Coronavirus Disease (COVID-19): A Perspective from Immunosenescence

The use of alpha 1 thymosin as an immunomodulator of the response against SARS-Cov2

BACKGROUND

Since the beginning of SARS-CoV2 pandemic, the mortality rate among elderly patients (60-90 years) has been around 50%, so age has been a determining factor of a worse COVID-19 prognosis. Associated with age, the thymic function involution and depletion plays an important role, that could be related to a dysregulated and ineffective innate and adaptive immune response against SARS-CoV2. Our study aims to further in vitro effect of human Thymosin-alpha-1 (α1Thy) treatment on the immune system in population groups with different thymic function levels in the scenario of SARS-CoV2 infection.

RESULTS

Activation markers such as CD40, CD80 and TIM-3 were upregulated in α1Thy presence, especially in plasmacytoid dendritic cells (pDCs) and, with increased TNFα production was observed compared to untreated condition. Co-cultures of CD4 + and CD8 + T cells with DCs treated with α1Thy in response to SARS-CoV2 peptides showed a decrease in the cytokine production compared to the condition without α1Thy pre-treated. A decrease in CD40L activation co-receptor expression in CD8 + LTs was also observed, as well as an increase in PD1 in CD4 + TLs expression in both age groups. In fact, there are no age-related differences in the immunomodulatory effect of the hormone, and it seems that effector memory and terminally differentiated memory T lymphocyte subsets were the most actively influenced by the immunomodulatory α1Thy effect. Finally, the polyfunctionality measured in SARS-CoV2 Specific-T cells response was maintained in α1Thy presence in total and memory subpopulations CD4 + and CD8 + T-cells, despite decreased proinflammatory cytokines production.

CONCLUSION

The hormone α1Thy could reduce, through the modulation of DCs, the amount of proinflammatory cytokines produced by T cells. Moreover, α1Thy improve lymphocyte functionality and could become a beneficial therapeutic alternative as an adjuvant in SARS-CoV2 treatment either in the acute phase after infection or reinfection. In addition, the effect on the T immune response means that α1Thy can be incorporated into the vaccination regimen, especially in the most immunologically vulnerable individuals such as the elderly.

SUBJECTS

Thymosin alpha 1, Dendritic cells, SARS-CoV2-specific T cells response, Immunomodulation.

Novel evidence of Thymosin α1 immunomodulatory properties in SARS-CoV-2 infection: Effect on innate inflammatory response in a peripheral blood mononuclear cell-based in vitro model

The peculiar property of Thymosin alpha 1 (Tα1) to act as master regulator of immune homeostasis has been successfully defined in different physiological and pathological contexts ranging from cancer to infection. Interestingly, recent papers also demonstrated its mitigating effect on the "cytokine storm" as well as on the T-cell exhaustion/activation in SARS-CoV-2 infected individuals. Nevertheless, in spite of the increasing knowledge on Tα1-induced effects on T cell response confirming the distinctive features of this multifaceted peptide, little is known on its effects on innate immunity during SARS-CoV-2 infection. Here, we interrogated peripheral blood mononuclear cell (PBMC) cultures stimulated with SARS-CoV-2 to disclose Tα1 properties on the main cell players of early response to infection, namely monocytes and myeloid dendritic cells (mDC). Moving from ex vivo data showing an enhancement in the frequency of inflammatory monocytes and activated mDC in COVID-19 patients, a PBMC-based experimental setting reproduced in vitro a similar profile with an increased percentage of CD16⁺ inflammatory monocytes and mDC expressing CD86 and HLA-DR activation markers in response to SARS-CoV-2 stimulation. Interestingly, the treatment of SARS-CoV-2-stimulated PBMC with Tα1 dampened the inflammatory/activation status of both monocytes and mDC by reducing the release of pro-inflammatory mediators, including TNF-α, IL-6 and IL-8, while promoting the production of the anti-inflammatory cytokine IL-10. This study further clarifies the working hypothesis on Tα1 mitigating action on COVID-19 inflammatory condition. Moreover, these evidence shed light on inflammatory pathways and cell types involved in acute SARS-CoV-2 infection and likely targetable by newly immune-regulating therapeutic approaches.

