Research published today in Nature Medicine examines the clinical characteristics of paediatric inflammatory multisystem syndrome (PIMS-TS).

PIMS-TS is a rare syndrome which has emerged in a small number of children during the COVID-19 pandemic. The condition causes severe inflammation in blood vessels and can lead to heart damage.

A team from King’s and the Evelina London Children’s Hospital analysed blood samples from 25 children who had PIMS-TS and compared these to healthy children. These samples were tested from these children at different stages of the disease, from the acute phase upon admission to hospital, through to their outpatient appointments.

The study showed that in the acute stage of PIMS-TS, children have raised levels of molecules called cytokines, and reduced levels of white blood cells called lymphocytes. They saw that by the time the children had recovered, the immune system changes had gradually returned to normal.

Although the cohort is small, this is the first evidence to show the role of the immune system in the disease. It provides vital evidence for future research and will indicate what treatments may help patients with the condition.

It also confirms that PIMS-TS affects the body in a different way to other known conditions, such as Kawasaki disease, and has been identified as a new syndrome.

He added: “Clinically, these children respond to treatments that calm the immune system such as corticosteroid and immunoglobulins. Although there are similarities to existing conditions such as Kawasaki Disease, these clinical and immunological changes that we observe imply that PIMS-TS is a distinct illness associated with SARS-Co-V-2 infections.”