Polyphenol Treatment of Peripheral Blood Mononuclear Cells from Individuals of Different Ages.

Human peripheral blood mononuclear cells (PBMCs) have been largely utilized to assess the cytotoxic, immunomodulatory, and anti-inflammatory properties of both synthetic and natural compounds. Within the latter category, polyphenols from dietary sources have been extensively analyzed. PBMCs represent a feasible in vitro model to study polyphenol hallmarks and activity according to quantitative and qualitative differences in immune responses in individuals of different age. In this chapter, we propose a method for PBMC treatment with polyphenols and analysis designed on age-dependent qualitative and quantitative variability in immune cell performance.

Monocyte-driven inflamm-aging reduces intestinal barrier function in females.

BACKGROUND: The intestinal barrier encompasses physical and immunological components that act to compartmentalize luminal contents, such as bacteria and endotoxins, from the host. It has been proposed that an age-related decline of intestinal barrier function may allow for the passage of luminal contents into the bloodstream, triggering a low-grade systemic inflammation termed inflamm-aging. Although there is mounting evidence to support this hypothesis in model species, it is unclear if this phenomenon occurs in humans. In addition, despite being well-established that biological sex impacts aging physiology, its influence on intestinal barrier function and inflamm-aging has not been explored. RESULTS: In this study, we observed sex differences in markers of intestinal barrier integrity, where females had increased epithelial permeability throughout life as compared to males. With age, females had an age-associated increase in circulating bacterial products and metabolites such as LPS and kynurenine, suggesting reduced barrier function. Females also had age-associated increases in established markers of inflamm-aging, including peripheral blood monocytes as well as TNF and CRP. To determine if impaired barrier function was driving inflamm-aging, we performed a mediation analysis. The results show that the loss of intestinal barrier integrity was not the mediator of inflamm-aging in humans. Instead, persistent, low-grade inflammation with age preceded the increase in circulating bacterial products, which we confirmed using animal models. We found, as in humans, that sex modified age-associated increases in circulating monocytes in mice, and that inflammation mediates the loss of intestinal barrier function. CONCLUSION: Taken together, our results suggest that higher basal intestinal permeability in combination with age-associated inflammation, increases circulating LPS in females. Thus, targeting barrier permeability in females may slow the progression of inflamm-aging, but is unlikely to prevent it.

Inflammation and aging-related disease: A transdisciplinary inflammaging framework.

Inflammaging, a state of chronic, progressive low-grade inflammation during aging, is associated with several adverse clinical outcomes, including frailty, disability, and death. Chronic inflammation is a hallmark of aging and is linked to the pathogenesis of many aging-related diseases. Anti-inflammatory therapies are also increasingly being studied as potential anti-aging treatments, and clinical trials have shown benefits in selected aging-related diseases. Despite promising advances, significant gaps remain in defining, measuring, treating, and integrating inflammaging into clinical geroscience research. The Clin-STAR Inflammation Research Interest Group was formed by a group of transdisciplinary clinician-scientists with the goal of advancing inflammaging-related clinical research and improving patient-centered care for older adults. Here, we integrate insights from nine medical subspecialties to illustrate the widespread impact of inflammaging on diseases linked to aging, highlighting the extensive opportunities for targeted interventions. We then propose a transdisciplinary approach to enhance understanding and treatment of inflammaging that aims to improve comprehensive care for our aging patients.

Inflammatory Trajectory of Type 2 Diabetes: Novel Opportunities for Early and Late Treatment.

