Glycosylated Ferritin in Macrophagic Activation Syndromes

In healthy subjects, from 50 to 80 % of the serum ferritin is glycosylated \[1, 2\] . A decrease in the percentage of ferritin glycosylation can be observed in inflammatory diseases, malignancies, infections, or liver disease but is rarely less than 20% \[3 , 4\] . Percentage of glycosylated ferritin below 20% have been described in patients with adult Still's disease and haemophagocytosis lymphohistiocytic syndromes (HLH). The glycosylated ferritin has been included in the diagnostic criteria for Still's disease in adults. A cut-off of less than 20 % has a sensitivity and specificity of 72 and 69 % respectively , and 35 and 94 % when combined with a total ferritin level greater than 5 times normal value. This parameter was also suggested to be a more specific marker to confirm a diagnosis of HLH than a high ferritin level ( \> 500μg / L). However, several limitations of this parameter