Oxidative stress profile and auto-antibodies production in Tunisian patients with COVID-19.

The clinical evidence, complications and the pathogenesis of COVID-19 are not clearly understood. In COVID-19 patients, cellular immune response biomarkers and oxidative stress parameters have been used as gravity markers. Indeed, oxidative stress has been proposed to play an essential role in the genesis of COVID-19. In the present research, we investigated lipid peroxidation, protein oxidation, superoxide dismutase activity and the production of auto-antibodies against superoxide dismutase, in the blood of Tunisian patients with corona virus. To evaluate lipid peroxidation, plasma malondialdehyde and conjugated dienes, have been determined in 69 corona virus patients and 30 controls. To determine protein oxidation the thiol level was measured. Plasma superoxide dismutase activity has been measured in 30 corona virus patients and 30 controls on one hand. Utilizing a standard enzyme-linked immunosorbent assay, the level of immunoglobulin G (IgG), and M (IgM) directed against superoxide dismutase was evaluated. To investigate the implication of auto-antibody production in COVID-19 patients in the generation of oxidative stress, a correlation study between auto-antibodies production and oxidative stress parameters was performed. High levels of both malondialdehyde and conjugated dienes were found in the plasma of patients (p < 0.001, respectively). Protein oxidation was confirmed by the high level of thiol (p < 0.001). Superoxide dismutase activity was not significantly lower in COVID-19 patients (p > 0.05). The level of immunoglobulin G (IgG), and M (IgM) directed against superoxide dismutase is significantly higher in COVID-19 patients than in control group (p < 0.001 respectively). Statistical analyses have demonstrated a positive correlation between superoxide dismutase activity and IgM and IgG isotypes antibodies level against superoxide dismutase (p < 0.001). A strong positive correlation was observed between IgG and malondialdehyde level in all cases (r = 0.368; p ≤ 0.01). In addition, a significant positive correlation was noted between IgM and malondialdehyde (r = 0.290; p = 0.024). Similarly, two significant positive relationship was found between IgG / conjugated dienes (r = 0.356; p = 0.005) and between IgM / conjugated dienes (r = 0.285; p = 0.027).