The Predictive Value of Serum IL-6 in Pediatric Critically Ill Patients with Multisystem Inflammatory Syndrome in Children (MIS-C) Associated with COVID-19

Abstract

Background Unexplained cases of fatal rapidly spreading viral pneumonia were reported in December 2019 in Wuhan, China. A novel type of coronavirus, SARS-COV-2, was isolated during the examination of patients' samples. By May 2019, the novel coronavirus has been responsible for more than 3 million infections worldwide with a case fatality rate up to 7%. Aim of the Work To evaluate the correlation between serum level of IL-6 and cases of COVID-19 and Multisystem inflammatory syndrome in children (MIS-C) progression and outcome. Patients and Methods This is a cohort study that was conducted at the Pediatric Intensive Care Unut, Ain Shams University. It included 53 patients whose median age was 6 years and ranged between 2-10 years. They were divided into 24 patients (45%) with COVID and 29 patients with MIS-C (55%). Laboratory work up done to both groups include : routine laboratory tests (CBC, CRP, ESR, serum ferritin) and measurement of serum IL-6 using ELISA (Normal values up to 7pg/ml). Results Median serum level of IL-6 was higher albeit insignificant in patients with MIS-C as compared to those with COVID (Median:72.7 pg/ml (range: 20.2-140.5 pg/ml) versus a median of 53 pg/ml (range:17.2-293.2) respectively. Serum IL 6 was significantly positively correlated with CRP, ESR and ferritin in both MIS-C and COVID patients groups (p < 0.05). Among MIS-C patients, the best cut off point of serum IL6 to predict severe course and mortality was >168.2 pg/ml, while among COVID patients, the best cut off level was slightly lower >146 pg/ml. Conclusion Systemic inflammation is a feature of COVID and MIS-C in part reflected by increased serum IL 6 and increased ESR, CRP and Ferritin. Increased serum IL 6 has excellent sensitivity to severe MIS-C and COVID with good specificity. It's low predictive value for mortality suggest it's limited value to predict the outcome in severe cases as indicated by the multiple factors interacting in the disease course.