5%, although this figure could be underestimated considering that most reported cases lacked information about some specific criteria (mainly the histopathological criteria and the measurement of NK cell function and sCD25 levels). Because HLH is a multi-organ syndrome, the diagnostic approach in a patient with severe COVID-19 in whom HLH is suspected must be carried out in a syndromic and holistic way, and not in the light of isolated clinical or laboratory features. In COVID-19 patients presenting with persistent high fever, progressive pancytopenia, and hepatosplenic involvement, together with the characteristic triad of laboratory abnormalities (hyperferritinaemia, hypertriglyceridaemia, and hypofibrinogenaemia), the suspicion of HLH is high, and the diagnostic workup must be completed with specific immunological and histopathological studies.

[Acquired hemophagocytic syndrome treated with HLH 94-04 chemotherapy protocol: Report of four cases]. / Síndrome hemofagocítico adquirido: reporte de casos de cuatro pacientes adultos tratados con protocolo HLH 94-04 y revisión de la literatura.

Hemophagocytic syndrome is a severe condition of excessive immune activation that has a high mortality in the absence of treatment. The syndrome is classified as primary if associated with congenital or hereditary problems, or secondary/acquired if associated with infectious, autoimmune or oncology diseases. We report four adult cases of the syndrome, one with viral, two with autoimmune and one with idiopathic causes who were successfully treated with HLH 94-04 chemotherapy protocol. Our experience shows that a high index of suspicion, early diagnosis and an opportune therapy are essential in the treatment of this disease.

Síndrome hemofagocítico adquirido: reporte de casos de cuatro pacientes adultos tratados con protocolo HLH 94-04 y revisión de la literatura / Acquired hemophagocytic syndrome treated with HLH 94-04 chemotherapy protocol: Report of four cases

Hemophagocytic syndrome is a severe condition of excessive immune activation that has a high mortality in the absence of treatment. The syndrome is classified as primary if associated with congenital or hereditary problems, or secondary/acquired if associated with infectious, autoimmune or oncology diseases. We report four adult cases of the syndrome, one with viral, two with autoimmune and one with idiopathic causes who were successfully treated with HLH 94-04 chemotherapy protocol. Our experience shows that a high index of suspicion, early diagnosis and an opportune therapy are essential in the treatment of this disease.

[Hemophagocytic syndrome. Current concepts]. / Síndrome hemofagocítico. Conceptos actuales.

Hemophagocytic lymphohistiocytosis is a syndrome characterized by pathological immune activation that may occur as either a primary a familial disorder (associated with genetic mutations), or as a sporadic condition, associated to infections, malignancies or autoimmune diseases. The clinical picture is characterized by a disproportionate inflammation that causes fever, cytopenias, splenomegaly, bone marrow hemophagocytosis, hypertriglyceridemia and hypofibrinogenemia. Syndrome-related mortality is high, so it is important to maintain a high index of suspicion and start early treatment with immunochemotherapy and bone marrow transplantation in primary and refractory cases. In this article, we review the clinical manifestations, pathology, diagnosis and treatment of these patients.

Novel syntaxin 11 gene (STX11) mutation in three Argentinean patients with hemophagocytic lymphohistiocytosis.

INTRODUCTION: Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening disease with major diagnostic and therapeutic difficulties, basically comprising two different conditions: primary and secondary forms. Recent advances regarding molecular diagnosis may be useful to distinguish from one another, especially in sporadic cases starting in early infancy. MATERIALS AND METHODS: In this report, we evaluated three Argentinean patients with clinical suspicion of HLH, but without family history. We excluded mutations in the perforin gene but identified in the three patients a novel homozygous deletion (c. 581_584delTGCC; p.Leu194ProfsX2) in the gene-encoding syntaxin 11 (STX11), causing a premature termination codon. RESULTS AND CONCLUSION: Each parent from the three unrelated families resulted heterozygous for this deletion confirming the diagnosis of familial hemophagocytic lymphohistiocytosis type 4. Patients shared the same single-nucleotide polymorphism profile in STX11 gene, and genotyping at ten microsatellites surrounding this gene support the presence of a single-haplotype block carrying the novel mutation.

Hepatitis A-associated macrophage activation syndrome in children with systemic juvenile idiopathic arthritis: report of 2 cases.

