The CD38/NAD/SIRTUIN1/EZH2 Axis Mitigates Cytotoxic CD8 T Cell Function and Identifies Patients with SLE Prone to Infections

Clinical characterization, outcomes, and prognosis in patients with systemic lupus erythematosus admitted to the intensive care unit

OBJECTIVE

Systemic lupus erythematosus (SLE) is a clinically heterogeneous autoimmune disease, and in some conditions, admission to the intensive care unit (ICUs) is required. This study describes the clinical and prognostic factors in SLE patients admitted to the ICU.

METHODS

We conducted a retrospective study that reviewed all clinical records of patients with SLE admitted to the ICU between 2011 and 2018.

RESULTS

We evaluated 188 patients, with 279 ICU admissions. Most patients were female (n = 159; 84.57%) with a median age of 35 years (interquartile range (IQR) = 25-48 years). Infection was the leading cause of admission in 77 (27.60%) cases, followed by lupus flare. The average length of hospitalization was 5 days (IQR 3-11 days), and the SLE Disease Activity Index 2000, Acute Physiology, Age and Chronic Health Evaluation (APACHE II), and Sequential Organ Failure Assessment (SOFA) scores were 9 (IQR 2-17), 14 (IQR 10-17), and 3 (IQR 2-5), respectively. Non-survivors presented with higher APACHE II and SOFA scores. Infection was the leading cause of mortality (n = 38; 20.21%), and predictors of mortality included invasive mechanical ventilation, vasoactive medication requirement, higher SOFA scores, and antiphospholipid syndrome comorbidity.

CONCLUSIONS

We found that infection was the leading cause of ICU admissions and mortality in patients with SLE. Factors identified here as predictors of mortality should be accurately identified at admission for the prompt treatment of SLE patients.

Epigenetic dysregulation of ACE2 and interferon-regulated genes might suggest increased COVID-19 susceptibility and severity in lupus patients

Infection caused by SARS-CoV-2 can result in severe respiratory complications and death. Patients with a compromised immune system are expected to be more susceptible to a severe disease course. In this report we suggest that patients with systemic lupus erythematous might be especially prone to severe COVID-19 independent of their immunosuppressed state from lupus treatment. Specifically, we provide evidence in lupus to suggest hypomethylation and overexpression of ACE2, which is located on the X chromosome and encodes a functional receptor for the SARS-CoV-2 spike glycoprotein. Oxidative stress induced by viral infections exacerbates the DNA methylation defect in lupus, possibly resulting in further ACE2 hypomethylation and enhanced viremia. In addition, demethylation of interferon-regulated genes, NFκB, and key cytokine genes in lupus patients might exacerbate the immune response to SARS-CoV-2 and increase the likelihood of cytokine storm. These arguments suggest that inherent epigenetic dysregulation in lupus might facilitate viral entry, viremia, and an excessive immune response to SARS-CoV-2. Further, maintaining disease remission in lupus patients is critical to prevent a vicious cycle of demethylation and increased oxidative stress, which will exacerbate susceptibility to SARS-CoV-2 infection during the current pandemic. Epigenetic control of the ACE2 gene might be a target for prevention and therapy in COVID-19.

Autoimmunity and organ damage in systemic lupus erythematosus

Impressive progress has been made over the last several years toward understanding how almost every aspect of the immune system contributes to the expression of systemic autoimmunity. In parallel, studies have shed light on the mechanisms that contribute to organ inflammation and damage. New approaches that address the complicated interaction between genetic variants, epigenetic processes, sex and the environment promise to enlighten the multitude of pathways that lead to what is clinically defined as systemic lupus erythematosus. It is expected that each patient owns a unique 'interactome', which will dictate specific treatment.

Coronavirus Disease-2019: Implication for the care and management of patients with systemic lupus erythematosus

Systemic lupus erythematosus is a chronic remitting-relapsing autoimmune disease that affects multiple organ systems. In this article we discuss aspects in the management of lupus patients that are particularly relevant during the current SARS-CoV-2 pandemic. We speculate that lupus patients might be more susceptible for a more severe COVID-19 disease course and emphasize the importance of maintaining remission in lupus patients. We discuss the critical role hydroxychloroquine plays in the management of lupus patients and suggest considering the psychosocial implications of the current pandemic on lupus care.

CD38: Modulating Histone Methyltransferase EZH2 Activity in SLE

To keep autoreactive T cells under control in SLE patients, immunosuppressive regimens are used, which can increase susceptibility to bacterial and viral infections. Recently, Katsuyama et al., demonstrated that the CD38/NAD/Sirtuin1/EZH2 axis reduces cytolytic CD8⁺ T cell function and might be targeted to overcome incidence of infections.

T cell Metabolism in Lupus

Abnormal T cell responses are central to the development of autoimmunity and organ damage in systemic lupus erythematosus. Following stimulation, naïve T cells undergo rapid proliferation, differentiation and cytokine production. Since the initial report, approximately two decades ago, that engagement of CD28 enhances glycolysis but PD-1 and CTLA-4 decrease it, significant information has been generated which has linked metabolic reprogramming with the fate of differentiating T cell in health and autoimmunity. Herein we summarize how defects in mitochondrial dysfunction, oxidative stress, glycolysis, glutaminolysis and lipid metabolism contribute to pro-inflammatory T cell responses in systemic lupus erythematosus and discuss how metabolic defects can be exploited therapeutically.