Hemophagocytic syndromes and infection

BENTA disease or CARD11 gain-of-function? A novel variant with atypical features and a literature review

INTRODUCTION

The CARD11 (Caspase Recruitment Domain Family Member 11) gene encodes a scaffold protein critical for NF-κB signaling, regulating B-cell differentiation and T-cell effector functions. Gain-of-function (GOF) mutations in CARD11 cause BENTA disease (B cell Expansion with NF-κB and T cell Anergy), an autosomal dominant disorder typically presenting with early-onset polyclonal B-cell lymphocytosis, splenomegaly, lymphadenopathy, and recurrent infections.

METHODS

We describe three related patients harboring a novel CARD11-GOF mutation (D357E), presenting with a BENTA phenotype with atypical features, including high IgM levels and a normal B-cell count, with life-threatening HLH in one case. Additionally, we conducted a systematic literature review using PubMed and EMBASE to identify previously reported cases of CARD11 GOF mutations.

RESULTS

In vitro functional analysis demonstrated that the D357E variant activates the NF-κB signaling pathway in primary lymphocytes and in HEK293T cells transfected with mutant CARD11. Our literature review identified 13 studies describing 29 patients. Notably, HLH emerged as a common complication of CARD11 GOF mutations (18.8 %), while B-lymphocytosis -though frequent- was not universally present.

CONCLUSION

We identified a novel pathogenic CARD11 variant and described its atypical phenotype, further expanding the clinical spectrum of CARD11 GOF disorders. These findings underscore the need for increased awareness of HLH risk in patients with CARD11 GOF mutations.

Case Report: Bilateral adrenal hemorrhage and hemophagocytosis in the reticuloendothelial system caused by Escherichia coli in a young woman: an autopsy case

Background

Sepsis can lead to life-threatening complications such as hemophagocytic lymphohistiocytosis (HLH) and bilateral adrenal hemorrhage (BAH), commonly known as Waterhouse-Friderichsen syndrome. HLH involves severe inflammation and organ damage, often linked with infections and autoimmune diseases, while BAH leads to adrenal insufficiency, typically caused by Neisseria meningitidis, though Escherichia coli (E. coli) is a rare cause.

Case presentation

A 27-year-old Japanese woman, with a history of diabetes mellitus and obesity, presented with a complicated urinary tract infection. She commenced oral levofloxacin treatment five days before hospital admission. Her medications included prednisolone 5 mg/day, trimethoprim-sulfamethoxazole for pyoderma gangrenosum, and oral hypoglycemic agents. Upon admission, her vital signs, including body temperature and blood pressure, were stable, and her body mass index was recorded at 49.8. Laboratory tests indicated elevated white blood cell count and C-reactive protein. She was diagnosed with a urinary tract infection and was treated with levofloxacin and trimethoprim-sulfamethoxazole. On day 16 of hospitalization, her general condition rapidly worsened, leading to her sudden death on day 18. Premortem blood tests showed cytopenia, and blood cultures tested positive for E. coli. Autopsy imaging using computed tomography revealed enlargement and high density of the left adrenal gland. Postmortem pathology identified bilateral adrenal hemorrhages with focal necrosis. Extensive erythrophagocytic macrophages were observed in the bone marrow, spleen, and liver. Disseminated intravascular coagulopathy was confirmed through the detection of a renal glomerular fibrin thrombus.

Conclusion

We concluded that E. coli infection had caused multiple fatal conditions, such as disseminated intravascular coagulopathy, bilateral adrenal hemorrhage, and suspected hemophagocytic lymphohistiocytosis leading to the death of the young woman.

Successful treatment of hemophagocytic lymphohistiocytosis in a trauma patient: a case report

Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening hyperinflammatory syndrome characterized by excessive activation of the immune system. This case report describes an unusual presentation of HLH triggered by severe trauma from a motorcycle accident, which is a departure from traditional associations with infections, malignancies, or autoimmune conditions. A 40-year-old man with multiple traumatic injuries developed persistent fever, pancytopenia, and elevated inflammatory markers following orthopedic surgery. Despite empiric antibiotic therapy, his condition deteriorated, exhibiting high fever, skin rash, hepatic dysfunction, and marked elevation of ferritin levels (32,901 ng/mL). Bone marrow biopsy confirmed the diagnosis of HLH, and treatment was initiated according to the HLH-2004 protocol, which included methylprednisolone, intravenous immunoglobulin, and immunosuppressive therapy. The patient demonstrated significant clinical improvement and was discharged after 37 days, with no recurrence observed during the follow-up period. This case underscores the need to consider HLH in trauma patients presenting with unexplained inflammatory responses and illustrates that prompt diagnosis and aggressive treatment can lead to successful outcomes.

Hemophagocytic Lymphohistiocytosis/Macrophage Activation Syndrome in pediatric Inflammatory Bowel Disease: clinical characteristics and outcomes

Hemophagocytic Lymphohistiocytosis (HLH)/Macrophage Activation Syndrome (MAS) in children with inflammatory bowel disease (IBD) has been reported only anecdotally. This study aimed at describing the clinical features and outcomes of children diagnosed with both IBD and HLH/MAS. Data on IBD and HLH/MAS characteristics, biochemical, microbiological and genetic assessments, treatments, and outcomes were collected from the Italian Pediatric IBD Registry and presented using descriptive statistics. Out of 4643 patients with IBD, 18 (0.4%) were diagnosed with HLH/MAS, including 12 with ulcerative colitis and 6 with Crohn disease. Among the 18 patients, 7 (39%) had early-onset IBD, but the median age at HLH/MAS diagnosis was 14.0 years (IQR 11.9-16.0). Half of the patients had active IBD at HLH/MAS diagnosis, 11 (61%) patients were on thiopurines, and 6 (33%) were on anti-TNF biologics. An infectious trigger was identified in 15 (83%) patients. One (5%) patients was diagnosed with XIAP deficiency. All patients discontinued thiopurines and 5 (83.3%) discontinued anti-TNF biologics; 16 (80%) patients received steroids for HLH/MAS. Three (17%) patients had a relapse of HLH/MAS. No patient developed lymphoma or died during a median follow-up of 2.7 years (IQR 0.8-4.4). Conclusions: HLH/MAS mainly affects children with early-onset IBD but primarily develops during adolescence, following an infection while on immunosuppressant treatment. Although the prognosis is generally favorable, it is crucial to investigate an underlying immune deficiency.

Control strategies for emerging infectious diseases: Crimean-Congo hemorrhagic fever management

Background and Aims

Crimean-Congo Hemorrhagic Fever (CCHF) is a significant public health concern transmitted by ticks. This study seeks to thoroughly grasp the epidemiology and transmission patterns of CCHF, which is caused by the CCHF virus (CCHFV), a member of the Nairovirus genus in the Bunyaviridae family.

Methods

The study investigates the global distribution and endemicity of CCHF, its mortality rates, modes of transmission (including tick bites, contact with infected animal blood, and limited person-to-person transmission), and factors influencing its prevalence across different regions. Genetic diversity within CCHFV and its impact on transmission dynamics are explored, along with efforts to control the disease through tick prevention, antiviral treatment, and the development of vaccines and diagnostics.

Results

CCHFV exhibits widespread distribution, particularly in the Middle East, Africa, Asia, and Eastern Europe, with an overall mortality rate of approximately 30% and a case fatality rate ranging from 10% to 40%. Transmission occurs primarily through tick bites and contact with infected animal blood, with limited person-to-person transmission. Livestock workers, slaughterhouse employees, and animal herders in endemic areas are most affected by their frequent interaction with sick animals and ticks. Genetic diversity within CCHFV contributes to variations in transmission dynamics, complicating control efforts. Antiviral ribavirin shows efficacy in treating CCHF infection.

Conclusion

This study underscores the importance of further research to understand the enzootic environment, transmission routes, and genetic diversity of CCHFV for effective control measures, including the development of vaccines, treatment options, and diagnostics.

