Introduction, The study of COVID-19 and its consequences remains an urgent task, as the risk of emergence of new dangerous strains of SARS-CoV-2 and other infectious agents because a similar mechanism of action is still relevant. The present study contributes to the understanding of the the immune system function during COVID-19 and its results may be useful for practical public health care. Aim - to determine the prognostic potential of sCD40L, MDC, FKN, IP-10 and VEGF in relation to the severity and outcome in COVID-19. Material and methods. Serum samples were collected from 1614 patients with various severity of COVID-19, including 302 fatal patients. Levels of sCD40L, MDC, FKN, IP-10 and VEGF were determined in the samples by multiplex immunofluorescence analysis. Results. In severe and fatal disease cases, MDC and sCD40L concentrations were significantly lower and IP-10 concentrations were higher than in cases with milder forms of COVID-19. The significance of differences in sCD40L levels disappears when analysing data from patients without comorbid load (Charlson index < 2). FKN concentration on admission to hospital was significantly lower in those cases that developed a cytokine storm. Conclusion. MDC and IP-10 levels can be used as prognostic markers of outcome in COVID-19. FKN level has prognostic potential concerning development of the cytokine storm in the early stages of the disease.