Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 20 de 90
Filter
Add filters

Document Type
Year range
1.
Mol Med ; 27(1): 160, 2021 12 20.
Article in English | MEDLINE | ID: covidwho-1582121

ABSTRACT

COVID-19 clinical presentation differs considerably between individuals, ranging from asymptomatic, mild/moderate and severe disease which in some cases are fatal or result in long-term effects. Identifying immune mechanisms behind severe disease development informs screening strategies to predict who are at greater risk of developing life-threatening complications. However, to date clear prognostic indicators of individual risk of severe or long COVID remain elusive. Autoantibodies recognize a range of self-antigens and upon antigen recognition and binding, important processes involved in inflammation, pathogen defence and coagulation are modified. Recent studies report a significantly higher prevalence of autoantibodies that target immunomodulatory proteins including cytokines, chemokines, complement components, and cell surface proteins in COVID-19 patients experiencing severe disease compared to those who experience mild or asymptomatic infections. Here we discuss the diverse impacts of autoantibodies on immune processes and associations with severe COVID-19 disease.


Subject(s)
Autoantibodies/immunology , Autoantibodies/metabolism , COVID-19/complications , COVID-19/immunology , SARS-CoV-2/immunology , Animals , Autoimmunity/physiology , COVID-19/metabolism , Humans , SARS-CoV-2/metabolism
2.
Cells ; 10(12)2021 12 18.
Article in English | MEDLINE | ID: covidwho-1580999

ABSTRACT

Atypical hemolytic uremic syndrome (aHUS) is a rare disorder characterized by dysregulation of the alternate pathway. The diagnosis of aHUS is one of exclusion, which complicates its early detection and corresponding intervention to mitigate its high rate of mortality and associated morbidity. Heterozygous mutations in complement regulatory proteins linked to aHUS are not always phenotypically active, and may require a particular trigger for the disease to manifest. This list of triggers continues to expand as more data is aggregated, particularly centered around COVID-19 and pediatric vaccinations. Novel genetic mutations continue to be identified though advancements in technology as well as greater access to cohorts of interest, as in diacylglycerol kinase epsilon (DGKE). DGKE mutations associated with aHUS are the first non-complement regulatory proteins associated with the disease, drastically changing the established framework. Additional markers that are less understood, but continue to be acknowledged, include the unique autoantibodies to complement factor H and complement factor I which are pathogenic drivers in aHUS. Interventional therapeutics have undergone the most advancements, as pharmacokinetic and pharmacodynamic properties are modified as needed in addition to their as biosimilar counterparts. As data continues to be gathered in this field, future advancements will optimally decrease the mortality and morbidity of this disease in children.


Subject(s)
Atypical Hemolytic Uremic Syndrome/genetics , Complement Factor H/genetics , Complement Factor I/genetics , Diacylglycerol Kinase/genetics , Mutation , Atypical Hemolytic Uremic Syndrome/drug therapy , Atypical Hemolytic Uremic Syndrome/immunology , Autoantibodies/immunology , COVID-19/drug therapy , COVID-19/genetics , COVID-19/immunology , COVID-19 Vaccines/adverse effects , COVID-19 Vaccines/immunology , COVID-19 Vaccines/therapeutic use , Child , Complement Factor H/immunology , Complement Factor I/immunology , Diacylglycerol Kinase/immunology , Humans , SARS-CoV-2/genetics , SARS-CoV-2/immunology
3.
Viruses ; 13(12)2021 12 20.
Article in English | MEDLINE | ID: covidwho-1580419

