Acute hepatitis with autoimmune features after COVID-19 vaccine: coincidence or vaccine-induced phenomenon?

Authors: José M Pinazo-Bandera 1Alicia Hernández-Albújar 1Ana Isabel García-Salguero 2Isabel Arranz-Salas 2Raúl J Andrade 1 3Mercedes Robles-Díaz 1 3

Gastroenterol Rep (Oxf) 2022 Apr 27;10:goac014. doi: 10.1093/gastro/goac014. eCollection 2022.

Introduction

Autoimmune diseases result from a breach of immunological self-tolerance and tissue damage by autoreactive T lymphocytes. Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection is characterized by an inflammatory dysregulation that has been associated with the development of autoimmune processes [1].

Molecular mimicry has been suggested as a potential mechanism for these associations as well as ‘bystander activation’ where the infection may lead to activation of antigen presenting cells that may activate autoreactive T-cells, with the production of pro-inflammatory mediators and tissue damage [1].

There is a potential antigenic cross-reactivity between SARS-CoV-2 and human tissue possibly linked to an increase in autoimmune diseases. A recent study showed that antibodies against the spike protein S1 of SARS-CoV-2 had high affinity against some human tissue proteins such as transglutaminase 2 and 3, or myelin basic protein, among others [2].

As both mRNA vaccine (Comirnaty BioNTech BNT162b2 and Spikevax ARNm-1273) and vectorial vaccine (ChAdOx1nCoV-19 Vaxzevria/Covishield) give rise to the production of protein S, the antibodies produced against this protein after vaccination may also trigger autoimmune conditions in predisposed individuals.

Thirteen case reports (including 16 patients) have recently reported an association between COVID-19 vaccines and acute hepatitis development [3–15].

Here we report two new cases of liver injury possibly related to COVID-19 vaccination.

Case 1

A 77-year-old woman developed intense malaise, vomiting and disorientation 2 days after receiving the second dose of Comirnaty vaccine and was hospitalized the following day. She did not have a history of autoimmune disorders. She denied alcohol drinking and was on long-term therapy with bromazepam, losartan, and omeprazole. Her previous liver tests back in 2020 were normal.

Physical examination was normal except for scleral icterus. Liver test showed acute hepatocellular injury: total bilirubin (TB) 3.1 mg/dL (reference, <1 mg/dL), aspartate aminotransferase (AST) 474 U/L (reference, <40 UI/L), alanine aminotransferase (ALT) 552 U/L (reference, <40 U/L), and alkaline phosphatase (ALP) 159 U/L (reference, <117 U/L). Immunoglobulin G levels were within normal ranges (reference, 800–1,600 mg/dL), while anti-nuclear antibody and anti-mitochondrial antibody M2 were detected with 1/160 and 1/40 titre, respectively. Human leukocyte antigen (HLA) testing was positive for HLA-DR4. All the other possible aetiologies were ruled out.

The patient was discharged and closely monitored. Due to increased transaminase levels, she underwent a liver biopsy (Supplementary Figure 1.1), which showed findings compatible with autoimmune hepatitis (AIH).

Prednisone 60 mg/day on tapering dose was initiated and 3 weeks later liver test had markedly improved. Azathioprine was added 2 months later, but it had to be withdrawn due to rash. Prednisone was then replaced by budesonide 9 mg/day. Five months after onset, transaminases were within the normal range; however, the subject was hospitalized with neurologic symptoms in relation to brain lesions in both hemispheres of probable infectious origin and died 1 month later.

Case 2

A 23-year-old man presented with mononucleosis syndrome-like symptoms and jaundice at the emergency room, 10 days after receiving the second dose of Spikevax vaccine. He did not suffer from previous autoimmune disorders. He denied having taken any conventional drug treatments as well as alcohol consumption.

Physical examination was unremarkable except for scleral icterus. Liver tests showed acute hepatocellular injury: TB 2.3 mg/dL, AST 702 U/L, ALT 587 U/L, and ALP 202 U/L. Immunoglobulin G levels were minimally elevated (1,647 mg/dL), while autoantibodies resulted as negative. HLA testing was positive for HLA-DR3. Serology ruled out viral causes and abdominal ultrasonography was normal. After admission to the hospital, a thoracic-abdominal scan was performed and revealed generalized lymphadenopathy.

He underwent a liver biopsy (Supplementary Figure 1.2), which showed findings compatible with AIH.

Prednisone 60 mg/day on tapering dose was initiated and 1 month later lymphadenopathies were undetectable and liver test had significantly improved. Three months after onset, transaminases were within the normal range and he is still on low-dose prednisone 10 mg/day.

Discussion

These new cases of liver injury compatible with AIH, which developed post COVID-19 vaccination, along with 13 prior published case reports (16 patients) reinforce that this association could be more than coincidental. In the previously published case reports, all the patients, except three, were females and their age ranged from 35 to 80 years [3–15]. Twelve of these patients received one of the mRNA vaccines [35–121415], while four patients received vectorial vaccines [41213]. In 6 of the 16 patients, liver biopsy revealed infiltration with eosinophils [347914] and IgG levels were increased in 12 cases [4–1215].

Fourteen reported patients were successfully treated with prednisolone whereas two died due to acute liver failure [412] (Table 1).

Table 1.

Characteristics of patients with liver injury after SARS-CoV-2 vaccine (published cases and two new cases)

