Cytokine producing ability of peripheral blood cells from COVID-19 patients after unspecific in vitro stimulation

Abstract

Objective and design: Perturbations of peripheral T cell homeostasis and dysregulation of the immune response to SARS-CoV-2, especially in severely ill patients, were observed. The aim of this study was to analyze the cytokine producing ability of peripheral blood cells from severely ill COVID-19 patients upon non-specific in vitro stimulation with phytohemagglutinin (PHA). Possible associations of cytokine levels with patients’ age and gender, glucocorticosteroid therapy, as well as the trend of the inflammatory process at the time of sampling (increased or decreased) were also analyzed. Subjects and methods: The study included 23 COVID-19 patients and 17 healthy control subjects. The concentrations of selected Th1/Th2/Th9/Th17/Th22 cytokines were determined using a multi-analyte flow assay kit. Results: Our results showed that peripheral blood cells from severely ill COVID-19 patients had a much reduced ability to produce cytokines in comparison to healthy controls. When inflammation was raised, blood cells produced more IL-6 and IL-17, which led to increases of some Th17/Th1 and Th17/Th2 ratios, skewing towards the Th17 type of response. The methylprednisolone used in the treatment of patients with COVID-19 influences the production of several cytokines in dose dependent manner. Conclusion: Our results indicate that the stage of the inflammatory process at the time of sampling and the dose of the applied glucocorticosteroid therapy might influence cytokine producing ability upon non-specific stimulation of T cells in vitro.