Clinical improvement in a patient with severe coronavirus disease 2019 after administration of hydroxychloroquine and continuous hemodiafiltlation with nafamostat mesylate.

The number of people infected with severe acute respiratory syndrome coronavirus 2 is increasing globally, and some patients have a fatal clinical course. In light of this situation, the World Health Organization (WHO) declared coronavirus disease 2019 (COVID-19) a pandemic on March 11, 2020. While clinical studies and basic research on a treatment for COVID-19 are ongoing around the world, no treatment has yet been proven to be effective. Several clinical studies have demonstrated the efficacy of chloroquine phosphate and nafamostat mesylate with COVID-19. Here, we report the case of a Japanese patient with COVID-19 with severe respiratory failure who improved following the administration of hydroxychloroquine and continuous hemodiafiltlation with nafamostat mesylate. Hence, hydroxychloroquine with nafamostat mesylate might be a treatment option for severe COVID-19.

Hydrophobic bile acids suppress expression of AE2 in biliary epithelial cells and induce bile duct inflammation in primary biliary cholangitis.

Understanding the mechanisms of chronic inflammation in primary biliary cholangitis (PBC) is essential for successful treatment. Earlier work has demonstrated that patients with PBC have reduced expression of the anion exchanger 2 (AE2) on biliary epithelial cells (BEC) and deletion of AE2 gene has led to a PBC-like disorder in mice. To directly address the role of AE2 in preventing PBC pathogenesis, we took advantage of our ability to isolate human BEC and autologous splenic mononuclear cells (SMC). We studied the influence of hydrophobic bile acids, in particular, glycochenodeoxycholic acid (GCDC), on AE2 expression in BEC and the subsequent impact on the phenotypes of BEC and local inflammatory responses. We demonstrate herein that GCDC reduces AE2 expression in BEC through induction of reactive oxygen species (ROS), which enhances senescence of BEC. In addition, a reduction of AE2 levels by either GCDC or another AE2 inhibitor upregulates expression of CD40 and HLA-DR as well as production of IL-6, IL-8 and CXCL10 from BEC in response to toll like receptor ligands, an effect suppressed by inhibition of ROS. Importantly, reduced AE2 expression enhances the migration of autologous splenic mononuclear cells (SMC) towards BEC. In conclusion, our data highlight a key functional role of AE2 in the maintenance of the normal physiology of BEC and the pathogenic consequences of reduced AE2 expression, including abnormal intrinsic characteristics of BEC and their production of signal molecules that lead to the chronic inflammatory responses in small bile ducts.

Natural killer cells regulate T cell immune responses in primary biliary cirrhosis.

UNLABELLED: The hallmark of primary biliary cirrhosis (PBC) is the presence of autoreactive T- and B-cell responses that target biliary epithelial cells (BECs). Biliary cell cytotoxicity is dependent upon initiation of innate immune responses followed by chronic adaptive, as well as bystander, mechanisms. Critical to these mechanisms are interactions between natural killer (NK) cells and BECs. We have taken advantage of the ability to isolate relatively pure viable preparations of liver-derived NK cells, BECs, and endothelial cells, and studied interactions between NK cells and BECs and focused on the mechanisms that activate autoreactive T cells, their dependence on interferon (IFN)-γ, and expression of BEC major histocompatibility complex (MHC) class I and II molecules. Here we show that at a high NK/BEC ratio, NK cells are cytotoxic for autologous BECs, but are not dependent on autoantigen, yet still activate autoreactive CD4(+) T cells in the presence of antigen presenting cells. In contrast, at a low NK/BEC ratio, BECs are not lysed, but IFN-γ production is induced, which facilitates expression of MHC class I and II molecules on BEC and protects them from lysis upon subsequent exposure to autoreactive NK cells. Furthermore, IFN-γ secreted from NK cells after exposure to autologous BECs is essential for this protective function and enables autoreactive CD4(+) T cells to become cytopathic. CONCLUSIONS: NK cell-mediated innate immune responses are likely critical at the initial stage of PBC, but also facilitate and maintain the chronic cytopathic effect of autoantigen-specific T cells, essential for progression of disease.

Clinical significance of SARS-CoV-2-specific IgG detection with a rapid antibody kit for COVID-19 patients.

BACKGROUND: The longitudinal observation of the detection of antibody responses to SARS-CoV-2 using antibody kits during the clinical course of COVID-19 is not yet fully investigated. OBJECTIVES: To understand the significance of the detection of anti-SARS-CoV-2 antibodies, particularly IgG, using a rapid antibody kit, during the clinical course of COVID-19 patients with different severities. METHODS: Sixty-three serum samples from 18 patients (5 asymptomatic and 13 symptomatic patients) were retrospectively examined using a commercial SARS-CoV-2 IgM/IgG antibody kit. PCR positivity of patient samples was also examined as a marker of current SARS-CoV-2 infection. RESULTS: IgG antibodies were detected in all cases in this study. The IgG detection rates reached 100.0% in samples collected on day 13 or later. IgG seropositivity after an initial negative status was observed in 13 patients (3/5 asymptomatic and 10/13 symptomatic cases). Interestingly, the persistence of both PCR and IgG positivity was detected in seven cases, of which three were asymptomatic. The longest overlap duration of the PCR and IgG positivity was 17 days in asymptomatic status. CONCLUSIONS: SARS-CoV-2-specific IgG production can be detected in all infected individuals, using a rapid antibody kit, irrespective of clinical status. However, these findings suggest that, in some infected individuals, particularly those with asymptomatic status, the presence of virus-specific IgG antibodies does not imply prompt viral clearance.

