Immune response induced by novel coronavirus infection

Inhibitory effect of food-functioned phytochemicals on dysregulated inflammatory pathways triggered by SARS-CoV-2: a mechanistic review

Inflammatory cascades of the dysregulated inflammatory pathways in COVID-19 can cause excessive production of pro-inflammatory cytokines and chemokines leading to cytokine storm syndrome (CSS). The molecular cascades involved in the pathways may be targeted for discovery of new anti-inflammatory agents. Many plant extracts have been used clinically in the management of COVID-19, however, their immunosuppressive activities were mainly investigated based on in silico activity. Dietary flavonoids of the extracts such as quercetin, luteolin, kaempferol, naringenin, isorhamnetin, baicalein, wogonin, and rutin were commonly identified as responsible for their inhibitory effects. The present review critically analyzes the anti-inflammatory effects and mechanisms of phytochemicals, including dietary compounds against cytokine storm (CS) and hyperinflammation via inhibition of the altered inflammatory pathways triggered by SARS-CoV-2, published since the emergence of COVID-19 in December 2019. Only a few phytochemicals, mainly dietary compounds such as nanocurcumin, melatonin, quercetin, 6-shagoal, kaempferol, resveratrol, andrographolide, and colchicine have been investigated either in in silico or preliminary clinical studies to evaluate their anti-inflammatory effects against COVID-19. Sufficient pre-clinical studies on safety and efficacy of anti-inflammatory effects of the phytochemicals must be performed prior to proper clinical studies to develop them into therapeutic adjuvants in the prevention and treatmemt of COVID-19 symptoms.

Association Between Hemoglobin-Albumin-Lymphocyte-Platelet Index and Mortality in Hospitalized COVID-19 Omicron BA.2 Infected Patients

Background

The hemoglobin-albumin-lymphocyte-platelet (HALP) index is a novel biomarker reflecting systemic inflammation and nutritional status which are important for coronavirus disease 2019 (COVID-19) mortality. However, the association between HALP and mortality in patients with COVID-19 has yet to be investigated.

Methods

A cohort of COVID-19 Omicron BA.2 infected patients admitted to the Shanghai Fourth People's Hospital, School of Medicine, Tongji University from April 12, 2022 to June 17, 2022 was retrospectively analyzed. Laboratory examinations on hospital admission, including hemoglobin, albumin, and lymphocyte and platelet, were collected. The association between baseline HALP and in-hospital poor overall survival (OS) was assessed using Kaplan-Meier curves, Cox regression models, interaction, and stratified analyses.

Results

A total of 2147 patients with COVID-19 Omicron BA.2 infection were included in the final analyses, and mortality in the hospital was 2.65%. Multivariate analysis indicated that low HALP index was independently associated with in-hospital mortality of COVID-19 patients [hazard ratio (HR) = 2.08; 95% confidence interval (CI) = 1.17-3.73]. Subgroup analysis demonstrated that low HALP index was an independent risk factor for in-hospital mortality in COVID-19 patients with age ≥70 (HR = 2.22, CI = 1.18-4.15) and severe cases (HR = 2.09, CI = 1.13-3.86).

Conclusion

HALP index is independently related to in-hospital poor OS for COVID-19 Omicron BA.2 infected patients, especially for age ≥70 and severe cases. HALP index on hospital admission is a useful candidate biomarker for identifying high risk of mortality in COVID-19 Omicron BA.2 infected patients.

Innate immune responses to SARS-CoV-2

This chapter provides an overview of the innate immune response to SARS-CoV-2, focusing on the recognition, activation, and evasion strategies employed by the virus. The innate immune system plays a crucial role in the early defense against viral infections, and understanding its response to SARS-CoV-2 is essential for developing effective therapeutic approaches. The chapter begins by explaining the basics of the innate immune system, including its components and salient features. It discusses the various pattern recognition receptors involved in recognizing SARS-CoV-2, such as toll-like receptors, RIG-I-like receptors, NOD-like receptors, and other cytosolic sensors. The binding and entry of the virus into host cells and subsequent activation of innate immune cells, including neutrophils, monocytes, macrophages, dendritic cells, NK cells, and ILCs, are explored. Furthermore, the secretion of key cytokines and chemokines, including type I interferons, IL-6, IL-17, and TNF-alpha, is discussed as part of the innate immune response. The concept of PANoptosis, involving programmed cell death mechanisms, is introduced as a significant aspect of the response to SARS-CoV-2. The chapter also addresses the innate immune evasion strategies employed by SARS-CoV-2, which allow the virus to evade or subvert the host immune response, contributing to viral persistence. Understanding these strategies is crucial for developing targeted therapies against the virus.