Hemophagocytic lymphohistiocytosis in Egyptian children: diagnosis, treatment challenges, and outcome

BACKGROUND

Hemophagocyticlymphohistiocytosis (HLH) is a spectrum of immune activation which could be genetically determined, or secondary to an underlying illness. Our aim was to present the clinico-genetic aspects of HLH among Egyptian children and to evaluate the patterns of reactivation and outcome with illustrations of overlap manifestations.

RESEARCH DESIGNAND METHODS

We retrospectively collected the data of 55 patients with HLH, registered at Ain Shams University Children's Hospital,Cairo, Egypt.

RESULTS

Median age at diagnosis was 19 months (range 2-180), 33 patients (60%) fulfilled the diagnostic HLH criteria at presentation. Fourteen (25.45%) patients had secondary HLH, 15 (27.27%) patients had genetically documented familial HLH (11 had variants in UNC13D gene and one in PRF1 gene), 3 had Griscelli and Chediak-Higashi syndromes. Sixteen patients (29.1%) had reactivations, 8 (50%) of them had molecularly confirmed HLH. We report the death of 40 patients, the median duration from the diagnosis to death of 5 months mostly due to disease activity.

CONCLUSIONS

This study confirms that the nonspecific signs and symptoms of HLH are challenging. Genetic testing, though expensive and sophisticated, is integral for the diagnosis. The difficulty in finding non-related donors for stem cell transplantation and the early reactivations are the causes of the inferior outcome.

Liver Dysfunction in Adult Hemophagocytic Lymphohistiocytosis: A Narrative Review

Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening condition that has been increasingly recognized in adults and is characterized by a hyperinflammatory state due to immune dysregulation. Its nonspecific presentation, the lack of clinician familiarity given its rarity, and shared clinical features with sepsis and other syndromes can lead to a delay in diagnosis and a poor prognosis. Significant liver function abnormalities as the initial manifestation of HLH are uncommon and can range from mild elevation of aminotransferases to fulminant hepatic failure with high mortality rates. The authors encountered a case of adult HLH mimicking acute viral hepatitis in which a markedly elevated ferritin level led to a prompt diagnosis, early initiation of treatment, and a successful outcome. Clinicians, including gastroenterologists and hepatologists, are often called upon to evaluate patients with abnormal liver tests and may lack experience in the early diagnosis and management of liver dysfunction in the context of HLH. Thus, we expand our reporting to a narrative review of literature which explores the pathogenesis of HLH, challenges associated with its diagnosis, previous reports of liver disease associated with the syndrome, recommended treatments for the familial and adult variations including the role of liver transplantation, and the outcomes of these treatments.

A Case of Pyrexia of Unknown Origin Diagnosed as Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a rare disease that is even rarer in the adult population. It requires a high degree of suspicion from the treating physician, and if diagnosed early, patients might have a survival benefit from this highly fatal condition. HLH is a disorder of immune regulation where the hyperactivity of cytokines attacks different cells, which leads to multiple organ dysfunctions. Varying presentations and similarities with other diseases make diagnosis difficult. Familial HLH is commonly seen in the pediatric population, while acquired or secondary HLH is seen in adults. Secondary HLH is commonly triggered by neoplasms, infections, rheumatological diseases, and other autoimmune diseases. Here is a case of HLH that presented as chronic undiagnosed fever. In this case report, we have discussed in detail this disease, its presentation, investigations, treatment, and other important information that will help practicing doctors better diagnose and treat HLH patients.

Chylothorax Chronicles: Tubercular Lymphadenopathy and Hemophagocytic Lymphohistiocytosis

Chylothorax delineates a state marked by the accumulation of chyle, an opalescent fluid laden with lipids, within the pleural cavity. This occurrence commonly ensues from the seepage of chyle originating from the thoracic duct, occasioned by trauma, surgical interventions, or underlying pathological conditions. This phenomenon induces respiratory distress, necessitating intricate and tailored interventions for its resolution. In this report, we present the case of a 27-year-old male who was admitted with a two-month history of symptoms, including dry cough, weakness, weight loss, and intermittent fever. Previously treated for pleural effusions and ascites, he was referred to our hospital with an intercostal drainage tube in place. Initial examinations revealed respiratory distress, fever, and bilateral pleural effusions. Laboratory results and fluid analysis indicated significant abnormalities, prompting further investigations, including CT scans and biopsies. The patient was diagnosed with chylothorax with chylous ascites due to abdominal tubular lymphadenopathy and hemophagocytic lymphohistiocytosis (HLH) and started on anti-tubercular therapy (AKT4) and octreotide. The patient was also initially managed with non-invasive ventilatory (NIV) support, intravenous antibiotics, nebulizations, an intercostal chest drain (ICD), and a thoracic duct embolization (TDE). Regular monitoring and collaboration between specialties were crucial, ultimately resulting in the removal of the drainage tube and the patient's stable discharge.

Infectious Triggers of Cytokine Storm Syndromes: Herpes Virus Family (Non-EBV)

The herpesviruses are the most common infectious agents associated with both primary and secondary cytokine storm syndromes (CSS). While Epstein-Barr Virus (EBV) is most frequently reported in association with CSS, cytomegalovirus (CMV) and many other herpesviruses (e.g., herpes simplex virus, varicella zoster virus, and human herpesviruses 6 and 8) are clearly associated with CSS in children and adults. Immunocompromised hosts, whether due to primary immunodeficiency or secondary immune compromise (e.g., solid organ or stem cell transplantation), appear to be at particularly increased risk of herpesvirus-associated CSS. In this chapter, the association of the non-EBV herpesviruses with CSS will be discussed, including predisposing factors and treatment considerations.

Hemophagocytic Lymphohistiocytosis and Anti-neutrophil Cytoplasmic Antibody-associated Vasculitis Possibly Caused by Enterococcus faecalis Infective Endocarditis

Infection can induce hemophagocytic lymphohistiocytosis (HLH) and anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). We herein report a 52-year-old man who had HLH and AAV simultaneously, possibly caused by Enterococcus faecalis infective endocarditis. The HLH diagnosis was based on the HLH-2004 criteria. AAV was diagnosed based on a positive result for proteinase-3 ANCA and necrotizing vasculitis of the small vessels on a skin biopsy. He eventually died and was sent for autopsy after combination treatment of valve replacement, antibiotics, and immunosuppressants, including corticosteroids. This case involved a challenging diagnosis and treatment of HLH with various complications in an adult.

Haemophagocytic lymphohistiocytosis due to Burkholderia pseudomallei in a primigravida

Introduction

Melioidosis is caused by Burkholderia pseudomallei, a Gram-negative, saprophytic bacillus, commonly found in soil or contaminated water. As infection with this bacterium produces a wide variety of clinical manifestations the organism is aptly called the 'great mimicker'. Even though it is non-fastidious and an easily cultivable organism, it can be misidentified in automated identification systems.

Case report

A 24-year-old primigravida presented with complaints of fever and myalgia of 45 days' duration. She was diagnosed to have haemophagocytic lymphohistiocytosis (HLH) based on clinical and laboratory parameters. Blood and bone marrow culture sent to the microbiology laboratory grew non-fermenting Gram-negative bacilli which were misidentified as Burkholderia cepacia by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) technology. It was subsequently identified as B. pseudomallei by 16S rRNA gene sequencing. The patient was commenced on intensive phase therapy with intravenous ceftazidime for 2 weeks, followed by maintenance therapy with oral trimethoprim and sulfamethoxazole for 3 months. In view of HLH, she was treated with intravenous dexamethasone for 2 weeks which was later switched to oral dexamethasone for a period of 6 weeks. She responded well to the treatment, but had to undergo medical termination of her pregnancy as there was severe intrauterine growth restriction of the fetus.

Conclusion

Prognosis of melioidosis is excellent if early diagnosis and appropriate antibiotic treatment is provided. In this era of automation, it is important to determine if the suspected pathogen is listed in the database of the automated identification system.

