Low glycosylated ferritin, a good marker for the diagnosis of hemophagocytic syndrome
A very low percentage of glycosylated ferritin (<20%) has only been reported in association with adult-onset Still's disease (AOSD), a disease classically associated with hemophagocytic syndrome. We undertook this study to determine whether hemophagocytic syndrome outside the context of AOSD is also associated with a very low percentage of glycosylated ferritin. From October 2006 to September 2007, the serum level of glycosylated ferritin was determined in all consecutive patients seen in 3 departments and for whom the diagnosis of hemophagocytic syndrome was suspected. The level of glycosylated ferritin in these patients was compared with that in age- and sex-matched controls with a marked inflammatory syndrome not associated with hemophagocytic syndrome. We assessed the value of glycosylated ferritin as a marker for the diagnosis of hemophagocytic syndrome. Forty-two patients were included in the study (14 with confirmed hemophagocytic syndrome, 7 with suspected but unconfirmed hemophagocytic syndrome, and 21 controls). The median level (interquartile range [IQR]) of total serum ferritin was significantly higher in patients with confirmed hemophagocytic syndrome (3,344 microg/liter [2,074-7,334]) than in patients with suspected but unconfirmed hemophagocytic syndrome (555 microg/liter [464-1,420]) (P = 0.02) or in controls (451 microg/liter [126-929]) (P < 0.001). The median (IQR) percentage of glycosylated ferritin was significantly lower in patients with confirmed hemophagocytic syndrome (10% [3-14]) than in patients with suspected but unconfirmed hemophagocytic syndrome (40% [36-47]) (P < 0.001) or in controls (36% [26-49]) (P < 0.001). The diagnostic performance of glycosylated ferritin tended to be higher than that of total serum ferritin for the diagnosis of hemophagocytic syndrome (area under the receiver operating characteristic curve [95% confidence interval] 0.97 [0.92-1.00] versus 0.79 [0.59-1.00]; P = 0.10). These results suggest that glycosylated ferritin may be a helpful marker for the diagnosis of hemophagocytic syndrome.