AuthorVaccineDoseDays until clinical onsetGenderAgeLiver-injury patternAutoimmune disease historyAuto- antibodiesIgGBiopsySteroid responseDeath
Compatible (Yes/No)Eosinophils infiltration (Yes/No)
Bril et al. [3Comirnaty BioNTech BNT162b2 1st 13 35 Hep None ANAAnti-dsDNA Normal Yes Yes Yes No 
Rela et al. [4(2 cases) ChAdOx1nCoV-19 Covishield (both patients) NA 20 38 NAa None ANA High Yes Yes Yes No 
NA 16 65 NAa None NA NA Yes Yes No Yes 
Rocco et al. [5Comirnaty BioNTech BNT162b2 2nd 80 Hep Hashimoto disease ANA High Yes No Yes No 
Londoño et al. [6Spikevax, ARNm-1273 2nd 41 Hep None ANASMASLALC-1 High Yes No Yes No 
Tan et al. [7Spikevax, ARNm-1273 1st 35 56 Hep None ANASMA High Yes Yes Yes No 
McShane et al. [8Spikevax, ARNm-1273 1st 71 Hep None SMA High Yes No Yes No 
Ghielmet-ti et al. [9Spikevax, ARNm-1273 1st 63 Hep None ASMAANCAANA High Yes Yes Yes No 
Garrido et al. [10Spikevax, ARNm-1273 1st 14 65 Hep None ANA High Yes No Yes No 
Avci et al. [11Comirnaty BioNTech BNT162b2 NA 14 61 Mix Hashimoto disease ANASMA High Yes No Yes No 
Erard et al. [12(3 cases) Spikevax, ARNm-1273(two first patients)ChAdOx1nCoV-19 Vaxzevria(third one) 2nd 10 80 NAa None Negative High Yes No Yes No 
1st 21 73 NAa None Negative High Yes No Yes No 
1st 20 68 NAa None Negative High Yes No No Yes 
Clayton-Chubb et al. [13ChAdOx1nCoV-19 Vaxzevria 1st 26 36 Hep None ANA Normal Yes No Yes No 
Lodato et al. [14Comirnaty BioNTech BNT162b2 1st 15 43 NAa None Negative Normal Yes Yes Yes No 
Vuille-Lessard et al. [15Spikevax, ARNm-1273 1st 76 Hep Hashimoto disease ANA High Yes No Yes No 
Pinazo et al. (2 cases) Comirnaty BioNTech BNT162b2(First one)Spikevax, ARNm-1273(second one) 2nd 77 Hep None ANAAMANegative Normal Yes Yes Yes Yesb 
2nd 10 23 Hep None High Yes No Yes No 

M, male; F, female; NA, not available; Hep, hepatocellular; Mix, mixed; IgG, immunoglobulin G; ANA, anti-nuclear antikor; SMA, smooth muscle antibodies; dsDNA, double-stranded DNA antibodies; LC1, liver sitozol antibody; anti-SLA, soluble liver antigen antibodies; ANCA, anti-neutrophil cytoplasmic antibodies; AMA, anti-mitochondrial antibodies.a

ALP (alkaline phosphatase) not available.b

The patient died due to an extrahepatic cause (brain lesions in both hemispheres of probable infectious origin).Open in new tab

In both cases of the present study, a number of laboratory (including HLA testing) and histological features supported the autoimmune nature of the liver injury. In our first case, the short period elapsed after vaccine administration, the laboratory and histopathological findings (showing moderate liver fibrosis), the positive HLA-DR4, and the response to therapy suggest unmasking of AIH by the vaccine. However, in our second case, the medical history negative for liver and autoimmune diseases, the short time interval after vaccination, the typical onset of symptoms to which was added generalized lymphadenopathy, the elevated immunoglobulin G levels, the positive HLA-DR3, histopathological findings with absence of liver fibrosis, and the response to therapy reinforce the hypothesis of SARS-CoV-2 vaccine as a trigger of an autoimmune liver injury debut. We realize that there are no pathognomonic (laboratory or histological) features of AIH, but the appropriate exclusion of viral and metabolic causes of liver injury makes the autoimmune mechanisms the more likely explanation for both cases.

Taking into account the large number of vaccinated subjects worldwide, the suspicion of vaccine-related AIH carries important clinical implications. It is unknown whether prolonged immunosuppression would be required in these cases or whether re-exposure to a new dose of COVID-19 vaccine might trigger fulminant liver injury. Nevertheless, the risk of receiving another dose must be balanced against the risk of contracting SARS-CoV-2 infection. In addition, it remains unclear whether patients who have developed liver injury after vaccination with one type of vaccine can receive other COVID-19 vaccine with a different mechanism of action.

Post COVID-19 vaccination, AIH has been rarely reported so far [3–15], which might be due to either minimal awareness of this disease or because patients without jaundice often do not seek medical attention. However, given the growing number of cases compatible with AIH reported after SARS-CoV-2 vaccination, regulators should consider the inclusion of this potential adverse event in the label of COVID-19 vaccines.

In conclusion, clinicians should be aware of the potential association between the vaccines and the onset of immune mediated disorders such as AIH. However, this rare complication should not discourage people from getting vaccinated.

References

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2 Google ScholarCrossrefPubMed2Vojdani A, Kharrazian D. Potential antigenic cross-reactivity between SARS-CoV-2 and human tissue with a possible link to an increase in autoimmune diseases. Clin Inmunol 2020;217:108480.

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14 Google ScholarCrossrefPubMed14Lodato F, Larocca A, D’Errico A et al.  An unusual case of acute cholestatic hepatitis after m-RNABNT162b2 (comirnaty) SARS-COV-2 vaccine: coincidence, autoimmunity or drug related liver injury? J Hepatol 2021;75:1254–6.

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COVID‐19‐induced endotheliitis: emerging evidence and possible therapeutic strategies

Authors: Eleonora Calabretta, 1 , 12 Jose M. Moraleda, 2 Massimo Iacobelli, 3 Ruben Jara, 4 Israel Vlodavsky, 5 Peter O’Gorman, 6 Antonio Pagliuca, 7 Clifton Mo, 8 Rebecca M. Baron, 9 Alessio Aghemo, 10 , 12 Robert Soiffer, 8 Jawed Fareed, 11 Carmelo Carlo‐Stella, 1 , 12 , * and Paul Richardson 8 , *

Br J Haematol. 2021 Apr; 193(1): 43–51.Published online 2021 Feb 4.  doi:  10.1111/bjh.17240 PMCID:  PMC8014053PMID: 33538335

Introduction

The coronavirus disease 2019 (COVID‐19) pandemic, a viral illness caused by the severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2), 1 has produced at the time of this writing nearly 33 million cases of infection, with over a million deaths in 235 countries, 2 causing an unprecedented burden on healthcare systems and a severe global socioeconomic crisis. As the pandemic spreads, knowledge on the disease course, as well as potential risk factors and predictors of severity is increasing daily, and initial data from randomised controlled studies have allowed care providers to refine therapeutic strategies. Nonetheless, mortality is markedly elevated among those presenting with severe disease, long‐term sequelae among survivors are unknown, and vaccine‐based therapies currently remain at early stages of development.