Spectrum of Hemophagocytosis in Bone Marrow Aspirates: Experience from a Tertiary Care Hospital in North India

Background

Hemophagocytosis refers to the engulfment of hematopoietic cells by histiocytes. It can be seen in various conditions but is usually reported in the setting of hemophagocytic lymphohistiocytosis (HLH). Optimal interpretation of hemophagocytosis in the bone marrow in relation to the underlying disease significantly contributes to correct patient management.

Aim

The present study was done to identify the spectrum of conditions associated with hemophagocytosis in the bone marrow aspirates and grade the degree of hemophagocytosis.

Material and Methods

This retrospective observational study included all the bone marrow aspirates showing hemophagocytosis, identified over a period of 5 years (January 2015 to January 2020). Two pathologists independently reviewed bone marrow slides. Hemophagocytosis was graded as mild, moderate, or severe by observing the number of histiocytes showing hemophagocytosis per 500 nucleated cells.

Results

Eighty-eight patients showing hemophagocytosis in the bone marrow aspirate smear were included in the study. The most common cause of hemophagocytosis was infection (18%). There were 4 (5%) cases of HLH. Grade 1 (mild) hemophagocytosis was seen in 25 (29%) cases followed by Grade 2 (moderate) in 53 (60%) cases and Grade 3 (severe) in 10 (11%) cases. Fever was the most common clinical symptom present in 45 (51%) cases.

Conclusion

Hemophagocytosis in bone marrow aspirates is a common and under-reported finding. It is not only seen in cases of HLH but also in infections and other conditions. Documenting hemophagocytosis, even in the absence of fulfilled HLH criteria, is vital to explain cytopenias.

SFTSV infection is associated with transient overproliferation of monoclonal lambda-type plasma cells

The impairment of antibody-mediated immunity is a major factor associated with fatal cases of severe fever with thrombocytopenia syndrome (SFTS). By collating the clinical diagnosis reports of 30 SFTS cases, we discovered the overproliferation of monoclonal plasma cells (MCP cells, CD38⁺cLambda⁺cKappa^-) in bone marrow, which has only been reported previously in multiple myeloma. The ratio of CD38⁺cLambda⁺ versus CD38⁺cKappa⁺ in SFTS cases with MCP cells was significantly higher than that in normal cases. MCP cells presented transient expression in the bone marrow, which was distinctly different from multiple myeloma. Moreover, the SFTS patients with MCP cells had higher clinical severity. Further, the overproliferation of MCP cells was also observed in SFTS virus (SFTSV)-infected mice with lethal infectious doses. Together, SFTSV infection induces transient overproliferation of monoclonal lambda-type plasma cells, which have important implications for the study of SFTSV pathogenesis, prognosis, and the rational development of therapeutics.

A young Saudi female with combined hemophagocytic lympho-histiocytosis and Kikuchi's disease: A case report

Kikuchi's disease is an idiopathic self-limiting condition first reported in Japan in 1972. However, hemophagocytic lympho-histiocytosis is a condition that occurs due to overstimulation of the immune system. The presence of the two conditions is rare, and the clinical observation of this unusual clinical syndrome is worth reporting. We are reporting an 18-year-old Saudi female patient who presented with high-grade fever and diaphoresis 3 weeks before her presentation. Physical examination showed palpable cervical and axillary lymphadenopathy; laboratory investigation found neutropenia, a high lactate dehydrogenase of 550 U/L, and high ferritin levels. A thoracoabdominal computed tomographic study revealed generalized lymphadenopathy. She was diagnosed with hemophagocytic lympho-histiocytosis based on a bone marrow biopsy finding and Kikuchi's disease based on an excisional cervical lymph node biopsy. She received a high dose of dexamethasone with complete resolution of the condition. In conclusion, hemophagocytic lympho-histiocytosis and Kikuchi's Disease are uncommon conditions. The presence of a combination of such two conditions is extremely rare and worth reporting. Early diagnosis and initiation of the management with high dexamethasone dose could save patient life.

Distribution pattern of Crimean-Congo Hemorrhagic Fever in Asia and the Middle East

Crimean-Congo Hemorrhagic Fever (CCHF) is one of the most important vector-borne diseases of zoonotic potential that can be acquired following the bite of the Hyalomma species of ticks. It is a highly prevalent disease in Asia and the Middle East. The risk factors of this disease are contact with infected tissue, blood, patient, or livestock in the acute viremic phase, infected tick bites, or the manual removal of ticks. The disease is clinically described as progressive hemorrhages, fever, and pain in musculature. Biochemical tests reveal elevated levels of creatinine phosphokinase, alanine transaminase, aspartate aminotransferase, and lactate dehydrogenase. Clotting time is prolonged in pro-thrombin tests, and pathogenesis is mostly related to the disruption of the epithelium during viral replication and indirectly by secreting cytotoxic molecules. These molecules cause endothelial activation and result in the loss of function. Supportive therapy is given through blood or plasma infusions to treat or manage the patients. According to the most advanced studies, CCHF can be treated by Ribavirin, which is an antiviral drug that shows excellent results in preventing the disease. Health-care staff are more prone to infection. The hemorrhagic phase represents a high risk for accidental exposures. This literature review presents a comprehensive overview of the viral epidemiology, zoonotic perspectives, and significant risk factors of CCHF in various Middle East and Asian countries. Furthermore, the pathophysiology and preventive strategies of CCHF have also been discussed as well as legislation and policies regarding public outreach programs, research, and development aimed at infection prevention and control that are required at a global level.

Serum thrombin-activatable fibrinolysis inhibitor levels and its relation with pathogenesis and bleeding and prognosis in patients with Crimean Congo hemorrhagic fever

Crimean-Congo hemorrhagic fever (CCHF) is a viral hemorrhagic fever, which is common in Turkey and globally. The pathogenesis of coagulation disorders, which is seen in viral hemorrhagic fevers remains to be elucidated. Thrombin-activatable fibrinolysis inhibitor (TAFI) has a key role in this process In this study, we aimed to evaluate whether TAFI levels contributed to bleeding and whether it is related to prognosis in CCHF patients. Eighty-four patients older than 15 years of age, who were admitted to our hospital who had positive immunoglobulin M (enzyme-linked immunosorbent assay [ELISA]) and/or polymerase chain reaction test results for CCHF between 2009 and 2010, were included in the study. The control group included 30 healthy adults. The plasma TAFI levels were compared between patients and controls, and also between patients with bleeding and no bleeding, and between patients with mild-moderate and severe disease. The mean TAFI levels were lower in patients (mean: 87.82 ng/ml, median: 61.69 ng/ml (interquartile range [IQR] 30.49-537.95) than controls (mean: 313.5 ng/ml with a median: 338.5 ng/ml (IQR 182-418). However, median TAFI levels were significantly higher in patients with bleeding compared to those without bleeding (78.99 and 50.28 ng/ml, respectively; p = 0.032). Median IQR TAFI levels were similar between patients with mild-moderate and severe disease (64.72 (41.37-113.85), and, 58.66 (42.44-118.93) ng/ml, respectively; p = 0.09) and survivors and nonsurvivors (86.14 ± 77.98 and 103.48 ± 69.92, respectively; p = 0.3). Although TAFI levels were lower in the patients with CCHF compared to healthy controls, it does not seem to be a major player in the prognosis.

A Review of Current and Emerging Therapeutic Options for Hemophagocytic Lymphohistiocytosis

Objective:

To provide an overview of clinical sequelae and emerging treatment options for hemophagocytic lymphohistiocytosis (HLH).

Data Sources:

A literature search was conducted using the search terms “hemophagocytic lymphohistiocytosis,” “hemophagocytic syndrome,” “macrophage activation syndrome,” and “treatment” on Ovid and PubMed from January 1, 2017, through September 28, 2022.

