In Silico Structure-Based Design of Antiviral Peptides Targeting the Severe Fever with Thrombocytopenia Syndrome Virus Glycoprotein Gn.

Severe fever with thrombocytopenia syndrome virus (SFTSV) is an emerging tick-borne bunyavirus in Asia that causes severe disease. Despite its clinical importance, treatment options for SFTSV infection remains limited. The SFTSV glycoprotein Gn plays a major role in mediating virus entry into host cells and is therefore a potential antiviral target. In this study, we employed an in silico structure-based strategy to design novel cyclic antiviral peptides that target the SFTSV glycoprotein Gn. Among the cyclic peptides, HKU-P1 potently neutralizes the SFTSV virion. Combinatorial treatment with HKU-P1 and the broad-spectrum viral RNA-dependent RNA polymerase inhibitor favipiravir exhibited synergistic antiviral effects in vitro. The in silico peptide design platform in this study may facilitate the generation of novel antiviral peptides for other emerging viruses.

Thrombocytopenia in COVID-19: Focused Summary of Current Understanding of Mechanisms and Clinical Implications.

Thrombocytopenia is noted in corona virus disease-2019 (COVID-19) with a prevalence of 5% to 41%, and has been observed to be associated with inferior outcomes. The pathogenesis of thrombocytopenia in COVID-19 is unique and differs from other viral syndromes in terms of clinical presentation and causative mechanisms. Platelets act as both targets and the initial defense against severe acute respiratory syndrome-coronavirus 2 and work in concert with the underlying thrombophilic mechanisms to modulate the final disease phenotype. Understanding these mechanisms may possibly allow targeting of a key component of COVID-19 pathogenesis. We provide a focused review of the current mechanisms implicated in development of thrombocytopenia in COVID-19 and therapeutic implications of the same.

Coronavirus Disease 2019 (COVID-19): A Haematologist's Perspective.

Coronavirus disease 2019 (COVID-19) is affecting millions of patients worldwide. It is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which belongs to the family Coronaviridae, with 80% genomic similarities to SARS-CoV. Lymphopenia was commonly seen in infected patients and has a correlation to disease severity. Thrombocytopenia, coagulation abnormalities, and disseminated intravascular coagulation were observed in COVID-19 patients, especially those with critical illness and non-survivors. This pandemic has caused disruption in communities and hospital services, as well as straining blood product supply, affecting chemotherapy treatment and haematopoietic stem cell transplantation schedule. In this article, we review the haematological manifestations of the disease and its implication on the management of patients with haematological disorders.

Two patients, two viruses and multiple sites of injury in the kidney.

Viral nephropathy is a term defines glomerular, tubular and/or vascular injury in kidney caused by viruses itself or virus-induced immune mechanisms. It is difficult to prove causality between the renal disease and the viral infection, however, renal biopsy findings can help in this regard. Several viruses such as hepatitis B and C, Human immun deficiciency virus (HIV), Hantavirus, Cytomegalovirus (CMV), an recently Coronavirus are shown to affect the kidney. Treatment of viral nephropathies are unique regarding the diagnosis which can be made only with renal biopsy in most of the situations. We present two patients presented with acute kidney injury and thrombocytopenia caused by different viruses (Hantavirus and HIV) that affect multiple areas in kidney that revealed with kidney biopsy. Supportive treatment in the patient with Hantavirus nephropathy and HIV treatment along with eculizumab and supportive treatment in the patient with HIVAN were successfully implemented.

A Novel Use of Romiplostim for SARS-CoV-2-induced Thrombocytopenia.

The literature regarding coronavirus disease of 2019 (COVID-19) infection in pediatrics indicates that children have less severe clinical presentations and lower mortality rates. There remains limited data regarding hematologic sequelae in pediatric patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Romiplostim has shown a platelet response in pediatric patients with chronic immune thrombocytopenic purpura, and eltrombopag is proven to increase platelet counts in patients with inherited thrombocytopenia. We review SARS-CoV-2-associated thrombocytopenia and present a pediatric patient with acute on chronic thrombocytopenia in the setting of COVID-19 with subsequent platelet recovery using romiplostim.

Severe thrombocytopaenia secondary to COVID-19.

The SARS-CoV-2 infection has caused a pandemic with a case rate of over 290 000 lab-confirmed cases and over 40 000 deaths in the UK. There is little evidence to inform the optimal management of a patient presenting with new or relapsed acute idiopathic thrombocytopaenic purpura with concurrent SARS-CoV-2 infection. We present a case of severe thrombocytopaenia complicated by subdural haematoma and rectal bleed associated with COVID-19. A 67-year-old man, admitted with a non-productive cough and confusion, was found to be positive for COVID-19. Ten days after admission, his platelets decreased from 146×109/L to 2×109/L. His platelets did not increase despite receiving frequent platelet transfusions. He was non-responsive to corticosteroids and intravenous immunoglobulins. Romiplostim and eltrombopag were given and after 9 weeks of treatment, his platelet count normalised. He was deemed medically fit with outpatient follow-up in a haematology clinic.

