The effect of post-covid syndrome on the cytokine cascade in patients with type 2 diabetes mellitus

With the increasing prevalence of type 2 diabetes, it is of interest to study the characteristics of the immunological status in this category of patients. According to modern data, in type 2 diabetes, a pro-inflammatory type of immune response is formed with an imbalance between T-helper 1 (Th1), T-helper 2 (Th2), T-helper 17 (Th17) types and T-regulatory cells (Treg). The COVID-19 pandemic makes a certain contribution to changes in the immune response in patients with type 2 diabetes mellitus, since in patients who have had coronavirus infection, significant changes in the composition of circulating immune cells are observed: the proportion of Th17 increases and the number of Tregs decreases. This study is devoted to identifying the features of the cytokine cascade in patients with type 2 diabetes mellitus, depending on the presence of a confirmed history of SARS-CoV-2 infection. The study included 75 patients with type 2 diabetes, in 36 of them the diagnosis was verified in the post-Covid period. The study was conducted at least 6 months after pneumonia caused by SARS-CoV-2 infection. All study participants signed informed consent. The study was approved by the Independent Local Ethics Committee at the State Autonomous Institution of Regional Clinical Hospital “City Clinical Hospital No. 1” of Chelyabinsk, protocol No. 8 dated 04/11/2022, on the basis of which these studies were conducted. Using the multiplex assessment method, the concentrations of 15 cytokines in the blood serum were assessed in patients: GM-CSF, IFNγ, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12 (p70), IL-13, IL-17A, MIP-1β, TNFα. The results obtained during the study showed not only a change in the number of cytokines, but also a change in the balance of pro- and anti-inflammatory cytokines, cytokines that regulate forms of development of acquired immunity, in the group of patients with type 2 diabetes in the post-Covid period. In the post-Covid period, in patients with type 2 diabetes mellitus, the concentrations of cytokines secreted by Th1, Th2, Th17 cells, and Tregs sharply decreased. It has been determined that patients with type 2 diabetes mellitus after SARS-CoV-2 infection develop a functionally inferior virus-specific T-cell response, characterized by reduced or suppressed secretion of the cytokines GM-CSF, IFNγ, IL-1β, IL-2, IL -4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12 (p70), IL-13, IL-17A, MIP-1β, TNFα. A weak T-cell response may increase the likelihood of developing pathological processes associated with an inadequate response to viral antigens (including repeated infections with the SARSCoV-2 virus, exacerbation of chronic infections).