Higher plasma levels of thymosin-α1 are associated with a lower waning of humoral response after COVID-19 vaccination: an eight months follow-up study in a nursing home

BACKGROUND

Older people achieve lower levels of antibody titers than younger populations after Covid-19 vaccination and show a marked waning humoral immunity over time, likely due to the senescence of the immune system. Nevertheless, age-related predictive factors of the waning humoral immune response to the vaccine have been scarcely explored. In a cohort of residents and healthcare workers from a nursing home that had received two doses of the BNT162b2 vaccine, we measured specific anti-S antibodies one (T1), four (T4), and eight (T8) months after receiving the second dose. Thymic-related functional markers, including thymic output, relative telomere length, and plasma thymosin-α1 levels, as well as immune cellular subsets, and biochemical and inflammatory biomarkers, were determined at T1, and tested for their associations with the magnitude of the vaccine response (T1) and the durability of such response both, at the short- (T1-T4) and the long-term (T1-T8). We aimed to identify age-related factors potentially associated with the magnitude and persistence of specific anti-S immunoglobulin G (IgG)-antibodies after COVID-19 vaccination in older people.

RESULTS

Participants (100% men, n = 98), were subdivided into three groups: young (< 50 years-old), middle-age (50-65 years-old), and older (≥65 years-old). Older participants achieved lower antibody titers at T1 and experienced higher decreases in both the short- and long-term. In the entire cohort, while the magnitude of the initial response was mainly associated with the levels of homocysteine [β (95% CI); - 0.155 (- 0.241 to - 0.068); p = 0.001], the durability of such response at both, the short-term and the long-term were predicted by the levels of thymosin-α1 [- 0.168 (- 0.305 to - 0.031); p = 0.017, and - 0.123 (- 0.212 to - 0.034); p = 0.008, respectively].

CONCLUSIONS

Higher plasma levels of thymosin-α1 were associated with a lower waning of anti-S IgG antibodies along the time. Our results suggest that plasma levels of thymosin-α1 could be used as a biomarker for predicting the durability of the responses after COVID-19 vaccination, possibly allowing to personalize the administration of vaccine boosters.

Aging, inflammaging and immunosenescence as risk factors of severe COVID-19

Coronavirus disease 2019 (COVID-19) is a respiratory infectious disease caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID-19 is characterized by having a heterogeneous disease course, ranging from asymptomatic and mild symptoms to more severe and critical cases. In most cases the severity of COVID-19 is related to host factors, especially deregulation of the immune response in patients. Even if COVID-19 indiscriminately affects individuals of different age group, ethnicity and economic status; most severe cases and disproportional mortality occur in elderly individuals. This point out that aging is one risk factor for unfavourable clinical outcomes among COVID-19 patients. The biology of aging is a complex process; Aging can alter the structure and function of cells, tissues, and organs resulting in impaired response to stress. Alongside with other systems, the immune system is also affected with the aging process. Immunosenescence is an age associated change in the immune system that affects the overall response to immunological challenges in the elderly. Similarly, apart from the normal inflammatory process, aging is associated with a low grade, sterile, chronic inflammation which is termed as inflammaging. We hypothesized that inflammaging and immunosenescence could play an important role in SARS-CoV-2 pathogenesis and poor recovery from COVID-19 in elderly individuals. This review summarizes the changes in the immune system with age and how these changes play part in the pathogenesis of SARS-CoV-2 and clinical outcome of COVID-19 which could add to the understanding of age associated targeted immunotherapy in the elderly.