Most reported cases are asymptomatic or present with mild symptoms; however, 7–26% of hospitalised patients experience severe disease, often requiring admission to intensive care units (ICUs), with progressive multiple organ dysfunction and high mortality. 3 Such differences in clinical outcomes have led physicians to initiate diverse pharmacological therapies at various stages of the disease, generating challenges as to the most appropriate therapeutic choice for COVID‐19. In this context, the use of dexamethasone has significantly reduced mortality rates in critically ill patients requiring supplemental oxygen or mechanical ventilation, 6 and remdesivir has demonstrated clinical benefit in hospitalised patients, but with unknown survival benefit to date 7 ; additional effective treatment options are therefore urgently needed.

In an initial attempt to provide a uniform and widely reproducible methodology to guide systematic treatment strategies, a three‐stage classification of COVID‐19 has been proposed. 8 The Stage I or ‘early infection’ occurs at the initial establishment of disease with high viral replication, and commonly presents with a range of complaints that can include mild and often non‐specific influenza‐like signs and symptoms. Stage II is the ‘pulmonary phase’, with preferential viral‐mediated injury of the lung parenchyma and this is characterised by shortness of breath, hypoxia and pulmonary infiltrates with some degree of lung inflammation. Stage III is characterised by an exaggerated host immune‐inflammatory response to the virus, leading to acute respiratory distress syndrome (ARDS) and multi‐organ failure (MOF).Go to:

Endothelial cells are a preferential target of COVID‐19 resulting in widespread endotheliitis

Emerging evidence suggests that endothelial damage and subsequent morphological and functional changes in the endothelium play important roles in COVID‐19‐induced hyperinflammation. The virus, which binds to the angiotensin‐converting enzyme 2 (ACE2) receptor, 9 displays a profound tropism for human lung and small intestine epithelium, as well as the vascular endothelium. 10 In an important case series from Varga et al., 11 postmortem histology from three patients affected by late‐stage COVID‐19, revealed viral inclusions in endothelial apoptotic cells and microvascular lymphocytic endotheliitis, with infiltration of inflammatory cells around the vessels and endothelial cells (ECs), as well as evidence of endothelial apoptotic cell death in the lung, kidney, small bowel and heart. Additionally, autopsy findings of 27 patients in another series confirmed the detection of the SARS‐CoV‐2 in multiple organs, including the respiratory tract, pharynx, heart, liver, brain, and kidneys. 12 Immunofluorescence of kidney specimens from six of the 27 patients showed the presence of SARS‐CoV‐2 protein in all renal compartments, and in three of the patients preferentially in the endothelium of the glomerulus. Similar microscopic findings were also noted in lung specimens from seven patients with COVID‐19, which displayed small vessel endotheliitis, microvascular thrombosis and angiogenesis, along with the presence of SARS‐CoV‐2 in pulmonary ECs, an observation strongly supporting the vascular tropism of the virus. 13 Lastly, Stahl et al. 14 have identified in the plasma and serum of 19 critically ill patients with COVID‐19 evidence of disruption of the endothelial glycocalyx, reflected by increased levels of the Tie‐2 receptor and syndecan‐1 (SDC‐1), a heparan sulphate (HS) proteoglycan. This particular observation is of interest as the endothelial glycocalyx covers the luminal surface of ECs, and its integrity is vital for the maintenance of vascular homeostasis.

Such findings suggest that virus‐mediated apoptosis may promote endothelial barrier disruption with interstitial oedema and increased recruitment of circulating activated immune cells, thus causing widespread endothelial dysfunction, as well as activation of platelets and the coagulation cascade leading to venous and arterial thrombosis. 15 Altered pro‐inflammatory and pro‐thrombotic status is confirmed by the presence of elevated inflammation‐related indices (e.g. C‐reactive protein and serum ferritin), humoral biomarkers [interleukin (IL)‐2, IL‐6, IL‐7, granulocyte‐colony stimulating factor (G‐CSF), tumour necrosis factor‐alpha (TNF‐α)], and indicators of an increased pro‐coagulant‐fibrinolytic state [e.g. von Willebrand factor (VWF), D‐dimer, fibrinogen]. Further, factor VIII (FVIII), a potent and key factor in the coagulation process, is greatly increased in ICU patients with COVID‐19. 16

In this setting, it has been proposed that the systemic hyperinflammation observed in severe COVID‐19 is comparable to a cytokine release syndrome (CRS), or cytokine storm. IL‐6 has a central role in the generation of the cytokine storm, and is commonly elevated in the serum of severely ill patients with COVID‐19. 17 High levels of IL‐6 activate ECs, thus resulting in vascular leakage, further cytokine secretion and activation of the complement and coagulation cascades. 18 Interestingly, a population of IL‐6 producing monocytes was found to be expanded in the peripheral blood of ICU patients 19 and an aberrant macrophage response exhibiting increased levels of pro‐inflammatory cytokines has been detected in bronchoalveolar fluid, especially in severely ill patients. 20 Although the exact driver of monocyte activation remains unclear, such cells are attracted to the endothelium, where the release of highly noxious molecules, such as reactive oxygen species (ROS), contributes to endothelial dysfunction and promotes hyperinflammation. 21 Further, activated monocytes enhance tissue factor expression and form aggregates with platelets through P‐selectin interaction and hence augmenting the pro‐coagulant response. 22 Indeed, significantly increased levels of VWF and FVIII and thrombomodulin, 16 aberrant coagulation, thrombosis and microangiopathy are very common in critically ill patients with COVID‐19, resulting in a disseminated intravascular coagulation (DIC)‐like syndrome characterised by massive fibrin formation and organ dysfunction. 23 Likewise, adaptive immunity actively participates in the establishment of the inflammatory response; specifically, activated and proliferating CD8+ T cells are prevalent in mild COVID‐19, whereas critically ill patients display higher levels of hyperactive IL‐6‐producing CD4+ T cells, which may contribute to disease severity, even after viral clearance. 17 Interestingly, T cells show phenotypical signs of an exhausted, functionally unresponsive state, thus allowing viral escape from immune surveillance. 22 Once initiated, the endotheliitis and resultant cytokine storm become self‐sustaining, leading to widespread organ damage. Some patients may also display features of haemophagocytic lymphohistiocytosis, such as cytopenias, hyperferritinaemia and rapid onset of MOF.

