382 - Response To High Dose IVIG In Multisystem Inflammatory Syndrome In Children

In February 2022, the American College of Rheumatology (ACR) updated its guidance for multisystem inflammatory syndrome in children (MIS-C). The treatment recommendation is to use intravenous immunoglobulin (IVIG) at 2 grams/kg with a maximum dose of 100 grams based on a moderate level of consensus among the task force members. To date, there are no studies comparing the response to doses of more than 100 grams in MIS-C.


Objective: The objective is to determine if there is a dose dependent response to treatment with IVIG above 100 grams.

Design/Methods:

A retrospective review was conducted of patients admitted to Loma Linda University Children’s Hospital for MIS-C from May 2020 to March 2021. Demographic, symptom, laboratory, and treatment data were systematically collected from the electronic medical record. The PRISM III score was calculated for all patients admitted to the PICU. Patients were designated non-responders if anakinra or a second IVIG dose was given. A binomial logistic regression was used to model response to the IVIG dose in univariate and multivariate analysis with and without the PRISM III score and PICU length of stay. A Fisher’s exact test was used to compare categorical variables.


Results:

There were 77 children treated for MIS-C. The median age was 9.9 years with a range of 0.25 to 17.4 years There was a total of 30 patients who initially received at least 100 grams of IVIG, of which 20 were in the PICU. All patients given at least 100 grams of IVIG received steroids concurrently. A univariate binomial regression using IVIG dose for patients admitted to the PICU showed an odds ratio of non-response was 0.98 (CI 0.94 – 1.02). The analysis is the same for all patients who received greater than 100 grams of IVIG. In a multivariate binomial regression, which included the PRISM III score, length of PICU stay and days of symptoms prior to admission, the odds ratio of non-response to IVIG was 0.98 (CI 0.92 – 1.03). Of the 10 patients who were not admitted to the PICU, only 1 failed to respond to IVIG and required anakinra. None of the patients who received more than 100 grams of IVIG were tested for hemolytic anemia but only 1 patient who received more than 1 dose of IVIG had a decline in hemoglobin.


Conclusion(s):

In this single center cohort of patients who were admitted to the PICU for MIS-C who received more than 100 grams of IVIG initially, there was no relationship between higher doses of IVIG and success in halting inflammation. This study agrees with the ACR guidance regarding the dose of IVIG in MIS-C and adds evidence to give no more than 100 grams of IVIG.