Several studies demonstrated that COVID-19 in children is a relatively mild 
disease. However, recently a more serious condition characterized by systemic 
inflammation with clinical or microbiological evidence of exposure to SARS-CoV-2 
has been described. This syndrome is now known as either "Pediatric Inflammatory 
Multisystem Syndrome temporally related with COVID-19" (PIMS-TS) (1), or 
Multisystem Inflammatory Syndrome in Children (MIS-C) (2) and is currently 
considered a rare post-COVID-19 complication which, in a minority of cases, can 
lead to death. The signs and symptoms of PIMS-TS are largely overlapping with 
the for Kawasaki disease (KD) and toxic shock syndrome (TSS) and are 
characterized, by fever, systemic inflammation, abdominal pain and cardiac 
involvement. In this study, we describe clinical and immunological 
characteristics shared by PIMS-TS, acute rheumatic fever and TSS, in order to 
provide hypotheses to direct future clinical and basic research studies.