Study Selection and Data Extraction:

Relevant clinical trials, meta-analyses, case reports, review articles, package inserts, and guidelines to identify current and emerging therapeutic options for the management of HLH.

Data Synthesis:

Genetic disorders and secondary causes may trigger HLH in both children and adults. Notable improvements in the diagnosis of HLH were seen with implementation of the HLH-2004 standard diagnostic criteria; however, timely and accurate identification of HLH remain significant barriers to optimal management. Multiagent immunochemotherapy are the backbone of aggressive therapy for acutely ill patients with HLH.

Relevance to Patient Care and Clinical Practice:

The global coronavirus 2019 (COVID-19) pandemic and emerging immune effector cell therapies have served to highlight the concerns with immune dysregulation and subsequent HLH precipitation. Without prompt identification and treatment, HLH can be fatal. Historically, the clinician’s armamentarium for managing HLH was sparse, with etoposide-based protocols serving as the standard of care. Relapsed or refractory disease portends a poor prognosis and requires additional treatment options. Second- or subsequent-line options now include hematopoietic stem cell transplantation, emapalumab, alemtuzumab, anakinra, ruxolitinib, and tocilizumab.

Conclusions:

Improvements in diagnostic methods and novel immunosuppressive treatment strategies, including noncytotoxic immunochemotherapy, have transformed the therapeutic landscape. Unfortunately, many unanswered questions remain. Additional studies are required to optimize dosing, schedules, treatment sequences, and indications for novel treatment options.

Babesia microti-induced fulminant sepsis in an immunocompromised host: A case report and the case-specific literature review

Babesia microti is an obligate intra-erythrocytic parasite transmitted by infected ticks. B. microti is a eukaryote much larger than prokaryotic microbes and more similar to human hosts in their biochemistry and metabolism. Moreover, Babesia spp. possess various immune evasion mechanisms leading to persistent and sometimes life-threatening diseases in immunocompromised hosts. Chronic lymphocytic leukemia (CLL) is the most prevalent adult B-cell malignancy, and a small percentage of CLL transforms into aggressive lymphomas. CLL also causes immune dysfunction due to the over-expansion of immature and ineffective B-cells. When our patient with indolent CLL presented with anemia, pancytopenia, and splenomegaly, all his healthcare providers presumptively assumed a malignant transformation of CLL. However, these are also the signs and symptoms of babesiosis. Herein, we report a case where B. microti infection was presumed as a malignant transformation of CLL and narrowly avoided a devastating outcome. Although the patient developed fulminant sepsis, he finally received the correct diagnosis and treatment. Unfortunately, the disease recrudesced twice. Each time, it became more difficult to control the infection. We describe the clinical course of the case and discuss the case-specific literature review. This report highlights the importance of differential diagnoses ruling out infections which include babesiosis, prior to initiating the treatment of B-cell malignancy.

Tuberculosis infection related hemophagocytic lymphohistiocytosis diagnosed in patient with GZMB mutation: A case report and literature review

BACKGROUND

Secondary hemophagocytic lymphohistiocytosis (HLH) is a life-threatening syndrome associated with infections, tumors and connective tissue disease. However rapid identification of the underlying infectious cause of HLH is challenging because traditional etiological diagnostics are time-consuming and sometimes fail to identify the pathogens. Metagenomic next-generation sequencing (mNGS) may be a potential optimal solution, which may help improve the clinical diagnosis of underlying infections in hematological diseases.

CASE PRESENTATION

A 28-year-old man presented with a 2-month history of intermittent fever and cytopenia. The HLH was diagnosed based on the manifestations of fever, splenomegaly, anemia, thrombocytopenia, hyperferritinemia, hyperglyceridemia, and elevated IL-2R levels. High-through-put sequencing analysis detected a GZMB mutation. While the initial detection of cultures and smears of tuberculosis was negative, TB infection was eventually identified by mNGS of blood sample. The symptoms rapidly abated during the initial administration of TB.

CONCLUSION

The present case proposed that mNGS might be an effective diagnostic tool for diagnosing rare infectious cause of secondary HLH. GZMB mutation was first discovered to be present in secondary HLH.

Exploring the Immunomodulatory Aspect of Mesenchymal Stem Cells for Treatment of Severe Coronavirus Disease 19

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is an enveloped, positive sense, single stranded RNA (+ssRNA) virus, belonging to the genus Betacoronavirus and family Coronaviridae. It is primarily transmitted from infected persons to healthy ones through inhalation of virus-laden respiratory droplets. After an average incubation period of 2–14 days, the majority of infected individuals remain asymptomatic and/or mildly symptomatic, whereas the remaining individuals manifest a myriad of clinical symptoms, including fever, sore throat, dry cough, fatigue, chest pain, and breathlessness. SARS-CoV-2 exploits the angiotensin converting enzyme 2 (ACE-2) receptor for cellular invasion, and lungs are amongst the most adversely affected organs in the body. Thereupon, immune responses are elicited, which may devolve into a cytokine storm characterized by enhanced secretion of multitude of inflammatory cytokines/chemokines and growth factors, such as interleukin (IL)-2, IL-6, IL-7, IL-8, IL-9, tumor necrosis factor alpha (TNF-α), granulocyte colony-stimulating factor (GCSF), basic fibroblast growth factor 2 (bFGF2), monocyte chemotactic protein-1 (MCP1), interferon-inducible protein 10 (IP10), macrophage inflammatory protein 1A (MIP1A), platelet-derived growth factor subunit B (PDGFB), and vascular endothelial factor (VEGF)-A. The systemic persistence of inflammatory molecules causes widespread histological injury, leading to functional deterioration of the infected organ(s). Although multiple treatment modalities with varying effectiveness are being employed, nevertheless, there is no curative COVID-19 therapy available to date. In this regard, one plausible supportive therapeutic modality may involve administration of mesenchymal stem cells (MSCs) and/or MSC-derived bioactive factors-based secretome to critically ill COVID-19 patients with the intention of accomplishing better clinical outcome owing to their empirically established beneficial effects. MSCs are well established adult stem cells (ASCs) with respect to their immunomodulatory, anti-inflammatory, anti-oxidative, anti-apoptotic, pro-angiogenic, and pro-regenerative properties. The immunomodulatory capabilities of MSCs are not constitutive but rather are highly dependent on a holistic niche. Following intravenous infusion, MSCs are known to undergo considerable histological trapping in the lungs and, therefore, become well positioned to directly engage with lung infiltrating immune cells, and thereby mitigate excessive inflammation and reverse/regenerate damaged alveolar epithelial cells and associated tissue post SARS-CoV-2 infection. Considering the myriad of abovementioned biologically beneficial properties and emerging translational insights, MSCs may be used as potential supportive therapy to counteract cytokine storms and reduce disease severity, thereby facilitating speedy recovery and health restoration.

Deepening the knowledge of rare diseases dependent on angiogenesis through semantic similarity clustering and network analysis

BACKGROUND

Angiogenesis is regulated by multiple genes whose variants can lead to different disorders. Among them, rare diseases are a heterogeneous group of pathologies, most of them genetic, whose information may be of interest to determine the still unknown genetic and molecular causes of other diseases. In this work, we use the information on rare diseases dependent on angiogenesis to investigate the genes that are associated with this biological process and to determine if there are interactions between the genes involved in its deregulation.

RESULTS

We propose a systemic approach supported by the use of pathological phenotypes to group diseases by semantic similarity. We grouped 158 angiogenesis-related rare diseases in 18 clusters based on their phenotypes. Of them, 16 clusters had traceable gene connections in a high-quality interaction network. These disease clusters are associated with 130 different genes. We searched for genes associated with angiogenesis througth ClinVar pathogenic variants. Of the seven retrieved genes, our system confirms six of them. Furthermore, it allowed us to identify common affected functions among these disease clusters.

AVAILABILITY

https://github.com/ElenaRojano/angio_cluster.

CONTACT

seoanezonjic@uma.es and elenarojano@uma.es.

