Stress proteins as predictors of COVID-19 outcomes

SARS-CoV-2 in patients with cancer: possible role of mimicry of human molecules by viral proteins and the resulting anti-cancer immunity

A few reports suggest that molecular mimicry can have a role in determining the more severe and deadly forms of COVID-19, inducing endothelial damage, disseminated intravascular coagulation, and multiorgan failure. Heat shock proteins/molecular chaperones can be involved in these molecular mimicry phenomena. However, tumor cells can display on their surface heat shock proteins/molecular chaperones that are mimicked by SARS-CoV-2 molecules (including the Spike protein), similarly to what happens in other bacterial or viral infections. Since molecular mimicry between SARS-CoV-2 and tumoral proteins can elicit an immune reaction in which antibodies or cytotoxic cells produced against the virus cross-react with the tumor cells, we want to prompt clinical studies to evaluate the impact of SARS-CoV-2 infection on prognosis and follow up of various forms of tumors. These topics, including a brief historical overview, are discussed in this paper.

Autoantibodies to heat shock protein 60, 70, and 90 are not altered in the anti-SARS-CoV-2 IgG-seropositive humans without or with mild symptoms

Highly conserved heat shock proteins (Hsps) are localized in the cytoplasm and cellular organelles, and act as molecular chaperones or proteases. Members of Hsp families are released into the extracellular milieu under both normal and stress conditions. It is hypothesized that the severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) has the potential to elicit autoimmunity due to molecular mimicry between human extracellular Hsps and immunogenic proteins of the virus. To confirm the above hypothesis, levels of circulating autoantibodies directed to the key human chaperones i.e., Hsp60, Hsp70, and Hsp90 in the anti-SARS-CoV-2 IgG-seropositive participants have been evaluated. Twenty-six healthy volunteers who got two doses of the mRNA vaccine encoding the viral spike protein, anti-SARS-CoV-2 IgG-positive participants (n = 15), and healthy naïve (anti-SARS-CoV-2 IgG-negative) volunteers (n = 51) have been included in this study. We found that the serum levels of anti-Hsp60, anti-Hsp70, and anti-Hsp90 autoantibodies of the IgG, IgM, or IgA isotype remained unchanged in either the anti-COVID-19-immunized humans or the anti-SARS-CoV-2 IgG-positive participants when compared to healthy naïve volunteers, as measured by enzyme-linked immunosorbent assay. Our results showing that the humoral immune response to SARS-CoV-2 did not include the production of anti-SARS-CoV-2 antibodies that also recognized extracellular heat shock protein 60, 70, and 90 represent a partial evaluation of the autoimmunity hypothesis stated above. Further testing for cell-based immunity will be necessary to fully evaluate this hypothesis.