Angiotensin-converting enzyme 2 (ACE2) has been established as the functional host receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for the current devastating worldwide pandemic of coronavirus disease 2019 (COVID-19). ACE2 is abundantly expressed in a variety of cells residing in many different human organs. In human physiology, ACE2 is a pivotal counter-regulatory enzyme to ACE by the breakdown of angiotensin II, the central player in the renin-angiotensin-aldosterone system (RAAS) and the main substrate of ACE2. Many factors have been associated with both altered ACE2 expression and COVID-19 severity and progression, including age, sex, ethnicity, medication, and several co-morbidities, such as cardiovascular disease and metabolic syndrome. Although ACE2 is widely distributed in various human tissues and many of its determinants have been well recognised, ACE2-expressing organs do not equally participate in COVID-19 pathophysiology, implying that other mechanisms are involved in orchestrating cellular infection resulting in tissue damage. Reports of pathologic findings in tissue specimens of COVID-19 patients are rapidly emerging and confirm the established role of ACE2 expression and activity in disease pathogenesis. Identifying pathologic changes caused by SARS-CoV-2 infection is crucially important as it has major implications for understanding COVID-19 pathophysiology and the development of evidence-based treatment strategies. Currently, many interventional strategies are being explored in ongoing clinical trials, encompassing many drug classes and strategies, including antiviral drugs, biological response modifiers, and RAAS inhibitors. Ultimately, prevention is key to combat COVID-19 and appropriate measures are being taken accordingly, including development of effective vaccines. In this review, we describe the role of ACE2 in COVID-19 pathophysiology, including factors influencing ACE2 expression and activity in relation to COVID-19 severity. In addition, we discuss the relevant pathological changes resulting from SARS-CoV-2 infection. Finally, we highlight a selection of potential treatment modalities for COVID-19. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

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Angiotensin?converting enzyme 2 (ACE2), SARS?CoV?2 and the pathophysiology of coronavirus disease 2019 (COVID?19)

Cancer immunotherapies, including checkpoint inhibitors and adoptive cell therapy, manipulate the immune system to recognize and attack cancer cells. These therapies have the potential to induce durable responses in multiple solid and hematologic malignancies and thus have transformed treatment algorithms for numerous tumor types. Cancer immunotherapies lead to unique toxicity profiles distinct from the toxicities of other cancer therapies, depending on their mechanism of action. These toxicities often require specific management, which can include steroids and immune-modulating therapy and for which consensus guidelines have been published. This review will focus on the toxicities of checkpoint inhibitors and chimeric antigen receptor T cells, including pathophysiology, diagnosis, and management.

https://acsjournals.onlinelibrary.wiley.com/doi/pdf/10.3322/caac.21596

A review of cancer immunotherapy toxicity.

Cancer immunotherapies have changed the landscape of cancer treatment during the past few decades. Among them, immune checkpoint inhibitors, which target PD-1, PD-L1 and CTLA-4, are increasingly used for certain cancers; however, this increased use has resulted in increased reports of immune-related adverse events (irAEs). These irAEs are unique and are different to those of traditional cancer therapies, and typically have a delayed onset and prolonged duration. IrAEs can involve any organ or system. These effects are frequently low grade and are treatable and reversible; however, some adverse effects can be severe and lead to permanent disorders. Management is primarily based on corticosteroids and other immunomodulatory agents, which should be prescribed carefully to reduce the potential of short-term and long-term complications. Thoughtful management of irAEs is important in optimizing quality of life and long-term outcomes.

Immune-related adverse events of checkpoint inhibitors.

Infection with the severe acute respiratory syndrome novel coronavirus produces a clinical syndrome known as 2019 novel coronavirus disease (COVID-19). When severe, COVID-19 is a systemic illness characterized by hyperinflammation, cytokine storm, and elevations of cardiac injury biomarkers. Here, we review what is known about the pathophysiology of COVID-19, its cardiovascular manifestations, and emerging therapeutic prospects. In this rapidly moving field, this review was comprehensive as of April 3, 2020.

COVID-19 and the Heart.

Challenges of combination therapy with immune checkpoint inhibitors for hepatocellular carcinoma

BackgroundImmune checkpoint inhibitors are poised to revolutionize the management of a growing number of malignancies. Unfortunately, the management of steroid-refractory immune mediated adverse events is based on a paucity of randomized data and limited to single center experiences. Our initial experience with the IL-6 receptor antagonist tocilizumab showed clinical improvement in a wide variety of irAEs. As a result, we adopted the use of tocilizumab for the management of steroid refractory irAEs.MethodsThe character and clinical course of irAEs were abstracted from the medical record and analyzed. The dose of tocilizumab was 4 mg/kg given IV over one hour. C-reactive protein was drawn at first nivolumab infusion and at q two weeks (and with irAEs) thereafter. Clinical improvement was defined as either: documentation of resolution of symptoms or hospital discharge within seven days.ResultsOf the initial 87 patients that were treated with nivolumab, 34 required tocilizumab (39.1%). All patients were on c...

Tocilizumab for the management of immune mediated adverse events secondary to PD-1 blockade.

3061Background: Immune checkpoint blockade has emerged as an attractive treatment option in a wide spectrum of malignancies. Optimal use of these agents requires prompt recognition and management o...

Systemic inflammatory response syndrome (SIRS) with immune checkpoint inhibitors.

38Background: Immune checkpoint inhibitors have shown promising responses in advanced lung cancer as well as a number of other malignancies. However, efficacy appears to be variable based on the si...

Srikala Addepalli

Papers

Tocilizumab for the management of immune mediated adverse events secondary to PD-1 blockade.

Systemic inflammatory response syndrome (SIRS) with immune checkpoint inhibitors.

Outcomes with immune checkpoint inhibitor use in lung cancer patients with hepatic metastases.