Macrophage activation syndrome (MAS) is an acute', potentially fatal complication of pediatric rheumatic disorders, which is seen most commonly in systemic juvenile idiopathic arthritis (sJIA).
Because MAS is a serious condition that can follow a rapidly fatal course, its prompt recognition and an immediate therapeutic intervention are critical. However, diagnosis of MAS can be difficult and hard to distinguish from “confusable” conditions such as sJIA flare and sepsis-like syndromes.

Aims of the project
The project is aimed to develop a new set of classification criteria for MAS occurring in the context of sJIA, based on the combination of expert consensus and analysis of real patient data. Well validated and widely agreed upon criteria for MAS will be useful to enable timely diagnosis and correct classification of patients, to assist in the evaluation of different therapeutic approaches, and to facilitate communication among specialists in different fields who are interested in reactive hemophagocytic syndromes.

Project steps
The project is meant to be conducted through the following 4 steps: 1) a Delphi survey among international pediatric rheumatologists; 2) a large-scale data collection of patients with sJIA-associated MAS and patients with conditions potentially confusable with MAS (sJIA flare and sepsis-like syndromes); 3) a consensus conference of physicians with specific expertise in MAS; 4) a prospective validation of the new criteria.
The first and the second phases of the project have already been completed and the results of the Delphi survey have been published.
Toward the analysis of data obtained from the data-collection phase we evaluated the ability of each clinical, laboratory, and histopathologic feature to discriminate patients with MAS from patients with “confusable” conditions. Altogether, these analyses suggested a core set of criteria and the combinations of features with the greatest classifcation accuracy for MAS.

Objectives to be accomplished
Consensus conference.The third step of the project consists in a consensus conference, among pediatric rheumatologists and pediatric hemato-oncologists with specific expertise in MAS, which will be held in Genoa on 21-22 march 2014.The overall goal of the meeting will be to decide upon the classification criteria for MAS using a combination of statistical and consensus formation techniques.
Prospective validation of the new classification criteria.Prospective validation of the criteria set promulgated by the consensus conference will be conducted by asking international pediatric rheumatologists to test the criteria in their patients with MAS complicating sJIA.