Hemophagocytic Lymphohistiocytosis Secondary to Tuberculosis After Liver Transplantation: A Case Report

Hemophagocytic lymphohistiocytosis (HL) is a rare syndrome characterized by a hyperinflammatory state, resulting from an excessive but ineffective immune response. There is a continuous stimulation of TCD8 + lymphocytes, associated with an uncontrolled release of cytokines, causing the infiltration of multiple organs by histiocytes and activated lymphocytes. HL can be a primary condition as a consequence of genetic disorder that most often affects children, or it can be secondary to neoplasms, autoimmune conditions or various infectious diseases in patients of all ages. HL caused by infection by Mycobacterium tuberculosis is highly unusual, with few cases reported in the literature. There is no clinical manifestation or laboratorial finding that is specific to HL, and a high index of clinical suspicion is necessary for the correct diagnosis, which is usually confirmed by biopsy. Treatment consists of controlling the causative event and the use of immunosuppressant drugs such as corticosteroids, etoposide, and cyclosporine to suppress the exacerbated immune response. We report the case of a patient who developed HL 2 months after liver transplantation. The initial presentation was persistent fever, prompting a search for a site of infection and the use of broad-spectrum antibiotics. As the clinical condition of the patient continued to deteriorate, HL was diagnosed through a bone marrow biopsy, and a cerebrospinal fluid culture positive for M. tuberculosis established the diagnosis of disseminated tuberculosis. Despite optimal treatment with immunosuppressors and antituberculosis drugs, there was no significant response and the patient died. This article is compliant with the Helsinki Congress and the Istanbul Declaration.

Secondary Hemophagocytic Lymphohistiocytosis - A Common Ramification of Different Diseases

Hemophagocytic lymphohistiocytosis is a rare and potentially fatal disorder caused by immune dysregulation. It can occur as a primary genetic disease or secondarily due to various causes including infections, malignancies or autoimmune diseases. In this case report, we present two cases of Hemophagocytic lymphohistiocytosis which were secondary to typhoid and dengue fever. While primary disease occurs predominantly in infants, secondary hemophagocytic lymphohistiocytosis can occur in any age group. Both primary and secondary hemophagocytic lymphohistiocytosis are characterised by fever, hepatosplenomegaly, pancytopenia and multiorgan dysfunction. But unusual persistence of fever and other organ involvement should need further workup for hemophagocytic lymphohistiocytosis. Secondary hemophagocytic lymphohistiocytosis may resolve on treating the underlying disorder. But severe cases need treatment with immunosuppressive/immunomodulation therapy to prevent morbidity. Early clinical suspicion, prompt diagnosis and treatment of hemophagocytic lymphohistiocytosis are essential to prevent deleterious effects to health.

Outcome of Viral-associated Hemophagocytic Lymphohistiocytosis at a Tertiary Hospital

BACKGROUND

Little is known about viral-associated hemophagocytic lymphohistiocytosis (HLH) in Oman. This study was done to assess the epidemiology, clinical features and outcome of viral-associated HLH in our setting.

METHODS

We retrospectively reviewed children (0-18 years) managed for viral-associated HLH at the Sultan Qaboos University Hospital, Oman, over a 15-year period (2006-2020). Patients' medical records were used to describe their demographic, clinical and laboratory features, management and outcome.

RESULTS

Fifty-six children were managed for HLH at Sultan Qaboos University Hospital over the last 15 years (2006-2020) of whom a third (19; 34%) had a viral trigger. The median age at the time of diagnosis of viral-associated HLH was 83 (13-96) months. Fever, cytopenia, hyperferritinemia and evidence of hemophagocytosis in bone marrow were the most consistent findings. Most of these children had either genetic predisposition to HLH (8/19; 42%) or underlying immunodeficiency secondary to malignant conditions or chemotherapy/hematopoietic stem cell transplantation (6/19; 32%). Epstein-Barr virus (9; 47%) followed by cytomegalovirus (6; 31%) was the most common viral trigger in our setting. Treatment included antivirals (8; 42%), HLH 2004 protocol (4; 21%), rituximab (4; 21%) and hematopoietic stem cell transplantation (3; 16%). Fourteen children (74%) had full recovery.

CONCLUSIONS

In our small cohort, viral-associated HLH was more frequently encountered in children with genetic predisposition to HLH or children with underlying immunodeficiency. In addition, we found that the outcome is overall good for children who have no genetic predisposition to HLH and children with genetic predisposition who underwent hematopoietic stem cell transplantation.

Hemophagocytic lymphohistiocytosis associated with parvovirus B19-induced aplastic crisis in a hereditary spherocytosis patient: A case report and literature review

Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of pathologic immune activation. It occurs because of severe inflammation due to uncontrolled proliferation of activated lymphocytes and histiocytes, characterized by the production of excessive levels of cytokines. Virus-associated HLH is a well-known entity, and parvovirus B19 is one of the common causes. Parvovirus B19 can also affect blood cell lineages. Therefore, HLH may be accompanied by several diseases such as cytopenia, aplastic anemia, and myelodysplastic syndrome. Herein, we report the case of a patient with hereditary spherocytosis who was diagnosed with parvovirus B19-induced HLH and aplastic crisis. A 7-year-old girl presented to our hospital with fever, pleural effusion, pancytopenia, hepatosplenomegaly, and hypotension. A bone marrow biopsy was performed under the suspicion of HLH, which revealed hemophagocytes. The diagnostic criteria for HLH were met, and prompt chemoimmunotherapy was initiated considering the clinically unstable situation. Her health improved rapidly after initiating treatment. Further study revealed that she had hereditary spherocytosis, and parvovirus B19 had caused aplastic crisis and HLH. The patient's clinical progress was excellent, and chemoimmunotherapy was reduced and discontinued at an early stage. This case shows that aplastic crisis and HLH can coexist with parvovirus B19 infection in patients with hereditary spherocytosis. Although the prognosis was good in this case of HLH caused by parvovirus B19, early detection and active treatment are essential.

Acute hepatitis A infection-associated hemophagocytic lymphohistiocytosis in adult presenting as impending acute liver failure: A case report and literature review

Hemophagocytic lymphohistiocytosis has been reported as a severe complication of various viral infections but unusual for the hepatitis A virus. We report a case of 25-year-old man with hepatitis A infection-associated hemophagocytic lymphohistiocytosis and impending acute liver failure to emphasize the importance of early diagnosis and treatment of this condition.

An infant with omenn syndrome: A case report

Background

Omenn syndrome is a rare, autosomal recessive disorder. It is a disorder that stems from severe combined immunodeficiency in an affected individual. The disease is also of rare occurrence in children in Pakistan because this is the age where this disease usually presents, after having developed in the child. This case report will explore all the reasons that lead to the occurrence of this syndrome while also reflecting on the management profile of the child.

Case presentation

This case report deals with the discussion of one such child who was diagnosed with Omenn Syndrome after being diagnosed with several other diseases, which were being mistaken for being the actual problem and disease, but the reality was that the child was suffering from Omenn syndrome.

Discussion

The child is only 3 months old and his symptoms pose a great risk to his overall health status while also making him predisposed to develop several complications and nutritional deficiencies as a result, all of which keep on adding to the burden of diseases that the child faced. In Omenn syndrome, there is an increased susceptibility to develop infections of the skin, lungs, joints, as well as sepsis. Usually, the death of the patient ensues due to pneumonia and septicemia or septic shock.

Conclusion

Omenn syndrome is a rare disease caused by missense mutations in the recombinase activating genes. It can be treated by bone marrow transplantation or lymphocytic stimulation depending on the severity of the presenting underlying immunodeficiency.

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Omenn syndrome is severe combined immune deficiency syndrome which is rare in children.

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Omenn syndrome are caused by missense mutations in the recombinase activating genes (RAG-1 and RAG-2). Mutations in these genes cause dysregulation in the B and T-cell functions.