Efficacy of thromboelastography in the management of anticoagulation for veno-venous extracorporeal membrane oxygenation in a coronavirus disease 2019 patient: A case report.

RATIONALE: In coronavirus disease 2019 (COVID-19) patients with acute respiratory distress syndrome refractory to optimal conventional management, we should consider the indication for veno-venous extracorporeal membrane oxygenation (V-V ECMO). Growing evidence indicates that COVID-19 frequently causes coagulopathy, presenting as hypercoagulation and incidental thrombosis. For these reasons, a multifactorial approach with several anticoagulant markers should be considered in the management of anticoagulation using heparin in COVID-19 patients on V-V ECMO. PATIENT CONCERNS: A 48-year-old man was infected with COVID-19 with a worsening condition manifesting as acute respiratory distress syndrome. DIAGNOSES: He was refractory to conventional therapy, thus we decided to introduce V-V ECMO. We used heparin as an anticoagulant therapy for V-V ECMO and adjusted the doses of heparin by careful monitoring of the activated clotting time (ACT) and activated partial thromboplastin time (APTT) to avoid both hemorrhagic and thrombotic complications. We controlled the doses of heparin in the therapeutic ranges of ACT and APTT, but clinical hemorrhaging and profound elevation of coagulant marker became apparent. INTERVENTIONS: Using thromboelastography (TEG; Haemonetics) in addition to ACT and APTT, we were able to clearly detect not only sufficient coagulability of COVID19 on V-V ECMO (citrated rapid thromboelastography-R 0.5 min, angle 75.5°, MA 64.0 mm, citrated functional fibrinogen-MA 20.7 mm) but also an excessive effect of heparin (citrated kaolin -R 42.7 min, citrated kaolin with heparinase 11.7 min). OUTCOMES: Given the TEG findings indicating an excessive heparin effect, the early withdrawal of ECMO was considered. After an evaluation of the patient's respiratory capacity, withdrawal from V-V ECMO was achieved and then anticoagulation was stopped. The hemorrhagic complications and elevated thrombotic marker levels dramatically decreased. LESSONS: TEG monitoring might be a useful option for managing anticoagulation in COVID-19 patients on V-V ECMO frequently showing a hypercoagulative state and requiring massive doses of heparin, to reduce both hemorrhagic and thrombotic complications.

Infective endocarditis caused by Listeria monocytogenes forming a pseudotumor.

A 73-year-old woman with breast cancer and metastasis under chemotherapy suffered from fever, pleural effusion and pericardial effusion. Despite the administration of treatment with cefozopran and prednisolone, the patient's fever relapsed. An electrocardiogram identified a new complete atrioventricular block and an echocardiogram revealed vegetation with an unusual pseudotumoral mass in the right atrium. Blood cultures grew Listeria monocytogenes. The patient was eventually diagnosed with right-sided infective endocarditis, which improved following the six-week administration of ampicillin and gentamicin. Homemade yoghurt was suspected to be the cause of infection in this case. Listeria endocarditis is rare; however, physicians should pay more attention to preventing this fatal disease in immunocompromised patients.

Interferon- α -Induced Changes to Natural Killer Cells Are Associated with the Treatment Outcomes in Patients with HCV Infections.

Aim. We analyzed the pretreatment natural killer (NK) cell functions with the aim of predicting the sustained virological response (SVR) or the interleukin (IL) 28B polymorphism that is strongly associated with the treatment response. Methods. The peripheral NK cells from chronic hepatitis patients with HCV genotype 1 and high virus titers were activated using a Toll-like receptor (TLR) 4 ligand and IFN- α . The cell surface markers were evaluated using a flow cytometric analysis, and IFN- γ production was evaluated using an enzyme-linked immunosorbent assay (ELISA). The genotyping of the polymorphisms in the IL28B gene region (rs8099917) on chromosome 19 was performed on the DNA collected from each patient. Results. The production of IFN- γ was significantly higher in the SVR patients compared with the no-response (NR) patients, whereas the cell surface markers were similar between the SVR and the NR patients. There were no significant differences found in the IL28B genotype distribution associated with the production of IFN- γ . Conclusion. Differences in the NK cell functions were observed between the SVR patients and the NR patients, suggesting that NK cells play a potential role in the treatment response independent of the IL28B genotype.