RESUMO
Aberrant mucosal immunity has been suggested to play a pivotal role in pathogenesis of IgA nephropathy (IgAN), the most common form of glomerulonephritis worldwide. The outbreak of severe acute respiratory syndrome coronavirus (SARS-CoV-2), the causal pathogen of coronavirus disease 2019 (COVID-19), has become a global concern. However, whether the mucosal immune response caused by SARS-CoV-2 influences the clinical manifestations of IgAN patients remains unknown. Here we tracked the SARS-CoV-2 anti-receptor binding domain (RBD) antibody levels in a cohort of 88 COVID-19 patients. We found that 52.3% of the COVID-19 patients produced more SARS-CoV-2 anti-RBD IgA than IgG or IgM, and the levels of the IgA were stable during 4-41 days of infection. Among these IgA-dominated COVID-19 patients, we found a severe COVID-19 patient concurrent with IgAN. The renal function of the patient declined presenting with increased serum creatinine during the infection and till 7 months post infection. This patient predominantly produced anti-RBD IgA as well as total IgA in the serum compared to that of healthy controls. The analysis of the IgA-coated microbiota as well as proinflammatory cytokine IL-18, which was mainly produced in the intestine, reveals intestinal inflammation, although no obvious gastrointestinal symptom was reported. The mucosal immune responses in the lung are not evaluated due to the lack of samples from respiratory tract. Collectively, our work highlights the potential adverse effect of the mucosal immune response towards SARS-CoV-2, and additional care should be taken for COVID-19 patients with chronic diseases like IgAN.
RESUMO
The current global COVID-19 pandemic is caused by beta coronavirus Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), which already infected over 10 million and caused 500 thousand deaths by June 2020. Overproduction of cytokines triggered by COVID-19 infection, known as "cytokine storm", is a highly risk factor associated with disease severity. However, how COVID-19 infection induce cytokine storm is still largely unknown. Accumulating in vitro and in vivo evidence suggests that gut is also susceptible to COVID19 infection: Human intestinal organoids, an in vitro model which mimic the specific cell type and spatial structure of the intestine, were susceptible to SARS-CoV2 infection; A significant fraction of patients reported gut symptoms; Viral RNA may persist for more than 30 days and infectious virus could be isolated in fecal samples. The gastrointestinal tract is the primary site of interaction between the host immune system with symbiotic and pathogenic microorganisms. The bacteria resident in our gastrointestinal tract, known as gut microbiota, is important to maintain the homeostasis of our immune system. While imbalance of gut microbiota, or dysbiosis, is associated with multiple inflammation diseases5. It's possible that SARS-CoV-2 infection may lead to alternation of gut microbiota thus worsen the host symptom. IL-18 is a proinflammatory cytokine produced multiple enteric cells, including intestinal epithelial cells (IECs), immune cells as well as enteric nervous system, and was shown to increase in the serum of COVID-19 patients. Immunoglobin A (IgA) is mainly produced in the mucosal surfaces, in humans 40-60mg kg-1 day-1 than all other immunoglobulin isotypes combined, and at least 80% of all plasma cells are located in the intestinal lamina propria. Recent study showed that SARS-CoV-2 specific IgA in the serum is positively correlate with the disease severity in COVID-19 patients11. Here we investigated the alterations of microbiota in COVID-19 patients, and its correlation with inflammatory factor IL-18 and SARS-CoV2 specific IgA.
RESUMO
Hepatitis C virus (HCV)is an important human pathogen that causes chronic viral hepatitis worldwide.HCV infection,often persistent and asymptomatic,could lead to liver fibrosis/cirrhosis and hepatocellular carcinoma.The interferon/ribavirin therapy has been widely used for treating chronic hepatitis C,but it is not always effective and has strong side effects.The development of small-molecule di-rect antiviral agents (DAA)has greatly improved the curing efficiency of chronic hepatitis C therapeutics and will likely replace the interfer-on-based therapy in the future.However,these developments do not necessarily suggest that the problems of chronic hepatitis C have been completely solved.The HCV research is still facing many challenges in this new DAA era.