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This case report deals with the discussion of one such child diagnosed with Omenn’ Syndrome who was mistakenly diagnosed with other disease, but the reality was that the child was suffering from Omenn syndrome.

Dengue-Induced Hemophagocytic Lymphohistiocytosis: A Case Report and Literature Review

Hemophagocytic lymphohistiocytosis (HLH) is an uncommon fatal disease of otherwise normal but hyperactive lymphocytes and histocytes. HLH could be primary (hereditary) or secondary (acquired). Fever, hepatosplenomegaly, lymphadenopathy, and neurologic dysfunction are among the common symptoms of HLH. The diagnosis of HLH is based on clinical and biochemical findings. We report here a case of a patient infected with the dengue virus who developed HLH during hospitalization. A 63-year-old female known case of asthma on inhalers, chronic hepatitis B virus, gastritis on proton pump inhibitors, and hemoglobin H disease presented to the emergency department (ED) with a history of high-grade fever (highest recorded temperature 40° C/ 104° F), which was relieved partially by antipyretics, generalized fatigability, body aches, headache and mosquito bites for four days. The physical examination was significant for hepatomegaly of 4 cm below the right costal margin. Investigations revealed pancytopenia with elevated ferritin levels (> 40000 µg/L). Viral serology was positive for dengue NS1 antigen. After hematology consultation, a bone marrow biopsy was done, which showed trilineage hematopoiesis with increased histiocytes and occasional hemophagocytosis. Given that the patient was clinically stable and there was a clear triggering condition, we opted for supportive measures rather than HLH-specific therapy. The patient was given 2 units packed red blood cells for anemia. On the following days, the patient has no recurrence of fever, with marked improvement in the biochemical profile including ferritin level (1165 µg/L). HLH is a deleterious disease with a high fatality rate, which requires the clinician to have a low threshold for suspicion in the differentials of children and adults with symptoms of persistent fever, hepatosplenomegaly, and cytopenia. Dengue-associated HLH diagnosis is challenging, but it is very important to be recognized, as early recognition is associated with better outcomes. Physicians must work in collaboration with pathologists and microbiologists for the proper diagnosis.

Untreated Squamous Cell Lung Carcinoma May Contribute to the Occurrence of Hemophagocytic Syndrome

A 44-year-old man presented at our hospital to be evaluated for persistent fever and dyspnea. A chest computed tomography (CT) scan showed diffuse ground glass shadows and a left hilar tumor shadow. Upon further examination, he was found to have leukopenia, thrombocytopenia, and elevated lactate dehydrogenase and ferritin levels. He was diagnosed with both squamous cell lung carcinoma by a transbronchial lung biopsy and hemophagocytic syndrome by a bone marrow biopsy. After receiving treatment with dexamethasone and etoposide, the blood test abnormalities and performance status improved. Chemotherapy for lung cancer was initiated. He had a partial response after first-line chemotherapy and thereafter underwent left upper sleeve lobectomy.

Epidemiological and Clinicopathological Features of Anaplasma phagocytophilum Infection in Dogs: A Systematic Review

Anaplasma phagocytophilum is a worldwide emerging zoonotic tick-borne pathogen transmitted by Ixodid ticks and naturally maintained in complex and incompletely assessed enzootic cycles. Several studies have demonstrated an extensive genetic variability with variable host tropisms and pathogenicity. However, the relationship between genetic diversity and modified pathogenicity is not yet understood. Because of their proximity to humans, dogs are potential sentinels for the transmission of vector-borne pathogens. Furthermore, the strong molecular similarity between human and canine isolates of A. phagocytophilum in Europe and the USA and the positive association in the distribution of human and canine cases in the USA emphasizes the epidemiological role of dogs. Anaplasma phagocytophilum infects and survives within neutrophils by disregulating neutrophil functions and evading specific immune responses. Moreover, the complex interaction between the bacterium and the infected host immune system contribute to induce inflammatory injuries. Canine granulocytic anaplasmosis is an acute febrile illness characterized by lethargy, inappetence, weight loss and musculoskeletal pain. Hematological and biochemistry profile modifications associated with this disease are unspecific and include thrombocytopenia, anemia, morulae within neutrophils and increased liver enzymes activity. Coinfections with other tick-borne pathogens (TBPs) may occur, especially with Borrelia burgdorferi, complicating the clinical presentation, diagnosis and response to treatment. Although clinical studies have been published in dogs, it remains unclear if several clinical signs and clinicopathological abnormalities can be related to this infection.

Line-selective macrophage activation with an anti-CD40 antibody drives a hemophagocytic syndrome in mice

Hemophagocytic syndromes comprise a cluster of hyperinflammatory disorders, including hemophagocytic lymphohistiocytosis and macrophage activation syndrome. Overwhelming macrophage activation has long been considered a final common pathway in the pathophysiology of hemophagocytic syndromes leading to the characteristic cytokine storm, laboratory abnormalities, and organ injuries that define the clinical spectrum of the disease. So far, it is unknown whether primary macrophage activation alone can induce the disease phenotype. In this study, we established a novel mouse model of a hemophagocytic syndrome by treating mice with an agonistic anti-CD40 antibody (Ab). The response in wild-type mice is characterized by a cytokine storm, associated with hyperferritinemia, high soluble CD25, erythrophagocytosis, secondary endothelial activation with multiple organ vaso-occlusion, necrotizing hepatitis, and variable cytopenias. The disease is dependent on a tumor necrosis factor-α-interferon-γ-driven amplification loop. After macrophage depletion with clodronate liposomes or in mice with a macrophage-selective deletion of the CD40 gene (CD40flox/flox/LysMCre), the disease was abolished. These data provide a new preclinical model of a hemophagocytic syndrome and reinforce the key pathophysiological role of macrophages.

Macrophage activation syndrome revealing Hodgkin's lymphoma: a case report

Macrophage activation syndrome (MAS) is a rare immunologic syndrome, rapidly fatal in the absence of specific etiological treatment. It is defined by clinical, biological and cyto-histological criteria. Numerous etiologies have been described in MAS, the association with Hodgkin lymphoma (LH) is exceptional. We report the case of a young woman in whom a macrophage activation syndrome reveals a Hodgkin's lymphoma.

Ruxolitinib treatment permits lower cumulative glucocorticoid dosing in children with secondary hemophagocytic lymphohistiocytosis

BACKGROUND

This study aimed to analyze the effects of ruxolitinib on children with secondary hemophagocytic lymphohistiocytosis (HLH).

METHODS

Eleven pediatric patients diagnosed with HLH and treated with ruxolitinib (ruxolitinib group: group R) between November 2017 and August 2018 were retrospectively analyzed. Eleven age-matched pediatric patients with HLH undergoing conventional treatment (control group: group C) during the same period were also analyzed.

RESULTS

In group R, three patients who did not respond to methylprednisolone (MP) pulse and intravenous immunoglobulin (IVIG) therapies were treated with Ruxolitinib and their temperature decreased to normal levels. Four patients had normal temperature after conventional treatment (dexamethasone and etoposide, with or without cyclosporine A), but they had severe organ involvement, including obvious yellowing of the skin, increased liver enzyme levels and neuropsychiatric symptoms, and they were all ameliorated with ruxolitinib treatment. Four patients were relieved with ruxolitinib therapy alone. In group C, the body temperatures of eleven patients decreased to normal levels after conventional treatment. The body temperature of group R patients decreased to normal levels more rapidly than that of group C patients. The glucocorticoid dosage in group R was significantly lower than that in group C. Both groups were followed-up for 2-2.5 years. No obvious adverse drug reactions to ruxolitinib were observed during treatment and follow-up.

CONCLUSION

Ruxolitinib might be an effective drug in controlling body temperature and reducing inflammation indicators. It might be a potential replacement for glucocorticoid therapy for HLH treatment in children, thereby reducing or avoiding glucocorticoid-related adverse reactions.

