Klocperk et al. described few differences between patients with PIMS-TS and healthy post-COVID-19 children, where children with this complication were characterized with elevated IFN-γ activity, increased serum cytokine B cell activating factor (BAFF) and decreased proliferation-inducing ligand (APRIL) concentration [18]. The gene discussed is TNFSF13B; the disease is COVID-19.