Successful management of COVID-19 and associated coagulopathy in a patient with durable left ventricular assist device.

Patients with durable left ventricular assist devices pose special problems for management in the setting of COVID-19 infection. We describe the successful management of a 44-year-old man with severe COVID-19 infection and HeartMate 3 left ventricular assist device. His course was complicated by cytokine storm and COVID-19-associated coagulopathy. We describe our institutional protocol for managing COVID-19 infection in patients on mechanical circulatory support, focusing on the need for a thoughtful, multidisciplinary approach.

Hematological manifestations of COVID-19.

The emergence of the Coronavirus Disease -19 (COVID-19) pandemic, has had a tremendous global impact, resulting in substantial morbidity and mortality worldwide and especially in the United States, where nearly one third of the cases are located. Although involvement of the lower respiratory track accounts for most of the morbidity and mortality seen, the virus involves several organ systems and the syndrome exhibits clinical diversity with a wide range of symptoms and manifestations. The involvement of elements of the hematopoietic system is prominent in severe cases and associated with poor outcomes and mortality. Lymphopenia, leukopenia, thrombocytopenia, disseminated intravascular coagulation, and a prothrombotic state are common manifestations of COVID-19 and have important treatment and prognostic implications. Better understanding of the mechanisms of the pathophysiology of COVID-19-induced hematological abnormalities may ultimately result in better ways to treat them and decrease the associated morbidity and mortality.

Hematological findings in coronavirus disease 2019: indications of progression of disease.

Coronavirus disease 2019 (COVID-19) is a new human infectious disease. The etiology for this outbreak is a novel coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Thus far, related research on COVID-19 is still in preliminary stage. This paper summarized the latest outcomes of corresponding study from Chinese centers and clarified the hematopoietic abnormality caused by SARS-CoV-2 and potential mechanism. Lymphopenia was common in the early stage after the onset of COVID-19. A significant decrease was observed in peripheral CD4+ and CD8+ T lymphocytes. As the illness progressed, neutrophilia emerged in several cases, and patients with severe critical pulmonary conditions showed higher neutrophils than common type. Thrombocytopenia was resulting from the consumption and/or the reduced production of platelets in damaged lungs. Anemia was not observed notably, but the decrease in hemoglobin was frequent. The activation of monocyte-macrophage system aggravates the immune damage of lung and other tissues, which leads to the increase of D-dimer, prothrombin time, and platelet consumption.

Delayed-phase thrombocytopenia in patients with coronavirus disease 2019 (COVID-19).

Coronavirus disease 2019 (COVID-19) can affect the haematopoietic system. Thrombocytopenia at admission was prevalent, while late-phase or delayed-phase thrombocytopenia (occurred 14 days after symptom onset) is rare. This retrospective, single-centre study screened 450 COVID-19 patients and enrolled 271 patients at the Union Hospital, Wuhan, China, from January 25 to March 9, 2020. COVID-19-associated delayed-phase thrombocytopenia occurred in 11·8% of enrolling patients. The delayed-phase thrombocytopenia in COVID-19 is prone to develop in elderly patients or patients with low lymphocyte count on admission. The delayed-phase thrombocytopenia is significantly associated with increased length of hospital stay and higher mortality rate. Delayed-phase nadir platelet counts demonstrated a significantly negative correlation with B cell percentages. We also provided and described bone marrow aspiration pathology of three patients with delayed-phase thrombocytopenia, showing impaired maturation of megakaryocytes. We speculated that immune-mediated platelet destruction might account for the delayed-phase thrombocytopenia in a group of patients. In addition, clinicians need to pay attention to the delayed-phase thrombocytopenia especially at 3-4 weeks after symptom onset.

Serial analysis of cytokine and chemokine profiles and viral load in severe fever with thrombocytopenia syndrome: Case report and review of literature.