ABSTRACT

A microarray-based assay to detect IgG and IgM antibodies against betacoronaviruses (SARS-CoV-2, SARS, MERS, OC43, and HKU1), other respiratory viruses and type I interferons (IFN-Is) was developed. This multiplex assay was applied to track antibody cross-reactivity due to previous contact with similar viruses and to identify antibodies against IFN-Is as the markers for severe COVID-19. In total, 278 serum samples from convalescent plasma donors, COVID-19 patients in the intensive care unit (ICU) and patients who recovered from mild/moderate COVID-19, vaccine recipients, prepandemic and pandemic patients with autoimmune endocrine disorders, and a heterogeneous prepandemic cohort including healthy individuals and chronically ill patients were analyzed. The anti-SARS-CoV-2 microarray results agreed well with the ELISA results. Regarding ICU patients, autoantibodies against IFN-Is were detected in 10.5% of samples, and 10.5% of samples were found to simultaneously contain IgM antibodies against more than two different viruses. Cross-reactivity between IgG against the SARS-CoV-2 nucleocapsid and IgG against the OC43 and HKU1 spike proteins was observed, resulting in positive signals for the SARS-CoV-2 nucleocapsid in prepandemic samples from patients with autoimmune endocrine disorders. The presence of IgG against the SARS-CoV-2 nucleocapsid in the absence of IgG against the SARS-CoV-2 spike RBD should be interpreted with caution.


Subject(s)
Antibodies, Viral/immunology , Interferon Type I/immunology , SARS-CoV-2/immunology , Viruses/immunology , Antibodies, Viral/blood , Antigens, Viral/immunology , Autoantibodies/blood , Autoantibodies/immunology , COVID-19/immunology , COVID-19 Serological Testing , Cross Reactions , Humans , Immunoglobulin G/blood , Immunoglobulin G/immunology , Immunoglobulin M/blood , Immunoglobulin M/immunology , Protein Array Analysis , Respiratory Tract Diseases/immunology , Respiratory Tract Diseases/virology , Viruses/classification
5.
J Neuroinflammation ; 18(1): 245, 2021 Oct 28.
Article in English | MEDLINE | ID: covidwho-1496192

ABSTRACT

Approximately 30% of individuals with severe SARS-CoV-2 infections also develop neurological and psychiatric complaints. In rare cases, the occurrence of autoimmune encephalitis has been reported after SARS-CoV-2 infection. In this systematic review, we have identified eight SARS-CoV-2-associated cases of anti-NMDA receptor encephalitis. All had cerebrospinal fluid antibodies against the NMDA receptor and a recent onset of working memory deficits, altered mental status, or psychiatric symptoms, such as confusion, agitation, auditory hallucination, catatonia and speech dysfunction. All patients received high-dose steroid and immunoglobulin therapeutics and conditions improved in each case. These findings suggest that clinical attention should be paid to warning signs of autoimmune encephalitis in severe COVID-19 cases. If characteristic features of autoimmune encephalitis are present, autoantibody diagnostics should be performed and confirmed cases should be treated with immunotherapy to minimize neurological impairments.


Subject(s)
Anti-N-Methyl-D-Aspartate Receptor Encephalitis/virology , COVID-19/complications , Mental Disorders/virology , Receptors, N-Methyl-D-Aspartate/immunology , Adolescent , Adult , Autoantibodies/immunology , COVID-19/immunology , Child , Female , Humans , Infant , Male , Middle Aged , Molecular Mimicry , SARS-CoV-2/immunology , Young Adult
6.
PLoS One ; 16(9): e0257016, 2021.
Article in English | MEDLINE | ID: covidwho-1484849

ABSTRACT

BACKGROUND: Activation of the immune system is implicated in the Post-Acute Sequelae after SARS-CoV-2 infection (PASC) but the mechanisms remain unknown. Angiotensin-converting enzyme 2 (ACE2) cleaves angiotensin II (Ang II) resulting in decreased activation of the AT1 receptor and decreased immune system activation. We hypothesized that autoantibodies against ACE2 may develop after SARS-CoV-2 infection, as anti-idiotypic antibodies to anti-spike protein antibodies. METHODS AND FINDINGS: We tested plasma or serum for ACE2 antibodies in 67 patients with known SARS-CoV-2 infection and 13 with no history of infection. None of the 13 patients without history of SARS-CoV-2 infection and 1 of the 20 outpatients that had a positive PCR test for SARS-CoV-2 had levels of ACE2 antibodies above the cutoff threshold. In contrast, 26/32 (81%) in the convalescent group and 14/15 (93%) of patients acutely hospitalized had detectable ACE2 antibodies. Plasma from patients with antibodies against ACE2 had less soluble ACE2 activity in plasma but similar amounts of ACE2 protein compared to patients without ACE2 antibodies. We measured the capacity of the samples to inhibit ACE2 enzyme activity. Addition of plasma from patients with ACE2 antibodies led to decreased activity of an exogenous preparation of ACE2 compared to patients that did not have antibodies. CONCLUSIONS: Many patients with a history of SARS-CoV-2 infection have antibodies specific for ACE2. Patients with ACE2 antibodies have lower activity of soluble ACE2 in plasma. Plasma from these patients also inhibits exogenous ACE2 activity. These findings are consistent with the hypothesis that ACE2 antibodies develop after SARS-CoV-2 infection and decrease ACE2 activity. This could lead to an increase in the abundance of Ang II, which causes a proinflammatory state that triggers symptoms of PASC.