Overall, once hyperinflammation and CRS develop, rates of mortality significantly increase. 24 25 26 As direct viral activation of the vascular endothelium has an important role in initiating and maintaining the hyperinflammatory response, attempting to blunt such a response with endothelial‐protective agents is a very rational strategy. Controlled clinical trials focussing on the use of anti‐cytokine antibodies, including tocilizumab (IL‐6 inhibitor), have failed to show significant activity in this stage of the disease. 27 However, increasing evidence suggests that the altered homeostasis of the endothelium may be a key initiating event in the pathogenesis of the disease, therefore representing a potentially more promising target. 28Go to:

Endothelial cell‐related disorders in haematology: post‐bone marrow transplantation syndromes and sickle cell disease and the overlap with the pathobiology of COVID‐19

Clinically and histopathologically, COVID‐19‐associated endotheliitis resembles a spectrum of post‐bone marrow and stem cell transplantation (BMT) syndromes characterised by disruption of endothelial homeostasis and consequently dysregulation of coagulation, vascular tone, endothelial permeability and vascular inflammation. 29 These disorders include hepatic veno‐occlusive disease (VOD)/sinusoidal obstruction syndrome (SOS), idiopathic pneumonia syndrome (IPS), transplant‐associated thrombotic microangiopathy and graft‐versus‐host disease (GvHD).

Hepatic VOD/SOS develops as a result of endothelial damage to hepatic sinusoids and subsequent hepatocyte necrosis 30 . Damage to the ECs leads to a hypercoagulable state, production of inflammatory mediators, and the upregulation as well as release of heparanase. 31 Heparanase degrades the heparan sulphate scaffold of the subendothelial basement membrane, consequently allowing the extravasation of blood‐borne cells, including activated T lymphocytes, neutrophils and macrophages. 32 This cascade of events leads to postsinusoidal hypertension, hyperinflammation and ultimately MOF. Severe VOD/SOS associated with MOF without effective therapy is fatal in >80% of cases. 33 Interestingly, the histopathological examination of lung lesions in VOD/SOS shows early alveolar epithelial and lung endothelial injury, resulting in accumulation of protein‐ and fibrin‐rich inflammatory oedematous fluid in the alveolar space and progression to interstitial fibrosis, 34 35 as is also seen in fatal COVID‐19 cases.

Similarly, IPS, a widespread alveolar injury in the absence of identifiable infectious or non‐infectious causes, is characterised by histological evidence of EC injury with fibrin accumulation, luminal thrombosis and fibrotic processes. Adhesion molecules, such as intercellular adhesion molecule 1 (ICAM‐1) and/or vascular cell adhesion molecule 1 (VCAM‐1), are commonly upregulated, thus reflecting profound endothelial activation. 36 It has been suggested that TNF‐α directly causes endothelial injury, and increased levels of angiopoietin‐2 (Ang‐2), have been recently reported in cases of acute exacerbations of IPS, 37 similar to that seen in severely ill patients with COVID‐19. 38

Likewise, multifactorial endothelial damage has been also implicated in the development of transplant‐associated thrombotic microangiopathy, where micro‐vessel intimal swelling and necrosis lead to the formation of luminal microthrombi and subsequent microangiopathic haemolytic anaemia. Plasma levels of markers of EC injury and inflammation, such as thrombomodulin, plasminogen activator inhibitor‐1 (PAI‐1), ICAM‐1, VCAM‐1, IL‐1, TNF‐α, interferon gamma and IL‐8 are commonly elevated. 39 40 Endothelial dysfunction predominantly affects the kidneys and the brain, but may become widespread and progress to MOF, which in turn is associated with high mortality.

Lastly, acute GvHD (aGvHD) develops as a consequence of the activation of the immune system. Antigen‐presenting cells become activated by endothelial and tissue damage derived from direct toxicity of the conditioning regimen, thus initiating an alloreactive T‐cell response directed against recipient tissues. 41 As a result, SDC‐1 is commonly elevated in the serum of patients with GvHD and correlates with disease severity. 42 In addition to cell‐mediated cytotoxic damage, the cytokine storm generated in response to T‐cell activation and proliferation causes targeted organ damage involving mainly the skin, liver and gut. 43 It has recently been suggested that endothelial vulnerability and pro‐thrombotic shift precedes clinically evident aGvHD and that angiogenesis driven by early endothelial activation is an initiating event. 44 Indeed, increased plasma levels of VWF, 45 Ang‐2 46 and TNF receptor 1 47 have been detected in patients prior to development of aGvHD, correlating with response to therapy.

Similarly, markers of endothelial dysfunction and inflammatory activation have been detected also in the serum of patients with sickle cell disease (SCD), especially during vaso‐occlusive episodes. SCD is characterised by a chronic course of relapsing‐remitting episodes of ischaemia and then reperfusion. The polymerisation of defective haemoglobin S upon deoxygenation initiates many pathological processes, such as complement activation, generation of ROS and pro‐thrombotic molecules, secretion of numerous pro‐inflammatory cytokines and chemokines and ultimately leucocyte recruitment. 48 Oxidative stress and endothelial dysregulation plays a key role in vaso‐occlusion; ECs activated by substances released by the haemolytic process and by red blood cell adhesion initiate production and release of soluble mediators such as IL‐1β, IL‐8, IL‐6, IL‐1α and PAI‐1, 49 50 and increase the expression of adhesion molecules such as VCAM‐1, ICAM‐1, E‐selectin and P‐selectin, 51 52 reflecting a pro‐inflammatory and pro‐thrombotic shift. Vaso‐occlusive phenomena commonly affect the lung vasculature, provoking acute chest syndrome (ACS), a spectrum of diseases ranging from mild pneumonia to ARDS and MOF, which is the leading cause of morbidity and mortality in SCD. 53 Lung specimens from ACS cases showed micro‐thrombotic occlusion, endothelial VWF deposition and arterial vessel re‐modelling with initial fibrotic processes, 54 fascinatingly all comparable to the histopathological findings in COVID‐19. 55 Importantly, heme‐mediated endothelial damage to alveolar cells is regulated by the p38 mitogen‐activated protein kinase (MAPK) pathway, which plays a crucial role in the biosynthesis of pro‐inflammatory cytokines and collagen production. 56 This key pathway is also upregulated in COVID‐19 as a result of decreased ACE2 tissue functionality consequent to viral binding, and may consequently promote endotheliitis, hypercoagulation and end‐stage fibrosis. 57 58

