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1.
Int Immunol ; 33(12): 787-790, 2021 11 25.
Article in English | MEDLINE | ID: covidwho-1398105

ABSTRACT

Dysbiosis is alterations in the microbial composition compared with a healthy microbiota and often features a reduction in gut microbial diversity and a change in microbial taxa. Dysbiosis, especially in the gut, has also been proposed to play a crucial role in the pathogenesis of a wide variety of diseases, including inflammatory bowel disease, colorectal cancer, cardiovascular disease, obesity, diabetes and multiple sclerosis. A body of evidence has shown that intestinal polymeric immunoglobulin A (IgA) antibodies are important to regulate the gut microbiota as well as to exclude pathogenic bacteria or viral infection such as influenza and SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) at mucosal sites. Since the 1970s, trials for oral administration of therapeutic IgA or IgG have been performed mainly to treat infectious enteritis caused by pathogenic Escherichia coli or Clostridium difficile. However, few of them have been successfully developed for clinical application up to now. In addition to the protective function against intestinal pathogens, IgA is well known to modulate the gut commensal microbiota leading to symbiosis. Nevertheless, the development of therapeutic IgA drugs to treat dysbiosis is not progressing. In this review, the advantages of therapeutic IgA antibodies and the problems for their development will be discussed.


Subject(s)
Bacteria/drug effects , Gastrointestinal Microbiome/drug effects , Immunoglobulin A/therapeutic use , Inflammatory Bowel Diseases/drug therapy , Intestines/drug effects , Animals , Bacteria/immunology , Dysbiosis , Host-Pathogen Interactions , Humans , Immunoglobulin A/adverse effects , Inflammatory Bowel Diseases/immunology , Inflammatory Bowel Diseases/microbiology , Intestines/immunology , Intestines/microbiology , Species Specificity
2.
Front Immunol ; 12: 619906, 2021.
Article in English | MEDLINE | ID: covidwho-1290728

ABSTRACT

The role of sMAdCAM, an important gut immune migratory marker, remains unexplored in COVID-19 pathogenesis considering recent studies positing the gut as a sanctuary site for SARS-CoV-2 persistence. Thus, assimilating profiles of systemic inflammatory mediators with sMAdCAM levels may provide insights into the progression of COVID-19 disease. Also, the role of these markers in governing virus specific immunity following infection remains largely unexplored. A cohort (n = 84) of SARS-C0V-2 infected individuals included a group of in-patients (n = 60) at various stages of disease progression together with convalescent individuals (n = 24) recruited between April and June 2020 from Mumbai, India. Follow-up of 35 in-patients at day 7 post diagnosis was carried out. Th1/Th2/Th17 cytokines along with soluble MAdCAM (sMAdCAM) levels in plasma were measured. Also, anti-viral humoral response as measured by rapid antibody test (IgG, IgM), Chemiluminescent Immunoassay (IgG), and antibodies binding to SARS-CoV-2 proteins were measured by Surface Plasmon Resonance (SPR) from plasma. IL-6 and sMAdCAM levels among in-patients inversely correlated with one another. When expressed as a novel integrated marker-sMIL index (sMAdCAM/IL-6 ratio)-these levels were incrementally and significantly higher in various disease states with convalescents exhibiting the highest values. Importantly, sMAdCAM levels as well as sMIL index (fold change) correlated with peak association response units of receptor binding domain and fold change in binding to spike respectively as measured by SPR. Our results highlight key systemic and gut homing parameters that need to be monitored and investigated further to optimally guide therapeutic and prophylactic interventions for COVID-19.


Subject(s)
COVID-19/immunology , Cell Adhesion Molecules/blood , Interleukin-6/blood , Mucoproteins/blood , Adolescent , Adult , Aged , Biomarkers/blood , COVID-19/drug therapy , COVID-19/physiopathology , Cohort Studies , Cytokines/blood , Disease Progression , Female , Humans , Intestines/immunology , Male , Middle Aged , Surface Plasmon Resonance , Young Adult
4.
Am J Surg Pathol ; 46(1): 89-96, 2022 01 01.
Article in English | MEDLINE | ID: covidwho-1254925

ABSTRACT

Approximately 20% of patients with symptomatic syndrome-associated coronavirus-2 (SARS-CoV-2) infection have gastrointestinal bleeding and/or diarrhea. Most are managed without endoscopic evaluation because the risk of practitioner infection outweighs the value of biopsy analysis unless symptoms are life-threatening. As a result, much of what is known about the gastrointestinal manifestations of coronavirus disease-2019 (COVID-19) has been gleaned from surgical and autopsy cases that suffer from extensive ischemic injury and/or poor preservation. There are no detailed reports describing any other gastrointestinal effects of SARS-CoV-2 even though >3,000,000 people have died from COVID-19 worldwide. The purpose of this study is to report the intestinal findings related to SARS-CoV-2 infection by way of a small case series including one with evidence of direct viral cytopathic effect and 2 with secondary injury attributed to viral infection. Infection can be confirmed by immunohistochemical stains directed against SARS-CoV-2 spike protein, in situ hybridization for spike protein-encoding RNA, and ultrastructural visualization of viruses within the epithelium. It induces cytoplasmic blebs and tufted epithelial cells without inflammation and may not cause symptoms. In contrast, SARS-CoV-2 infection can cause gastrointestinal symptoms after the virus is no longer detected, reflecting systemic activation of cytokine and complement cascades rather than direct viral injury. Reversible mucosal ischemia features microvascular injury with hemorrhage, small vessel thrombosis, and platelet-rich thrombi. Systemic cytokine elaboration and dysbiosis likely explain epithelial cell injury that accompanies diarrheal symptoms. These observations are consistent with clinical and in vitro data and contribute to our understanding of the protean manifestations of COVID-19.