Subject(s)
Autoantibodies/blood , COVID-19/immunology , SARS-CoV-2/isolation & purification , Spike Glycoprotein, Coronavirus/blood , Angiotensin II/blood , Angiotensin II/immunology , Angiotensin-Converting Enzyme 2/genetics , Autoantibodies/immunology , Autoantibodies/isolation & purification , COVID-19/blood , COVID-19/virology , Female , Humans , Male , Peptidyl-Dipeptidase A/blood , Receptor, Angiotensin, Type 1/blood , Receptor, Angiotensin, Type 1/genetics , Receptor, Angiotensin, Type 1/immunology , Renin-Angiotensin System/genetics , Renin-Angiotensin System/immunology , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/isolation & purification
7.
Cells ; 10(10)2021 10 18.
Article in English | MEDLINE | ID: covidwho-1477931

ABSTRACT

Several recent reports have highlighted the onset of vaccine-induced thrombotic thrombocytopaenia (VITT) in some recipients (approximately 1 case out of 100k exposures) of the ChAdOx1 nCoV-19 vaccine (AstraZeneca). Although the underlying events leading to this blood-clotting phenomenon has yet to be elucidated, several critical observations present a compelling potential mechanism. Thrombus formation requires the von Willebrand (VWF) protein to be in ultra-large multimeric state. The conservation of this state is controlled by the ADAMTS13 enzyme, whose proteolytic activity reduces the size of VWF multimers, keeping blood clotting at bay. However, ADAMTS13 cannot act on VWF that is bound to platelet factor 4 (PF4). As such, it is of particular interest to note that a common feature between subjects presenting with VITT is high titres of antibodies against PF4. This raises the possibility that these antibodies preserve the stability of ultra-large VWF complexes, leading to the formation of endothelium-anchored VWF strings, which are capable of recruiting circulating platelets and causing uncontrolled thrombosis in terminal capillaries. Here, we share our viewpoint about the current understanding of the VITT pathogenesis involving the prevention of ADAMTS13's activity on VWF by PF4 antibody-mediated stabilisation/ protection of the PF4-VWF complex.


Subject(s)
ADAMTS13 Protein/metabolism , COVID-19 Vaccines/adverse effects , COVID-19/prevention & control , Thrombocytopenia/immunology , Antibodies , Autoantibodies/immunology , Blood Platelets/metabolism , Crystallography, X-Ray , Endothelial Cells/immunology , Humans , Platelet Factor 4/metabolism , Polymorphism, Genetic , Protein Domains , Thrombocytopenia/etiology , Thrombosis/etiology , von Willebrand Factor/metabolism
9.
Sci Immunol ; 6(62)2021 08 19.
Article in English | MEDLINE | ID: covidwho-1434875

