Therefore, the aim of our proof-of-concept study was to assess the serum levels of the well-known immunoregulatory cytokine IL-6 but also the aforementioned “bi-directional” molecules, among them ADA, as well as both soluble TNF receptors, and the aim was also to analyze their possible association with some clinical parameters in small group of children with COVID-19 and PIMS. Here, ADA is linked to COVID-19.