Cladribine Tablets Mode of Action, Learning from the Pandemic: A Narrative Review

Multiple sclerosis (MS) is an immune-mediated disease of the central nervous system, characterized by chronic, inflammatory, demyelinating, and neurodegenerative processes. MS management relies on disease-modifying drugs that suppress/modulate the immune system. Cladribine tablets (CladT) have been approved by different health authorities for patients with various forms of relapsing MS. The drug has been demonstrated to deplete CD4+ and CD8+ T-cells, with a higher effect described in the former, and to decrease total CD19+, CD20+, and naive B-cell counts. COVID-19 is expected to become endemic, suggesting its potential infection risk for immuno-compromised patients, including MS patients treated with disease-modifying drugs. We report here the available data on disease-modifying drug-treated-MS patients and COVID-19 infection and vaccination, with a focus on CladT. MS patients treated with CladT are not at higher risk of developing severe COVID-19. While anti-SARS-CoV-2 vaccination is recommended in all MS patients with guidelines addressing vaccination timing according to the different disease-modifying drugs, no vaccination timing restrictions seem to be necessary for cladribine, based on its mechanism of action and available evidence. Published data suggest that CladT treatment does not impact the production of anti-SARS-CoV-2 antibodies after COVID-19 vaccination, possibly due to its relative sparing effect on naïve B-cells and the rapid B-cell reconstitution following treatment. Slightly lower specific T-cell responses are likely not impacting the risk of breakthrough COVID-19. It could be stated that cladribine's transient effect on innate immune cells likely contributes to maintaining an adequate first line of defense against the SARS-CoV-2 virus.

Risk of cytomegalovirus diseases among coronavirus disease survivors: A retrospective cohort study

This study was aimed at investigating the risk of cytomegalovirus (CMV) disease among coronavirus disease 2019 (COVID-19) survivors. In this retrospective cohort study, we used the TriNetX research network to identify adults with and without COVID-19 between January 1, 2022 and December 31, 2022. Propensity score matching was used to match the patients with and without COVID-19. The primary outcome was the risk of CMV disease during the 90-day follow-up period. Two matched cohorts comprising 2 501 634 patients with balanced baseline characteristics were created using propensity score matching. During the follow-up period, patients with COVID-19 had a higher risk of CMV disease than those without COVID-19 (hazard ratio [HR], 2.55; 95% confidence interval: 2.01-3.23). The higher risk of CMV disease in the COVID-19 cohort compared with that of the non-COVID-19 cohort remained unchanged in the subgroup analyses by sex (men: HR, 1.85 [1.38-2.47]; women: HR, 2.31 [1.63-3.27]), age (18-64 years: HR, 2.21 [1.71-2.85]; ≥65 years: HR, 1.97 [1.20-3.25]), obesity (HR, 1.54 [1.04-2.30]), diabetes mellitus (HR, 1.50 [1.08-2.08]), cancer (HR, 3.10 [1.95-4.92]), glucocorticoid use (HR, 3.14 [2.45-4.02]), transplantation (HR, 1.38 [1.08-1.77]), and unvaccinated status (HR, 2.37 [1.82-3.08]). In conclusion, COVID-19 can increase the risk of CMV disease. Clinicians should be aware of the risk of CMV disease in patients with COVID-19.

Long-term risk of herpes zoster following COVID-19: A retrospective cohort study of 2 442 686 patients

The long-term risk of herpes zoster (HZ) after recovery from a SARS-CoV-2 infection is unclear. This retrospective cohort study assessed the risk of HZ in patients following a COVID-19 diagnosis. This retrospective, propensity score-matched cohort study was based on the multi-institutional research network TriNetX. The risk of incident HZ in patients with COVID-19 was compared with that of those not infected with SARS-CoV-2 during a 1-year follow-up period. Hazard ratios (HRs) and 95% confidence intervals (CIs) of HZ and its subtypes were calculated. This study identified 1 221 343 patients with and without COVID-19 diagnoses with matched baseline characteristics. During the 1-year follow-up period, patients with COVID-19 had a higher risk of HZ compared with those without COVID-19 (HR: 1.59; 95% CI: 1.49-1.69). In addition, compared with the control group patients, those with COVID-19 had a higher risk of HZ ophthalmicus (HR: 1.31; 95% CI: 1.01-1.71), disseminated zoster (HR: 2.80; 95% CI: 1.37-5.74), zoster with other complications (HR: 1.46; 95% CI: 1.18-1.79), and zoster without complications (HR: 1.66; 95% CI: 1.55-1.77). Kaplan-Meier curve analysis (log-rank p < 0.05) results indicated that the risk of HZ remained significantly higher in patients with COVID-19 compared with those without COVID-19. Finally, the higher risk of HZ in the COVID-19 cohort compared with that in the non-COVID-19 cohort remained consistent across subgroup analyses regardless of vaccine status, age, or sex. The risk of HZ within a 12-month follow-up period was significantly higher in patients who had recovered from COVID-19 compared with that in the control group. This result highlights the importance of carefully monitoring HZ in this population and suggests the potential benefit of the HZ vaccine for patients with COVID-19.