Low-grade inflammation (LGI) represents a key driver of type 2 diabetes (T2D) and its associated cardiovascular diseases (CVDs). Indeed, inflammatory markers such as hs-CRP and IL-6 predict the development of T2D and its complications, suggesting that LGI already increases before T2D diagnosis and remains elevated even after treatment. Overnutrition, unhealthy diets, physical inactivity, obesity, and aging are all recognized triggers of LGI, promoting insulin resistance and sustaining the pathogenesis of T2D. Once developed, and even before frank appearance, people with T2D undergo a pathological metabolic remodeling, with an alteration of multiple CVD risk factors, i.e., glycemia, lipids, blood pressure, and renal function. In turn, such variables foster a range of inflammatory pathways and mechanisms, e.g., immune cell stimulation, the accrual of senescent cells, long-lasting epigenetic changes, and trained immunity, which are held to chronically fuel LGI at the systemic and tissue levels. Targeting of CVD risk factors partially ameliorates LGI. However, some long-lasting inflammatory pathways are unaffected by common therapies, and LGI burden is still increased in many T2D patients, a phenomenon possibly underlying the residual inflammatory risk (i.e., having hs-CRP > 2 mg/dL despite optimal LDL cholesterol control). On the other hand, selected disease-modifying drugs, e.g., GLP-1RA, seem to also act on the pathogenesis of T2D, curbing the inflammatory trajectory of the disease and possibly preventing it if introduced early. In addition, selected trials demonstrated the potential of canonical anti-inflammatory therapies in reducing the rate of CVDs in patients with this condition or at high risk for it, many of whom had T2D. Since colchicine, an inhibitor of immune cell activation, is now approved for the prevention of CVDs, it might be worth exploring a possible therapeutic paradigm to identify subjects with T2D and an increased LGI burden to treat them with this drug. Upcoming studies will reveal whether disease-modifying drugs reverse early T2D by suppressing sources of LGI and whether colchicine has a broad benefit in people with this condition.

The Nrf2-HO-1 system and inflammaging.

Nrf2 is a master transcriptional regulator of a number of genes involved in the adaptive response to oxidative stress. Among the genes upregulated by Nrf2, heme oxygenase-1 (HO-1) has received significant attention, given that the products of HO-1-induced heme catabolism have well established antioxidant and anti-inflammatory properties. This is evidenced in numerous models of inflammatory and autoimmune disease whereby induction of HO-1 expression or administration of tolerable amounts of HO-1 reaction products can ameliorate disease symptoms. Unsurprisingly, Nrf2 and HO-1 are now considered viable drug targets for a number of conditions. In recent years, the term 'inflammaging' has been used to describe the low-grade chronic inflammation observed in aging/aged cells. Increased oxidative stress is also a key factor associated with aging and there is convincing evidence that Nrf2, not only declines with age, but that Nrf2 and HO-1 can reduce cellular senescence and the senescence-associated secretory phenotype (SASP) which is now considered an underlying driver of age-related inflammatory disease. In this review, we describe the role of oxidative stress in 'inflammaging' and highlight the potential anti-aging properties of the Nrf2-HO-1 system. We also highlight established and newly emerging Nrf2 activators and their therapeutic application in age-related disease.

High-throughput N-glycan analysis in aging and inflammaging: State of the art and future directions.

As the global population ages at an unprecedented rate, the prevalence of age-related diseases is increasing, making inflammaging - a phenomenon characterized by a chronic, low-grade inflammatory state that follows aging - a significant concern. Understanding the mechanisms of inflammaging and its impact on health is critical for developing strategies to improve the quality of life and manage health in the aging population. Despite their crucial roles in various biological processes, including immune response modulation, N-glycans, oligosaccharides covalently attached to many proteins, are often overlooked in clinical and research studies. This repeated oversight is largely due to their inherent complexity and the complexity of the analysis methods. High-throughput N-glycan analysis has emerged as a transformative tool in N-glycosylation research, enabling cost- and time-effective, detailed, and large-scale examination of N-glycan profiles. This paper is the first to explore the application of high-throughput N-glycomics techniques to investigate the complex interplay between N-glycosylation and the immune system in aging. Technological advancements have significantly improved Nglycan detection and characterization, providing insights into age-related changes in Nglycosylation. Key findings highlight consistent shifts in immunoglobulin G (IgG) and plasma/serum glycoprotein glycosylation with age, with a pronounced rise in agalactosylated structures bound to IgG that also affect the composition of the total plasma N-glycome. These N-glycan modifications seem to be strongly associated with inflammaging and have been identified as valuable biomarkers for biological age, predictors of disease risk, and proxy biomarkers for monitoring intervention efficacy at the individual level. Despite current challenges related to data complexity and methodological limitations, ongoing technological innovations and interdisciplinary research are expected tofurther advance our knowledge of glycan biology, improve diagnostic and therapeutic strategies, and promote healthier aging. The integration of glycomics with other omics approaches holds promise for a more comprehensive understanding of the aging immune system, paving the way for personalized medicine and targeted interventions to mitigate inflammaging. In conclusion, this paper underscores the transformative impact of high-throughput Nglycan analysis in aging and inflammaging.