RATIONALE: Severe fever with thrombocytopenia syndrome (SFTS) is a recently recognized fatal infectious disease caused by the SFTS virus, and severe cases are complicated by the presence of hemophagocytic lymphohistiocytosis (HLH) associated with a cytokine storm. Herein, we report on serial changes of serum cytokine levels and viral load in a severe case of SFTS. PATIENT CONCERNS: A 63-year-old Japanese woman presented with high-grade fever, abdominal pain, diarrhea, impaired consciousness, leukocytopenia, and thrombocytopenia. DIAGNOSIS: SFTS was diagnosed based on a positive serum test for SFTS virus RNA and electroencephalogram (EEG) findings of encephalopathy. INTERVENTIONS: The patient was treated with supportive therapy, including steroid pulse therapy (intravenous methylprednisolone 1 g/d for 3 days) for HLH and intravenous recombinant thrombomodulin 19200 U/d for 7 days for disseminated intravascular coagulation. OUTCOMES: Treatment for 7 days improved both symptoms and abnormal EEG findings, and SFTS virus RNA disappeared from the serum at day 10 from the onset of symptoms. The serum cytokines and chemokines analysis during the clinical course revealed 2 distinct phases: the acute phase and the recovery phase. The cytokines and chemokines elevated in the acute phase included interleukin (IL)-6, IL-10, interferon (IFN)-α2, IFN-γ, tumor necrosis factor-α, interferon-γ-induced protein-10, and fractalkine, while the IL-1ß, IL-12p40, IL-17, and vascular endothelial growth factor levels were higher in the recovery phase. CONCLUSION: These observations suggest that the cytokines and chemokines elevated in the acute phase may reflect the disease severity resulted in a cytokine storm, while those in the recovery phase may be attributed to T-cell activation and differentiation.

Severe Fever With Thrombocytopenia Syndrome Virus-Induced Macrophage Differentiation Is Regulated by miR-146.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging hemorrhagic fever with a high mortality rate in humans, which is caused by SFTS virus (SFTSV), a novel phlebovirus in the Bunyaviridae family, is tick borne and endemic in Eastern Asia. Previous study found that SFTSV can infect and replicate in macrophages in vivo and in vitro. However, the role of macrophages in virus replication and the potential pathogenic mechanisms of SFTSV in macrophage remain unclear. In this study, we provided evidence that the SFTSV infection drove macrophage differentiation skewed to M2 phenotype, facilitated virus shedding, and resulted in viral spread. We showed evidence that miR-146a and b were significantly upregulated in macrophages during the SFTSV infection, driving the differentiation of macrophages into M2 cells by targeting STAT1. Further analysis revealed that the elevated miR-146b but not miR-146a was responsible for IL-10 stimulation. We also found that SFTSV increased endogenous miR-146b-induced differentiation of macrophages into M2 cells mediated by viral non-structural protein (NSs). The M2 skewed differentiation of macrophages may have important implication to the pathogenesis of SFTS.

Higher Fatality for Severe Fever with Thrombocytopenia Syndrome Complicated by Hemophagocytic Lymphohistiocytosis.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious zoonosis caused by the SFTS virus. Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening syndrome associated with excessive immune activation. Cytokine storms are often seen in both SFTS and HLH, resulting in rapid disease progression and poor prognosis. The aim of this study was to identify whether SFTS cases complicated by HLH are related to higher rates of mortality. Descriptive analysis of the frequency of clinical and laboratory data, complications, treatment outcomes, and HLH-2004 criteria was performed. Cases presenting with five or more clinical or laboratory findings corresponding to the HLH-2004 diagnostic criteria were defined as SFTS cases complicated by HLH. Eighteen cases of SFTS were identified during a 2-year study period, with a case-fatality proportion of 22.2% (4 among 18 cases, 95% confidence interval 9%-45.2%). SFTS cases complicated by HLH were identified in 33.3% (6 among 18 cases). A mortality rate of 75% (3 among 4 cases) was recorded among SFTS cases complicated by HLH. Although there were no statistically significant differences in outcomes, fatal cases exhibited more frequent correlation with HLH-2004 criteria than non-fatal cases [3/14 (21.4%) vs. 3/4 (75%), p=0.083]. In conclusion, the present study suggests the possibility that SFTS cases complicated by HLH are at higher risk of poor prognosis.

Cutaneous histopathology of the tick-bite region in severe fever with thrombocytopenia syndrome.

A case of severe fever with thrombocytopenia syndrome (SFTS) in which a skin biopsy from the tick-bite region was analyzed is reported. The patient was a 72-year-old woman who developed fever and thrombocytopenia after a tick bite. SFTS was diagnosed from polymerase chain reaction (PCR) analysis of a blood sample. Histopathological analysis of a skin biopsy specimen from the tick-bite region showed CD20-positive perivascular and interstitial immunoblastic cells, which were positive to anti-SFTS virus (SFTSV) nucleoprotein antibody. In addition, SFTSV RNA was detected by real-time PCR from this biopsy specimen. Moreover, hemophagocytosis was also found in the tick-bite region. To the best of our knowledge, this is the first report to analyze the details of the tick-bite region of skin in SFTS, and the first to detect virus-infected cells in the skin. The present findings may help elucidate the mechanisms of entry of SFTSV.

Evaluation of anti-dengue activity of Carica papaya aqueous leaf extract and its role in platelet augmentation.

