To identify clinical and laboratory predictors for early macrophage activation syndrome (MAS) associated with systemic juvenile idiopathic arthritis (sJIA).
This is a retrospective cohort study of 149 sJIA patients, of which 27 patients had 31 episodes of MAS. We evaluated the clinical and laboratory features of sJIA patients with MAS and compared them with those without MAS. We focused our analysis on the overall process of MAS development, especially MAS onset.
As shown in previous studies, we found a high percentage of fever, absence of arthritis, and central nervous system dysfunction at MAS onset in our study cohort. We also found that 35% MAS patients had hypotension although not shock, and 22.6% MAS patients had gastrointestinal involvement at MAS onset. Compared with MAS patients without hypotension, MAS patients with hypotension had higher ICU admission, presented with more arthritis, serositis, pneumonia, and gastrointestinal involvement, and had higher white blood cell and absolute neutrophil counts and serum bilirubin levels, and lower serum total protein. We confirmed laboratory markers such as platelet counts, lactate dehydrogenase, and aspartate aminotransferase can help to identify early MAS and that ferritin: ESR ratio of around 20.0 had a high diagnostic sensitivity and specificity for MAS. In addition, we discovered that the combination of interferon (IFN)-γ >17.1 pg/mL and interleukin (IL)-10 >7.8 pg/mL appeared to be a good cytokine pattern for the recognition of MAS onset.
Sudden hypotension, elevated ferritin: ESR ratio, and the cytokine pattern of significantly increased IFN-γ and IL-10 levels are important markers for early identification of MAS in addition to the traditional characteristics of sJIA-associated MAS.