Immunosenescence and Inflammaging: Mechanisms and Role in Diseases.

Age-related changes initiate a cascade of cellular and molecular alterations that lead to immune system dysfunction or abnormal activation, predisposing individuals to age-related diseases. This phenomenon, commonly referred to as immunosenescence, highlighting aging-associated progressive decline of the immune system. Moreover, mounting evidence suggests that immunosenescence contributes to a related pathological phenomenon known as inflammaging. Inflammaging refers to chronic, low-grade, and systemic inflammation associated with aging, occurring despite the absence of overt stimuli. In the body, inflammation is typically activated in response to overt stimuli such as bacterial/microbial invasion or a pathological state, however, inflammaging occurrence and its underpinning mechansisms seem to be independent and in the absence of such stimuli. Despite recent advancements in molecular characterization and the scrutiny of disease relevance, these two interconnected concepts have remained largely unexplored and unrecognized. In this comprehensive review, we aim to shed light on the mechanistic and cellular aspects of immunosenescence and inflammaging, as well as their pivotal roles in the pathogenesis of aging-related diseases, including cancer, infections, dementia, and neurodegenerative disorders.

Frailty assessment in patients with Behçet's syndrome: A cross-sectional monocentric study.

AIMS: Evidence evaluating the association between pre-frailty and frailty, and risk of adverse health outcomes in patients with Behçet's syndrome (BS) is limited in the literature. The aim of this study was to characterize the prevalence of frailty and associated factors in a single-centre cohort of patients with BS. METHODS: Based on the International Study Group's criteria, this was a monocentric cross-sectional study of BS patients. The Fried frailty criteria were used to define frailty. The Turkish version of the Behçet's Disease Current Activity Form was used to measure the disease activity of BS. Damage index was assessed with the Behçet's Syndrome Overall Damage Index. RESULTS: Forty-four patients were enrolled. According to Fried frailty criteria, patients were classified as 13.6% frail, 59% pre-frail, and 27.2% robust, respectively. Compared to pre-frail and robust patients, frail patients had higher levels of inflammatory markers at the time of diagnosis. CRP levels at time of diagnosis and at the last visit were higher in the frail group than in the pre-frail and robust groups (p=0.039 and p=0.023, respectively). When active drugs for BS were evaluated, systemic glucocorticoid (50%, p=0.030) and cyclophosphamide (33.3%, p=0.006) treatments were higher in the frail group. CONCLUSIONS: Frailty and pre-frailty are commonly detected even in younger patients with BS. Inflammation can be described as potential determinants of frailty status.

Emerging Targets and Treatments for Sarcopenia: A Narrative Review.

BACKGROUND: Sarcopenia is characterized by the progressive loss of skeletal muscle mass, strength, and function, significantly impacting overall health and quality of life in older adults. This narrative review explores emerging targets and potential treatments for sarcopenia, aiming to provide a comprehensive overview of current and prospective interventions. METHODS: The review synthesizes current literature on sarcopenia treatment, focusing on recent advancements in muscle regeneration, mitochondrial function, nutritional strategies, and the muscle-microbiome axis. Additionally, pharmacological and lifestyle interventions targeting anabolic resistance and neuromuscular junction integrity are discussed. RESULTS: Resistance training and adequate protein intake remain the cornerstone of sarcopenia management. Emerging strategies include targeting muscle regeneration through myosatellite cell activation, signaling pathways, and chronic inflammation control. Gene editing, stem cell therapy, and microRNA modulation show promise in enhancing muscle repair. Addressing mitochondrial dysfunction through interventions aimed at improving biogenesis, ATP production, and reducing oxidative stress is also highlighted. Nutritional strategies such as leucine supplementation and anti-inflammatory nutrients, along with dietary modifications and probiotics targeting the muscle-microbiome interplay, are discussed as potential treatment options. Hydration and muscle-water balance are emphasized as critical in maintaining muscle health in older adults. CONCLUSIONS: A combination of resistance training, nutrition, and emerging therapeutic interventions holds potential to significantly improve muscle function and overall health in the aging population. This review provides a detailed exploration of both established and novel approaches for the prevention and management of sarcopenia, highlighting the need for further research to optimize these strategies.

Management of inflammaging in kidney diseases: focusing on the current investigational drugs.