OBJECTIVE: We describe two 3-year-old patients with systemic juvenile idiopathic arthritis (SJIA) who developed hepatitis A-associated macrophage activation syndrome (MAS). One patient showed MAS as the presenting manifestation of SJIA, while MAS complicated SJIA during the second year of the disease course in the other child. Both girls presented with fever, jaundice, hepatosplenomegaly, neurological involvement, mucosal hemorrhage, and purpura. Cytopenias, hypofibrinogenemia, and hemophagocytosis confirmed the diagnosis. After aggressive treatment with high-dose corticosteroids and immunosuppressants one patient entered remission while the other one died. Hepatitis A virus may induce severe MAS in SJIA.

[Reactive hemophagocytic syndrome in critical care patients. Report of 4 cases]. / Sindrome hemofagocitico reactivo en pacientes graves. Comunicacion de 4 casos.

Reactive hemophagocytic syndrome or hemophagocytic lymphohistiocytosis comprises a variety of disorders, many of them associated with infection. It is characterized by hemophagocytosis, with cytopenia involving at least two cellular lines, increase in cytokines and serum ferritin. The clinical course resembles sepsis, sharing similar physiopathological features. We propose that hemophagocytic syndrome is an underdiagnosed entity in the critical care setting; simple tests aid to identify which patients should undergo diagnostic procedures. We discuss current therapeutic approaches.

Síndrome hemofagocítico reactivo en pacientes graves: Comunicación de 4 casos / Reactive hemophagocytic syndrome in critical care patients. Report of 4 cases

El síndrome hemofagocítico reactivo, o linfohistiocitosis hemofagocítica secundaria, comprende un grupo numeroso de enfermedades, muchas de ellas de causa infecciosa, caracterizado por hemofagocitosis con citopenia de al menos dos de las tres series sanguíneas, aumento de los niveles de citoquinas y de la ferritina sérica. El cuadro clínico comprende manifestaciones inflamatorias sistémicas semejantes a la sepsis, entidad muy frecuente en las unidades de Terapia Intensiva, y posee elementos fisiopatológicos en común con ella. Proponemos mediante la presentación de cuatro casos clínicos, considerar al síndrome hemofagocítico reactivo como una entidad frecuente en los pacientes graves, con pruebas sencillas para orientar a qué pacientes realizar un procedimiento diagnóstico. Por último actualizamos los tratamientos específicos conocidos. (AU)

Reactive hemophagocytic syndrome or hemophagocytic lymphohistiocytosis comprises a variety of disorders, many of them associated with infection. It is characterized by hemophagocytosis, with cytopenia involving at least two cellular lines, increase in cytokines and serum ferritin. The clinical course resembles sepsis, sharing similar physiopathological features. We propose that hemophagocytic syndrome is an underdiagnosed entity in the critical care setting; simple tests aid to identify which patients should undergo diagnostic procedures. We discuss current therapeutic approaches. (AU)

Síndrome hemofagocítico reactivo en pacientes graves: Comunicación de 4 casos / Reactive hemophagocytic syndrome in critical care patients. Report of 4 cases

El síndrome hemofagocítico reactivo, o linfohistiocitosis hemofagocítica secundaria, comprende un grupo numeroso de enfermedades, muchas de ellas de causa infecciosa, caracterizado por hemofagocitosis con citopenia de al menos dos de las tres series sanguíneas, aumento de los niveles de citoquinas y de la ferritina sérica. El cuadro clínico comprende manifestaciones inflamatorias sistémicas semejantes a la sepsis, entidad muy frecuente en las unidades de Terapia Intensiva, y posee elementos fisiopatológicos en común con ella. Proponemos mediante la presentación de cuatro casos clínicos, considerar al síndrome hemofagocítico reactivo como una entidad frecuente en los pacientes graves, con pruebas sencillas para orientar a qué pacientes realizar un procedimiento diagnóstico. Por último actualizamos los tratamientos específicos conocidos.

Reactive hemophagocytic syndrome or hemophagocytic lymphohistiocytosis comprises a variety of disorders, many of them associated with infection. It is characterized by hemophagocytosis, with cytopenia involving at least two cellular lines, increase in cytokines and serum ferritin. The clinical course resembles sepsis, sharing similar physiopathological features. We propose that hemophagocytic syndrome is an underdiagnosed entity in the critical care setting; simple tests aid to identify which patients should undergo diagnostic procedures. We discuss current therapeutic approaches.