PIMS-TS immunophenotype: description and comparison with healthy children, Kawasaki disease and severe viral and bacterial infections

A new clinical syndrome named Paediatric Inflammatory Multisystem Syndrome Temporally Associated with SARS-CoV-2 (PIMS-TS) has been described. This new disease is a leading cause of hospital and paediatric intensive care unit (PICU). It has been related to immunity dysregulation.

Prospective-retrospective observational study to describe the innate cell signature and immunophenotype of children admitted to PICU because of PIMS-TS (from March 2020 to September 2020). The immunophenotype was done through the expression analysis of these proteins of mononuclear cells: CD64, CD18, CD11a and CD11b. They were compared with previous healthy controls and children admitted to PICU because of bacterial infection, viral infection and Kawasaki disease (KD). Two hundred and forty-seven children were studied: 183 healthy controls, 25 viral infections, 20 bacterial infections, 6 KD and 13 PIMS-TS.

PIMT-TS showed the lowest percentage of lymphocytes and monocytes with higher relative numbers of CD4+ (p = .000). Monocytes and neutrophils in PIMS-TS showed higher levels of CD64 expression (p = .000). Also, CD11a and CD11b were highly expressed (p =,000).

We observed a differential cell innate signature in PIMS-TS. These findings are consistent with a proinflammatory status (CD64 elevated expression) and lymphocyte trafficking to tissues (CD11a and CD11b). More studies should be carried out to confirm our results.