ABSTRACT

Circulating autoantibodies (auto-Abs) neutralizing high concentrations (10 ng/mL, in plasma diluted 1 to 10) of IFN-α and/or -ω are found in about 10% of patients with critical COVID-19 pneumonia, but not in subjects with asymptomatic infections. We detect auto-Abs neutralizing 100-fold lower, more physiological, concentrations of IFN-α and/or -ω (100 pg/mL, in 1/10 dilutions of plasma) in 13.6% of 3,595 patients with critical COVID-19, including 21% of 374 patients > 80 years, and 6.5% of 522 patients with severe COVID-19. These antibodies are also detected in 18% of the 1,124 deceased patients (aged 20 days-99 years; mean: 70 years). Moreover, another 1.3% of patients with critical COVID-19 and 0.9% of the deceased patients have auto-Abs neutralizing high concentrations of IFN-ß. We also show, in a sample of 34,159 uninfected subjects from the general population, that auto-Abs neutralizing high concentrations of IFN-α and/or -ω are present in 0.18% of individuals between 18 and 69 years, 1.1% between 70 and 79 years, and 3.4% >80 years. Moreover, the proportion of subjects carrying auto-Abs neutralizing lower concentrations is greater in a subsample of 10,778 uninfected individuals: 1% of individuals <70 years, 2.3% between 70 and 80 years, and 6.3% >80 years. By contrast, auto-Abs neutralizing IFN-ß do not become more frequent with age. Auto-Abs neutralizing type I IFNs predate SARS-CoV-2 infection and sharply increase in prevalence after the age of 70 years. They account for about 20% of both critical COVID-19 cases in the over-80s, and total fatal COVID-19 cases.


Subject(s)
Autoantibodies/immunology , COVID-19/immunology , Interferon Type I/immunology , Adolescent , Adult , Aged , Aged, 80 and over , Antibodies, Neutralizing/blood , Antibodies, Neutralizing/immunology , Autoantibodies/blood , COVID-19/mortality , Case-Control Studies , Child , Child, Preschool , Critical Illness , Humans , Immunoglobulin G/blood , Immunoglobulin G/immunology , Infant , Infant, Newborn , Interferon-alpha/immunology , Middle Aged , Young Adult
10.
Med Sci Monit ; 27: e934766, 2021 Sep 20.
Article in English | MEDLINE | ID: covidwho-1431155

ABSTRACT

During the past two years, clinical studies have attempted to identify risk factors to predict clinical outcomes following infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In July 2021, a study using a high-throughput technique detected autoantibodies to chemokines, cytokines, and complement components in patients with symptomatic coronavirus disease 2019 (COVID-19). In August 2021, a study identified pre-existing autoantibodies to type 1 interferons (IFNs) in 10% of patients with severe COVID-19 but not asymptomatic individuals. Autoantibodies may be the long-awaited markers of clinical risk for severe COVID-19 in patients with SARS-CoV-2 infection. This Editorial aims to present some recent findings of autoantibodies to components of the immune system, including type 1 IFNs, and the risk of severe COVID-19.


Subject(s)
Autoantibodies/immunology , COVID-19/immunology , Interferon Type I/immunology , SARS-CoV-2/immunology , COVID-19/virology , Humans , Interferon Type I/genetics , SARS-CoV-2/genetics
12.
Nat Commun ; 12(1): 5417, 2021 09 14.
Article in English | MEDLINE | ID: covidwho-1410404

ABSTRACT

COVID-19 is associated with a wide range of clinical manifestations, including autoimmune features and autoantibody production. Here we develop three protein arrays to measure IgG autoantibodies associated with connective tissue diseases, anti-cytokine antibodies, and anti-viral antibody responses in serum from 147 hospitalized COVID-19 patients. Autoantibodies are identified in approximately 50% of patients but in less than 15% of healthy controls. When present, autoantibodies largely target autoantigens associated with rare disorders such as myositis, systemic sclerosis and overlap syndromes. A subset of autoantibodies targeting traditional autoantigens or cytokines develop de novo following SARS-CoV-2 infection. Autoantibodies track with longitudinal development of IgG antibodies recognizing SARS-CoV-2 structural proteins and a subset of non-structural proteins, but not proteins from influenza, seasonal coronaviruses or other pathogenic viruses. We conclude that SARS-CoV-2 causes development of new-onset IgG autoantibodies in a significant proportion of hospitalized COVID-19 patients and are positively correlated with immune responses to SARS-CoV-2 proteins.