Subject(s)
COVID-19/pathology , Intestinal Diseases/pathology , Intestinal Diseases/virology , Intestines/pathology , Intestines/virology , Adult , Aged , Aged, 80 and over , Biomarkers/metabolism , Biopsy , COVID-19/diagnosis , COVID-19/immunology , Cytokines/metabolism , Gastrointestinal Hemorrhage/diagnosis , Gastrointestinal Hemorrhage/immunology , Gastrointestinal Hemorrhage/pathology , Gastrointestinal Hemorrhage/virology , Humans , Intestinal Diseases/diagnosis , Intestinal Diseases/immunology , Intestines/immunology , Ischemia/diagnosis , Ischemia/immunology , Ischemia/pathology , Ischemia/virology , Male , Thrombosis/diagnosis , Thrombosis/immunology , Thrombosis/pathology , Thrombosis/virology
5.
Mol Syst Biol ; 17(4): e10232, 2021 04.
Article in English | MEDLINE | ID: covidwho-1204403

ABSTRACT

Exacerbated pro-inflammatory immune response contributes to COVID-19 pathology. However, despite the mounting evidence about SARS-CoV-2 infecting the human gut, little is known about the antiviral programs triggered in this organ. To address this gap, we performed single-cell transcriptomics of SARS-CoV-2-infected intestinal organoids. We identified a subpopulation of enterocytes as the prime target of SARS-CoV-2 and, interestingly, found the lack of positive correlation between susceptibility to infection and the expression of ACE2. Infected cells activated strong pro-inflammatory programs and produced interferon, while expression of interferon-stimulated genes was limited to bystander cells due to SARS-CoV-2 suppressing the autocrine action of interferon. These findings reveal that SARS-CoV-2 curtails the immune response and highlights the gut as a pro-inflammatory reservoir that should be considered to fully understand SARS-CoV-2 pathogenesis.


Subject(s)
Intestines/immunology , SARS-CoV-2/physiology , Single-Cell Analysis , COVID-19/virology , Gastrointestinal Microbiome , Humans , In Situ Hybridization, Fluorescence , Organoids/metabolism , Sequence Analysis, RNA
7.
Nature ; 591(7851): 639-644, 2021 03.
Article in English | MEDLINE | ID: covidwho-1065898

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected 78 million individuals and is responsible for over 1.7 million deaths to date. Infection is associated with the development of variable levels of antibodies with neutralizing activity, which can protect against infection in animal models1,2. Antibody levels decrease with time, but, to our knowledge, the nature and quality of the memory B cells that would be required to produce antibodies upon reinfection has not been examined. Here we report on the humoral memory response in a cohort of 87 individuals assessed at 1.3 and 6.2 months after infection with SARS-CoV-2. We find that titres of IgM and IgG antibodies against the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2 decrease significantly over this time period, with IgA being less affected. Concurrently, neutralizing activity in plasma decreases by fivefold in pseudotype virus assays. By contrast, the number of RBD-specific memory B cells remains unchanged at 6.2 months after infection. Memory B cells display clonal turnover after 6.2 months, and the antibodies that they express have greater somatic hypermutation, resistance to RBD mutations and increased potency, indicative of continued evolution of the humoral response. Immunofluorescence and PCR analyses of intestinal biopsies obtained from asymptomatic individuals at 4 months after the onset of coronavirus disease 2019 (COVID-19) revealed the persistence of SARS-CoV-2 nucleic acids and immunoreactivity in the small bowel of 7 out of 14 individuals. We conclude that the memory B cell response to SARS-CoV-2 evolves between 1.3 and 6.2 months after infection in a manner that is consistent with antigen persistence.


