Systemic juvenile idiopathic arthritis (SoJIA) is one of the most common underlying etiologies to the macrophage activation syndrome (MAS).
An worldwide expert consortium has developed new criteria for the classification of MAS in SoJIA patients . The proces involved 28 experts who classified 428 case profiles from 161 SoJIA patients. The final criteria were established in a consensus conference.
Overall there was consensus on 91.4% of the cases. From a total of 982 criteria, the panel settled on the final criteria that had a sensitivity of 0.73 and a specificity of 0.99 in In validation studies. We have developed a set of classification criteria for MAS complicating systemic JIA and provided preliminary evidence of its validity. Use of these criteria will potentially improve understanding of MAS in systemic JIA and enhance efforts to discover effective therapies, by ensuring appropriate patient enrollment in studies.