Subject(s)
Autoantibodies/immunology , COVID-19/immunology , Immunoglobulin G/immunology , SARS-CoV-2/immunology , Aged , Antibodies, Antinuclear/blood , Antibodies, Antinuclear/immunology , Antibodies, Viral/blood , Antibodies, Viral/immunology , Autoantibodies/blood , Autoantigens/immunology , Connective Tissue Diseases/immunology , Cytokines/immunology , Female , Hospitalization , Humans , Immunoglobulin G/blood , Male , Middle Aged , SARS-CoV-2/pathogenicity , Viral Proteins/immunology
13.
Life Sci Alliance ; 4(11)2021 11.
Article in English | MEDLINE | ID: covidwho-1404295

ABSTRACT

High levels of autoimmune antibodies are observed in COVID-19 patients but their specific contribution to disease severity and clinical manifestations remains poorly understood. We performed a retrospective study of 115 COVID-19 hospitalized patients with different degrees of severity to analyze the generation of autoimmune antibodies to common antigens: a lysate of erythrocytes, the lipid phosphatidylserine (PS) and DNA. High levels of IgG autoantibodies against erythrocyte lysates were observed in a large percentage (up to 36%) of patients. Anti-DNA and anti-PS antibodies determined upon hospital admission correlated strongly with later development of severe disease, showing a positive predictive value of 85.7% and 92.8%, respectively. Patients with positive values for at least one of the two autoantibodies accounted for 24% of total severe cases. Statistical analysis identified strong correlations between anti-DNA antibodies and markers of cell injury, coagulation, neutrophil levels and erythrocyte size. Anti-DNA and anti-PS autoantibodies may play an important role in the pathogenesis of COVID-19 and could be developed as predictive biomarkers for disease severity and specific clinical manifestations.


Subject(s)
Antibodies, Antinuclear/immunology , Autoantibodies/immunology , COVID-19/immunology , COVID-19/metabolism , Adult , Aged , Aged, 80 and over , Antibodies, Antinuclear/blood , Autoantibodies/blood , Biomarkers , DNA/chemistry , DNA/immunology , Erythrocytes/immunology , Female , Humans , Male , Middle Aged , Phosphatidylserines/immunology , Prognosis , Retrospective Studies , SARS-CoV-2/isolation & purification , Severity of Illness Index
14.
Front Immunol ; 12: 722979, 2021.
Article in English | MEDLINE | ID: covidwho-1399139

ABSTRACT

The immunopathology of type I diabetes (T1D) presents a complicated case in part because of the multifactorial origin of this disease. Typically, T1D is thought to occur as a result of autoimmunity toward islets of Langerhans, resulting in the destruction of insulin-producing cells (ß cells) and thus lifelong reliance on exogenous insulin. However, that explanation obscures much of the underlying mechanism, and the actual precipitating events along with the associated actors (latent viral infection, diverse immune cell types and their roles) are not completely understood. Notably, there is a malfunctioning in the regulation of cytotoxic CD8+ T cells that target endocrine cells through antigen-mediated attack. Further examination has revealed the likelihood of an imbalance in distinct subpopulations of tolerogenic and cytotoxic natural killer (NK) cells that may be the catalyst of adaptive immune system malfunction. The contributions of components outside the immune system, including environmental factors such as chronic viral infection also need more consideration, and much of the recent literature investigating the origins of this disease have focused on these factors. In this review, the details of the immunopathology of T1D regarding NK cell disfunction is discussed, along with how those mechanisms stand within the context of general autoimmune disorders. Finally, the rarer cases of latent autoimmune, COVID-19 (viral), and immune checkpoint inhibitor (ICI) induced diabetes are discussed as their exceptional pathology offers insight into the evolution of the disease as a whole.