In summary, post‐BMT syndromes, vaso‐occlusive organ dysfunction in SCD and COVID‐19‐associated endotheliitis share common pathological mechanisms including: i) dysregulation of the homeostasis of the endothelial milieu toward a pro‐inflammatory and pro‐thrombotic phenotype with thrombotic microangiopathy; ii) hyperproduction of inflammatory cytokines such as IL‐6, IL‐8 and TNF‐α; 59 60 61 62 and iii) small vessel endotheliitis and endothelial barrier dysfunction, leading to oedema of the microvascular bed, protein and fibrin accumulation and subsequent fibrotic shift. 34 36 All these conditions if untreated irremediably lead to MOF and display similar microscopic and macroscopic features in target organs upon pathological examination. At the molecular level, the p38 MAPK pathway may also be critical in promoting vasoconstrictive and inflammatory phenomena; its activation is described in SCD, COVID‐19 and also as a result of conditioning regimen‐induced endothelial damage in BMT. 63 Together, these findings support the notion that the pleiotropic character of the endothelium as a key regulator of the internal homeostasis, vascular tone, blood coagulation and the inflammatory process and therefore of so called ‘immune‐thrombosis’ events, make it an intriguing therapeutic target for post‐BMT disorders, SCD, and COVID‐19.Go to:

Agents targeting EC‐related disorders

Heparins

Classically, heparins have been the most widely used drugs for the treatment and prevention of endothelial cell disorders. Several animal studies and clinical trials have suggested that, in addition to its well‐known anticoagulant effects, heparin also possesses anti‐inflammatory properties, mainly mediated by inhibition of IL‐6 release and its activity, 64 a phenomena also demonstrated in patients with COVID‐19 treated with low‐molecular‐weight heparin. 65 Further, heparin is structurally related to HS, 66 a negatively charged glycosaminoglycan as described earlier, which serves as binding sites for growth factors, cytokines, selectins, extracellular‐matrix molecules, and a large number of human viruses, 67 including the SARS‐CoV‐2 virus. 68 69 Indeed, Clausen et al. 70 have recently demonstrated that the SARS‐CoV‐2 spike protein must bind both the ACE2 receptor and HS to enter human cells. The structural analogies between heparin and HS may result in competitive inhibition, where heparin and related compounds compete with the cell surface HS for viral binding to target cells, 68 69 thus potentially blocking or at least attenuating viral entry. The beneficial effects of heparin‐based therapies are also linked to their inhibition of circulating heparanase enzymatic activity. 32 Heparanase, an endo‐β‐glucuronidase, physiologically cleaves HS chains located in extracellular matrices and on cell surfaces. 32 It is often overexpressed during viral infections and act as a regulator of virus release after replication has occurred, promoting its dissemination. 71 72 73 74 Additionally, it may be upregulated by pro‐inflammatory molecules such as IL‐1 and TNF‐α. Once activated, heparanase stimulates the expression and release of pro‐inflammatory cytokines, including TNF‐α, IL‐1 and IL‐6. 75 The enzyme has been implicated in cancer progression, inflammation, 76 VOD/SOS development 77 and other vascular pathologies. 71

Currently, numerous clinical trials are underway to investigate the therapeutic potential of intravenous and subcutaneous heparin, as well as the appropriate dose regimen in COVID‐19. Further, nebulised heparin delivered directly to the airways may be effective in preventing infection and mitigating lung disease (clinicaltrials.gov; NCT04545541NCT04511923). Notwithstanding their anticoagulant, anti‐inflammatory and anti‐viral properties, the use of heparins is associated with a substantially increased risk of systemic bleeding, and other challenging ‘off‐target’ effects, making its use potentially part of the standard of care, but not without qualification, as well as highlighting the need for combination approaches.

Defibrotide

The use of defibrotide (DF), which has both comparable but distinct properties from heparins and negligible haemorrhagic risk 78 may therefore be warranted, especially given the established propensity for the development of DIC later in the COVID‐19 clinical course. DF is a naturally derived, complex mixture of poly‐deoxyribonuleotides extracted originally from bovine lung and now exclusively from porcine gut mucosa. 79 80 Since its original isolation >30 years ago, DF has demonstrated locally acting pro‐fibrinolytic, 81 82 83 84 anti‐thrombotic, 85 86 anti‐ischaemic and anti‐inflammatory activities, which exert protective effects on small vessel endothelia. It is currently approved for the treatment of paediatric and adult hepatic VOD/SOS with MOF. 87 88 89 In this setting, DF has demonstrated efficacy and safety in critically ill patients with MOF, as well as a significant reduction in PAI‐1 and other markers of endothelial stress in patients with VOD/SOS and MOF successfully treated with DF. 89 90 91 Furthermore, in a pivotal Phase III trial, DF prophylaxis reduced the incidence and severity of VOD/SOS in high‐risk children undergoing BMT. 92 In a more recent study, Palomo et al. 93 demonstrated that DF directly interacts with the cell membrane and becomes internalised by ECs, thus providing physical evidence of its endothelial‐protective properties. In particular, DF appears to decrease levels of pro‐inflammatory proteins, such as TNF‐α, 94 IL‐6, vascular endothelial growth factor (VEGF) 95 and to downregulate major histocompatibility complex (MHC) Class I and Class II molecules, 96 97 therefore attenuating both the inflammatory and immune responses. Furthermore, it appears to decrease interaction between leucocytes and ECs by downregulating P‐selectin, 98 ICAM‐1 95 and VCAM‐1. 99 Lastly, DF displays potent adenosine agonism. 100 Such activity may be clinically relevant, not least based on substantial improvement observed in an animal model of acute lung injury upon treatment with adenosine receptor agonists. 101