Dengue disease is characterized by a marked decrease in platelet count, which is life threatening. In the present study, we investigated the antiviral activity of an aqueous extract of Carica papaya leaves (PLE) against dengue virus (DENV) and its effect on platelet augmentation. The anti-dengue activity of PLE in DENV-infected THP-1 cells was examined by immunoblotting and flow cytometry. The effect of PLE on erythrocyte damage was investigated using hemolytic and anti-hemolytic assays. Virus-infected THP-1 cells were assayed for IFN-α secretion. The effect of PLE on platelet augmentation in rats with cyclophosphamide-induced thrombocytopenia was also investigated. The platelet count of blood from the retro-orbital plexus of rats was determined on the 1st, 4th, 7th, 11th and 14th day of study. On the 14th day, the rats were sacrificed for histopathological examination of the liver, kidney and spleen. Plasma of thrombocytopenic rats was tested for thrombopoietin (TPO) and IL-6 secretion. The data suggest that PLE significantly decreases the expression of the envelope and NS1 proteins in DENV-infected THP-1 cells. A marked decrease in intracellular viral load upon PLE treatment confirmed its antiviral activity. This also resulted in a significant decrease in erythrocyte damage and hydrogen-peroxide-induced lipid peroxidation. A significant increase in the number of platelets was found in thrombocytopenic rats treated with PLE, along with an increase in IL-6 and TPO levels. These findings suggest that PLE can potentially be used as an antiviral agent, as it helps in platelet augmentation and exhibits antiviral activity against DENV.

Experimental infection of Japanese macaques with simian retrovirus 5.

Recently, a large number of Japanese macaques (Macaca fuscata) died of an unknown hemorrhagic syndrome at Kyoto University Primate Research Institute (KUPRI) and an external breeding facility for National Institute for Physiological Sciences (NIPS). We previously reported that the hemorrhagic syndrome of Japanese macaques at KUPRI was caused by infection with simian retrovirus 4 (SRV-4); however, the cause of similar diseases that occurred at the external breeding facility for NIPS was still unknown. In this study, we isolated SRV-5 from Japanese macaques exhibiting thrombocytopenia and then constructed an infectious molecular clone of the SRV-5 isolate. When the SRV-5 isolate was inoculated into two Japanese macaques, severe thrombocytopenia was induced in one of two macaques within 22 days after inoculation. Similarly, the clone-derived virus was inoculated into the other two Japanese macaques, and one of two macaques developed severe thrombocytopenia within 22 days. On the other hand, the remaining two of four macaques survived as asymptomatic carriers even after administering an immunosuppressive agent, dexamethasone. As determined by real-time PCR, SRV-5 infected a variety of tissues in Japanese macaques, especially in digestive and lymph organs. We also identified the SRV-5 receptor as ASCT2, a neutral amino acid transporter in Japanese macaques. Taken together, we conclude that the causative agent of hemorrhagic syndrome occurred at the external breeding facility for NIPS was SRV-5.

Polymorphisms and haplotypes in the promoter of the TNF-α gene are associated with disease severity of severe fever with thrombocytopenia syndrome in Chinese Han population.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease that is caused by a novel bunyavirus, SFTSV. We assessed whether the single nucleotide polymorphisms (SNPs) in the tumor necrosis factor-alpha (TNF-α) were associated with risk to severity of SFTS. Five TNF-α SNPs (SNP1: T-1031C; SNP2: C-863A; SNP3: C-857T; SNP4: G-308A; SNP5: G-238A) were genotyped in 987 hospitalized SFTS patients and 633 asymptomatic/mild SFTSV-infected subjects of Chinese Han origin. Multivariate logistic regression analysis was used to calculate adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs). The hospitalized SFTS patients had significantly lower frequency of G-238A A allele than those with mild/asymptomatic infection (P = 0.006). Furthermore, T-1031C C allele (P < 0.001) and G-238A A allele (P < 0.001) were significantly associated with decreased risk of death. Multiple haplotypes were significantly associated with decreased risk of SFTS hospital admission (SNP1-2, CC; SNP1-3, CCC; SNP1-4, CCCG; SNP1-5, CCCGA; SNP2-4, CCGA; SNP3-5, CGA; SNP4-5, GA) and death (SNP1-2, CA; SNP1-3, CAG; SNP1-4, CACG; SNP1-5, CACGG; SNP2-3, AC; SNP2-4, ACG; SNP2-5, ACGG) after correction for multiple comparisons. By using the ELISA assay, we observed that TNF-α concentration of hospitalized patients was significantly increased in acute phase than in convalescent phase (P < 0.001). Elevated TNF-α concentration was also revealed from fatal patients (P < 0.001). The -238A allele was associated with decreased serum TNF-α levels in SFTS patients in acute phase (P = 0.01). Our findings suggest that polymorphisms in TNF-α gene may play a role in mediating the risk to disease severity of SFTS in Chinese Han population.