Subject(s)
Autoimmune Diseases/immunology , Diabetes Mellitus, Type 1/immunology , Diabetes Mellitus, Type 1/pathology , Killer Cells, Natural/immunology , Killer Cells, Natural/pathology , Autoantibodies/immunology , Autoimmune Diseases/pathology , COVID-19/complications , Diabetes Mellitus, Type 1/etiology , Humans , Insulin/metabolism , Insulin-Secreting Cells/immunology , Virus Diseases/complications
15.
Eur J Clin Invest ; 51(11): e13661, 2021 Nov.
Article in English | MEDLINE | ID: covidwho-1398398

ABSTRACT

BACKGROUND: Unravelling autoimmune targets triggered by SARS-CoV-2 infection may provide crucial insights into the physiopathology of the disease and foster the development of potential therapeutic candidate targets and prognostic tools. We aimed at determining (a) the association between anti-SARS-CoV-2 and anti-apoA-1 humoral response and (b) the degree of linear homology between SARS-CoV-2, apoA-1 and Toll-like receptor 2 (TLR2) epitopes. DESIGN: Bioinformatics modelling coupled with mimic peptides engineering and competition experiments were used to assess epitopes sequence homologies. Anti-SARS-CoV-2 and anti-apoA-1 IgG as well as cytokines were assessed by immunoassays on a case-control (n = 101), an intensive care unit (ICU; n = 126) and a general population cohort (n = 663) with available samples in the pre and post-pandemic period. RESULTS: Using bioinformatics modelling, linear sequence homologies between apoA-1, TLR2 and Spike epitopes were identified but without experimental evidence of cross-reactivity. Overall, anti-apoA-1 IgG levels were higher in COVID-19 patients or anti-SARS-CoV-2 seropositive individuals than in healthy donors or anti-SARS-CoV-2 seronegative individuals (P < .0001). Significant and similar associations were noted between anti-apoA-1, anti-SARS-CoV-2 IgG, cytokines and lipid profile. In ICU patients, anti-SARS-CoV-2 and anti-apoA-1 seroconversion rates displayed similar 7-day kinetics, reaching 82% for anti-apoA-1 seropositivity. In the general population, SARS-CoV-2-exposed individuals displayed higher anti-apoA-1 IgG seropositivity rates than nonexposed ones (34% vs 16.8%; P = .004). CONCLUSION: COVID-19 induces a marked humoral response against the major protein of high-density lipoproteins. As a correlate of poorer prognosis in other clinical settings, such autoimmunity signatures may relate to long-term COVID-19 prognosis assessment and warrant further scrutiny in the current COVID-19 pandemic.


Subject(s)
Antibodies, Viral/immunology , Apolipoprotein A-I/immunology , Autoantibodies/immunology , COVID-19/immunology , Cytokines/immunology , Immunity, Humoral/immunology , Spike Glycoprotein, Coronavirus/immunology , Adult , Aged , Aged, 80 and over , Apolipoprotein A-I/chemistry , Computational Biology , Epitopes/chemistry , Female , Humans , Immunoglobulin G/immunology , Male , Middle Aged , Peptide Fragments/chemistry , Peptide Fragments/immunology , Peptides , SARS-CoV-2 , Sequence Homology, Amino Acid , Spike Glycoprotein, Coronavirus/chemistry , Toll-Like Receptor 2/chemistry , Toll-Like Receptor 2/immunology , Young Adult
16.
J Autoimmun ; 121: 102662, 2021 07.
Article in English | MEDLINE | ID: covidwho-1385817