Based on such properties, the use of DF can be reasonably extended to other post‐BMT syndromes and other microangiopathies involving CRS complicating a variety of disease states and treatment modalities, such as chimeric antigen receptor (CAR) T‐cell therapy. 102 Indeed, paediatric and adult patients receiving DF as VOD/SOS prophylaxis also exhibited a reduced incidence of aGvHD, 92 103 a finding that is strongly supported by a preclinical model of aGvHD. 99 Additionally, a retrospective survey from paediatric patients treated with DF for transplant‐associated thrombotic microangiopathy showed resolution of clinical disease in 77% of patients. 104 Currently, Phase II studies investigating the use of DF for prevention of transplant‐associated thrombotic microangiopathy and VOD, and in the same context the treatment of ACS are ongoing (clinicaltrials.gov; NCT03384693NCT03805581NCT02675959). Notably, DF suppresses the expression of heparanase transcripts, cell surface expression and enzymatic activity, 95 suggesting that DF may have anti‐viral properties, although this remains to be confirmed. 71 72 73 Heparanase is putatively upregulated by the cytokine storm of advanced COVID‐19 and may contribute to further inflammation, oedema of the microvascular bed and coagulopathy. 28 75 105 106 DF is a potent inhibitor of heparanase in terms of both cell surface and gene expression, and therefore is especially attractive. Furthermore, the therapeutic use of DF in a murine model of IPS significantly improved survival compared to untreated controls by reducing, among other biomarkers, the levels of Ang‐2, 107 which is known to correlate with ARDS and is markedly elevated in critically ill patients with COVID‐19. 38

In addition, ICU‐admitted patients with COVID‐19 may display increased platelet activation and subsequent formation of platelet‐monocyte aggregates upon interaction with P‐selectin, thus stimulating monocyte‐induced inflammation and thrombosis. 22 By reducing P‐selectin and other adhesion molecules expression, DF may inhibit monocyte‐derived inflammatory and pro‐coagulant signals. Lastly and most importantly, DF has also been shown to decrease the activity of p38 MAPK and its pathway, 93 the importance of which is increasingly recognised in the pathogenesis of the COVID‐19 hyperinflammation syndrome and this may be a key therapeutic target in this process. 58 108

In summary, the multitargeted endothelial‐based therapeutic properties of DF and its relative safety, as well as its regulatory approval, make it an ideal potential therapeutic candidate for the treatment of COVID‐19 vascular complications. 28 In contrast to heparin, DF also exhibits broader anti‐cytokine, anti‐inflammatory and endothelial‐stabilising properties. Importantly, by acting on the heparanase‐HS axis, 74 102 DF may limit viral infectivity given its capacity to i) compete with HS and thereby possibly inhibit virus–cell adhesion and entry, ii) inhibit heparanase enzymatic activity and thereby attenuate virus detachment/release and spread 74 and iii) inhibit heparanase‐mediated activation of immune cells and thereby upregulation of pro‐inflammatory cytokines and the associated self‐sustaining systemic inflammatory host response (Fig 1). Actively accruing, international Phase II clinical trials are now underway and should shed critical light on DF’s therapeutic potential in patients with COVID‐19 (examples include clinicaltrials.gov; NCT04348383NCT04335201). Strikingly, two critically ill paediatric patients treated with DF for a SARS‐CoV‐2‐associated multisystem inflammatory syndrome experienced complete resolution and no attributable toxicity, with correlative studies supporting the mechanistic effects described above, as well as favourable effects seen on complement activation. 109 Similarly, preliminary results from the current studies as part of the international DEFACOVID (Defibrotide as Prevention and Treatment of Respiratory Distress and Cytokine Release Syndrome of COVID‐19) study group support both safety and promising potential efficacy to date.Fig 1

Potential mechanisms of action of defibrotide in the treatment of COVID‐19. Left, defibrotide limits viral attachment by interfering with Syndecan‐1, the primary cell surface heparan sulfate on ECs, and reduces viral dissemination, by inhibiting HPSE‐mediated viral release. Right, effects of defibrotide on endothelial‐mediated pathological processes. Viral infection of ECs promotes apoptosis with breakdown of endothelial barrier and exposure of the subendothelium, with subsequent platelet activation and thrombotic phenomena. Defibrotide inhibits platelet activation and leukocyte recruitment and blocks the generation of the cytokine storm; specifically, HPSE‐mediated activation of immune cells is suppressed, thus limiting the development of cytokine release syndrome. Sars‐Cov‐2, severe acute respiratory syndrome coronavirus‐2; ACE2, angiotensin‐converting enzyme 2; Ang‐2, angiopoietin‐2; GI, gastrointestinal; IL, interleukin; NFKB, nuclear factor kappa‐light chain‐enhancer of activated B cells; TNF‐α, tumor necrosis factor‐alpha; VWF, von Willebrand Factor.

Other heparanase inhibitors

Given the heparanase‐inhibiting activity of heparin, effort has been directed towards modifications of its structure to endow candidate molecules with potentiated anti‐heparanase activity while limiting anticoagulant effects. Specifically, N‐acetylated and glycol‐split heparins are promising agents presenting such characteristics. Indeed, administration of N‐acetylheparin (NAH) in murine models of sepsis ameliorated lung and intestinal injury and subsequent oedema by reducing tissue neutrophilic infiltration and suppressing IL‐6, IL‐1β and TNF‐α production. 110 111 Furthermore, roneparstat, the most developed glycol‐split NAH, restored pathological renal cellular damage caused by ischaemia‐reperfusion by reducing release of pro‐inflammatory cytokines and reverted established fibrotic processes, thus restoring normal tissue histology in preclinical models. 112 This aspect is especially relevant, considering the extensive formation of fibrosis and irreversible end‐organ damage in post‐BMT syndromes, SCD and advanced COVID‐19.

Additionally, much interest has been directed towards the novel heparanase‐inhibiting agent pixatimod, a modified oligosaccharide glycoside with heparan sulphate‐mimetic properties. Pixatimod is a potent inhibitor of Type 1 T‐helper cells (Th1)/Th17 effector functions, 113 IL‐6 expression, 114 M2 macrophage activation, 115 angiogenesis and tumour progression in vivo. Furthermore, it exhibits mild anticoagulant activity and despite transient infusion reactions is otherwise generally well tolerated. Guimond et al. 116 have recently demonstrated that pixatimod interacts with the SARS‐CoV‐2 spike protein binding site, and this is coherent with its heparan sulphate‐mimetic activity. Moreover, pixatimod was found to markedly inhibit SARS‐CoV‐2 infectivity, 116 supporting its clinical application as a novel therapeutic intervention for prophylaxis and treatment of COVID‐19. Taken together, heparanase emerges as a host‐encoded virulence factor that once activated enhances viral spread and triggers downstream inflammatory cascades. These preliminary data indicate that heparanase inhibitors currently under development are possible candidates for multisystem inflammatory conditions, such as COVID‐19, sepsis, thrombotic microangiopathies and cancer, but as of now studies remain preclinical with clinical application pending.

