Persistent Immune and Clotting Dysfunction Detected in Saliva and Blood Plasma after COVID-19

Abstract

A growing number of studies indicate that coronavirus disease 2019 (COVID-19) is associated with inflammatory sequelae, but molecular signatures governing the normal vs. pathologic convalescence process have not been well-delineated. We characterized global immune and proteome responses in matched plasma and saliva samples obtained from COVID-19 patients collected between 4-6 weeks after initial clinical symptoms resolved. Convalescent subjects showed robust IgA and IgG responses and positive antibody correlations between matched saliva and plasma samples. However, global shotgun proteomics revealed persistent inflammatory patterns in convalescent samples including dysfunction of salivary innate immune cells and clotting factors in plasma (e.g., fibrinogen and antithrombin), with positive correlations to acute COVID-19 disease severity. Saliva samples were characterized by higher concentrations of IgA, and proteomics showed altered pathways that correlated positively with IgA levels. Our study positions saliva as a viable fluid to monitor immunity beyond plasma to document COVID-19 immune, inflammatory, and coagulation-related sequelae.

Proteomic analysis of sialoliths from calcified, lipid and mixed groups as a source of potential biomarkers of deposit formation in the salivary glands

“…Fibrinogen is allowed to protect the neutrophils against the cytotoxic effects caused by, for example, the presence of bacteria and, consequently, the formation of neutrophil extracellular traps is delayed. The reduced level of fibrinogen alpha chain can cause the abnormal activity of neutrophils, leading to the formation of NETs [ 89 , 90 ]. Non-unique but down-regulated in many samples was eosinophil cationic protein (RNASE3) and immunoglobulin gamma-1 heavy chain (P0DOX5), pointing to the disturbance in the immune response.…”