Most patients known to be infected with SARS-CoV-2 appear to exhibit a typical immune response. Various immune cells and cytokines cause a mild inflammatory state in a normal immune response. The first cytokines released are interleukin-1 (Beta) and tumor necrosis factor-alpha. Cells of the innate immune system-neutrophils, monocytes, macrophages, and natural killer (NK) cells are also associated with the immune response. These cells directly attack the invading virus and release additional cytokines (e.g., Interleukin-6 (IL-6)). IL-6 is essential for invoking T, B, and T helper (Th) cells.7
In a study conducted by the Mayo Clinic8, most suspected female long COVID patients had a sharp rise in IL-6. These patients had high IL-6 levels up to three months after being infected with SARS-CoV-2. IL-6 has been associated with fatigue and sleep problems and causes inflammation.
Anti-inflammatory cytokines help to turn off the pro-inflammatory response and return the immune system to a nonactivated but vigilant state. Cytokine Storm Syndrome is the deadliest manifestation of an abnormal immunological response, which can result in significant tissue damage in various body organ systems. A Cytokine Storm is now associated with the severe increase of cytokines in COVID-19 caused by SARS-CoV-2. Although the concept of a cytokine storm and the biological consequences of cytokine overproduction are not yet completely understood, one important molecular factor associated with overproduction is the kinetics of cytokine and chemokine gene expression.9
7. Turgeon, M. (2022). Immunology and serology in laboratory medicine. (7th ed.).8. Ganesh, R., Grach, S., & Bierle, D. (2021). Post-COVID symptoms: Women differ distinctly from men. Mayo Clinic, https://newsnetwork.mayoclinic.org/discussion/post-covid-symptoms-women-differ-distinctly-from-men/. 9. Turgeon, M. Immunology and serology in laboratory medicine. (7th ed.).