Combination regimen proves effective for multisystem inflammatory syndrome in children

July 26, 2021
Dr. Elizabeth Mack with a pediatric patient
Dr. Elizabeth Mack with a pediatric patient

A team of pediatricians at MUSC Children’s Health contributed to a nationwide study of effective treatments for multisystem inflammatory syndrome (MIS-C), a novel COVID-19-associated disease found in children and adolescents. The results of the study, published in the New England Journal of Medicine, show that a combination of steroids and intravenous immunoglobulin (IVIG) is effective against MIS-C.

MIS-C affects patients who are younger than 21 years old. It is associated with a positive COVID-19 test or a history of exposure or infection within a month. The syndrome causes the immune system to flare up, leading to fever and inflammation. MIS-C can affect anywhere in the body, including the cardiovascular, respiratory, renal, neurological and dermatological systems. For a diagnosis of MIS-C, two organ systems must be involved.

Due to the novelty of the disease, treatment plans have been only recently established.

“This is literally a brand-new disease, and we have been able to participate in developing the science,” said Elizabeth Mack, M.D., pediatric critical care physician and principal investigator for the MUSC site for the study.

"The kids treated upfront with both IVIG and steroids have better cardiovascular outcomes.”

-- Dr. Elizabeth Mack

The study was funded by the Centers for Disease Control and Prevention and was conducted at 58 children’s hospitals across the nation, including the MUSC Shawn Jenkins Children’s Hospital. The 518 patients enrolled in the study are children and adolescents who have or have had MIS-C.

The study describes the outcomes associated with treating MIS-C with IVIG alone or in combination with steroids. The results show that the use of the combination therapy is effective against MIS-C.

Once introduced via a vein, IVIG, a type of protein, modulates the immune system. Steroids are hormones that can also regulate the immune system.

“In this case, we're trying to calm down the wildly inflamed immune system,” explained Mack.

To evaluate the effectiveness of the treatment, the researchers turned to echocardiograms and heart ultrasounds to look at cardiovascular outcomes. The cardiovascular system is one of the organ systems most frequently affected by MIS-C.

“The kids treated upfront with both IVIG and steroids have better cardiovascular outcomes,” said Mack.

“This is literally a brand-new disease, and we have been able to participate in developing the science.”

-- Dr. Elizabeth Mack

The study is ongoing and will use blood tests and patient interviews to evaluate physical activity and functional outcomes after six months.

The MIS-C team at MUSC Children’s Health provided the depth of subspecialty expertise and clinical experience needed to make contributions to this study, which has identified a much-needed therapy for MIS-C.

“It really requires a high level of networking and attention to science as it comes out to be able to provide the best therapy,” said Mack.

Even though the novelty of MIS-C was part of the challenge, it also provided the multidisciplinary health care team with an opportunity to learn and to provide children with solutions to a new problem.

“I loved seeing learners, including myself, engaged in developing science and answers to hard novel questions,” said Mack.