Comparison of plasma inflammatory biomarkers between MIS-C and potentially serious infections in pediatric patients.

Background: Inflammatory biomarkers have been used for the diagnosis and management of multisystemic inflammatory syndrome in children (MIS-C). We aimed to compare the clinical and laboratory findings of MIS-C cases versus other febrile cases cataloged as potentially suspected bacterial infection (non-MIS-C).

Methods: Unicentric ambispective observational cohort study (June 2020-February 2022). We analyzed demographics, clinical symptoms and laboratory findings in MIS-C cases and in non-MIS-C cases with febrile processes of patients under 15 years of age admitted to hospital.

Results: We enrolled 54 patients with potential suspected bacterial infection and 20 patients with MIS-C for analysis. Fever (100%), gastrointestinal (80%) and mucocutaneous findings (35%) were common in MIS-C patients, also hypotension (36.8%) and tachycardia (55%). Laboratory findings showed significantly elevated proBNP (70%), ferritin (35%), D-dimer (80%) and lymphopenia (55%) and thrombocytopenia (27.8%) in MIS-C cases. IL-6 values were high in non-MIS-C patients (92.6%).

Conclusions: In the management of MIS-C patients, the dynamic monitoring of proBNP, ferritin, D-dimer, lymphocytes and platelets could be helpful to pediatricians to effectively evaluate the progress of MIS-C in the early phases, not IL-6 values. The applicability of the IL-6 level as a prognostic biomarker in MIS-C patients may require closer discussion. In addition, the optimal laboratory markers, as stated in our study, can help establish a biomarkers model to early distinguish the MIS-C versus non-MIS-C in patients who are admitted to febrile syndrome.