Potential role of aberrant mucosal immune response to SARS-CoV-2 in pathogenesis of IgA Nephropathy (preprint)

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.

Tocilizumab treatment in severe COVID-19 patients attenuates the inflammatory storm incited by monocyte centric immune interactions revealed by single-cell analysis (preprint)

ABSTRACTDespite the current devastation of the COVID-19 pandemic, several recent studies have suggested that the immunosuppressive drug Tocilizumab can powerfully treating inflammatory responses that occur in this disease. Here, by employing single-cell analysis of the immune cell composition of severe-stage COVID-19 patients and these same patients in post Tocilizumab-treatment remission, we have identified a monocyte subpopulation specific to severe disease that contributes to inflammatory storms in COVID-19 patients. Although Tocilizumab treatment attenuated the strong inflammatory immune response, we found that immune cells including plasma B cells and CD8+ T cells still exhibited an intense humoral and cell-mediated anti-virus immune response in COVID-19 patients after Tocilizumab treatment. Thus, in addition to providing a rich, very high-resolution data resource about the immune cell distribution at multiple stages of the COVID-19 disease, our work both helps explain Tocilizumab’s powerful therapeutic effects and defines a large number of potential new drug targets related to inflammatory storms.Competing Interest StatementJingwen Fang is the executive officer of HanGen BiotechView Full Text

Aberrant pathogenic GM-CSF+ T cells and inflammatory CD14+CD16+ monocytes in severe pulmonary syndrome patients of a new coronavirus (preprint)

Pathogenic human coronavirus infections, such as severe acute respiratory syndrome CoV (SARS-CoV) and Middle East respiratory syndrome CoV (MERS-CoV), cause high morbidity and mortality 1,2. Recently, a severe pneumonia-associated respiratory syndrome caused by a new coronavirus was reported at December 2019 (2019-nCoV) in the city Wuhan, Hubei province, China3-5, which was also named as pneumonia-associated respiratory syndrome (PARS)6. Up to 9th of February 2020, at least 37, 251 cases have been reported with 812 fatal cases according to the report from China CDC. However, the immune mechanism that potential orchestrated acute mortality from patients of 2019-nCoV is still unknown. Here we show that after the 2019-nCoV infection, CD4+T lymphocytes are rapidly activated to become pathogenic T helper (Th) 1 cells and generate GM-CSF etc. The cytokines environment induces inflammatory CD14+CD16+ monocytes with high expression of IL-6 and accelerates the inflammation. These aberrant and excessive immune cells may enter the pulmonary circulation in huge numbers and play an immune damaging role to causing lung functional disability and quick mortality. Our results demonstrate that excessive non-effective host immune responses by pathogenic T cells and inflammatory monocytes may associate with severe lung pathology. Therefore, we suggest that monoclonal antibody that targets the GM-CSF or interleukin 6 receptor may potentially curb immunopathology caused by 2019-nCoV and consequently win more time for virus clearance.

Pathogenic T cells and inflammatory monocytes incite inflammatory storm in severe COVID-19 patients

Pathogenic human coronavirus infections, such as severe acute respiratory syndrome CoV (SARS-CoV) and Middle East respiratory syndrome CoV (MERS-CoV), cause high morbidity and mortality1, 2 . Recently, a severe pneumonia-associated respiratory syndrome caused by a new coronavirus (SARS-CoV-2) was reported at December 2019 in the city Wuhan, Hubei province, China3, 4, 5, which was also named as pneumonia-associated respiratory syndrome (PARS)6 and can cause coronavirus disease 2019 (COVID-19) to seriously endanger human health. Up to 24th of February 2020, at least 77779 cases have been reported with 2666 fatal cases according to the report from China CDC. However, the immune mechanism that potential orchestrated acute mortality from COVID-19 patients is still unknown. Here we show that after the SARS-CoV-2 infection, CD4+ T lymphocytes are rapidly activated to become pathogenic T helper (Th) 1 cells and generate GM-CSF etc. The cytokines environment induces inflammatory CD14+CD16+ monocytes with high expression of IL-6 and accelerate the inflammation. Given that large amount of inflammatory cells infiltrations have been observed in lungs from severe COVID-19 patients7, 8, these aberrant pathogenic Th1 cells and inflammatory monocytes may enter the pulmonary circulation in huge numbers and play an immune damaging role to causing lung functional disability and quick mortality. Our results demonstrate that excessive non-effective host immune responses by pathogenic T cells and inflammatory monocytes may associate with severe lung pathology. Thus, we suggest that monoclonal antibodies targeting GM-CSF or interleukin 6 may be effective in blocking inflammatory storms and, therefore, be a promising treatment of severe COVID-19 patients