The Importance of Behavioral and Native Factors on COVID-19 Infection and Severity: Insights from a Preliminary Cross-Sectional Study

The COVID-19 pandemic has had a major impact on a global scale. Understanding the innate and lifestyle-related factors influencing the rate and severity of COVID-19 is important for making evidence-based recommendations. This cross-sectional study aims at establishing a potential relationship between human characteristics and vulnerability/resistance to SARS-CoV-2. We hypothesize that the impact of the virus is not the same due to cultural and ethnic differences. A cross-sectional study was performed using an online questionnaire. The methodology included the development of a multi-language survey, expert evaluation, and data analysis. Data were collected using a 13-item pre-tested questionnaire based on a literature review between 9 December 2020 and 21 July 2021. Data were statistically analyzed using logistic regression. For a total of 1125 respondents, 332 (29.5%) were COVID-19 positive; among them, 130 (11.5%) required home-based treatment, and 14 (1.2%) intensive care. The significant and most influential factors on infection included age, physical activity, and health status (p < 0.05), i.e., better physical activity and better health status significantly reduced the possibility of infection, while older age significantly increased it. The severity of infection was negatively associated with the acceptance (adherence and respect) of preventive measures and positively associated with tobacco (p < 0.05), i.e., smoking regularly significantly increases the severity of COVID-19 infection. This suggests the importance of behavioral factors compared to innate ones. Apparently, individual behavior is mainly responsible for the spread of the virus. Therefore, adopting a healthy lifestyle and scrupulously observing preventive measures, including vaccination, would greatly limit the probability of infection and prevent the development of severe COVID-19.

Management of asthma patients during the COVID-19 pandemic: pathophysiological considerations to address the challenges

Background

The coronavirus disease 2019 (COVID-19) has become a serious global health issue, especially for people with pre-existing health conditions. Patients dealing with asthma are presumed to be at higher risk as COVID-19 may cause severe respiratory distress.

Main body

From the initial stage of the pandemic, several clinical trials and studies have assessed the association between COVID-19 and asthma; however, no significant association was reported. This may be due to the fact that most of the asthma cases remained undiagnosed and overlapping respiratory features make it difficult to differentiate between these two diseases. The pathomechanism of the conditions and the immune response generated in response to the conditions suggest that the presence of any of the conditions is very likely to influence the presence or severity of the other condition. So far, no specific treatments are known for COVID-19; however, the use of plasma therapy and broad-spectrum antiviral drugs during the initial phase of the pandemic and widespread vaccination during the latter phase has given positive outcomes in reducing COVID-19 cases as well as disease severity.

Short conclusion

Taking asthma as an increased risk factor for COVID-19 morbidity, this article aims to provide comprehensive insights into the risk and proper management of asthma patients during this COVID-19 pandemic. The common medications of asthma patients suppress their respiratory immune response that might facilitate cytokine storm in COVID-19 patients. Similarly, there are risks of viral-induced asthma exacerbations. Besides, different social issues such as shortage of medicines, SDOH, and delayed clinical trials put asthma patients through inconvenience. The primary focus at this point should be to reduce probable asthma attacks and severity to prevent hospitalization of asthma patients. Moreover, for better management of asthma patients maintaining an asthma action plan and healthy lifestyle, ensuring a nutritious diet, and developing self-management interventions can play a crucial role.

Possible effects of sirolimus treatment on the long‑term efficacy of COVID‑19 vaccination in patients with β‑thalassemia: A theoretical perspective

