title: Differentiating macrophage activation syndrome in systemic juvenile idiopathic arthritis from other forms of hemophagocytic lymphohistiocytosis.
abstract: OBJECTIVE
  To identify measures distinguishing macrophage activation syndrome (MAS) in systemic juvenile idiopathic arthritis (sJIA) from familial hemophagocytic lymphohistiocytosis (FHL) and virus-associated hemophagocytic lymphohistiocytosis (VA-HLH) and to define appropriate cutoff values. To evaluate suggested dynamic measures differentiating MAS in patients with sJIA from sJIA flares.
  
  
  METHODS
  In a cohort of patients referred for evaluation of hemophagocytic lymphohistiocytosis, we identified 27 patients with sJIA and MAS (MAS/sJIA) fulfilling the criteria of the proposed preliminary diagnostic guideline for the diagnosis of MAS in sJIA. Ten measures at diagnosis were compared between the MAS/sJIA group and 90 patients with FHL and 42 patients with VA-HLH, and cutoff values were determined. In addition, 5 measures were analyzed for significant change from before MAS until MAS diagnosis.
  
  
  RESULTS
  Neutrophil count and C-reactive protein were significantly higher in patients with MAS/sJIA compared with patients with FHL and patients with VA-HLH, with 1.8×10(9)/L neutrophils (sensitivity 85%, specificity 83%) and 90 mg/L C-reactive protein (74%, 89%) as cutoff values. Soluble CD25<7900 U/L (79%, 76%) indicated MAS/sJIA rather than FHL/VA-HLH. Platelet (-59%) and white blood cell count (-46%) displayed a significant decrease, and neutrophil count (-35%) and fibrinogen (-28%) showed a trend during the development of MAS. However, a substantial portion of patients had values at diagnosis of MAS within or above the normal range for white blood cells (84%), neutrophils (77%), platelets (26%), and fibrinogen (71%).
  
  
  CONCLUSIONS
  Readily available measures can rapidly differentiate between MAS/sJIA and FHL/VA-HLH. The findings substantiate that a decline of measures may facilitate the distinction of MAS from flares of sJIA.
authors: Department of Pediatric Hematology and Oncology, University Medical Center Eppendorf, Germany. k.lehmberg@uke.de
authors: Kai
authors: K
authors: Lehmberg
authors: Isabell
authors: I
authors: Pink
authors: Christine
authors: C
authors: Eulenburg
authors: Karin
authors: K
authors: Beutel
authors: Andrea
authors: A
authors: Maul-Pavicic
authors: Gritta
authors: G
authors: Janka
mesh_terms: D001171:Arthritis, Juvenile / Q000175:diagnosis* / Q000276:immunology; D015415:Biomarkers / Q000032:analysis; D002648:Child; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D051359:Lymphohistiocytosis, Hemophagocytic / Q000175:diagnosis* / Q000276:immunology; D055501:Macrophage Activation Syndrome / Q000175:diagnosis* / Q000276:immunology; D008297:Male
chemical_list: D015415:Biomarkers