COVID-19: imbalanced cell-mediated immune response drives to immunopathology.

The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), poses an imminent threat to humanity. SARS-CoV-2 invades host cells, causing a failure of host immune recognition. Instead of an effective antiviral immunological response after SARS-CoV-2 invasion, the cascading pathological syndrome of COVID-19, especially in severe disease, is exacerbated by an overt inflammatory response and the suppression of SARS-CoV-2-specific immune responses. As is known, excessive inflammation leads to pathophysiological changes in virus-infected tissues or organs, manifested by imbalanced immune responses, cytokine storm, and aggressive neutrophil activation, ultimately leading to lung damage, such as alveolar damage, endotheliitis, and fluid overload. However, the triggers and consequences of a disruption to immune system homeostasis and the underlying mechanisms of uncontrolled immunopathology following viral infection remain unclear. Here, we review the dynamic and systemic immune progression from an imbalance in cell-mediated immune responses to COVID-19 lung injury. Our understanding of key mechanisms involved in pathogenesis is critical for the development of therapeutic agents and to optimize therapeutic strategies.

Safety and immunogenicity of SARS-CoV-2 vaccines in Chinese patients with cirrhosis: a prospective multicenter study.

BACKGROUND: Data on safety and immunogenicity of coronavirus disease 2019 (COVID-19) vaccination in patients with compensated (C-cirrhosis) and decompensated cirrhosis (D-cirrhosis) are limited. METHODS: In this prospective multicenter study, adult participants with C-cirrhosis and D-cirrhosis were enrolled and received two doses of inactivated whole-virion COVID-19 vaccines. Adverse events were recorded within 14 days after any dose of vaccination, and serum samples of enrolled patients were collected and tested for SARS-CoV-2 neutralizing antibodies at least 14 days after the second dose. Risk factors for negative neutralizing antibody were analyzed. RESULTS: In total, 553 patients were enrolled from 15 centers in China, including 388 and 165 patients with C-cirrhosis and D-cirrhosis. The vaccines were well tolerated, most adverse reactions were mild and transient, and injection site pain (23/388 [5.9%] vs 9/165 [5.5%]) and fatigue (5/388 [1.3%] vs 3/165 [1.8%]) were the most frequently local and systemic adverse events in both the C-cirrhosis and D-cirrhosis groups. Overall, 4.4% (16/363) and 0.3% (1/363) of patients were reported Grades 2 and 3 alanine aminotransferase (ALT) elevations (defined as ALT > 2 upper limit of normal [ULN] but ≤ 5 ULN, and ALT > 5 ULN, respectively). The positive rates of COVID-19 neutralizing antibodies were 71.6% (278/388) and 66.1% (109/165) in C-cirrhosis and D-cirrhosis groups. Notably, Child-Pugh score of B and C levels was an independent risk factor of negative neutralizing antibody. CONCLUSIONS: Inactivated COVID-19 vaccinations are safe with acceptable immunogenicity in cirrhotic patients, and Child-Pugh score of B and C levels is associated with hyporesponsive to COVID-19 vaccination.

Safety and immunogenicity of COVID-19 vaccination in patients with non-alcoholic fatty liver disease (CHESS2101): A multicenter study.

BACKGROUND & AIMS: The development of COVID-19 vaccines has progressed with encouraging safety and efficacy data. Concerns have been raised about SARS-CoV-2 vaccine responses in the large population of patients with non-alcoholic fatty liver disease (NAFLD). The study aimed to explore the safety and immunogenicity of COVID-19 vaccination in NAFLD. METHODS: This multicenter study included patients with NAFLD without a history of SARS-CoV-2 infection. All patients were vaccinated with 2 doses of inactivated vaccine against SARS-CoV-2. The primary safety outcome was the incidence of adverse reactions within 7 days after each injection and overall incidence of adverse reactions within 28 days, and the primary immunogenicity outcome was neutralizing antibody response at least 14 days after the whole-course vaccination. RESULTS: A total of 381 patients with pre-existing NAFLD were included from 11 designated centers in China. The median age was 39.0 years (IQR 33.0-48.0 years) and 179 (47.0%) were male. The median BMI was 26.1 kg/m2 (IQR 23.8-28.1 kg/m2). The number of adverse reactions within 7 days after each injection and adverse reactions within 28 days totaled 95 (24.9%) and 112 (29.4%), respectively. The most common adverse reactions were injection site pain in 70 (18.4%), followed by muscle pain in 21 (5.5%), and headache in 20 (5.2%). All adverse reactions were mild and self-limiting, and no grade 3 adverse reactions were recorded. Notably, neutralizing antibodies against SARS-CoV-2 were detected in 364 (95.5%) patients with NAFLD. The median neutralizing antibody titer was 32 (IQR 8-64), and the neutralizing antibody titers were maintained. CONCLUSIONS: The inactivated COVID-19 vaccine appears to be safe with good immunogenicity in patients with NAFLD. LAY SUMMARY: The development of vaccines against coronavirus disease 2019 (COVID-19) has progressed rapidly, with encouraging safety and efficacy data. This study now shows that the inactivated COVID-19 vaccine appears to be safe with good immunogenicity in the large population of patients with non-alcoholic fatty liver disease.