Conclusions

In conclusion, increasing evidence suggests that the SARS‐CoV‐2 directly targets ECs, promoting the release of pro‐inflammatory and pro‐thrombotic molecules. Endothelial dysfunction appears to be a crucial initiating step in the pathogenesis of the disease and its ensuing morbidity and mortality. Endotheliitis with the hyperproduction of cytokines leading to CRS, hypercoagulability and thrombotic microangiopathy are hallmarks shared by COVID‐19, VOD/SOS and other endothelial injury syndromes, underpinned by inflammation and including the vaso‐occlusive crises of SCD, so providing a common pathobiology across these respective syndromes. Most importantly, endothelial‐protective agents, such as DF, represent a promising and rational therapeutic strategy in COVID‐19, with DF currently under investigation in a variety of settings and combinations. As a unifying concept, heparanase inhibition, with the modulation of related pathways and other effects on endothelial stress responses may thus be crucial in mediating anti‐viral and anti‐inflammatory activity. In particular, as this relates to endotheliitis, it may directly abrogate CRS and its sequelae, which in turn may lead to improved patient outcome.

Author Contributions

Eleonora Calabretta, Jose M. Moraleda, Israel Vlodavsky, Ruben Jara, Carmelo Carlo‐Stella and Paul Richardson drafted the manuscript; all authors participated in the critical revision and approval of the final report.Go to:

Conflict of interest

Jose M. Moraleda declares Advisory Board fees from Jazz Pharmaceuticals; Antonio Pagliuca has received Advisory Board and Speaker fees from Jazz Pharmaceuticals; Rebecca M. Baron is on a Merck Advisory Board and a Consultant for Genentech. Robert Soiffer serves on the Board of Directors for Kiadis and Be The Match/National Marrow Donor Program; provided consulting for Gilead, Rheos Therapeutics, Cugene, Precision Bioscience, Mana Therapeutics, VOR Biopharma, and Novartis; and Data Safety Monitoring Board for Juno/Celgene; Paul Richardson is an Advisory Committee Member for Jazz Pharmaceuticals; Carmelo Carlo‐Stella is a Consultant/Advisory Board Member for Genente Science srl, ADC Therapeutics, Novartis, Roche, Karyopharm, Sanofi, Boehringer Igelheim and Servier. The remaining authors declare nothing to disclose.

Acknowledgments

This work was supported in part by a grant from the Italian Association for Cancer Research (AIRC, grant #20575 to CC‐S).Go to:

Contributor Information

Carmelo Carlo‐Stella, Email: ue.deminuh@alletsolrac.olemrac.

Paul Richardson, Email: ude.dravrah.icfd@nosdrahcir_luap.Go to:

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Recent Randomized Trials of Antithrombotic Therapy for Patients With COVID-19

Authors: JACC State-of-the-Art ReviewAzita H. Talasaz, PharmD,a,bParham Sadeghipour, MD,cHessam Kakavand, PharmD,a,bMaryam Aghakouchakzadeh, PharmD,aElaheh Kordzadeh-Kermani, PharmD,aBenjamin W. Van Tassell, PharmD,d,eAzin Gheymati, PharmD,aHamid Ariannejad, MD,bSeyed Hossein Hosseini, PharmD,aSepehr Jamalkhani,cMichelle Sholzberg, MDCM, MSc,f,gManuel Monreal, MD, PhD,hDavid Jimenez, MD, PhD,iGregory Piazza, MD, MS,jSahil A. Parikh, MD,k,lAjay J. Kirtane, MD, SM,k,lJohn W. Eikelboom, MBBS,mJean M. Connors, MD,nBeverley J. Hunt, MD,oStavros V. Konstantinides, MD, PhD,p,qMary Cushman, MD, MSc,r,sJeffrey I. Weitz, MD,t,uGregg W. Stone, MD,k,vHarlan M. Krumholz, MD, SM,w,x,yGregory Y.H. Lip, MD,z,aaSamuel Z. Goldhaber, MD,j and Behnood Bikdeli, MD, MSj,k,w,∗

Abstract

Endothelial injury and microvascular/macrovascular thrombosis are common pathophysiological features of coronavirus disease-2019 (COVID-19). However, the optimal thromboprophylactic regimens remain unknown across the spectrum of illness severity of COVID-19. A variety of antithrombotic agents, doses, and durations of therapy are being assessed in ongoing randomized controlled trials (RCTs) that focus on outpatients, hospitalized patients in medical wards, and patients critically ill with COVID-19. This paper provides a perspective of the ongoing or completed RCTs related to antithrombotic strategies used in COVID-19, the opportunities and challenges for the clinical trial enterprise, and areas of existing knowledge, as well as data gaps that may motivate the design of future RCTs.

Thromboembolism in Patients With Coronavirus Disease-2019

Microvascular and macrovascular thrombotic complications, including arterial and especially venous thromboembolism (VTE), seem to be common clinical manifestations of coronavirus disease-2019 (COVID-19), particularly among hospitalized and critically ill patients (1234). Pooled analyses have helped in providing aggregate estimates of thrombotic events (4,5). In a recent systematic review and meta-analysis, the overall incidence of VTE among inpatients with COVID-19 was estimated at 17% (95% confidence interval [CI]: 13.4 to 20.9), with variation based on study design and method of ascertainment; there was a four-fold higher incidence rate in patients in the intensive care units (ICUs) compared with non-ICU settings (28% vs. 7%) (6). In addition, postmortem studies show frequent evidence of microvascular thrombosis in patients with COVID-19 (7,8). The influence of these events on mortality rates remains unknown (9).Go to:

Pathophysiology of Thromboembolism in COVID-19: Virchow’s Triad in Action

COVID-19 can potentiate all 3 components of Virchow’s triad and increases the risk of thrombosis (Figure 1 ). First, severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection may trigger endothelial dysfunction. Using the angiotensin-converting enzyme 2, which is expressed on the surface of many cells, SARS-CoV-2 enters endothelial cells and may impair their intrinsic antithrombotic properties. It is proposed that viremia, hypoxia, the inflammatory response, increased expression of tissue factor, and elevated levels of neutrophil extracellular traps (NETs) can together disrupt the hemostasis equilibrium and promote endothelial activation (101112). This induction of a procoagulant state along with the reduction in plasminogen activators further results in increased platelet reactivity (131415). Inflammatory cytokines and endothelial activation can lead to downregulation of antithrombin and protein C expression. They can also lead to an increase in the levels of plasminogen activator inhibitor; fibrinogen; factors V, VII, VIII, and X; and von Willebrand factor (16). Increased platelet reactivity, NETosis, and alterations in the aforementioned hemostatic factors result in a hypercoagulable state (171819202122).