Unique immunological profile in patients with COVID-19

The relationship between severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and host immunity is poorly understood. We performed an extensive analysis of immune responses in 32 patients with severe COVID-19, some of whom succumbed. A control population of healthy subjects was included. Patients with COVID-19 had an altered distribution of peripheral blood lymphocytes, with an increased proportion of mature natural killer (NK) cells and low T-cell numbers. NK cells and CD8⁺ T cells overexpressed T-cell immunoglobulin and mucin domain-3 (TIM-3) and CD69. NK cell exhaustion was attested by increased frequencies of programmed cell death protein 1 (PD-1) positive cells and reduced frequencies of natural killer group 2 member D (NKG2D)-, DNAX accessory molecule-1 (DNAM-1)- and sialic acid-binding Ig-like lectin 7 (Siglec-7)-expressing NK cells, associated with a reduced ability to secrete interferon (IFN)γ. Patients with poor outcome showed a contraction of immature CD56^bright and an expansion of mature CD57⁺ FcεRIγ^neg adaptive NK cells compared to survivors. Increased serum levels of IL-6 were also more frequently identified in deceased patients compared to survivors. Of note, monocytes secreted abundant quantities of IL-6, IL-8, and IL-1β which persisted at lower levels several weeks after recovery with concomitant normalization of CD69, PD-1 and TIM-3 expression and restoration of CD8⁺ T cell numbers. A hyperactivated/exhausted immune response dominate in severe SARS-CoV-2 infection, probably driven by an uncontrolled secretion of inflammatory cytokines by monocytes. These findings unveil a unique immunological profile in COVID-19 patients that will help to design effective stage-specific treatments for this potentially deadly disease.

Secondary Hemophagocytic Lymphohistiocytosis in a Young Hispanic Adult

Hemophagocytic lymphohistiocytosis (HLH) is a disease caused by a severe immune system reaction that involves an overwhelming inflammatory response with overproduction of cytokines and hemophagocytosis. HLH is classified as primary HLH or familial HLH (PHLH or FHLH) and secondary HLH. PHLH is due to mutations in several genes that regulate immune cells, while secondary HLH is triggered by a severe illness (viral infections or malignancies) that induce an excessive immune response that is difficult to control. We present a case of a young Hispanic adult female with a medical history of diabetes mellitus type 1 and hepatitis E that was diagnosed with HLH secondary to lymphoma caused by Epstein Barr virus infection. The patient was started on broad-spectrum antibiotics and steroid therapy; however, the patient succumbed to the disease. HLH is associated with high mortality, mainly because it is not a very common entity and patients usually present critically ill and deteriorate very fast. Immunosuppression and treatment of the underlying disorder is the target of the treatment of HLH, however, the prognosis remains poor.

Clinical, immunological and genetic findings in patients with UNC13D deficiency (FHL3): A systematic review

BACKGROUND

Familial hemophagocytic lymphohistiocytosis (FHL) is a rare autosomal recessive immune disorder that is caused by mutations in 6 different genes related to the formation and function of secretory lysosomes within cytotoxic T lymphocytes and natural killer (NK) cells. Thus, defect in these genes is associated with the accumulation of antigens due to defective cytotoxic function. FHL type 3 (FHL3) accounts for nearly 30-40% of FHL, and its underlying reason is mutation in UNC13D gene which encodes Munc13-4 protein.

METHODS

For the first time, we aimed to systematically review clinical features, immunologic data, and genetic findings of patients with FHL3. We conducted electronic searches for English-language articles in PubMed, Web of Science, EMBASE, and Scopus databases to collect comprehensive records related to patients with UNC13D mutations.

RESULTS

A total of 279 abstracts were initially reviewed for inclusion. Among them, 57 articles corresponding to 322 individual FHL3 patients fulfilled our selection criteria. Finally, 73 and 249 patients were considered as severe and mild feature groups, respectively. Our results confirmed that fever, hepatosplenomegaly, and hemophagocytosis are common clinical features in the disease. Moreover, reduced fibrinogen and NK cell activity, as well as increased ferritin and triglycerides, are important markers for early diagnosis of the FHL3 disease. Investigation of genotype showed that the most prevalent type and zygosity of UNC13D are splice-site errors and compound heterozygous, respectively.

CONCLUSION

FHL3 patients have a wide range of clinical manifestations, which makes it difficult to diagnose. Therefore, it seems that the sequencing of the entire UNC13D gene (coding and non-coding regions) is the most appropriate way to accurate diagnosis of FHL3 patients.

Report of a Fatal Case of Hemophagocytic Lymphohistiocytosis Syndrome and a Review of the Literature

Hemophagocytic lymphohistiocytosis (HLH) is a rare condition in children, with a high mortality rate of 41.99%. Often, due to the atypical presentation of HLH, the syndrome is difficult to diagnose. We report a case of an atypical presentation of HLH and the diagnostic dilemma that we faced. An 11-year-old boy was hospitalized with recurrent fever, hepatosplenomegaly, and worsening jaundice. Initial laboratory workup revealed an elevated prothrombin time (PT), high bilirubin, increased alanine transaminase (ALT), and positive Epstein Barr virus (EBV) deoxyribonucleic acid (DNA) polymerase chain reaction (PCR) and EBV immunoglobulin G (IgG). Based on our patient's presentation and initial laboratory findings, further extensive workup was done, which revealed cytopenias, hypofibrinogenemia, hemophagocytosis on biopsy, absent natural killer (NK) cell activity, high serum ferritin level, and high soluble CD25 (sIL-2 receptor); a diagnosis of HLH was made. He was started on broad-spectrum antibiotics, antivirals, antifungals, and cyclosporine. He became hypoxic and hypotensive and hence was intubated and started on vasopressors. However, his coagulation profile continued to deteriorate. He started bleeding from multiple sites and became unresponsive to ventilatory support, eventually dying as a result of complications of HLH. The ambiguous clinical presentation makes the diagnosis of this syndrome difficult. However, due to the high fatality rate, early recognition and prompt treatment are of utmost importance.

Unique immunological profile in patients with COVID-19

The relationship between severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and host immunity is poorly understood. We performed an extensive analysis of immune responses in 32 patients with severe COVID-19, some of whom succumbed. A control population of healthy subjects was included. Patients with COVID-19 had an altered distribution of peripheral blood lymphocytes, with an increased proportion of mature natural killer (NK) cells and low T-cell numbers. NK cells and CD8⁺ T cells overexpressed T-cell immunoglobulin and mucin domain-3 (TIM-3) and CD69. NK cell exhaustion was attested by increased frequencies of programmed cell death protein 1 (PD-1) positive cells and reduced frequencies of natural killer group 2 member D (NKG2D)-, DNAX accessory molecule-1 (DNAM-1)- and sialic acid-binding Ig-like lectin 7 (Siglec-7)-expressing NK cells, associated with a reduced ability to secrete interferon (IFN)γ. Patients with poor outcome showed a contraction of immature CD56^bright and an expansion of mature CD57⁺ FcεRIγ^neg adaptive NK cells compared to survivors. Increased serum levels of IL-6 were also more frequently identified in deceased patients compared to survivors. Of note, monocytes secreted abundant quantities of IL-6, IL-8, and IL-1β which persisted at lower levels several weeks after recovery with concomitant normalization of CD69, PD-1 and TIM-3 expression and restoration of CD8⁺ T cell numbers. A hyperactivated/exhausted immune response dominate in severe SARS-CoV-2 infection, probably driven by an uncontrolled secretion of inflammatory cytokines by monocytes. These findings unveil a unique immunological profile in COVID-19 patients that will help to design effective stage-specific treatments for this potentially deadly disease.

