Clinical characteristics and diagnostic indicators of childhood-onset systemic lupus erythematosus complicated with macrophage activation syndrome

Different autoimmune diseases complicated by MAS exhibit variations in laboratory indicators due to the distinct characteristics of the underlying diseases. Applying uniform diagnostic criteria for MAS may lead to misdiagnosis or missed diagnoses. This study provides new laboratory indicators and cutoff values for the diagnosis of cSLE complicated with MAS. Refining the 2016 sJIA-MAS classification criteria can improve both sensitivity and specificity, thereby contributing to enhancing diagnostic accuracy and timeliness. Key Points • For other autoimmune diseases (such as SLE) associated MAS, there is a lack of widely accepted diagnostic criteria and treatment protocols. • The 2016 sJIA-MAS classification criteria demonstrated both sensitivity and specificity of 90.6% in the diagnosis of cSLE-MAS. • ROC curve analysis revealed that the following cutoff values provided optimal diagnostic differentiation for cSLE-MAS: ferritin ≥ 621.6 µg/L, aspartate aminotransferase ≥ 75.5 U/L, fibrinogen ≤ 1.96 g/L, triglycerides ≥ 2.31 mmol/L, and lactate dehydrogenase ≥ 382 U/L. • Refining the 2016 sJIA-MAS classification criteria can improve the sensitivity to 93.8% and the specificity to 96.9%.