Early diagnostic value of low percentage of glycosylated ferritin in secondary hemophagocytic lymphohistiocytosis

Abstract

Elevated levels of serum ferritin and a low percentage of glycosylated ferritin have been reported in adult-onset Still's disease (AOSD) as well as in hemophagocytic lymphohistiocytosis (HLH). The objective of the current study was to investigate total ferritin levels and the percentage of glycosylated ferritin in patients with secondary HLH. From October 2007 to October 2008, 29 patients with suspected HLH older than 14 years of age treated at Beijing Friendship Hospital were enrolled. Twenty-five healthy volunteers were recruited as controls. The suspected HLH patients were further divided into secondary HLH-confirmed (confirmed) (22 out of 29) and HLH-unconfirmed (unconfirmed) (7 out of 29) groups based on HLH-2004 diagnostic criteria. Total serum ferritin levels and the percentage of glycosylated ferritin were determined in subjects at the time of admission. Significantly higher levels of total serum ferritin were observed in confirmed (2,897.6 +/- 1,837.2 microg/L) compared with unconfirmed (653.1 +/- 249.1 microg/L) patients (P < 0.01) or controls (414.6 +/- 212.6 microg/L) (P < 0.01). A significantly lower percentage of glycosylated ferritin was observed in the confirmed (20.5 +/- 10.1%) compared with the unconfirmed (48.7 +/- 12.1%) group (P < 0.01) or the control group (53.6 +/- 13.3%) (P < 0.01). In addition, a low percentage of glycosylated ferritin was observed in HLH patients. Finally, regarding the diagnosis of HLH based on a low percentage of glycosylated ferritin, the sensitivity and specificity, as well as positive and negative predictive values were 0.86, 0.71, 0.91, and 0.63, respectively. For the diagnosis of HLH based on hyperferritinemia, the sensitivity, specificity, positive, and negative predictive values were 0.82, 0.43, 0.82, and 0.43, respectively. The results of this study suggest that a low percentage of glycosylated ferritin is associated with HLH. On comparison with hyperferritinemia, a low percentage of glycosylated ferritin appeared to be more specific, sensitive, and predictive of HLH. In conclusion, a low percentage of glycosylated ferritin may be a useful marker for the early diagnosis of secondary HLH.