For More Information: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7963001/

COVID-19 vaccines and thrombosis with thrombocytopenia syndrome

Authors: Chih-Cheng Lai 1Wen-Chien Ko 2Chih-Jung Chen 3Po-Yen Chen 4Yhu-Chering Huang 3Ping-Ing Lee 5Po-Ren Hsueh 6 7

Abstract

Introduction: To combat COVID-19, scientists all over the world have expedited the process of vaccine development. Although interim analyses of clinical trials have demonstrated the efficacy and safety of COVID-19 vaccines, a serious but rare adverse event, thrombosis with thrombocytopenia syndrome (TTS), has been reported following COVID-19 vaccination.

Areas covered: This review, using data from both peer-reviewed and non-peer-reviewed studies, aimed to provide updated information about the critical issue of COVID-19 vaccine-related TTS.

Expert opinion: : The exact epidemiological characteristics and possible pathogenesis of this adverse event remain unclear. Most cases of TTS developed in women within 2 weeks of the first dose of vaccine on the receipt of the ChAdOx1 nCoV-19 and Ad26.COV2.S vaccines. In countries with mass vaccination against COVID-19, clinicians should be aware of the relevant clinical features of this rare adverse event and perform related laboratory and imaging studies for early diagnosis. Non-heparin anticoagulants, such as fondaparinux, argatroban, or a direct oral anticoagulant (e.g. apixaban or rivaroxaban) and intravenous immunoglobulins are recommended for the treatment of TTS. However, further studies are required to explore the underlying mechanisms of this rare clinical entity.

Plain language summary: What is the context? Thrombosis with thrombocytopenia syndrome (TTS) usually develops within 2 weeks of the first doses of the ChAdOx1 nCoV-19 and Ad26.COV2.S COVID-19 vaccines. TTS mainly occurs in patients aged < 55 years and is associated with high morbidity and mortality. What is new? TTS mimics autoimmune heparin-induced thrombocytopenia and can be mediated by platelet-activating antibodies against platelet factor 4. Non-heparin anticoagulants, such as fondaparinux, argatroban, or a direct oral anticoagulant (e.g. apixaban or rivaroxaban) should be considered as the treatment of choice if the platelet count is > 50 × 109/L and there is no serious bleeding. Intravenous immunoglobulins and glucocorticoids may help increase the platelet count within days and reduce the risk of hemorrhagic transformation when anticoagulation is initiated. What is the impact? TTS should be a serious concern during the implementation of mass COVID-19 vaccination, and patients should be educated about this complication along with its symptoms such as severe headache, blurred vision, seizure, severe and persistent abdominal pain, painful swelling of the lower leg, and chest pain or dyspnea. The incidence of TTS is low; therefore, maintenance of high vaccination coverage against COVID-19 should be continued.

For More Information: https://pubmed.ncbi.nlm.nih.gov/34176415/

Anticoagulation in COVID-19: current concepts and controversies

  1. Authors: http://orcid.org/0000-0002-3809-8926Atanu Chandra16289Uddalak Chakraborty2, Shrestha Ghosh1, Sugata Dasgupta3

Abstract

Rising incidence of thromboembolism secondary to COVID-19 has become a global concern, with several surveys reporting increased mortality rates. Thrombogenic potential of the SARS-CoV-2 virus has been hypothesised to originate from its ability to produce an exaggerated inflammatory response leading to endothelial dysfunction. Anticoagulants have remained the primary modality of treatment of thromboembolism for decades. However, there is no universal consensus regarding the timing, dosage and duration of anticoagulation in COVID-19 as well as need for postdischarge prophylaxis. This article seeks to review the present guidelines and recommendations as well as the ongoing trials on use of anticoagulants in COVID-19, identify discrepancies between all these, and provide a comprehensive strategy regarding usage of these drugs in the current pandemic.

This article is made freely available for use in accordance with BMJ’s website terms and conditions for the duration of the covid-19 pandemic or until otherwise determined by BMJ. You may use, download and print the article for any lawful, non-commercial purpose (including text and data mining) provided that all copyright notices and trade marks are retained.

Introduction

The novel beta-coronavirus, appropriately named SARS-CoV-2 by the International Committee of Taxonomy of Viruses, belongs to a family of single-stranded RNA viruses, members of which have been recognised as causative agents of the SARS-CoV and Middle East respiratory syndrome coronavirus outbreak in 2002 and 2012, respectively.1 2 Presently, the novel COVID-19 poses a major global health crisis, having been declared a pandemic on 11 March 2020 by the WHO.

Over the past several months, an overwhelming amount of literature suggests an increased risk of thromboembolic manifestations associated with COVID-19.2 Several hypotheses have been suggested to understand the underlying pathophysiology behind development of a prothrombotic state in COVID-19 such as exaggerated inflammatory response resulting in activation of the coagulation cascade and endothelial injury.3 4 Usage of anticoagulants in COVID-19 remains an area of conjecture with no definite guidelines published to date highlighting the timing, dosage and duration of anticoagulation as well as the drug of choice. Most internationally published guidelines, based on consensus statements and expert opinions, recommend therapeutic doses of heparin only in patients diagnosed with or highly suspected of developing macrothrombi such as pulmonary embolism (PE) or deep vein thrombosis (DVT). However, these guidelines including those by CHEST, rarely address the requirement of post discharge thromboprophylaxis.5

For More Information: https://pmj.bmj.com/content/early/2021/04/12/postgradmedj-2021-139923