INTRODUCTION: To improve kidney disease treatments, it is crucial to understand how inflammaging affects patients´ longevity. We could potentially slow down kidney disease progression and enhance longevity by targeting specific pathways involved in inflammaging with potential drugs. AREAS OF COVERED: This review offers an updated overview of 'anti-inflammaging' drugs currently in the kidney disease research pipeline, as well as those with potential for future therapeutic use. Furthermore, these drugs are categorized according to their mechanisms, including targeting inflammation, immune and metabolic regulation, oxidative stress, senescence, and autophagy, as demonstrated in preclinical and early clinical trials. Additionally, the review provides insights into key challenges and opinions for future advancements in this field. EXPERT OPINION: We reviewed recent advancements in applying different therapies to mitigate inflammaging in kidney diseases. We underscore the need for continued research to elucidate the complex pathways underlying inflammaging, which will be essential for the development of more precise and effective treatments. As research in this field advances, several emerging drugs appear promising for future investigation. While current findings are encouraging, further clinical studies are required to validate the therapeutic potential of these agents in kidney diseases, ultimately paving the way for more targeted and efficacious interventions.

Heart rate variability and autonomic nervous system imbalance: Potential biomarkers and detectable hallmarks of aging and inflammaging.

The most cutting-edge issue in the research on aging is the quest for biomarkers that transcend molecular and cellular domains to encompass organismal-level implications. We recently hypothesized the role of Autonomic Nervous System (ANS) imbalance in this context. Studies on ANS functions during aging highlighted an imbalance towards heightened sympathetic nervous system (SNS) activity, instigating a proinflammatory milieu, and attenuated parasympathetic nervous system (PNS) function, which exerts anti-inflammatory effects via the cholinergic anti-inflammatory pathway (CAP) and suppression of the hypothalamic-pituitary-adrenal (HPA) axis. This scenario strongly suggests that ANS imbalance can fuel inflammaging, now recognized as one of the most relevant risk factors for age-related disease development. Recent recommendations have increasingly highlighted the need for actionable strategies to improve the quality of life for older adults by identifying biomarkers that can be easily measured, even in asymptomatic individuals. We advocate for considering ANS imbalance as a biomarker of aging and inflammaging. Measures of ANS imbalance, such as heart rate variability (HRV), are relatively affordable, non-invasive, and cost-effective, making this hallmark easily diagnosable. HRV gains renewed significance within the aging research landscape, offering a tangible link between pathophysiological perturbations and age-related health outcomes.

Changes in Innate Immunity and Microbiome in Different Aging Phenotypes.

The indicators of innate immunity and the composition of the microbiome in the nasopharyngeal mucosa in centenarians with different aging phenotypes were analyzed. A significant increase in the expression of pattern-recognizing receptor genes (TLR2, TLR4, and NLRP3) and proinflammatory cytokines (IL1B, IL18) was shown in the group of centenarians with pathological aging phenotype. In centenarians with successful aging phenotype, increased diversity of the microbiome composition was observed. At the same time, a moderate inverse correlation was found between an increase in the growth of the commensal bacterium Streptococcus salivarius and a decrease in the expression of proinflammatory cytokine genes IL1B and IL18. These findings can serve as biomarkers for the timely identification of the phenotype of aging in senile and elderly people.

Immune system dysfunction and inflammation in aging Shank3b mutant mice, a model of autism spectrum disorder.

Introduction: Autism spectrum disorder (ASD) is a heterogeneous group of neurodevelopmental Q8 conditions characterized by deficits in social interaction/communication and restrictive/repetitive behaviors. Recent studies highlight the role of immune system dysfunction and inflammation in ASD pathophysiology. Indeed, elevated levels of pro-inflammatory cytokines were described in the brain and peripheral blood of ASD individuals. Despite this, how this pro-inflammatory profile evolves with aging and whether it may be associated with behavioral deficits is unknown. In this work, we explored the impact of aging on motor behavior and inflammation using Shank3b mutant mice, a model for syndromic ASD. Methods: Using RT-qPCR and flow cytometry, we examined the expression of key pro-inflammatory molecules in the cerebellum, bone marrow, spleen, and peripheral blood, comparing adult and old Shank3b +/+, Shank3b +/-, and Shank3b -/- mice. Results and discussion: Our findings revealed genotype- and age-related differences in inflammation and motor behavior, with Shank3b-/- mice exhibiting accelerated aging and motor impairments. Correlations between pro-inflammatory molecules and behavioral deficits suggest that a link may be present between systemic inflammation and ASD-related behaviors, underscoring the potential role of age-related inflammation ("inflammaging") in exacerbating ASD symptoms.

