Approaches to correction of immune system disturbances in post-COVID patients

SARS-CoV-2 virus can induce immune system disorders in post-COVID patients, which may persist for an extended period beyond the acute phase of the disease. Therefore, the search for immunocorrection approaches to address the detected disorders is a significant challenge in clinical immunology. This study aimed to investigate the impact of a synthetic peptide derived from the active center of GM-CSF on the immune system of patients with post-COVID immunopathological syndrome. A total of 21 patients who previously suffered with SARS-CoV-2 infection were included in the study. Flow cytometry was used to analyze various immune cell populations, including panleukocyte markers for gated lymphocytes (CD45+ and CD46+), T lymphocytes (CD3+), helper inducers (CD3+, CD4+), cytotoxic T lymphocytes (CD3+, CD8+), TNK cells (CD3+, CD56+), natural killer cells (CD3-, CD56+), B lymphocytes (CD3-, CD19+), activated helper cells (CD3+, CD4+, CD25+), and activated T lymphocytes (CD3+, HLA-DR). Moreover, IgA, IgM, IgG antibodies specific to SARS-CoV-2, phagocytosis and NBT activity of neutrophils, and complement fragments C1q, C3a, and C5a were assessed. The results demonstrated that topical application of the synthetic peptide derived from the active center of GM-CSF (Acegram-spray) upon mucous membranes significantly influenced the functional bactericidal activity of neutrophils (NBT-activity), increased the percentage of T helper cells, and elevated the C3a complement fragment. These findings indicate that the synthetic peptide primarily affects innate immunity factors. However, no significant differences were observed in other immune system parameters. Therefore, the development of therapeutic approaches for post-COVID patients with impaired immune systems may require a search for additional immunomodulators that target T, B, and NK cells. Further research is needed to explore the effects of various immunomodulators on the immune system of post-COVID patients.