Levels of Interleukin-6, STAT3, and NF-κB Activation in the Post-Covid Period

IL-6 (interleukin 6), STAT3 (signal transducer and activator of transcription 3) and NF-κB (nuclear factor-κB) are the main factors causing cytokine storm in severe cases of COVID-19. The aim of the work was to establish the levels and activity of NF-κB, IL-6, and STAT3 in the post-COVID period (2024/2025) in diabetic patients who had COVID-19 in 2020–2022 compared to the pre-COVID (2018/2019) period. Plasma and blood mononuclear cells were used in the studies. The amount of IL-6 and STAT3 was determined by enzyme-linked immunosorbent assay and NF-κB activation by Western blotting. The amount of IL-6 in the blood plasma of diabetic patients who recovered from COVID-19 in 2020–2022 was higher than in healthy individuals and diabetic patients who did not have COVID-19. The highest level of STAT3 in the blood plasma is observed in diabetic patients who are guaranteed not to have COVID-19. In patients who have recovered from COVID-19, the amount of the factor is noticeably reduced. In the blood of diabetic and COVID-19 patients who took insulin, the amount of STAT3 increases. Determination of the expression of phospho-IKK and IκB in the blood mononuclear cells of patients showed an almost complete absence of phospho-IKK in patients who did not have COVID-19 and a high level of expression of this kinase in patients who recovered from COVID-19. The opposite pattern was observed for the NF-κB inhibitor, IκB. Thus, in patients who have recovered from COVID-19, activation of NF-κB is observed, which may be associated with inflammatory processes.