ABSTRACT

Herein, we consider venous immunothrombotic mechanisms in SARS-CoV-2 infection and anti-SARS-CoV-2 DNA vaccination. Primary SARS-CoV-2 infection with systemic viral RNA release (RNAaemia) contributes to innate immune coagulation cascade activation, with both pulmonary and systemic immunothrombosis - including venous territory strokes. However, anti-SARS-CoV-2 adenoviral-vectored-DNA vaccines -initially shown for the ChAdOx1 vaccine-may rarely exhibit autoimmunity with autoantibodies to Platelet Factor-4 (PF4) that is termed Vaccine-Induced Thrombotic Thrombocytopenia (VITT), an entity pathophysiologically similar to Heparin-Induced Thrombocytopenia (HIT). The PF4 autoantigen is a polyanion molecule capable of independent interactions with negatively charged bacterial cellular wall, heparin and DNA molecules, thus linking intravascular innate immunity to both bacterial cell walls and pathogen-derived DNA. Crucially, negatively charged extracellular DNA is a powerful adjuvant that can break tolerance to positively charged nuclear histone proteins in many experimental autoimmunity settings, including SLE and scleroderma. Analogous to DNA-histone interactons, positively charged PF4-DNA complexes stimulate strong interferon responses via Toll-Like Receptor (TLR) 9 engagement. A chain of events following intramuscular adenoviral-vectored-DNA vaccine inoculation including microvascular damage; microbleeding and platelet activation with PF4 release, adenovirus cargo dispersement with DNA-PF4 engagement may rarely break immune tolerance, leading to rare PF4-directed autoimmunity. The VITT cavernous sinus cerebral and intestinal venous territory immunothrombosis proclivity may pertain to venous drainage of shared microbiotal-rich areas of the nose and in intestines that initiates local endovascular venous immunity by PF4/microbiotal engagement with PF4 autoantibody driven immunothrombosis reminiscent of HIT. According to the proposed model, any adenovirus-vectored-DNA vaccine could drive autoimmune VITT in susceptible individuals and alternative mechanism based on molecular mimicry, vaccine protein contaminants, adenovirus vector proteins, EDTA buffers or immunity against the viral spike protein are secondary factors. Hence, electrochemical DNA-PF4 interactions and PF4-heparin interactions, but at different locations, represent the common denominator in HIT and VITT related autoimmune-mediated thrombosis.


Subject(s)
Autoantibodies/immunology , COVID-19/immunology , Purpura, Thrombocytopenic, Idiopathic/immunology , SARS-CoV-2/immunology , Thrombosis/immunology , Vaccines/adverse effects , COVID-19/pathology , COVID-19/prevention & control , Humans , Platelet Activation/immunology , Platelet Factor 4/immunology , Purpura, Thrombocytopenic, Idiopathic/chemically induced , Purpura, Thrombocytopenic, Idiopathic/pathology , Thrombosis/chemically induced , Thrombosis/pathology , Vaccines/immunology
17.
PLoS One ; 16(9): e0257016, 2021.
Article in English | MEDLINE | ID: covidwho-1388955

ABSTRACT

BACKGROUND: Activation of the immune system is implicated in the Post-Acute Sequelae after SARS-CoV-2 infection (PASC) but the mechanisms remain unknown. Angiotensin-converting enzyme 2 (ACE2) cleaves angiotensin II (Ang II) resulting in decreased activation of the AT1 receptor and decreased immune system activation. We hypothesized that autoantibodies against ACE2 may develop after SARS-CoV-2 infection, as anti-idiotypic antibodies to anti-spike protein antibodies. METHODS AND FINDINGS: We tested plasma or serum for ACE2 antibodies in 67 patients with known SARS-CoV-2 infection and 13 with no history of infection. None of the 13 patients without history of SARS-CoV-2 infection and 1 of the 20 outpatients that had a positive PCR test for SARS-CoV-2 had levels of ACE2 antibodies above the cutoff threshold. In contrast, 26/32 (81%) in the convalescent group and 14/15 (93%) of patients acutely hospitalized had detectable ACE2 antibodies. Plasma from patients with antibodies against ACE2 had less soluble ACE2 activity in plasma but similar amounts of ACE2 protein compared to patients without ACE2 antibodies. We measured the capacity of the samples to inhibit ACE2 enzyme activity. Addition of plasma from patients with ACE2 antibodies led to decreased activity of an exogenous preparation of ACE2 compared to patients that did not have antibodies. CONCLUSIONS: Many patients with a history of SARS-CoV-2 infection have antibodies specific for ACE2. Patients with ACE2 antibodies have lower activity of soluble ACE2 in plasma. Plasma from these patients also inhibits exogenous ACE2 activity. These findings are consistent with the hypothesis that ACE2 antibodies develop after SARS-CoV-2 infection and decrease ACE2 activity. This could lead to an increase in the abundance of Ang II, which causes a proinflammatory state that triggers symptoms of PASC.