The pandemic caused by the severe acute respiratory syndrome coronavirus (SARS‑CoV‑2), responsible for coronavirus disease 2019 (COVID‑19) has posed a major challenge for global health. In order to successfully combat SARS‑CoV‑2, the development of effective COVID‑19 vaccines is crucial. In this context, recent studies have highlighted a high COVID‑19 mortality rate in patients affected by β‑thalassemia, probably due to their co‑existent immune deficiencies. In addition to a role in the severity of SARS‑CoV‑2 infection and in the mortality rate of COVID‑19‑infected patients with thalassemia, immunosuppression is expected to deeply affect the effectivity of anti‑COVID‑19 vaccines. In the context of the interplay between thalassemia‑associated immunosuppression and the effectiveness of COVID‑19 vaccines, the employment of immunomodulatory molecules is hypothesized. For instance, short‑term treatment with mammalian target of rapamycin inhibitors (such as everolimus and sirolimus) has been found to improve responses to influenza vaccination in adults, with benefits possibly persisting for a year following treatment. Recently, sirolimus has been considered for the therapy of hemoglobinopathies (including β‑thalassemia). Sirolimus induces the expression of fetal hemoglobin (and this may contribute to the amelioration of the clinical parameters of patients with β‑thalassemia) and induces autophagy (thereby reducing the excessive levels of α‑globin). It may also finally contribute to the mobilization of erythroid cells from the bone marrow (thereby reducing anemia). In the present study, the authors present the hypothesis that sirolimus treatment, in addition to its beneficial effects on erythroid‑related parameters, may play a crucial role in sustaining the effects of COVID‑19 vaccination in patients with β‑thalassemia. This hypothesis is based on several publications demonstrating the effects of sirolimus treatment on the immune system.

Immunopathology and Immunosenescence, the Immunological Key Words of Severe COVID-19. Is There a Role for Stem Cell Transplantation?

The outcomes of Coronavirus disease-2019 (COVID-19) vary depending on the age, health status and sex of an individual, ranging from asymptomatic to lethal. From an immunologic viewpoint, the final severe lung damage observed in COVID-19 should be caused by cytokine storm, driven mainly by interleukin-6 and other pro-inflammatory cytokines. However, which immunopathogenic status precedes this "cytokine storm" and why the male older population is more severely affected, are currently unanswered questions. The aging of the immune system, i.e., immunosenescence, closely associated with a low-grade inflammatory status called "inflammageing," should play a key role. The remodeling of both innate and adaptive immune response observed with aging can partly explain the age gradient in severity and mortality of COVID-19. This review discusses how aging impacts the immune response to the virus, focusing on possible strategies to rejuvenate the immune system with stem cell-based therapies. Indeed, due to immunomodulatory and anti-inflammatory properties, multipotent mesenchymal stem cells (MSCs) are a worth-considering option against COVID-19 adverse outcomes.

Fat-Soluble Vitamins and the Current Global Pandemic of COVID-19: Evidence-Based Efficacy from Literature Review

The outbreak of pneumonia caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), later named COVID-19 by the World Health Organization (WHO), was initiated at Wuhan, Hubei, China, and there was a rapid spread of novel SARS-CoV-2 and the disease COVID-19 in late 2019. The entire world is now experiencing the challenge of COVID-19 infection. However, still very few evidence-based treatment options are available for the prevention and treatment of COVID-19 disease. The present review aims to summarize the publicly available information to give a comprehensive yet balanced scientific overview of all the fat-soluble vitamins concerning their role in SARS-CoV-2 virus infection. The roles of different fat-soluble vitamins and micronutrients in combating SARS-CoV-2 infection have been recently explored in several studies. There are various hypotheses to suggest their use to minimize the severity of COVID-19 infection. These vitamins are pivotal in the maintenance and modulation of innate and cell-mediated, and antibody-mediated immune responses. The data reported in recent literature demonstrate that deficiency in one or more of these vitamins compromises the patients’ immune response and makes them more vulnerable to viral infections and perhaps worse disease prognosis. Vitamins A, D, E, and K boost the body’s defense mechanism against COVID-19 infection and specifically prevent its complications such as cytokine storm and other inflammatory processes, leading to increased morbidity and mortality overemphasis. However, more detailed randomized double-blind clinical pieces of evidence are required to define the use of these supplements in preventing or reducing the severity of the COVID-19 infection.