Covid-19 linked diseases in children causing changes in blood cells: Study

A newly described disease occurring in children and linked to Covid-19 is associated with significant changes in the immune system's white blood cells, according to a study that may allow doctors to better assess their young patients' condition and predict their resistance to current treatments.

Paediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 infection (PIMS-TS) is a new disease which shares some features with Kawasaki Disease -- an inflammation of blood vessels mostly affecting children under five -- as well as toxic shock syndrome.

Researchers, led by those at the University of Birmingham in the UK, examined blood samples from children admitted with these diseases to Birmingham Children's Hospital during the country's coronavirus lockdown.

The yet-to-be peer-reviewed findings, published in the preprint platform medRxiv, described large changes in the monocytes -- a type of white blood cell -- in patients with PIMS-TS and Kawasaki's Disease.

"Our study is the first to reveal that Kawasaki's Disease and PIMS-TS are both characterised by profound changes in the numbers of monocytes and their genetic make-up," said study co-lead author Graham Taylor from the Institute of Immunology and Immunotherapy at the University of Birmingham.

"Our results require confirmation in a larger patient cohort, but the changes we have observed are likely to be highly relevant -- potentially allowing us to predict the disease resistance of children with PIMS-TS and Kawasaki's Disease, as well as identifying alternative therapies for both diseases," Taylor said.

In the study, the researchers recruited nine children with signs of PIMS-TS presenting at Birmingham Women and Children's Hospital from April to May 2020.

Seven of them, according to the scientists, met the UK's Royal College of Paediatrics and Child Health case definition of PIMS-TS, and were SARS-CoV-2 antibody positive, while two children fulfilled the criteria for diagnosis of Kawasaki's Disease, and were SARS-CoV-2 antibody negative.

According to Barney Scholefield, Paediatric Intensive Care consultant from Birmingham Women and Children's Hospital NHS Foundation Trust, "Sick children admitted to intensive care units globally with PIMS-TS require urgent research to understand this rare but potentially life changing condition."

"The University of Birmingham team have rapidly performed novel, in-depth analysis to identify potential targets for treatment. The cutting edge approaches used will help future children affected by Covid19," Scholefield said.

The scientists identified large changes in the the immune system's monocyte cells among children with both diseases.

While the novel coronavirus usually causes only mild respiratory infection in children and young adults, in rare cases, they may subsequently develop PIMS-TS - presenting with fever, inflammation and evidence of organ failure resulting in cardiac dysfunction, hypotension and life-threatening shock, the study noted.

According to the researchers, PIMS-TS shares clinical features with Kawasaki's Disease.

They said this disease can cause inflammation of heart muscle if left untreated, and is the leading cause of acquired heart disease in children in developed nations.

Given the recent emergence of PIMS-TS, the scientists said very little is known about the immunological processes driving the condition, and whether these are similar or different to Kawasaki's Disease.