Unusual Manifestations of Dengue Fever: A Review on Expanded Dengue Syndrome

Dengue infection may manifest as dengue fever (DF), dengue hemorrhagic fever (DHF), and dengue shock syndrome (DSS). The World Health Organization (WHO) came up with the term "expanded dengue syndrome" (EDS) to designate cases which do not fall into either DHF or DSS, with unusual manifestations in other organs such as the cardiovascular system, the nervous system, the kidneys, the gut, and the hematological system, which have been increasingly reported and called EDS. Furthermore, EDS is becoming widespread globally with unusual features and increased severity. There are increasing reports of under-recognized and infrequent manifestations with severe organ involvement. This review gives knowledge of expanded dengue syndrome which helps to catch the diagnosis of dengue early, particularly during the ongoing epidemics and escaping from further series of unnecessary investigations.

Insights on SARS-CoV-2 Molecular Interactions With the Renin-Angiotensin System

The emergence of SARS-CoV-2/human/Wuhan/X1/2019, a virus belonging to the species Severe acute respiratory syndrome-related coronavirus, and the recognition of Coronavirus Disease 2019 (COVID-19) as a pandemic have highly increased the scientific research regarding the pathogenesis of COVID-19. The Renin Angiotensin System (RAS) seems to be involved in COVID-19 natural course, since studies suggest the membrane-bound Angiotensin-converting enzyme 2 (ACE2) works as SARS-CoV-2 cellular receptor. Besides the efforts of the scientific community to understand the virus' molecular interactions with human cells, few studies summarize what has been so far discovered about SARS-CoV-2 signaling mechanisms and its interactions with RAS molecules. This review aims to discuss possible SARS-CoV-2 intracellular signaling pathways, cell entry mechanism and the possible consequences of the interaction with RAS components, including Angiotensin II (Ang II), Angiotensin-(1-7) [Ang-(1-7)], Angiotensin-converting enzyme (ACE), ACE2, Angiotensin II receptor type-1 (AT1), and Mas Receptor. We also discuss ongoing clinical trials and treatment based on RAS cascade intervention. Data were obtained independently by the two authors who carried out a search in the PubMed, Embase, LILACS, Cochrane, Scopus, SciELO and the National Institute of Health databases using Medical Subject Heading terms as "SARS-CoV-2," "COVID-19," "Renin Angiotensin System," "ACE2," "Angiotensin II," "Angiotensin-(1-7)," and "AT1 receptor." Similarly to other members of Coronaviridae family, the molecular interactions between the pathogen and the membrane-bound ACE2 are based on the cleavage of the spike glycoprotein (S) in two subunits. Following the binding of the S1 receptor-binding domain (RBD) to ACE2, transmembrane protease/serine subfamily 2 (TMPRSS2) cleaves the S2 domain to facilitate membrane fusion. It is very likely that SARS-CoV-2 cell entry results in downregulation of membrane-bound ACE2, an enzyme that converts Ang II into Ang-(1-7). This mechanism can result in lung injury and vasoconstriction. In addition, Ang II activates pro-inflammatory cascades when binding to the AT1 Receptor. On the other hand, Ang-(1-7) promotes anti-inflammatory effects through its interactions with the Mas Receptor. These molecules might be possible therapeutic targets for treating COVID-19. Thus, the understanding of SARS-CoV-2 intracellular pathways and interactions with the RAS may clarify COVID-19 physiopathology and open perspectives for new treatments and strategies.

Dengue Hemorrhagic Fever Complicated With Hemophagocytic Lymphohistiocytosis in an Adult With Diabetic Ketoacidosis

Dengue infection can cause a wide spectrum of presentations extending from simple self-limiting febrile illness to severe dengue, including dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). Dengue associated hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening condition characterized by the uncontrolled activation of macrophages and T cells, eliciting clusters of symptoms and signs and abnormal biochemical parameters. Herein we report a 28-year-old Sri Lankan female with no past medical history who presented with dengue hemorrhagic fever and diabetic ketoacidosis complicated with hemophagocytic lymphohistiocytosis. She was treated with a three-day course of intravenous methylprednisolone in addition to standard care for diabetic ketoacidosis and dengue hemorrhagic fever. She made an uneventful recovery.

Infectious Mononucleosis Resulting in Acute Necrotizing Mediastinitis: A Case Report and Literature Review

The serological prevalence of Epstein-Barr virus (EBV) among young adults exceeds 90% worldwide. Even though EBV primary infection is usually benign, severe complications can occur in adolescents and young adults and so the disease must be promptly diagnosed. The development of an oropharyngeal abscess leading to a descending necrotizing mediastinitis (DNM) is exceptional and potentially lethal, so early diagnosis with a CT scan, appropriate antibiotics and surgery are essential. The authors present a case where DNM was associated with reactive hemophagocytic syndrome as a result of infectious mononucleosis, as well as a review of similar cases in the English literature.

LEARNING POINTS

The incidence of serious complications in Epstein-Barr virus (EBV) primary infection increases with age.Respiratory symptoms (e.g., pleuritic pain, dyspnoea) and unusually prolonged fever (>10 days) in patients with infectious mononucleosis could be 'red flags' for life-threatening complications such as empyema and descending necrotizing mediastinitis.The threshold for performing cervical and chest computed tomography in septic patients with infectious mononucleosis should be low.

Cytomegalovirus and disseminated histoplasmosis-related hemophagocytic lymphohistiocytosis syndrome in an HIV-patient late presenter with IRIS: a case report

Background

Hemophagocytic lymphohistiocytosis syndrome (HLS) is an immune-mediated life-threatening disease considered as a medical emergency, with a potentially fatal multisystem inflammatory outcome. We present a patient that developed HLS and was able to be diagnosed efficiently with the help of an academic research institute of immunology.

Case presentation

A 21 years old male Mexican with human immunodeficiency virus (HIV), late presenter; who developed cytomegalovirus (CMV) infection and a disseminated histoplasmosis-related HLS, as part of an immune reconstitution inflammatory syndrome (IRIS). The patient required a long course of corticotherapy, intravenous immunoglobulin and massive transfusions (more than 10 units in 24 h, and a total of 83 units), besides amphotericin-B and ganciclovir treatment. An academic research institute of immunology aided in the accurate diagnosis of HLS with the implementation of tests not available within the hospital, thus improving the care provided to the patient. The patient recovered, was discharged, and continue to improve.

Conclusion

The objective of this report is to highlight the importance of having multidisciplinary support, including basic medical sciences groups providing specific tests that are sometimes very difficult to get, which provides a benefit to patients in the well-aimed diagnosis as part of applied translational medicine.

An Intriguing Presentation of Epstein-Barr Virus-Associated Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is an immune related clinical syndrome with protean manifestations, varying presentation, clinically complex, with diverse causes, and is an under-recognized entity which carries high morbidity and mortality. It is precipitated by an immunological trigger in a susceptible host resulting in immune activation and dysregulation leading to disruption of immune homeostasis, cytokine storm and multi-organ failure. We describe a case of Epstein-Barr virus (EBV) associated HLH with its typical diagnostic challenges and associated high mortality rate. Certain diagnostic criteria and online tools may help to arrive at an earlier presumptive diagnosis which, in turn, may expedite treatment and lead to better clinical outcomes.

Cardiovascular manifestation and treatment in COVID-19

The novel coronavirus disease 2019 (COVID-19), with first presentation of atypical pneumonia, has spread rapidly from Wuhan, China, on December 12, 2019 to over 200 countries, caused 2 310 572 infected individuals and 158 691 mortalities, updated on April 19, 2020. Many studies have published timely to help global healthcare workers to understand and control the disease. Vulnerable patients with risk factors such as elderly, cardiovascular diseases (eg, hypertension, coronary disease, or cardiomyopathy), diabetes, and chronic kidney disease have worse outcomes after COVID-19 infection. COVID-19 could directly cause cardiovascular injuries such as pericarditis, myocarditis, myocardial infarction, heart failure, arrhythmias, or thromboembolic events, which urge cardiologists to be involved in the frontline to practice. Here, we provide a review of COVID-19 on cardiovascular system to assist clinical cardiologists to better understand the disease and being capable of providing comprehensive medical support.