A new clinical age of aging research.

Aging is a major risk factor for a variety of diseases, thus, translation of aging research into practical applications is driven by the unmet need for existing clinical therapeutic options. Basic and translational research efforts are converging at a critical stage, yielding insights into how fundamental aging mechanisms are used to identify promising geroprotectors or therapeutics. This review highlights several research areas from a clinical perspective, including senescent cell targeting, alleviation of inflammaging, and optimization of metabolism with endogenous metabolites or precursors. Refining our understanding of these key areas, especially from the clinical angle, may help us to better understand and attenuate aging processes and improve overall health outcomes.

Fasting and calorie restriction modulate age-associated immunosenescence and inflammaging.

Aging is a multifaceted process impacting cells, tissues, organs, and organ systems of the body. Like other systems, aging affects both the adaptive and the innate components of the immune system, a phenomenon known as immunosenescence. The deregulation of the immune system puts elderly individuals at higher risk of infection, lower response to vaccines, and increased incidence of cancer. In the Western world, overnutrition has increased the incidence of obesity (linked with chronic inflammation) which increases the risk of metabolic syndrome, cardiovascular disease, and cancer. Aging is also associated with inflammaging a sterile chronic inflammation that predisposes individuals to age-associated disease. Genetic manipulation of the nutrient-sensing pathway, fasting, and calorie restriction (CR) has been shown to increase the lifespan of model organisms. As well in humans, fasting and CR have also been shown to improve different health parameters. Yet the direct effect of fasting and CR on the aging immune system needs to be further explored. Identifying the effect of fasting and CR on the immune system and how it modulates different parameters of immunosenescence could be important in designing pharmacological or nutritional interventions that slow or revert immunosenescence and strengthen the immune system of elderly individuals. Furthermore, clinical intervention can also be planned, by incorporating fasting or CR with medication, chemotherapy, and vaccination regimes. This review discusses age-associated changes in the immune system and how these changes are modified by fasting and CR which add information on interventions that promote healthy aging and longevity in the growing aging population.

The emerging links between immunosenescence in innate immune system and neurocryptococcosis.

Immunosenescence refers to the age-related progressive decline of immune function contributing to the increased susceptibility to infectious diseases in older people. Neurocryptococcosis, an infectious disease of central nervous system (CNS) caused by Cryptococcus neoformans (C. Neoformans) and C. gattii, has been observed with increased frequency in aged people, as result of the reactivation of a latent infection or community acquisition. These opportunistic microorganisms belonging to kingdom of fungi are capable of surviving and replicating within macrophages. Typically, cryptococcus is expelled by vomocytosis, a non-lytic expulsive mechanism also promoted by interferon (IFN)-I, or by cell lysis. However, whereas in a first phase cryptococcal vomocytosis leads to a latent asymptomatic infection confined to the lung, an enhancement in vomocytosis, promoted by IFN-I overproduction, can be deleterious, leading the fungus to reach the blood stream and invade the CNS. Cryptococcus may not be easy to diagnose in older individuals and, if not timely treated, could be potentially lethal. Therefore, this review aims to elucidate the putative causes of the increased incidence of cryptococcal CNS infection in older people discussing in depth the mechanisms of immunosenscence potentially able to predispose to neurocryptococcosis, laying the foundations for future research. A deepest understanding of this relationship could provide new ways to improve the prevention and recognition of neurocryptococcosis in aged frail people, in order to quickly manage pharmacological interventions and to adopt further preventive measures able to reduce the main risk factors.

Pomegranate (Punica granatum L.) Extract Effects on Inflammaging.