Subject(s)
Autoantibodies/blood , COVID-19/immunology , SARS-CoV-2/isolation & purification , Spike Glycoprotein, Coronavirus/blood , Angiotensin II/blood , Angiotensin II/immunology , Angiotensin-Converting Enzyme 2/genetics , Autoantibodies/immunology , Autoantibodies/isolation & purification , COVID-19/blood , COVID-19/virology , Female , Humans , Male , Peptidyl-Dipeptidase A/blood , Receptor, Angiotensin, Type 1/blood , Receptor, Angiotensin, Type 1/genetics , Receptor, Angiotensin, Type 1/immunology , Renin-Angiotensin System/genetics , Renin-Angiotensin System/immunology , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/isolation & purification
18.
Front Immunol ; 11: 604759, 2020.
Article in English | MEDLINE | ID: covidwho-1389169

ABSTRACT

Objective: To first describe and estimate the potential pathogenic role of Ig4 autoantibodies in complement-mediated thrombotic microangiopathy (TMA) in a patient with IgG4-related disease (IgG4-RD). Methods: This study is a case report presenting a retrospective review of the patient's medical chart. Plasma complement C3 and C4 levels, immunoglobulin isotypes and subclasses were determined by nephelometry, the complement pathways' activity (CH50, AP50, MBL) using WIESLAB® Complement System assays. Human complement factor H levels, anti-complement factor H auto-antibodies were analyzed by ELISA, using HRP-labeled secondary antibodies specific for human IgG, IgG4, and IgA, respectively. Genetic analyses were performed by exome sequencing of 14 gens implicated in complement disorders, as well as multiplex ligation-dependent probe amplification looking specifically for CFH, CFHR1-2-3, and 5. Results: Our brief report presents the first case of IgG4-RD with complement-mediated TMA originating from both pathogenic CFHR 1 and CFHR 4 genes deletions, and inhibitory anti-complement factor H autoantibodies of the IgG4 subclass. Remission was achieved with plasmaphereses, corticosteroids, and cyclophosphamide. Following remission, the patient was diagnosed with lymphocytic meningitis and SARS-CoV-2 pneumonia with an uneventful recovery. Conclusion: IgG4-RD can be associated with pathogenic IgG4 autoantibodies. Genetic predisposition such as CFHR1 and CFHR4 gene deletions enhance the susceptibility to the formation of inhibitory anti-Factor H IgG4 antibodies.


Subject(s)
Apolipoproteins/genetics , Atypical Hemolytic Uremic Syndrome/genetics , Autoantibodies/immunology , Complement C3b Inactivator Proteins/genetics , Complement Factor H/immunology , Immunoglobulin G4-Related Disease/genetics , Atypical Hemolytic Uremic Syndrome/immunology , Atypical Hemolytic Uremic Syndrome/pathology , Female , Gene Deletion , Genetic Predisposition to Disease/genetics , Humans , Immunoglobulin G/immunology , Immunoglobulin G4-Related Disease/immunology , Immunoglobulin G4-Related Disease/pathology , Middle Aged , Thrombotic Microangiopathies/immunology , Thrombotic Microangiopathies/pathology
20.
J Med Virol ; 94(1): 54-62, 2022 01.
Article in English | MEDLINE | ID: covidwho-1370368

ABSTRACT

Coronavirus disease 2019 (COVID-19) is still propagating a year after the start of the pandemic. Besides the complications patients face during the COVID-19 disease period, there is an accumulating body of evidence concerning the late-onset complications of COVID-19, of which autoimmune manifestations have attracted remarkable attention from the first months of the pandemic. Autoimmune hemolytic anemia, immune thrombocytopenic purpura, autoimmune thyroid diseases, Kawasaki disease, Guillain-Barre syndrome, and the detection of autoantibodies are the cues to the discovery of the potential of COVID-19 in inducing autoimmunity. Clarification of the pathophysiology of COVID-19 injuries to the host, whether it is direct viral injury or autoimmunity, could help to develop appropriate treatment.


Subject(s)
Autoimmune Diseases/epidemiology , Autoimmune Diseases/immunology , Autoimmunity/immunology , COVID-19/pathology , SARS-CoV-2/immunology , Autoantibodies/blood , Autoantibodies/immunology , Autoimmune Diseases/virology , COVID-19/immunology , Humans
SELECTION OF CITATIONS
SEARCH DETAIL
...