A retrospective view of pediatric cases infected with SARS-CoV-2 of a middle-sized city in mainland China.

ABSTRACT: The coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 had resulted in a global pandemic. A comprehensive analysis of pediatric COVID-19 cases is essential to decipher the natural features of children under the risk of this disease.In the epidemic period, all the children infected with SARS-CoV-2 in Wuxi, a city with a stable medical system during the COVID-19 outbreak in China, were enrolled for comprehensive data documenting their clinical, prognosis, follow-up, treatment and various tests results. Combing their family cluster characteristics, the epidemiological, hospitalization, and transmission features of children with SARS-CoV-2 were analyzed and discussed.A total of 7 children were enrolled, including 4 mild cases, 1 moderate case, and 2 asymptomatic cases. The common symptoms were fever and dry cough. The length of viral nucleic acid duration in nasopharynx varied and was irrelevant to the severity of the symptom, whether symptomatic or asymptomatic. Two cases showed viral nucleic acid positive recurrence after discharge from the hospital. A child with type 1 diabetes was also focused, for the elevated blood sugar during hospitalization. All these children had close contacts with their family members, some of those were confirmed COVID-19 cases.We provided a holistic and detailed portrayal of the pediatric COVID-19 cases in a typical city of timely response to the epidemic. While the family cluster exhibits the major transmission mode, attention should be paid for the potential risk since the expanded social space of children in future.

Recurrence of SARS-CoV-2 nucleic acid positive test in patients with COVID-19: a report of two cases.

BACKGROUND: The recurrence of positive SARS-CoV-2 nucleic acid test results in patients with COVID-19 is becoming more important and warrants more attention. CASE PRESENTATION: This study reports 2 cases, a child with mild COVID-19 and an adult female with moderate COVID-19, who were discharged after three consecutive negative nucleic acid tests and were later readmitted to the hospital for recurrence of SARS-CoV-2 nucleic acid positivity. By tracking the patients' symptoms, serum antibodies, and imaging manifestations after readmission, we found that they showed a trend of gradual improvement and recovery throughout treatment. They were cured without additional treatment, with the appearance of antibodies and the recovery of immune functions. CONCLUSIONS: It is deemed extremely necessary to improve the discharge standard of care. At the same time, nucleic acid detection is recommended to increase the dynamic monitoring of serum antibodies and imaging, strengthen the management of discharged patients, and appropriately extend the home or centralized isolation time.

Umbilical cord blood-derived mesenchymal stem cells in treating a critically ill COVID-19 patient.

INTRODUCTION: The coronavirus disease 2019 (COVID-19) pandemic is spreading rapidly. Critically ill cases of COVID-19 can rapidly progress to acute respiratory distress syndrome and multiple organ failures. However, no effective drugs have been available till now, leading to more than 300,000 deaths up to 29 April 2020. Here, we present a critically ill case utilizing umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs). CASE PRESENTATION: A 72-year-old man was admitted, with the diagnosis of COVID-19, ARDS, type-2 diabetes, diabetic nephropathy, renal insufficiency, and hypertension. His clinical condition continually developed to be life-threatening even receiving various treatment options including antiviral therapy and extracorporeal membrane oxygenation. Between 28 February and 8 March 2020, the patient was given 5-time intravenous infusions of UCB-MSCs. His hematological and biochemical indexes, including lymphocytes and renal function improved. Pulmonary static compliance increased significantly and PaO2/FiO2 ratio maintained stable. On March 10, he received lung transplantation. CONCLUSIONS: Our current findings suggested that UCB-MSCs therapy may show some positive effect in treating critical COVID-19 to some extent, for its delaying deterioration of the disease and efficacy in respiratory and renal function, though limited.

Excessive Neutrophils and Neutrophil Extracellular Traps in COVID-19.

Background: Cases of excessive neutrophil counts in the blood in severe coronavirus disease (COVID-19) patients have drawn significant attention. Neutrophil infiltration was also noted on the pathological findings from autopsies. It is urgent to clarify the pathogenesis of neutrophils leading to severe pneumonia in COVID-19. Methods: A retrospective analysis was performed on 55 COVID-19 patients classified as mild (n = 22), moderate (n = 25), and severe (n = 8) according to the Guidelines released by the National Health Commission of China. Trends relating leukocyte counts and lungs examined by chest CT scan were quantified by Bayesian inference. Transcriptional signatures of host immune cells of four COVID19 patients were analyzed by RNA sequencing of lung specimens and BALF. Results: Neutrophilia occurred in 6 of 8 severe patients at 7-19 days after symptom onset, coinciding with lesion progression. Increasing neutrophil counts paralleled lesion CT values (slope: 0.8 and 0.3-1.2), reflecting neutrophilia-induced lung injury in severe patients. Transcriptome analysis revealed that neutrophil activation was correlated with 17 neutrophil extracellular trap (NET)-associated genes in COVID-19 patients, which was related to innate immunity and interacted with T/NK/B cells, as supported by a protein-protein interaction network analysis. Conclusion: Excessive neutrophils and associated NETs could explain the pathogenesis of lung injury in COVID-19 pneumonia.