Comparison of baseline laboratory findings of macrophage activation syndrome complicating systemic juvenile idiopathic arthritis and multisystem inflammatory syndrome in children.

Abstract

Recently, multisystem inflammatory syndrome in children (MIS-C) has been recognized in association with coronavirus disease 2019 as a cytokine storm syndrome. MIS-C presents with symptoms similar to Kawasaki disease and macrophage activation syndrome (MAS). We aimed to better understand this cytokine storm syndrome by comparing the initial laboratory findings of MIS-C and MAS. Patients who were diagnosed with MAS due to systemic juvenile idiopathic arthritis in our clinic between March 2002 and November 2020 and with MIS-C between 20 September and 20 October 2020 were enrolled into the study. The medical files of all patients were reviewed retrospectively. A total of 13 MAS (9 boys, 4 girls) and 26 MIS-C (16 boys,10 girls) patients were included in the study. Hemoglobin, absolute neutrophil and lymphocyte counts, C-reactive protein (CRP), ferritin, fibrinogen and lactate dehydrogenase (LDH) levels showed significant differences between the two groups (P<0.05). Patients with MAS had lower hemoglobin (10.10g/dL) and fibrinogen (2.72g/dL), but higher ferritin (17863mg/dL) and LDH (890.61U/L) at the time of diagnosis. Patients with MIS-C had higher absolute neutrophil count (12180/mm3 ) and CRP (194.23mg/dL) values, but lower absolute lymphocyte count (1140/mm3 ) at the time of diagnosis. Left ventricle ejection fraction was significantly lower in the MIS-C group in echocardiographic evaluation (P<0.001). Ferritin, hemoglobin, LDH, and fibrinogen levels were significantly changed in MAS compared with MIS-C. However, patients with MIS-C have more severe signs than MAS, such as cardiac involvement.