Subject(s)
Antibodies, Viral/immunology , COVID-19/immunology , Immunity, Humoral/immunology , SARS-CoV-2/immunology , Adolescent , Adult , Aged , Antibodies, Monoclonal/blood , Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/blood , Antibodies, Neutralizing/genetics , Antibodies, Neutralizing/immunology , Antibodies, Viral/blood , Antibodies, Viral/genetics , Antigens, Viral/chemistry , Antigens, Viral/genetics , Antigens, Viral/immunology , B-Lymphocytes/cytology , B-Lymphocytes/immunology , Biopsy , COVID-19/blood , Cohort Studies , Fluorescent Antibody Technique , Humans , Immunity, Humoral/genetics , Immunoglobulin A/immunology , Immunoglobulin G/immunology , Immunoglobulin M/immunology , Immunologic Memory/immunology , Intestines/immunology , Middle Aged , Mutation , Somatic Hypermutation, Immunoglobulin , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Time Factors , Young Adult
8.
Gastroenterology ; 160(3): 809-822.e7, 2021 02.
Article in English | MEDLINE | ID: covidwho-990009

ABSTRACT

BACKGROUND AND AIMS: The host receptor for severe acute respiratory syndrome coronavirus 2, angiotensin-converting enzyme 2 (ACE2), is highly expressed in small bowel (SB). Our aim was to identify factors influencing intestinal ACE2 expression in Crohn's disease (CD), ulcerative colitis (UC), and non-inflammatory bowel disease (IBD) controls. METHODS: Using bulk RNA sequencing or microarray transcriptomics from tissue samples (4 SB and 2 colonic cohorts; n = 495; n = 387 UC; n = 94 non-IBD), we analyzed the relationship between ACE2 with demographics and disease activity and prognosis. We examined the outcome of anti-tumor necrosis factor and anti-interleukin-12/interleukin-23 treatment on SB and colonic ACE2 expression in 3 clinical trials. Univariate and multivariate regression models were fitted. RESULTS: ACE2 levels were consistently reduced in SB CD and elevated in colonic UC compared with non-IBD controls. Elevated SB ACE2 was also associated with demographic features (age and elevated body mass index) associated with poor coronavirus disease 2019 outcomes. Within CD, SB ACE2 was reduced in patients subsequently developing complicated disease. Within UC, colonic ACE2 was elevated in active disease and in patients subsequently requiring anti-tumor necrosis factor rescue therapy. SB and colonic ACE2 expression in active CD and UC were restored by anti-cytokine therapy, most notably in responders. CONCLUSIONS: Reduced SB but elevated colonic ACE2 levels in IBD are associated with inflammation and severe disease, but normalized after anti-cytokine therapy, suggesting compartmentalization of ACE2-related biology in SB and colonic inflammation. The restoration of ACE2 expression with anti-cytokine therapy might be important in the context of severe acute respiratory syndrome coronavirus 2 infection and potentially explain reports of reduced morbidity from coronavirus disease 2019 in IBD patients treated with anti-cytokines.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , Anti-Inflammatory Agents/therapeutic use , Colitis, Ulcerative/drug therapy , Crohn Disease/drug therapy , Intestines/drug effects , Tumor Necrosis Factor Inhibitors/therapeutic use , Tumor Necrosis Factor-alpha/antagonists & inhibitors , Adolescent , Adult , Aged , Aged, 80 and over , Angiotensin-Converting Enzyme 2/genetics , Anti-Inflammatory Agents/adverse effects , COVID-19/enzymology , COVID-19/immunology , COVID-19/virology , Case-Control Studies , Child , Child, Preschool , Colitis, Ulcerative/enzymology , Colitis, Ulcerative/genetics , Colitis, Ulcerative/immunology , Crohn Disease/enzymology , Crohn Disease/genetics , Crohn Disease/immunology , Databases, Genetic , Female , Gene Expression Regulation, Enzymologic , Host-Pathogen Interactions , Humans , Intestines/enzymology , Intestines/immunology , Male , Middle Aged , North America , RNA, Messenger/genetics , RNA, Messenger/metabolism , Receptors, Virus/metabolism , SARS-CoV-2/enzymology , SARS-CoV-2/immunology , Severity of Illness Index , Treatment Outcome , Tumor Necrosis Factor Inhibitors/adverse effects , Tumor Necrosis Factor-alpha/metabolism , Young Adult
10.
Eur J Gastroenterol Hepatol ; 33(5): 610-612, 2021 05 01.
Article in English | MEDLINE | ID: covidwho-900651

ABSTRACT

The main symptoms of coronavirus disease 2019 (COVID-19) are respiratory manifestations, while some confirmed patients developed gastrointestinal symptoms or even initially presented digestive symptoms. The link between pneumonia and gastrointestinal symptoms caused by severe acute respiratory symptoms coronavirus 2 focused our attention on the concept of 'gut-lung axis'. In this review, we discuss the inevitability and possible mechanisms of the occurrence of intestinal symptoms or intestinal dysfunction in COVID-19 from the perspective of the gut-lung axis, as well as the influence of the imbalance of intestinal homeostasis on the respiratory symptoms of COVID-19. The interaction between lung and intestine might lead to a vicious cycle of pulmonary and intestinal inflammation which may be a potential factor leading to the death of patients with COVID-19.


Subject(s)
Abdominal Pain/physiopathology , COVID-19/physiopathology , Diarrhea/physiopathology , Intestines/physiopathology , Lung/physiopathology , Vomiting/physiopathology , Feces/virology , Gastrointestinal Microbiome/immunology , Humans , Intestinal Mucosa/immunology , Intestines/immunology , Lung/immunology , Respiratory Mucosa/immunology , SARS-CoV-2
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