Immune responses in COVID-19 patients: Insights into cytokine storms and adaptive immunity kinetics

Protein disulphide isomerase A4 as a potential biomarker for coronavirus disease 2019: Correlation with cytokine profiles and disease progression

This study investigated the role of protein disulphide isomerase A4 (PDIA4) in the pathogenesis of coronavirus disease 2019 (COVID-19), focusing on its relationship with disease severity and potential as a biomarker. We analysed a cohort of adult COVID-19 patients with varying disease severity, grouped by vaccination status. Serum levels of PDIA4 and cytokines (interleukin [IL]-6, interferon gamma inducible protein-10 [IP-10], IL-16, monocyte chemoattractant protein-1 [MCP-1], and platelet-derived growth factor-BB [PDGF-BB]) were measured using enzyme-linked immunosorbent assay and compared among patients with different disease severities. Statistical analyses were performed to assess the correlation between PDIA4 levels, disease severity, and inflammatory markers. Unvaccinated COVID-19 patients with pneumonia had significantly higher PDIA4 levels than those without pneumonia (517.94 ± 264 vs. 284.86 ± 2.24; p = 0.0022). Although unvaccinated patients requiring oxygen support exhibited higher PDIA4 levels than those not requiring oxygen (519.30 ± 269.67 vs. 420.89 ± 240.49; p = 0.4825), the difference was not statistically significant. No significant difference was observed in the PDIA4 levels between unvaccinated patients with and without respiratory failure. Levels of PDIA4 were positively correlated with the levels of IL-16, MCP-1, IP-10, and IL-6 (correlation coefficients: 0.28-0.62), although this correlation was weaker or absent in vaccinated patients. Our findings suggest that PDIA4 is associated with COVID-19 severity and may serve as a potential biomarker of disease progression. Further studies are needed to elucidate the mechanisms by which PDIA4 influences the immune response and assess its potential for therapeutic exploration in COVID-19.

The impact of the mRNA COVID-19 vaccine on the Th-like cytokine profile in individuals with no history of COVID-19: insights into autoimmunity targeting heat shock proteins

Although some reports suggest that COVID-19 vaccination may exacerbate existing autoimmune diseases or trigger new-onset cases, a definitive causal relationship between the vaccines and these conditions has not been established. Several potential mechanisms have been proposed to explain this association, including: (i) molecular mimicry, which refers to a structural similarity between SARS-CoV-2 and human antigens; (ii) bystander activation, involving both B and T lymphocytes; and (iii) the effects of adjuvants. In this study, we investigated whether two doses of the mRNA COVID-19 vaccine influenced blood cytokine levels associated with major T helper cell populations, which are known to play a significant role in autoimmunity and revisited the role of the humoral autoimmune response directed against heat shock proteins (Hsps) in individuals with no history of COVID-19. While no significant differences were found in the levels of IFN-γ, IL-6, IL-22, IL-4, IL-8, IL-10, and IL-17A, between vaccinated and unvaccinated people, several positive correlations were observed between serum cytokine levels and circulating autoantibodies directed against self-Hsps exclusively in vaccinated individuals. These findings suggest that the mRNA COVID-19 vaccine does not impact cytokines involved in the pathogenesis of autoimmune diseases. Further research is required to evaluate the safety of COVID-19 vaccination in patients with autoimmune conditions, particularly those in whom anti-Hsps autoantibodies are suspected to contribute to disease development.

Exploring the Contrasts and Similarities of Dengue and SARS-CoV-2 Infections During the COVID-19 Era

Extensive research has been conducted on the SARS-CoV-2 virus in association with various infectious diseases to understand the pathophysiology of the infection and potential co-infections. In tropical countries, exposure to local viruses may alter the course of SARS-CoV-2 infection and coinfection. Notably, only a portion of the antibodies produced against SARS-CoV-2 proteins demonstrate neutralizing properties, and the immune response following natural infection tends to be temporary. In contrast, long-lasting IgG antibodies are common after dengue virus infections. In cases where preexisting antibodies from an initial dengue virus infection bind to a different dengue serotype during a subsequent infection, there is a potential for antibody-dependent enhancement (ADE) and the formation of immune complexes associated with disease severity. Both SARS-CoV-2 and dengue infections can result in immunodeficiency. Viral proteins of both viruses interfere with the host's IFN-I signaling. Additionally, a cytokine storm can occur after viral infection, impairing a proper response, and autoantibodies against a wide array of proteins can appear during convalescence. Most of the reported autoantibodies are typically short-lived. Vaccines against both viruses alter the immune response, affecting the course of viral infection and enhancing clearance. A comprehensive analysis of both viral infections and pathogenicity is revisited to prevent infection, severity, and mortality.