Pomegranate is a notable source of nutrients, containing a considerable proportion of organic acids, polysaccharides, vitamins, fatty acids, and polyphenols such as flavonoids, phenolic acids, and tannins. It is also rich in nutritionally important minerals and chemical elements such as K, P, Na, Ca, Mg, and N. The presence of several bioactive compounds and metabolites in pomegranate has led to its incorporation into the functional food category, where it is used for its numerous therapeutic properties. Pomegranate's bioactive compounds have shown antioxidant, anti-inflammatory, and anticancer effects. Aging is a process characterized by the chronic accumulation of damages, progressively compromising cells, tissues, and organs over time. Inflammaging is a chronic, subclinical, low-grade inflammation that occurs during the aging process and is linked to many age-related diseases. This review aims to summarize and discuss the evidence of the benefits of pomegranate extract and its compounds to slow the aging processes by intervening in the mechanisms underlying inflammaging. These studies mainly concern neurodegenerative and skin diseases, while studies in other fields of application need to be more practical. Furthermore, no human studies have demonstrated the anti-inflammaging effects of pomegranate. In the future, supplementation with pomegranate extracts, polyphenols, or urolithins could represent a valuable low-risk complementary therapy for patients with difficult-to-manage diseases, as well as a valid therapeutic alternative for the topical or systemic treatment of skin pathologies.

Innate immunity in peripheral tissues is differentially impaired under normal and endotoxic conditions in aging.

Chronic low-grade inflammation is a hallmark of aging, aka "inflammaging", which is linked to a wide range of age-associated diseases. Immune dysfunction increases disease susceptibility, and increases morbidity and mortality of aging. Innate immune cells, including monocytes, macrophages and neutrophils, are the first responders of host defense and the key mediators of various metabolic and inflammatory insults. Currently, the understanding of innate immune programming in aging is largely fragmented. Here we investigated the phenotypic and functional properties of innate immune cells in various peripheral tissues of young and aged mice under normal and endotoxic conditions. Under the steady state, aged mice showed elevated pro-inflammatory monocytes/macrophages in peripheral blood, adipose tissue, liver, and colon. Under lipopolysaccharide (LPS)-induced inflammatory state, the innate immune cells of aged mice showed a different response to LPS stimulus than that of young mice. LPS-induced immune responses displayed differential profiles in different tissues and cell types. In the peripheral blood, when responding to LPS, the aged mice showed higher neutrophils, but lower pro-inflammatory monocytes than that in young mice. In the peritoneal fluid, while young mice exhibited significantly elevated pro-inflammatory neutrophils and macrophages in response to LPS, aged mice exhibited decreased pro-inflammatory neutrophils and variable cytokine responses in macrophages. In the adipose tissue, LPS induced less infiltrated neutrophils but more infiltrated macrophages in old mice than young mice. In the liver, aged mice showed a more robust increase of pro-inflammatory macrophages compared to that in young mice under LPS stimulation. In colon, macrophages showed relatively mild response to LPS in both young and old mice. We have further tested bone-marrow derived macrophages (BMDM) from young and aged mice, we found that BMDM from aged mice have impaired polarization, displaying higher expression of pro-inflammatory markers than those from young mice. These data collectively suggest that innate immunity in peripheral tissues is impaired in aging, and the dysregulation of immunity is tissue- and cell-dependent. Our findings in the rodent model underscore the complexity of aging immunity. Further investigation is needed to determine whether the immune profile observed in aged mice is applicable in age-associated diseases in humans.

Rapid progression of CD8 and CD4 T cells to cellular exhaustion and senescence during SARS-CoV2 infection.

Risk factors for the development of severe COVID-19 include several comorbidities, but age was the most striking one since elderly people were disproportionately affected by SARS-CoV-2 infection. Among the reasons for this markedly unfavorable response in the elderly, immunosenescence and inflammaging appear as major drivers of this outcome. A finding that was also notable was that hospitalized patients with severe COVID-19 have an accumulation of senescent T cells, suggesting that immunosenescence may be aggravated by SARS-CoV-2 infection. The present work was designed to examine whether these immunosenescence changes are characteristic of COVID-19 and whether it is dependent on disease severity using cross-sectional and longitudinal studies. Our cross-sectional data show that COVID-19, but not other respiratory infections, rapidly increased cellular senescence and exhaustion in CD4 and CD8 T cells during early infection. In addition, longitudinal analyses with patients from Brazil and Portugal provided evidence of increased frequencies of senescent and exhausted T cells over a 7-d period in patients with mild/moderate and severe COVID-19. Altogether, the study suggests that accelerated immunosenescence in CD4 and especially CD8 T-cell compartments may represent a common and unique outcome of SARS-CoV2 infection.