Multifunction inflammatory syndrome in children (IIA-C) is a serious condition associated with a recent infection COVID-19th The syndrome is rare and it remains unclear how the viral infection leads to MIS-C and why it only develops in some children.
One of the hypotheses was that children with MIS-C could cause an abnormal response of T-cells — immune cells that help the body fight viral infections — to coronavirus, which causes inflammation.
However, abnormal T cell responses to the virus do not appear to be the cause of MIS-C, researchers at the University of California, San Diego School of Medicine said in a study published Oct. 2, 2021, in the European Journal of Immunology.
All children with MIS-C who participated had normal T-cell responses to COVID-19 virus, comparable to children and adults who recovered from COVID-19 without MIS-C. Children with clinically similar, but unrelated inflammatory condition called Kawasaki disease have also been the control group.
“Given the rarity of MIS-C and Kawasaki disease, we were fortunate to have a relatively large group of patients in this study — one that is only possible in this region because of early interventions by UC San Diego, Rady Children’s Hospital, and our Disease Research Center. Kawasaki, “said the author of higher Alessandra Franco, Doctor of medicine, associate professor of pediatrics at the Medical Faculty of UC San Diego. “This should be seen as a preliminary observation, but we believe that our study adds more and more evidence about how children respond to the virus COVID-19”.
The team compared responses to pieces of COVID-19 virus with T cells isolated from 11 children with MIS-C in two control groups: 1) two children and five adults who recovered from previous COVID-19 infections without MIS-C and 2) 10 children with Kawasaki disease.
They found that nine out of 11 children with MIS-C had T cells that specifically recognized the COVID-19 virus. But these T cell responses were not associated with disease severity or age. Their T cells functioned similarly to children and adults who had a previous infection with COVID-19 but not MIS-C.
When examining additional children with MIS-C, the group found that these patients had fewer other immune cells, such as tolerogenic myeloid dendritic cells, compared with children without MIS-C. These cells reduce inflammation and are especially numerous in children. Fewer of these cells could help develop MIS-C, Franco said.
Franco and team then plan to study how T-cell memory develops in children with MIS-C and how their immune system normalizes during recovery. They also hope to compare T cell dynamics in vaccinated and unvaccinated children.
Symptoms of MIS-C may include abdominal pain, bloodshot eyes, chest pain, headaches, rashes, and vomiting. Parents should seek emergency medical attention if the child has difficulty breathing, confusion, inability to stay awake, or blue skin. MIS-C is treated with supportive care such as fluids and anti-inflammatory drugs. Some children with MIS-C may need treatment in an intensive care unit.
According to the Centers for Disease Control and Prevention, parents are the best way to protect their children from MIS-C by taking measures to prevent the household from receiving the virus that causes COVID 19, such as masking, avoiding congestion and vaccinations for those who are eligible.
Co-authors include: Li-En Hsieh, Chisato Shimizu, Nanda Ramchandar, Elizabeth Moreno, Adriana H. Tremoulet, Jane C. Burns, UC San Diego; Alba Grifoni, John Sidney, La Jolla Institute of Immunology; Hiroko Shike, Penn State Milton S. Hershey Medical Center.
Funding for this research was contributed in part by the National Institutes of Health (RO1AI43586, 75N9301900065, 3R01HL140898-03S1, and 1R61HD105590 scholarships), the San Diego Medical School at the Middle Arthritis Resource Center, and the Marilyn and Gordon Macklin Foundation.
Disclosure: The La Jolla Institute of Immunology has filed patent protection for various aspects of COVID-19 vaccine design and identification of specific epitopes.